1
|
Chen LG, Tubbs JD, Liu Z, Thach TQ, Sham PC. Mendelian randomization: causal inference leveraging genetic data. Psychol Med 2024; 54:1461-1474. [PMID: 38639006 DOI: 10.1017/s0033291724000321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/20/2024]
Abstract
Mendelian randomization (MR) leverages genetic information to examine the causal relationship between phenotypes allowing for the presence of unmeasured confounders. MR has been widely applied to unresolved questions in epidemiology, making use of summary statistics from genome-wide association studies on an increasing number of human traits. However, an understanding of essential concepts is necessary for the appropriate application and interpretation of MR. This review aims to provide a non-technical overview of MR and demonstrate its relevance to psychiatric research. We begin with the origins of MR and the reasons for its recent expansion, followed by an overview of its statistical methodology. We then describe the limitations of MR, and how these are being addressed by recent methodological advances. We showcase the practical use of MR in psychiatry through three illustrative examples - the connection between cannabis use and psychosis, the link between intelligence and schizophrenia, and the search for modifiable risk factors for depression. The review concludes with a discussion of the prospects of MR, focusing on the integration of multi-omics data and its extension to delineating complex causal networks.
Collapse
Affiliation(s)
- Lane G Chen
- Department of Psychiatry, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Justin D Tubbs
- Department of Psychiatry, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Zipeng Liu
- Department of Psychiatry, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Thuan-Quoc Thach
- Department of Psychiatry, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Pak C Sham
- Department of Psychiatry, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
- Centre for PanorOmic Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China
| |
Collapse
|
2
|
Arellano Spano M, Morris TT, Davies NM, Hughes A. Genetic associations of risk behaviours and educational achievement. Commun Biol 2024; 7:435. [PMID: 38600303 PMCID: PMC11006670 DOI: 10.1038/s42003-024-06091-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 03/22/2024] [Indexed: 04/12/2024] Open
Abstract
Risk behaviours are common in adolescent and persist into adulthood, people who engage in more risk behaviours are more likely to have lower educational attainment. We applied genetic causal inference methods to explore the causal relationship between adolescent risk behaviours and educational achievement. Risk behaviours were phenotypically associated with educational achievement at age 16 after adjusting for confounders (-0.11, 95%CI: -0.11, -0.09). Genomic-based restricted maximum likelihood (GREML) results indicated that both traits were heritable and have a shared genetic architecture (Riskh 2 = 0.18, 95% CI: -0.11,0.47; educationh 2 = 0.60, 95%CI: 0.50,0.70). Consistent with the phenotypic results, genetic variation associated with risk behaviour was negatively associated with education (r g = -0.51, 95%CI: -1.04,0.02). Lastly, the bidirectional MR results indicate that educational achievement or a closely related trait is likely to affect risk behaviours PGI (β=-1.04, 95% CI: -1.41, -0.67), but we found little evidence that the genetic variation associated with risk behaviours affected educational achievement (β=0.00, 95% CI: -0.24,0.24). The results suggest engagement in risk behaviour may be partly driven by educational achievement or a closely related trait.
Collapse
Affiliation(s)
- Michelle Arellano Spano
- Medical Research Council Integrative Epidemiology Unit at the University of Bristol, Bristol, BS8 2BN, United Kingdom.
- Population Health Sciences, Bristol Medical School, University of Bristol, Barley House, Oakfield Grove, Bristol, BS8 2BN, United Kingdom.
| | - Tim T Morris
- Centre for Longitudinal Studies, Social Research Institute, University College London, London, United Kingdom
| | - Neil M Davies
- Division of Psychiatry, University College London, Maple House, 149 Tottenham Court Rd, London, W1T 7NF, United Kingdom
- Department of Statistical Sciences, University College London, London, WC1E 6BT, United Kingdom
- K.G. Jebsen Center for Genetic Epidemiology, Department of Public Health and Nursing, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | - Amanda Hughes
- Medical Research Council Integrative Epidemiology Unit at the University of Bristol, Bristol, BS8 2BN, United Kingdom
- Population Health Sciences, Bristol Medical School, University of Bristol, Barley House, Oakfield Grove, Bristol, BS8 2BN, United Kingdom
| |
Collapse
|
3
|
Yang T, Bi S, Zhang X, Yin M, Feng S, Li H. The Impact of Different Intensities of Physical Activity on Serum Urate and Gout: A Mendelian Randomization Study. Metabolites 2024; 14:66. [PMID: 38276301 PMCID: PMC10819057 DOI: 10.3390/metabo14010066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 01/07/2024] [Accepted: 01/16/2024] [Indexed: 01/27/2024] Open
Abstract
Physical activity is a potential protective factor against gout, but the role of exercise intensity in this context remains unclear. To overcome the limitations of observational studies in causal inference, this study employed a two-sample Mendelian randomization approach to explore the impact of different genetically proxied/predicted intensities of physical activity on serum urate concentration and the incidence of gout. Our data related to physical activity, serum urate, and gout were obtained from the UK Biobank, the Global Urate Genetics Consortium (GUGC), and the FinnGen dataset, respectively. Walking was included as representative of typical low-intensity physical activity in the analysis, and the other two types were moderate and vigorous physical activities. The estimation methods we used included the inverse-variance-weighted (IVW) method, MR-Egger regression, weighted-median method, simple-mode method, and weighted-mode method. Sensitivity analyses involved Rucker's framework, Cochran's Q test, funnel plots, MR-PRESSO outlier correction, and leave-one-out analysis. We found suggestive evidence from the inverse-variance-weighted method that moderate physical activity was a potential factor in reducing the incidence of gout (OR = 0.628, p = 0.034), and this association became more substantial in our subsequent sensitivity analysis (OR = 0.555, p = 0.006). However, we observed no distinctive effects of physical activity on serum urate concentration. In conclusion, our study supports some findings from observational studies and emphasizes the preventive role of moderate physical activity against gout. Given the limitations of the existing datasets, we call for future reexamination and expansion of our findings using new GWAS data.
Collapse
Affiliation(s)
- Tangxun Yang
- School of Physical Education, Xihua University, Chengdu 610039, China
| | - Shilin Bi
- National Institute of Education, Nanyang Technological University, Singapore 637616, Singapore
| | - Xing Zhang
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, 18071 Granada, Spain
| | - Mingyue Yin
- School of Athletic Performance, Shanghai University of Sport, Shanghai 200438, China
| | - Siyuan Feng
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Hansen Li
- Institute of Sports Science, College of Physical Education, Southwest University, Chongqing 400715, China
| |
Collapse
|
4
|
Schmengler H, Oldehinkel AJ, Vollebergh WAM, Pasman JA, Hartman CA, Stevens GWJM, Nolte IM, Peeters M. Disentangling the interplay between genes, cognitive skills, and educational level in adolescent and young adult smoking - The TRAILS study. Soc Sci Med 2023; 336:116254. [PMID: 37751630 DOI: 10.1016/j.socscimed.2023.116254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/17/2023] [Accepted: 09/15/2023] [Indexed: 09/28/2023]
Abstract
Recent studies suggest that smoking and lower educational attainment may have genetic influences in common. However, little is known about the mechanisms through which genetics contributes to educational inequalities in adolescent and young adult smoking. Common genetic liabilities may underlie cognitive skills associated with both smoking and education, such as IQ and effortful control, in line with indirect health-related selection explanations. Additionally, by affecting cognitive skills, genes may predict educational trajectories and hereby adolescents' social context, which may be associated with smoking, consistent with social causation explanations. Using data from the Dutch TRAILS Study (N = 1581), we estimated the extent to which polygenic scores (PGSs) for ever smoking regularly (PGSSMOK) and years of education (PGSEDU) predict IQ and effortful control, measured around age 11, and whether these cognitive skills then act as shared predictors of smoking and educational level around age 16, 19, 22, and 26. Second, we assessed if educational level mediated associations between PGSs and smoking. Both PGSs were associated with lower effortful control, and PGSEDU also with lower IQ. Lower IQ and effortful control, in turn, predicted having a lower educational level. However, neither of these cognitive skills were directly associated with smoking behaviour after controlling for covariates and PGSs. This suggests that IQ and effortful control are not shared predictors of smoking and education (i.e., no indirect health-related selection related to cognitive skills). Instead, PGSSMOK and PGSEDU, partly through their associations with lower cognitive skills, predicted selection into a lower educational track, which in turn was associated with more smoking, in line with social causation explanations. Our findings suggest that educational differences in the social context contribute to associations between genetic liabilities and educational inequalities in smoking.
Collapse
Affiliation(s)
- Heiko Schmengler
- Department of Interdisciplinary Social Science, Utrecht University, the Netherlands.
| | - Albertine J Oldehinkel
- Interdisciplinary Center Psychopathology and Emotion Regulation, Department of Psychiatry, University Medical Center of Groningen, University of Groningen, the Netherlands
| | - Wilma A M Vollebergh
- Department of Interdisciplinary Social Science, Utrecht University, the Netherlands
| | - Joëlle A Pasman
- Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Sweden
| | - Catharina A Hartman
- Interdisciplinary Center Psychopathology and Emotion Regulation, Department of Psychiatry, University Medical Center of Groningen, University of Groningen, the Netherlands
| | | | - Ilja M Nolte
- Department of Epidemiology, University Medical Center of Groningen, University of Groningen, the Netherlands
| | - Margot Peeters
- Department of Interdisciplinary Social Science, Utrecht University, the Netherlands
| |
Collapse
|
5
|
Xia C, Hill WD. Vertical pleiotropy explains the heritability of social science traits. Behav Brain Sci 2023; 46:e230. [PMID: 37695008 PMCID: PMC7615132 DOI: 10.1017/s0140525x22002382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
We contend that social science variables are the product of multiple partly heritable traits. Genetic associations with socioeconomic status (SES) may differ across populations, but this is a consequence of the intermediary traits associated with SES differences also varying. Furthermore, genetic data allow social scientists to make causal statements regarding the aetiology and consequences of SES.
Collapse
Affiliation(s)
- Charley Xia
- Lothian Birth Cohort studies, University of Edinburgh, Edinburgh, UK
- Department of Psychology, University of Edinburgh, Edinburgh, UK ; https://www.ed.ac.uk/profile/dr-charley-xia ; https://www.ed.ac.uk/profile/david-hill
| | - W David Hill
- Lothian Birth Cohort studies, University of Edinburgh, Edinburgh, UK
- Department of Psychology, University of Edinburgh, Edinburgh, UK ; https://www.ed.ac.uk/profile/dr-charley-xia ; https://www.ed.ac.uk/profile/david-hill
| |
Collapse
|
6
|
Li H, Zhang X, Cao Y, Zhang G. Potential protection of computer gaming against mental health issues: Evidence from a Mendelian randomization study. COMPUTERS IN HUMAN BEHAVIOR 2023. [DOI: 10.1016/j.chb.2023.107722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
|
7
|
Shivakumar S, Wilken MB, Tsao V, Bitarello BD, Thom CS. Genetically influenced tobacco and alcohol use behaviors impact erythroid trait variation. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.05.01.23289329. [PMID: 37205362 PMCID: PMC10187333 DOI: 10.1101/2023.05.01.23289329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Genome wide association studies (GWAS) have associated thousands of loci with quantitative human blood trait variation. Blood trait associated loci and related genes may regulate blood cell-intrinsic biological processes, or alternatively impact blood cell development and function via systemic factors and disease processes. Clinical observations linking behaviors like tobacco or alcohol use with altered blood traits can be subject to bias, and these trait relationships have not been systematically explored at the genetic level. Using a Mendelian randomization (MR) framework, we confirmed causal effects of smoking and drinking that were largely confined to the erythroid lineage. Using multivariable MR and causal mediation analyses, we confirmed that an increased genetic predisposition to smoke tobacco was associated with increased alcohol intake, indirectly decreasing red blood cell count and related erythroid traits. These findings demonstrate a novel role for genetically influenced behaviors in determining human blood traits, revealing opportunities to dissect related pathways and mechanisms that influence hematopoiesis.
Collapse
Affiliation(s)
- Shriya Shivakumar
- Division of Neonatology, Children’s Hospital of Philadelphia, Philadelphia, PA
- Bryn Mawr College, Bryn Mawr, PA
| | - Madison B Wilken
- Division of Neonatology, Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Victor Tsao
- Division of Neonatology, Children’s Hospital of Philadelphia, Philadelphia, PA
- University of Pennsylvania, Philadelphia, PA
| | | | - Christopher S Thom
- Division of Neonatology, Children’s Hospital of Philadelphia, Philadelphia, PA
| |
Collapse
|
8
|
Li H, Zhang X, Zhang X, Wang Z, Feng S, Zhang G. Can Intelligence Affect Alcohol-, Smoking-, and Physical Activity-Related Behaviors? A Mendelian Randomization Study. J Intell 2023; 11:jintelligence11020029. [PMID: 36826927 PMCID: PMC9968073 DOI: 10.3390/jintelligence11020029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 01/21/2023] [Accepted: 01/29/2023] [Indexed: 02/04/2023] Open
Abstract
People with high levels of intelligence are more aware of risk factors, therefore choosing a healthier lifestyle. This assumption seems reasonable, but is it true? Previous studies appear to agree and disagree. To cope with the uncertainty, we designed a mendelian randomization (MR) study to examine the causal effects of genetically proxied intelligence on alcohol-, smoking-, and physical activity (PA)-related behaviors. We obtained genome-wide association study (GWAS) datasets concerning these variables from separate studies or biobanks and used inverse-variance weighted (IVW) or MR-Egger estimator to evaluate the causal effects according to an MR protocol. The MR-Egger intercept test, MR-PRESSO, and funnel plots were employed for horizontal pleiotropy diagnosis. The Steiger test (with reliability test), Cochran's Q test, MR-PRESSO, and leave-one-out method were employed for sensitivity analysis. We found significant or potential effects of intelligence on alcohol dependence (OR = 0.749, p = 0.003), mental and behavioral disorders due to alcohol (OR = 0.814, p = 0.009), smoking (OR = 0.585, p = 0.005), and smoking cessation (OR = 1.334, p = 0.001). Meanwhile, we found significant or potential effects on walking duration (B = -0.066, p < 0.001), walking frequency (B = -0.055, p = 0.031), moderate PA frequency (B = -0.131, p < 0.001), and vigorous PA frequency (B = -0.070, p = 0.001), but all in a negative direction. In conclusion, our findings reinforce some existing knowledge, indicate the complexity of the health impacts of human intelligence, and underline the value of smoking and alcohol prevention in less intelligent populations. Given the existing limitations in this study, particularly the potential reverse causality in some estimations, re-examinations are warranted in future research.
Collapse
Affiliation(s)
- Hansen Li
- Key Laboratory of Physical Fitness Evaluation and Motor Function Monitoring, Institute of Sports Science, College of Physical Education, Southwest University, Chongqing 400715, China
| | - Xing Zhang
- Key Laboratory of Physical Fitness Evaluation and Motor Function Monitoring, Institute of Sports Science, College of Physical Education, Southwest University, Chongqing 400715, China
| | - Xinyue Zhang
- Graduate School, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Zhenhuan Wang
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, VIC 3011, Australia
| | - Siyuan Feng
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Guodong Zhang
- Key Laboratory of Physical Fitness Evaluation and Motor Function Monitoring, Institute of Sports Science, College of Physical Education, Southwest University, Chongqing 400715, China
- Correspondence:
| |
Collapse
|
9
|
Shi X, Yuan W, Cao Q, Cui W. Education plays a crucial role in the pathway from poverty to smoking: a Mendelian randomization study. Addiction 2023; 118:128-139. [PMID: 35929574 DOI: 10.1111/add.16019] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 07/27/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND AIMS Disproportionately high rates of smoking have been found in low-income communities, but the causal direction and role of education in this relationship remains less well understood. Here, we used bidirectional Mendelian randomization (MR) to measure the causal relationships between smoking, income and education. DESIGN Two-sample univariable and multivariable MR analyses were conducted to evaluate the total and direct effect of income and education on tobacco smoking. The effects of smoking on education and income were explored with reverse MR analysis. SETTING European ancestry. PARTICIPANTS The most recent large-scale genome-wide association study (GWAS) summary data on educational attainment, household income and smoking (n = 143 210-766 345). MEASUREMENTS Genetic variants for exposures including income, education and smoking. FINDINGS Both income and education had protective effects against smoking, especially for smoking initiation (education: β = -0.447, 95% CI = -0.508 to -0.387, P < 0.001; income: β = -0.290, 95% CI = -0.43 to -0.149, P < 0.001) and cessation (education: β = -0.364, 95% CI = -0.429 to -0.298, P < 0.001; income: β = -0.323, 95% CI = -0.448 to -0.197, P < 0.001). Here, higher scores in cessation indicated a lower likelihood of quitting according to the coding scheme. There was little evidence that income influenced smoking once education was controlled for, whereas education could significantly affect smoking behaviours independently of income (P = 3.40 × 10-10 -0.0272). The reverse MR results suggested that smoking may result in a loss of years of schooling (β = -0.190, 95% CI = -0.297 to -0.083, P < 0.001) and reduced earnings (β = -0.204, 95% CI = -0.347 to -0.060, P = 0.006). CONCLUSIONS Education appears to play an important role in the relationship between income and smoking. There is a bidirectional association of smoking with socioeconomic status.
Collapse
Affiliation(s)
- Xiaoqiang Shi
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wenji Yuan
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Qingyi Cao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wenyan Cui
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| |
Collapse
|
10
|
Cognitive performance protects against Alzheimer's disease independently of educational attainment and intelligence. Mol Psychiatry 2022; 27:4297-4306. [PMID: 35840796 DOI: 10.1038/s41380-022-01695-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 06/21/2022] [Accepted: 06/30/2022] [Indexed: 02/07/2023]
Abstract
Mendelian-randomization (MR) studies using large-scale genome-wide association studies (GWAS) have identified causal association between educational attainment and Alzheimer's disease (AD). However, the underlying mechanisms are still required to be explored. Here, we conduct univariable and multivariable MR analyses using large-scale educational attainment, cognitive performance, intelligence and AD GWAS datasets. In stage 1, we found significant causal effects of educational attainment on cognitive performance (beta = 0.907, 95% confidence interval (CI): 0.884-0.930, P < 1.145E-299), and vice versa (beta = 0.571, 95% CI: 0.557-0.585, P < 1.145E-299). In stage 2, we found that both increase in educational attainment (odds ratio (OR) = 0.72, 95% CI: 0.66-0.78, P = 1.39E-14) and cognitive performance (OR = 0.69, 95% CI: 0.64-0.75, P = 1.78E-20) could reduce the risk of AD. In stage 3, we found that educational attainment may protect against AD dependently of cognitive performance (OR = 1.07, 95% CI: 0.90-1.28, P = 4.48E-01), and cognitive performance may protect against AD independently of educational attainment (OR = 0.69, 95% CI: 0.53-0.89, P = 5.00E-03). In stage 4, we found significant causal effects of cognitive performance on intelligence (beta = 0.907, 95% CI: 0.877-0.938, P < 1.145E-299), and vice versa (beta = 0.957, 95% CI: 0.937-0.978, P < 1.145E-299). In stage 5, we identified that cognitive performance may protect against AD independently of intelligence (OR = 0.74, 95% CI: 0.61-0.90, P = 2.00E-03), and intelligence may protect against AD dependently of cognitive performance (OR = 1.17, 95% CI: 0.40-3.43, P = 4.48E-01). Collectively, our univariable and multivariable MR analyses highlight the protective role of cognitive performance in AD independently of educational attainment and intelligence. In addition to the intelligence, we extend the mechanisms underlying the associations of educational attainment with AD.
Collapse
|
11
|
Viinikainen J, Bryson A, Böckerman P, Kari JT, Lehtimäki T, Raitakari O, Viikari J, Pehkonen J. Does better education mitigate risky health behavior? A mendelian randomization study. ECONOMICS AND HUMAN BIOLOGY 2022; 46:101134. [PMID: 35354116 DOI: 10.1016/j.ehb.2022.101134] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/14/2022] [Accepted: 03/15/2022] [Indexed: 06/14/2023]
Abstract
Education and risky health behaviors are strongly negatively correlated. Education may affect health behaviors by enabling healthier choices through higher disposable income, increasing information about the harmful effects of risky health behaviors, or altering time preferences. Alternatively, the observed negative correlation may stem from reverse causality or unobserved confounders. Based on the data from the Cardiovascular Risk in Young Finns Study linked to register-based information on educational attainment and family background, this paper identifies the causal effect of education on risky health behaviors. To examine causal effects, we used a genetic score as an instrument for years of education. We found that individuals with higher education allocated more attention to healthy habits. In terms of health behaviors, highly educated people were less likely to smoke. Some model specifications also indicated that the highly educated consumed more fruit and vegetables, but the results were imprecise in this regard. No causal effect was found between education and abusive drinking. In brief, inference based on genetic instruments showed that higher education leads to better choices in some but not all dimensions of health behaviors.
Collapse
Affiliation(s)
- Jutta Viinikainen
- University of Jyväskylä, Jyväskylä University School of Business and Economics, Jyväskylä, Finland.
| | - Alex Bryson
- University College London, Social Research Institute, London, United Kingdom; National Institute of Economic and Social Research, London, United Kingdom; IZA Institute of Labor Economics, Bonn, Germany
| | - Petri Böckerman
- University of Jyväskylä, Jyväskylä University School of Business and Economics, Jyväskylä, Finland; IZA Institute of Labor Economics, Bonn, Germany; Labour Institute for Economic Research LABORE, Helsinki, Finland
| | - Jaana T Kari
- University of Jyväskylä, Jyväskylä University School of Business and Economics, Jyväskylä, Finland
| | - Terho Lehtimäki
- Tampere University, Department of Clinical Chemistry, Tampere, Finland; Fimlab Laboratories, Tampere, Finland; Tampere University, Faculty of Medicine and Health Technology, Tampere, Finland; Tampere University, Finnish Cardiovascular Research Center, Tampere, Finland
| | - Olli Raitakari
- University of Turku and Turku University Hospital, Centre for Population Health Research, Turku, Finland; University of Turku, Research Centre of Applied and Preventive Cardiovascular Medicine, Turku, Finland; Turku University Hospital, Department of Clinical Physiology and Nuclear Medicine, Turku, Finland
| | - Jorma Viikari
- University of Turku, Department of Medicine, Turku, Finland; Turku University Hospital, Division of Medicine, Turku, Finland
| | - Jaakko Pehkonen
- University of Jyväskylä, Jyväskylä University School of Business and Economics, Jyväskylä, Finland
| |
Collapse
|
12
|
Gage SH, Sallis HM, Lassi G, Wootton RE, Mokrysz C, Davey Smith G, Munafò MR. Does smoking cause lower educational attainment and general cognitive ability? Triangulation of causal evidence using multiple study designs. Psychol Med 2022; 52:1578-1586. [PMID: 33023701 PMCID: PMC9226381 DOI: 10.1017/s0033291720003402] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 08/18/2020] [Accepted: 09/03/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND Observational studies have found associations between smoking and both poorer cognitive ability and lower educational attainment; however, evaluating causality is challenging. We used two complementary methods to explore this. METHODS We conducted observational analyses of up to 12 004 participants in a cohort study (Study One) and Mendelian randomisation (MR) analyses using summary and cohort data (Study Two). Outcome measures were cognitive ability at age 15 and educational attainment at age 16 (Study One), and educational attainment and fluid intelligence (Study Two). RESULTS Study One: heaviness of smoking at age 15 was associated with lower cognitive ability at age 15 and lower educational attainment at age 16. Adjustment for potential confounders partially attenuated findings (e.g. fully adjusted cognitive ability β -0.736, 95% CI -1.238 to -0.233, p = 0.004; fully adjusted educational attainment β -1.254, 95% CI -1.597 to -0.911, p < 0.001). Study Two: MR indicated that both smoking initiation and lifetime smoking predict lower educational attainment (e.g. smoking initiation to educational attainment inverse-variance weighted MR β -0.197, 95% CI -0.223 to -0.171, p = 1.78 × 10-49). Educational attainment results were robust to sensitivity analyses, while analyses of general cognitive ability were less so. CONCLUSION We find some evidence of a causal effect of smoking on lower educational attainment, but not cognitive ability. Triangulation of evidence across observational and MR methods is a strength, but the genetic variants associated with smoking initiation may be pleiotropic, suggesting caution in interpreting these results. The nature of this pleiotropy warrants further study.
Collapse
Affiliation(s)
- Suzanne H. Gage
- Department of Psychological Sciences, University of Liverpool, Liverpool, UK
| | - Hannah M. Sallis
- School of Psychological Science, University of Bristol, Bristol, UK
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, UK
| | - Glenda Lassi
- School of Psychological Science, University of Bristol, Bristol, UK
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, UK
- Translational Science and Experimental Medicine, Research and Early Development, Respiratory & Immunology BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Robyn E. Wootton
- School of Psychological Science, University of Bristol, Bristol, UK
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, UK
| | - Claire Mokrysz
- Clinical Psychopharmacology Unit, University College London, London, UK
| | - George Davey Smith
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, UK
- School of Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Marcus R. Munafò
- School of Psychological Science, University of Bristol, Bristol, UK
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, UK
| |
Collapse
|
13
|
Peixinho J, Toseeb U, Mountford HS, Bermudez I, Newbury DF. The effects of prenatal smoke exposure on language development ‐ a systematic review. INFANT AND CHILD DEVELOPMENT 2022. [DOI: 10.1002/icd.2331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jessica Peixinho
- Faculty of Health and Life Sciences Oxford Brookes University Headington Campus Oxford UK
| | - Umar Toseeb
- Department of Education University of York York UK
| | - Hayley S. Mountford
- Faculty of Health and Life Sciences Oxford Brookes University Headington Campus Oxford UK
| | - Isabel Bermudez
- Faculty of Health and Life Sciences Oxford Brookes University Headington Campus Oxford UK
| | - Dianne F. Newbury
- Faculty of Health and Life Sciences Oxford Brookes University Headington Campus Oxford UK
| |
Collapse
|
14
|
Sanderson E, Glymour MM, Holmes MV, Kang H, Morrison J, Munafò MR, Palmer T, Schooling CM, Wallace C, Zhao Q, Smith GD. Mendelian randomization. NATURE REVIEWS. METHODS PRIMERS 2022; 2:6. [PMID: 37325194 PMCID: PMC7614635 DOI: 10.1038/s43586-021-00092-5] [Citation(s) in RCA: 436] [Impact Index Per Article: 218.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/21/2021] [Indexed: 06/17/2023]
Abstract
Mendelian randomization (MR) is a term that applies to the use of genetic variation to address causal questions about how modifiable exposures influence different outcomes. The principles of MR are based on Mendel's laws of inheritance and instrumental variable estimation methods, which enable the inference of causal effects in the presence of unobserved confounding. In this Primer, we outline the principles of MR, the instrumental variable conditions underlying MR estimation and some of the methods used for estimation. We go on to discuss how the assumptions underlying an MR study can be assessed and give methods of estimation that are robust to certain violations of these assumptions. We give examples of a range of studies in which MR has been applied, the limitations of current methods of analysis and the outlook for MR in the future. The difference between the assumptions required for MR analysis and other forms of non-interventional epidemiological studies means that MR can be used as part of a triangulation across multiple sources of evidence for causal inference.
Collapse
Affiliation(s)
- Eleanor Sanderson
- Medical Research Council (MRC) Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - M. Maria Glymour
- Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA
| | - Michael V. Holmes
- Medical Research Council (MRC) Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- MRC Population Health Research Unit, University of Oxford, Oxford, UK
- Clinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Hyunseung Kang
- Department of Statistics, University of Wisconsin-Madison, Madison, WI, USA
| | - Jean Morrison
- Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA
| | - Marcus R. Munafò
- Medical Research Council (MRC) Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- School of Psychological Science, University of Bristol, Bristol, UK
- National Institute for Health Research (NIHR), Biomedical Research Centre, University of Bristol, Bristol, UK
| | - Tom Palmer
- Medical Research Council (MRC) Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - C. Mary Schooling
- School of Public Health, Li Ka Shing, Faculty of Medicine, The University of Hong Kong, Hong Kong, China
- School of Public Health, City University of New York, New York, USA
| | - Chris Wallace
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), University of Cambridge, Cambridge, UK
| | - Qingyuan Zhao
- Statistical Laboratory, University of Cambridge, Cambridge, UK
| | - George Davey Smith
- Medical Research Council (MRC) Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
- National Institute for Health Research (NIHR), Biomedical Research Centre, University of Bristol, Bristol, UK
| |
Collapse
|
15
|
Darrous L, Mounier N, Kutalik Z. Simultaneous estimation of bi-directional causal effects and heritable confounding from GWAS summary statistics. Nat Commun 2021; 12:7274. [PMID: 34907193 PMCID: PMC8671515 DOI: 10.1038/s41467-021-26970-w] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 10/28/2021] [Indexed: 01/26/2023] Open
Abstract
Mendelian Randomisation (MR) is an increasingly popular approach that estimates the causal effect of risk factors on complex human traits. While it has seen several extensions that relax its basic assumptions, most suffer from two major limitations; their under-exploitation of genome-wide markers, and sensitivity to the presence of a heritable confounder of the exposure-outcome relationship. To overcome these limitations, we propose a Latent Heritable Confounder MR (LHC-MR) method applicable to association summary statistics, which estimates bi-directional causal effects, direct heritabilities, and confounder effects while accounting for sample overlap. We demonstrate that LHC-MR outperforms several existing MR methods in a wide range of simulation settings and apply it to summary statistics of 13 complex traits. Besides several concordant results with other MR methods, LHC-MR unravels new mechanisms (how disease diagnosis might lead to improved lifestyle) and reveals new causal effects (e.g. HDL cholesterol being protective against high systolic blood pressure), hidden from standard MR methods due to a heritable confounder of opposite effect direction.
Collapse
Affiliation(s)
- Liza Darrous
- University Center for Primary Care and Public Health, University of Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Ninon Mounier
- University Center for Primary Care and Public Health, University of Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Zoltán Kutalik
- University Center for Primary Care and Public Health, University of Lausanne, Lausanne, Switzerland.
- Swiss Institute of Bioinformatics, Lausanne, Switzerland.
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland.
| |
Collapse
|
16
|
Sanderson E, Spiller W, Bowden J. Testing and correcting for weak and pleiotropic instruments in two-sample multivariable Mendelian randomization. Stat Med 2021; 40:5434-5452. [PMID: 34338327 DOI: 10.1101/2020.04.02.021980] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/17/2021] [Accepted: 06/18/2021] [Indexed: 05/28/2023]
Abstract
Multivariable Mendelian randomization (MVMR) is a form of instrumental variable analysis which estimates the direct effect of multiple exposures on an outcome using genetic variants as instruments. Mendelian randomization and MVMR are frequently conducted using two-sample summary data where the association of the genetic variants with the exposures and outcome are obtained from separate samples. If the genetic variants are only weakly associated with the exposures either individually or conditionally, given the other exposures in the model, then standard inverse variance weighting will yield biased estimates for the effect of each exposure. Here, we develop a two-sample conditional F-statistic to test whether the genetic variants strongly predict each exposure conditional on the other exposures included in a MVMR model. We show formally that this test is equivalent to the individual level data conditional F-statistic, indicating that conventional rule-of-thumb critical values of F> 10, can be used to test for weak instruments. We then demonstrate how reliable estimates of the causal effect of each exposure on the outcome can be obtained in the presence of weak instruments and pleiotropy, by repurposing a commonly used heterogeneity Q-statistic as an estimating equation. Furthermore, the minimized value of this Q-statistic yields an exact test for heterogeneity due to pleiotropy. We illustrate our methods with an application to estimate the causal effect of blood lipid fractions on age-related macular degeneration.
Collapse
Affiliation(s)
- Eleanor Sanderson
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- Population Health Sciences, University of Bristol, Bristol, UK
| | - Wes Spiller
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- Population Health Sciences, University of Bristol, Bristol, UK
| | - Jack Bowden
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- College of Medicine and Health, University of Exeter, Exeter, UK
| |
Collapse
|
17
|
Abstract
Substance use disorders (SUDs) are conditions in which the use of legal or illegal substances, such as nicotine, alcohol or opioids, results in clinical and functional impairment. SUDs and, more generally, substance use are genetically complex traits that are enormously costly on an individual and societal basis. The past few years have seen remarkable progress in our understanding of the genetics, and therefore the biology, of substance use and abuse. Various studies - including of well-defined phenotypes in deeply phenotyped samples, as well as broadly defined phenotypes in meta-analysis and biobank samples - have revealed multiple risk loci for these common traits. A key emerging insight from this work establishes a biological and genetic distinction between quantity and/or frequency measures of substance use (which may involve low levels of use without dependence), versus symptoms related to physical dependence.
Collapse
|
18
|
Kjeldsen EW, Thomassen JQ, Frikke-Schmidt R. HDL cholesterol concentrations and risk of atherosclerotic cardiovascular disease - Insights from randomized clinical trials and human genetics. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1867:159063. [PMID: 34637926 DOI: 10.1016/j.bbalip.2021.159063] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 08/12/2021] [Accepted: 09/15/2021] [Indexed: 12/12/2022]
Abstract
Through seven decades the inverse association between HDL cholesterol concentrations and risk of atherosclerotic cardiovascular disease (ASCVD) has been observed in case-control and prospective cohort studies. This robust inverse association fuelled the enthusiasm towards development of HDL cholesterol increasing drugs, exemplified by the cholesteryl ester transfer protein (CETP) inhibitor trials and the extended-release niacin HPS2-THRIVE trial. These HDL cholesterol increasing trials were launched without conclusive evidence from human genetics, and despite discrepant species dependent evidence from animal studies. Evidence from human genetics and from randomized clinical trials over the last 13 years now point in the direction that concentrations of HDL cholesterol, do not appear to be a viable future path to target therapeutically for prevention of ASCVD. A likely explanation for the strong observational association between low HDL cholesterol and high ASCVD risk is the concomitant inverse association between HDL cholesterol and atherogenic triglyceride-rich lipoproteins. The purpose of the present review is to bring HDL cholesterol increasing trials into a human genetics context exemplified by candidate gene studies of key players in HDL biogenesis as well as by HDL cholesterol related genome-wide association studies.
Collapse
Affiliation(s)
- Emilie Westerlin Kjeldsen
- Department of Clinical Biochemistry, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jesper Qvist Thomassen
- Department of Clinical Biochemistry, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Ruth Frikke-Schmidt
- Department of Clinical Biochemistry, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| |
Collapse
|
19
|
Wells L, Östberg V. How do educational disparities in smoking develop during early life? A Swedish longitudinal study. SSM Popul Health 2021; 15:100859. [PMID: 34286059 PMCID: PMC8274329 DOI: 10.1016/j.ssmph.2021.100859] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/28/2021] [Accepted: 06/28/2021] [Indexed: 11/23/2022] Open
Abstract
Smoking contributes to health inequalities, but how social inequalities in smoking develop in early life remains unclear. This study examines how measures of education attained over the early life course (representing socioeconomic position of origin, socioeconomic position of destination, and in-between) contribute to smoking behavior in a Swedish longitudinal sample. We used data obtained from the Swedish Level-of-Living Surveys in addition to national register data. Young adults (aged 20-28, n = 749) self-reported their educational attainment and smoking behavior (initiation and cessation) in 2010. Ten years earlier, their parents self-reported their own education and smoking behavior. We used linked register data on school performance in adolescence (in grade 9). Logistic regression models showed that lower parental education, lower adolescent school performance, and low young adult educational attainment were respectively associated with young adult smoking initiation. The association between parental education and young adult smoking initiation was explained by adolescent school performance and not parental smoking. Young adult smoking cessation was associated with high parental education and high adolescent school performance (marks in the top quartile), but only school performance remained significant in the final model, which included all measures of education and parental smoking. Results suggest that school performance in adolescence (which connects adolescents' socioeconomic position of origin with their destination) may play an important role in how educational disparities in smoking form over the life course.
Collapse
Affiliation(s)
- Laura Wells
- Department of Public Health Sciences, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Viveca Östberg
- Department of Public Health Sciences, Stockholm University, SE-106 91, Stockholm, Sweden
| |
Collapse
|
20
|
Li L, He J, Ouyang F, Qiu D, Li Y, Luo D, Yu Y, Xiao S. Sociodemographic disparity in health-related behaviours and dietary habits among public workers in China: a cross-sectional study. BMJ Open 2021; 11:e047462. [PMID: 34344677 PMCID: PMC8336184 DOI: 10.1136/bmjopen-2020-047462] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
OBJECTIVE We aimed to estimate the distribution of health-related behaviours and dietary habits by sociodemographics among public workers in China. DESIGN Cross-sectional study. SETTING A representative sample was obtained from 10 government-run institutions in Hunan province of China. PARTICIPANTS A total of 5029 public workers were included in this study. PRIMARY AND SECONDARY OUTCOME MEASURES Prevalence on their sociodemographic characteristics, health-related behaviours and dietary habits. Socioeconomic status (SES) scores were calculated by multiplying ordinal numerical values assigned to consecutive categories of education level and annual household income. Multivariate logistic regression analysis and categorical principal component analysis were used to estimate differences in health-related behaviours and dietary habits by sociodemographics. RESULTS The distribution of health-related behaviours and dietary habits was varied by sociodemographic groups. Middle-aged groups (41-60 years) were more likely to smoke (for men, 34.5%), use alcohol (for men, 22.5%), and have short sleep duration (for men, 36.3%; for women, 39.6%). Young participants (≤30 years) were more likely to have multiple unhealthy behaviours and dietary habits. Those in low-SES have a significant higher rate of smoking (ORadj=1.46, 95% CI: 1.15 to 1.85) and leisure-time physical inactivity (ORadj=1.18, 95% CI: 1.02 to 1.37), but a lower rate of late sleeping (ORadj=0.69, 95% CI: 0.57 to 0.83) than those in high-SES. Notably, older men (≥51 years) with low-SES preferred the 'smoked and pickled foods and dessert' and 'fish and nut' pattern. In high-SES groups, 41-50 year old people preferred the 'traditional foods' and 'cereals and dairy product' pattern. No difference in dietary patterns by sociodemographics was found among women (p<0.05). CONCLUSIONS Our findings of the disparity distribution of health-related behaviours and dietary habits by specific gender, age and SES among Chinese public workers have important policy implications for developing targeted health interventions to facilitate health-related behaviours and dietary habits in this population.
Collapse
Affiliation(s)
- Ling Li
- Department of Social Medicine and Health Management, Xiangya School of Public Health, Central South University, Changsha, China
| | - Jun He
- Department of Social Medicine and Health Management, Xiangya School of Public Health, Central South University, Changsha, China
| | - Feiyun Ouyang
- Department of Social Medicine and Health Management, Xiangya School of Public Health, Central South University, Changsha, China
| | - Dan Qiu
- Department of Social Medicine and Health Management, Xiangya School of Public Health, Central South University, Changsha, China
| | - Yilu Li
- Department of Social Medicine and Health Management, Xiangya School of Public Health, Central South University, Changsha, China
| | - Dan Luo
- Department of Social Medicine and Health Management, Xiangya School of Public Health, Central South University, Changsha, China
| | - Yu Yu
- Department of Social Medicine and Health Management, Xiangya School of Public Health, Central South University, Changsha, China
| | - Shuiyuan Xiao
- Department of Social Medicine and Health Management, Xiangya School of Public Health, Central South University, Changsha, China
| |
Collapse
|
21
|
Sanderson E, Spiller W, Bowden J. Testing and correcting for weak and pleiotropic instruments in two-sample multivariable Mendelian randomization. Stat Med 2021; 40:5434-5452. [PMID: 34338327 PMCID: PMC9479726 DOI: 10.1002/sim.9133] [Citation(s) in RCA: 211] [Impact Index Per Article: 70.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/17/2021] [Accepted: 06/18/2021] [Indexed: 12/28/2022]
Abstract
Multivariable Mendelian randomization (MVMR) is a form of instrumental variable analysis which estimates the direct effect of multiple exposures on an outcome using genetic variants as instruments. Mendelian randomization and MVMR are frequently conducted using two-sample summary data where the association of the genetic variants with the exposures and outcome are obtained from separate samples. If the genetic variants are only weakly associated with the exposures either individually or conditionally, given the other exposures in the model, then standard inverse variance weighting will yield biased estimates for the effect of each exposure. Here, we develop a two-sample conditional F-statistic to test whether the genetic variants strongly predict each exposure conditional on the other exposures included in a MVMR model. We show formally that this test is equivalent to the individual level data conditional F-statistic, indicating that conventional rule-of-thumb critical values of F > 10, can be used to test for weak instruments. We then demonstrate how reliable estimates of the causal effect of each exposure on the outcome can be obtained in the presence of weak instruments and pleiotropy, by repurposing a commonly used heterogeneity Q-statistic as an estimating equation. Furthermore, the minimized value of this Q-statistic yields an exact test for heterogeneity due to pleiotropy. We illustrate our methods with an application to estimate the causal effect of blood lipid fractions on age-related macular degeneration.
Collapse
Affiliation(s)
- Eleanor Sanderson
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK.,Population Health Sciences, University of Bristol, Bristol, UK
| | - Wes Spiller
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK.,Population Health Sciences, University of Bristol, Bristol, UK
| | - Jack Bowden
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK.,College of Medicine and Health, University of Exeter, Exeter, UK
| |
Collapse
|
22
|
Munafò MR, Higgins JPT, Smith GD. Triangulating Evidence through the Inclusion of Genetically Informed Designs. Cold Spring Harb Perspect Med 2021; 11:a040659. [PMID: 33355252 PMCID: PMC8327826 DOI: 10.1101/cshperspect.a040659] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Much research effort is invested in attempting to determine causal influences on disease onset and progression to inform prevention and treatment efforts. However, this is often dependent on observational data that are prone to well-known limitations, particularly residual confounding and reverse causality. Several statistical methods have been developed to support stronger causal inference. However, a complementary approach is to use design-based methods for causal inference, which acknowledge sources of bias and attempt to mitigate these through the design of the study rather than solely through statistical adjustment. Genetically informed methods provide a novel and potentially powerful extension to this approach, accounting by design for unobserved genetic and environmental confounding. No single approach will be absent from bias. Instead, we should seek and combine evidence from multiple methodologies that each bring different (and ideally uncorrelated) sources of bias. If the results of these different methodologies align-or triangulate-then we can be more confident in our causal inference. To be truly effective, this should ideally be done prospectively, with the sources of evidence specified in advance, to protect against one final source of bias-our own cognitions, expectations, and fondly held beliefs.
Collapse
Affiliation(s)
- Marcus R Munafò
- School of Psychological Science, University of Bristol, Bristol BS8 1TU, United Kingdom
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol BS8 2BN, United Kingdom
- NIHR Bristol Biomedical Research Centre, University Hospitals Bristol NHS Foundation Trust and University of Bristol, Bristol BS8 2BN, United Kingdom
| | - Julian P T Higgins
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol BS8 2BN, United Kingdom
- NIHR Bristol Biomedical Research Centre, University Hospitals Bristol NHS Foundation Trust and University of Bristol, Bristol BS8 2BN, United Kingdom
- Bristol Medical School, University of Bristol, Bristol BS8 1UD, United Kingdom
| | - George Davey Smith
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol BS8 2BN, United Kingdom
- NIHR Bristol Biomedical Research Centre, University Hospitals Bristol NHS Foundation Trust and University of Bristol, Bristol BS8 2BN, United Kingdom
- Bristol Medical School, University of Bristol, Bristol BS8 1UD, United Kingdom
| |
Collapse
|
23
|
Larney S, Jones H, Rhodes T, Hickman M. Mapping drug epidemiology futures. THE INTERNATIONAL JOURNAL OF DRUG POLICY 2021; 94:103378. [PMID: 34321152 DOI: 10.1016/j.drugpo.2021.103378] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 07/05/2021] [Accepted: 07/06/2021] [Indexed: 01/19/2023]
Abstract
Epidemiology is a core discipline generating evidence to inform and drive drug policy. In this essay, we speculate on what the future of drug epidemiology might become. We highlight for attention two areas shaping the future of drug epidemiology: nesting epidemiology within a 'syndemic' and 'relational' approach; and innovating in relation to causal inference in the face of complexity. We argue that shifts towards a more relational approach emphasise contingency, including in relation to how drugs might constitute benefit or harm. This leads us to speculate on a 'positive epidemiology'; one that is configured not merely in relation to harm but also in relation to the potential benefits of drugs in relation to well-being. In responding to the complex challenges of delineating contingent causalities, we emphasise the potential of carefully conducted observational study designs that go beyond statistical associations to test causal inference. We acknowledge that each of these developments we describe - a shift towards more relational approaches which emphasise contingent causation, and methodological innovations in relation to establishing causal inference - can be at odds with the other in how they imagine drug epidemiology futures.
Collapse
Affiliation(s)
- Sarah Larney
- Centre de Recherche du CHUM and Université de Montréal, Canada.
| | - Hannah Jones
- Bristol Medical School, University of Bristol, UK; National Institute for Health Research Bristol Biomedical Research Centre, at University Hospitals Bristol and Weston NHS Foundation Trust and the University of Bristol, UK
| | - Tim Rhodes
- London School of Hygiene and Tropical Medicine, UK; Centre for Social Research in Health, University of New South Wales, Australia
| | | |
Collapse
|
24
|
Treur JL, Munafò MR, Logtenberg E, Wiers RW, Verweij KJH. Using Mendelian randomization analysis to better understand the relationship between mental health and substance use: a systematic review. Psychol Med 2021; 51:1593-1624. [PMID: 34030749 PMCID: PMC8327626 DOI: 10.1017/s003329172100180x] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 04/17/2021] [Accepted: 04/21/2021] [Indexed: 12/18/2022]
Abstract
BACKGROUND Poor mental health has consistently been associated with substance use (smoking, alcohol drinking, cannabis use, and consumption of caffeinated drinks). To properly inform public health policy it is crucial to understand the mechanisms underlying these associations, and most importantly, whether or not they are causal. METHODS In this pre-registered systematic review, we assessed the evidence for causal relationships between mental health and substance use from Mendelian randomization (MR) studies, following PRISMA. We rated the quality of included studies using a scoring system that incorporates important indices of quality, such as the quality of phenotype measurement, instrument strength, and use of sensitivity methods. RESULTS Sixty-three studies were included for qualitative synthesis. The final quality rating was '-' for 16 studies, '- +' for 37 studies, and '+'for 10 studies. There was robust evidence that higher educational attainment decreases smoking and that there is a bi-directional, increasing relationship between smoking and (symptoms of) mental disorders. Another robust finding was that higher educational attainment increases alcohol use frequency, but decreases binge-drinking and alcohol use problems, and that mental disorders causally lead to more alcohol drinking without evidence for the reverse. CONCLUSIONS The current MR literature increases our understanding of the relationship between mental health and substance use. Bi-directional causal relationships are indicated, especially for smoking, providing further incentive to strengthen public health efforts to decrease substance use. Future MR studies should make use of large(r) samples in combination with detailed phenotypes, a wide range of sensitivity methods, and triangulate with other research methods.
Collapse
Affiliation(s)
- Jorien L. Treur
- Department of Psychiatry, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
- Addiction Development and Psychopathology (ADAPT) Lab, Department of Psychology, University of Amsterdam, Amsterdam, the Netherlands
| | - Marcus R. Munafò
- School of Psychological Science, University of Bristol, Bristol, UK
- MRC Integrative Epidemiology Unit, the University of Bristol, Bristol, UK
| | - Emma Logtenberg
- Department of Psychiatry, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Reinout W. Wiers
- Addiction Development and Psychopathology (ADAPT) Lab, Department of Psychology, University of Amsterdam, Amsterdam, the Netherlands
- Center for Urban Mental Health, University of Amsterdam, Amsterdam, the Netherlands
| | - Karin J. H. Verweij
- Department of Psychiatry, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| |
Collapse
|
25
|
Han X, Ong JS, Hewitt AW, Gharahkhani P, MacGregor S. The effects of eight serum lipid biomarkers on age-related macular degeneration risk: a Mendelian randomization study. Int J Epidemiol 2021; 50:325-336. [PMID: 33211829 DOI: 10.1093/ije/dyaa178] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/18/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Age-related macular degeneration (AMD) is a leading cause of vision loss. Whereas lipids have been studied extensively to understand their effects on cardiovascular diseases, their relationship with AMD remains unclear. METHODS Two-sample Mendelian randomization (MR) analyses were performed to systematically evaluate the causal relationships between eight serum lipid biomarkers, consisting of apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB), total cholesterol (CHOL), high-density lipoprotein cholesterol (HDL-C), direct low-density lipoprotein cholesterol (LDL-C), lipoprotein A [Lp(a)], triglycerides (TG) and non-HDL cholesterol (non-HDL-C), and the risk of different AMD stages and subtypes. We derived 64-407 genetic instruments for eight serum lipid biomarkers in 419 649 participants of European descent from the UK Biobank cohort. We conducted genome-wide association studies (GWAS) for 12 711 advanced AMD cases [8544 choroidal neovascularization (CNV) and 2656 geographic atrophy (GA) specific AMD subtypes] and 5336 intermediate AMD cases with 14 590 controls of European descent from the International AMD Genomics Consortium. RESULTS Higher genetically predicted HDL-C and ApoA1 levels increased the risk of all AMD subtypes. LDL-C, ApoB, CHOL and non-HDL-C levels were associated with decreased risk of intermediate and GA AMD but not with CNV. Genetically predicted TG levels were associated with decreased risk of different AMD subtypes. Sensitivity analyses revealed no evidence for directional pleiotropy effects. In our multivariable MR analyses, adjusting for the effects of correlated lipid biomarkers yielded similar results. CONCLUSION These results suggest the role of lipid metabolism in drusen formation and particularly in AMD development at the early and intermediate stages. Mechanistic studies are warranted to investigate the utility of lipid pathways for therapeutic treatment in preventing AMD.
Collapse
Affiliation(s)
- Xikun Han
- Statistical Genetics, QIMR Berghofer Medical Research Institute, Brisbane, Australia.,School of Medicine, University of Queensland, Brisbane, Australia
| | - Jue-Sheng Ong
- Statistical Genetics, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Alex W Hewitt
- Menzies Institute for Medical Research, University of Tasmania, Australia.,Centre for Eye Research Australia, University of Melbourne, Australia
| | - Puya Gharahkhani
- Statistical Genetics, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Stuart MacGregor
- Statistical Genetics, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| |
Collapse
|
26
|
Wang M, Zhang Z, Liu D, Xie W, Ma Y, Yao J, Zhu L, Liu M, Sheng S, Lian X. Educational attainment protects against epilepsy independent of cognitive function: A Mendelian randomization study. Epilepsia 2021; 62:1362-1368. [PMID: 33818779 DOI: 10.1111/epi.16894] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 03/14/2021] [Accepted: 03/15/2021] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Observational studies have suggested that increased levels of education and cognition are associated with a reduced risk of epilepsy. However, such associations are easily influenced by confounding or reverse causality. Hence, we conducted a two-sample univariable and multivariable Mendelian randomization (MR) to estimate the total and independent causal effects of educational attainment and cognition on epilepsy risk. METHODS We performed MR estimates on International League Against Epilepsy (ILAE) Consortium genome-wide association study (GWAS) data (15 212 epilepsy cases and 29 677 controls). We then validated the results in FinnGen (3424 epilepsy cases and 110 963 controls) and applied meta-analysis to all the results. RESULTS In the meta-analysis of the ILAE and FinnGen results, genetically determined increased educational attainment was associated with a reduced risk of epilepsy (odds ratio [OR] 0.84, 95% confidence interval [CI] 0.80-0.88; P < .001). Similarly, genetically determined increased cognitive function was associated with a reduced risk of epilepsy (OR 0.94, 95% CI 0.88-1.00, P = .043). When educational attainment and cognitive function were included in the same multivariable MR, only educational attainment was still associated with a reduced risk of epilepsy (OR 0.88, 95% CI 0.81-0.95, P = .002). SIGNIFICANCE This MR study provides evidence to support that increased educational attainment can reduce the risk of developing epilepsy independent of cognitive function.
Collapse
Affiliation(s)
- Mengmeng Wang
- Department of Neurology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Zhizhong Zhang
- Department of Neurology, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Dandan Liu
- Department of Geriatrics, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Wei Xie
- Department of Neurology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Yazhou Ma
- Department of Neurology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Jianrong Yao
- Department of Neurology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Linfeng Zhu
- Department of Neurology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Meng Liu
- Department of Neurology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Shiying Sheng
- Department of Neurology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Xuegan Lian
- Department of Neurology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| |
Collapse
|
27
|
Deary IJ, Hill WD, Gale CR. Intelligence, health and death. Nat Hum Behav 2021; 5:416-430. [PMID: 33795857 DOI: 10.1038/s41562-021-01078-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 02/15/2021] [Indexed: 02/06/2023]
Abstract
The field of cognitive epidemiology studies the prospective associations between cognitive abilities and health outcomes. We review research in this field over the past decade and describe how our understanding of the association between intelligence and all-cause mortality has consolidated with the appearance of new, population-scale data. To try to understand the association better, we discuss how intelligence relates to specific causes of death, diseases/diagnoses and biomarkers of health through the adult life course. We examine the extent to which mortality and health associations with intelligence might be attributable to people's differences in education, other indicators of socioeconomic status, health literacy and adult environments and behaviours. Finally, we discuss whether genetic data provide new tools to understand parts of the intelligence-health associations. Social epidemiologists, differential psychologists and behavioural and statistical geneticists, among others, contribute to cognitive epidemiology; advances will occur by building on a common cross-disciplinary knowledge base.
Collapse
Affiliation(s)
- Ian J Deary
- Lothian Birth Cohorts, Department of Psychology, University of Edinburgh, Edinburgh, UK.
| | - W David Hill
- Lothian Birth Cohorts, Department of Psychology, University of Edinburgh, Edinburgh, UK
| | - Catharine R Gale
- Lothian Birth Cohorts, Department of Psychology, University of Edinburgh, Edinburgh, UK.,MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton General Hospital, Southampton, UK
| |
Collapse
|
28
|
Hammerton G, Munafò MR. Causal inference with observational data: the need for triangulation of evidence. Psychol Med 2021; 51:563-578. [PMID: 33682654 PMCID: PMC8020490 DOI: 10.1017/s0033291720005127] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 12/01/2020] [Accepted: 12/08/2020] [Indexed: 02/07/2023]
Abstract
The goal of much observational research is to identify risk factors that have a causal effect on health and social outcomes. However, observational data are subject to biases from confounding, selection and measurement, which can result in an underestimate or overestimate of the effect of interest. Various advanced statistical approaches exist that offer certain advantages in terms of addressing these potential biases. However, although these statistical approaches have different underlying statistical assumptions, in practice they cannot always completely remove key sources of bias; therefore, using design-based approaches to improve causal inference is also important. Here it is the design of the study that addresses the problem of potential bias - either by ensuring it is not present (under certain assumptions) or by comparing results across methods with different sources and direction of potential bias. The distinction between statistical and design-based approaches is not an absolute one, but it provides a framework for triangulation - the thoughtful application of multiple approaches (e.g. statistical and design based), each with their own strengths and weaknesses, and in particular sources and directions of bias. It is unlikely that any single method can provide a definite answer to a causal question, but the triangulation of evidence provided by different approaches can provide a stronger basis for causal inference. Triangulation can be considered part of wider efforts to improve the transparency and robustness of scientific research, and the wider scientific infrastructure and system of incentives.
Collapse
Affiliation(s)
- Gemma Hammerton
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, UK
| | - Marcus R. Munafò
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, UK
- School of Psychological Science, University of Bristol, Bristol, UK
| |
Collapse
|
29
|
Kim CY, Kim BK, Kim YJ, Lee SH, Kim YS, Kim JH. Longitudinal Evaluation of the Relationship Between Low Socioeconomic Status and Incidence of Chronic Obstructive Pulmonary Disease: Korean Genome and Epidemiology Study (KoGES). Int J Chron Obstruct Pulmon Dis 2021; 15:3447-3454. [PMID: 33447022 PMCID: PMC7801904 DOI: 10.2147/copd.s276639] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 12/11/2020] [Indexed: 12/12/2022] Open
Abstract
Background Socioeconomic status (SES) is a strong determinant in the development of various diseases. We evaluated the relationship between SES and the incidence of chronic obstructive pulmonary disease (COPD) by using a community-based cohort data. Patients and Methods Four-year follow-up data of 6341 adults (aged ≥ 40 years), who underwent serial pulmonary function test were analyzed. Incidence of COPD in the participants was defined as the absence of airflow obstruction compatible with COPD (pre-bronchodilator forced expiratory volume in 1 second/forced vital capacity ratio of <0.7) at baseline but documentation of airflow obstruction in serial testing. SES of patients was divided into quartiles according to household income and educational level. Multivariate logistic regression analyses were performed to estimate the association between SES and COPD incidence. Results A total of 280 (4.4%) patients developed COPD during the follow-up. The proportion of subjects with lowest education (elementary school) and lowest household income levels (1st quartile) was significantly higher in the COPD group than in the non-COPD group (37.9% vs 29.5%, p<0.011 and 48.4% vs 30.8%, p<0.001, respectively). Logistic regression analysis revealed that education level of elementary school was independently associated with COPD incidence after adjustment for sex, age, body mass index, white blood cell count, residence area, and occupation (odds ratio 1.879, 95% confidence interval 1.124–3.141, p=0.016). Conclusion In the general population, educational level of elementary school was an independent risk factor for COPD among the components comprising SES. Our results indicate that the implementation of preventive strategies for COPD in those with low educational status could be beneficial.
Collapse
Affiliation(s)
- Chi Young Kim
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Internal Medicine, Korea University Ansan Hospital, Ansan, Republic of Korea.,Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Beong Ki Kim
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Internal Medicine, Korea University Ansan Hospital, Ansan, Republic of Korea
| | - Yu Jin Kim
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Internal Medicine, Korea University Ansan Hospital, Ansan, Republic of Korea
| | - Seung Heon Lee
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Internal Medicine, Korea University Ansan Hospital, Ansan, Republic of Korea
| | - Young Sam Kim
- Division of Pulmonology, Department of Internal Medicine, Institute of Chest Diseases, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Je Hyeong Kim
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Internal Medicine, Korea University Ansan Hospital, Ansan, Republic of Korea
| |
Collapse
|
30
|
Rosoff DB, Kaminsky ZA, McIntosh AM, Davey Smith G, Lohoff FW. Educational attainment reduces the risk of suicide attempt among individuals with and without psychiatric disorders independent of cognition: a bidirectional and multivariable Mendelian randomization study with more than 815,000 participants. Transl Psychiatry 2020; 10:388. [PMID: 33168806 PMCID: PMC7653915 DOI: 10.1038/s41398-020-01047-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/22/2020] [Accepted: 10/05/2020] [Indexed: 12/16/2022] Open
Abstract
Rates of suicidal behavior are increasing in the United States and identifying causal risk factors continues to be a public health priority. Observational literature has shown that educational attainment (EA) and cognitive performance (CP) influence suicide attempt risk; however, the causal nature of these relationships is unknown. Using summary statistics from genome-wide association studies (GWAS) of EA, CP, and suicide attempt risk with > 815,000 combined white participants of European ancestry, we performed multivariable Mendelian randomization (MR) to disentangle the effects of EA and CP on attempted suicide. In single-variable MR (SVMR), EA and CP appeared to reduce suicide attempt risk (EA odds ratio (OR) per standard deviation (SD) increase in EA (4.2 years), 0.524, 95% CI, 0.412-0.666, P = 1.07 × 10-7; CP OR per SD increase in standardized score, 0.714, 95% CI, 0.577-0.885, P = 0.002). Conversely, bidirectional analyses found no effect of a suicide attempt on EA or CP. Using various multivariable MR (MVMR) models, EA seems to be the predominant risk factor for suicide attempt risk with the independent effect (OR, 0.342, 95% CI, 0.206-0.568, P = 1.61 × 10-4), while CP had no effect (OR, 1.182, 95% CI, 0.842-1.659, P = 0.333). In additional MVMR analyses accounting simultaneously for potential behavioral and psychiatric mediators (tobacco smoking; alcohol consumption; and self-reported nerves, tension, anxiety, or depression), the effect of EA was little changed (OR, 0.541, 95% CI, 0.421-0.696, P = 3.33 × 10-6). Consistency of results across complementary MR methods accommodating different assumptions about genetic pleiotropy strengthened causal inference. Our results show that even after accounting for psychiatric disorders and behavioral mediators, EA, but not CP, may causally influence suicide attempt risk among white individuals of European ancestry, which could have important implications for health policy and programs aimed at reducing the increasing rates of suicide. Future work is necessary to examine the EA-suicide relationship populations of different ethnicities.
Collapse
Affiliation(s)
- Daniel B Rosoff
- Section on Clinical Genomics and Experimental Therapeutics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Zachary A Kaminsky
- Royal's Institute of Mental Health Research, University of Ottawa, Ottawa, ON, Canada
| | - Andrew M McIntosh
- Division of Psychiatry, Royal Edinburgh Hospital, University of Edinburgh, Edinburgh, UK
| | | | - Falk W Lohoff
- Section on Clinical Genomics and Experimental Therapeutics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA.
| |
Collapse
|
31
|
Ranakusuma RW, McCullough AR, Safitri ED, Pitoyo Y, Widyaningsih W, Del Mar CB, Beller EM. Oral prednisolone for acute otitis media in children: a pilot, pragmatic, randomised, open-label, controlled study (OPAL study). Pilot Feasibility Stud 2020; 6:121. [PMID: 32874679 PMCID: PMC7455987 DOI: 10.1186/s40814-020-00671-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 08/19/2020] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Acute otitis media (AOM) is associated with high antibiotic prescribing rates. Antibiotics are somewhat effective in improving pain and middle ear effusion (MEE); however, they have unfavourable effects. Alternative treatments, such as corticosteroids as anti-inflammatory agents, are needed. Evidence for the efficacy of these remains inconclusive. We conducted a pilot study to test feasibility of a proposed large-scale randomised controlled trial (RCT) to assess the efficacy of corticosteroids for AOM. METHODS We conducted a pilot, pragmatic, parallel, open-label RCT of oral corticosteroids for paediatric AOM in primary and secondary/tertiary care centres in Indonesia. Children aged 6 months-12 years with AOM were randomised to either prednisolone or control (1:1). Physicians were blinded to allocation. Our objectives were to test the feasibility of our full RCT procedures and design, and assess the mechanistic effect of corticosteroids, using tympanometry, in suppressing middle ear inflammation by reducing MEE. RESULTS We screened 512 children; 62 (38%) of 161 eligible children were randomised and 60 were analysed for the primary clinical outcome. All study procedures were completed successfully by healthcare personnel and parents/caregivers, despite time constraints and high workload. All eligible, consenting children were appropriately randomised. One child did not take the medication and four received additional oral corticosteroids. Our revised sample size calculation verified 444 children are needed for the full RCT. Oral corticosteroids did not have any discernible effects on MEE resolution and duration. There was no correlation between pain or other symptoms and MEE change. However, prednisolone may reduce pain intensity at day 3 (Visual Analogue Scale mean difference - 7.4 mm, 95% confidence interval (CI) - 13.4 to - 1.3, p = 0.018), but cause drowsiness (relative risk (RR) 1.8, 95% CI 1.1 to 2.8, p = 0.016). Tympanometry curves at day 7 may be improved (RR 1.8, 95% CI 1.0 to 2.9). We cannot yet confirm these as effects of corticosteroids due to insufficient sample size in this pilot study. CONCLUSIONS It is feasible to conduct a large, pragmatic RCT of corticosteroids for paediatric AOM in Indonesia. Although oral corticosteroids may reduce pain and improve tympanometry curves, it requires an adequately powered clinical trial to confirm this. TRIAL REGISTRATION Study registry number: ACTRN12618000049279. Name of registry: the Australian New Zealand Clinical Trials Registry (ANZCTR). Date of registration: 16 January 2018.
Collapse
Affiliation(s)
- Respati W. Ranakusuma
- Institute for Evidence-Based Healthcare, Bond University, 14 University Drive, Robina, QLD 4226 Australia
- Clinical Epidemiology and Evidence-Based Medicine Unit, Dr. Cipto Mangunkusumo General Hospital – Faculty of Medicine Universitas Indonesia, Diponegoro 71, Jakarta, 10430 Indonesia
| | - Amanda R. McCullough
- Institute for Evidence-Based Healthcare, Bond University, 14 University Drive, Robina, QLD 4226 Australia
| | - Eka D. Safitri
- Clinical Epidemiology and Evidence-Based Medicine Unit, Dr. Cipto Mangunkusumo General Hospital – Faculty of Medicine Universitas Indonesia, Diponegoro 71, Jakarta, 10430 Indonesia
| | - Yupitri Pitoyo
- Clinical Epidemiology and Evidence-Based Medicine Unit, Dr. Cipto Mangunkusumo General Hospital – Faculty of Medicine Universitas Indonesia, Diponegoro 71, Jakarta, 10430 Indonesia
| | - Widyaningsih Widyaningsih
- Clinical Epidemiology and Evidence-Based Medicine Unit, Dr. Cipto Mangunkusumo General Hospital – Faculty of Medicine Universitas Indonesia, Diponegoro 71, Jakarta, 10430 Indonesia
| | - Christopher B. Del Mar
- Institute for Evidence-Based Healthcare, Bond University, 14 University Drive, Robina, QLD 4226 Australia
| | - Elaine M. Beller
- Institute for Evidence-Based Healthcare, Bond University, 14 University Drive, Robina, QLD 4226 Australia
| |
Collapse
|
32
|
Klugman M, Hosgood HD, Hua S, Xue X, Vu THT, Perreira KM, Castañeda SF, Cai J, Pike JR, Daviglus M, Kaplan RC, Isasi CR. A longitudinal analysis of nondaily smokers: the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Ann Epidemiol 2020; 49:61-67. [PMID: 32951805 DOI: 10.1016/j.annepidem.2020.06.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 05/27/2020] [Accepted: 06/18/2020] [Indexed: 10/24/2022]
Abstract
PURPOSE Nondaily smoking is increasing in the United States and common among Hispanic/Latino smokers. We characterized factors related to longitudinal smoking transitions in Hispanic/Latino nondaily smokers. METHODS The Hispanic Community Health Study/Study of Latinos is a population-based cohort study of Hispanics/Latinos aged 18-74 years. Multinomial logistic regression assessed the baseline factors (2008-2011) associated with follow-up smoking status (2014-2017) in nondaily smokers (n = 573), accounting for complex survey design. RESULTS After ∼6 years, 41% of nondaily smokers became former smokers, 22% became daily smokers, and 37% remained nondaily smokers. Factors related to follow-up smoking status were number of days smoked in the previous month, household smokers, education, income, and insurance. Those smoking 16 or more of the last 30 days had increased risk of becoming a daily smoker [vs. < 4 days; relative risk ratio (RRR) = 5.65, 95% confidence interval (95% CI) = 1.96-16.33]. Greater education was inversely associated with transitioning to daily smoking [>high school vs. <ninth grade: RRR (95% CI) = 0.30 (0.09-0.95)]. Living with smokers was associated with decreased likelihood of quitting [RRR (95% CI) = 0.45 (0.24-0.86)]. Having insurance was associated with quitting [RRR (95% CI) = 2.11 (1.18-3.76)] and becoming a daily smoker [RRR (95% CI) = 3.00 (1.39-6.48)]. CONCLUSIONS Many Hispanic/Latino nondaily smokers became daily smokers, which may increase their risk of adverse health outcomes. Addressing different smoking patterns in primary care may be useful to prevent smoking-related diseases.
Collapse
Affiliation(s)
- Madelyn Klugman
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY
| | - H Dean Hosgood
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY
| | - Simin Hua
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY
| | - Xiaonan Xue
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY
| | - Thanh-Huyen T Vu
- Department of Preventative Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Krista M Perreira
- Department of Social Medicine, University of North Carolina School of Medicine, Chapel Hill
| | | | - Jianwen Cai
- Collaborative Studies Coordinating Center, Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill
| | - James R Pike
- Collaborative Studies Coordinating Center, Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill
| | - Martha Daviglus
- Department of Preventative Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Robert C Kaplan
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY; Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Carmen R Isasi
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY.
| |
Collapse
|
33
|
Morris TT, Davies NM, Davey Smith G. Can education be personalised using pupils' genetic data? eLife 2020; 9:e49962. [PMID: 32151313 PMCID: PMC7064332 DOI: 10.7554/elife.49962] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 01/22/2020] [Indexed: 12/11/2022] Open
Abstract
The increasing predictive power of polygenic scores for education has led to their promotion by some as a potential tool for genetically informed policy. How accurately polygenic scores predict an individual pupil's educational performance conditional on other phenotypic data is however not well understood. Using data from a UK cohort study with data linkage to national schooling records, we investigated how accurately polygenic scores for education predicted pupils' test score achievement. We also assessed the performance of polygenic scores over and above phenotypic data that are available to schools. Across our sample, there was high overlap between the polygenic score and achievement distributions, leading to poor predictive accuracy at the individual level. Prediction of educational outcomes from polygenic scores were inferior to those from parental socioeconomic factors. Conditional on prior achievement, polygenic scores failed to accurately predict later achievement. Our results suggest that while polygenic scores can be informative for identifying group level differences, they currently have limited use for accurately predicting individual educational performance or for personalised education.
Collapse
Affiliation(s)
- Tim T Morris
- MRC Integrative Epidemiology Unit, University of BristolBristolUnited Kingdom
- Population Health Sciences, Bristol Medical School, University of BristolBristolUnited Kingdom
| | - Neil M Davies
- MRC Integrative Epidemiology Unit, University of BristolBristolUnited Kingdom
- Population Health Sciences, Bristol Medical School, University of BristolBristolUnited Kingdom
| | - George Davey Smith
- MRC Integrative Epidemiology Unit, University of BristolBristolUnited Kingdom
- Population Health Sciences, Bristol Medical School, University of BristolBristolUnited Kingdom
| |
Collapse
|
34
|
Ding X, Barban N, Mills MC. Educational attainment and allostatic load in later life: Evidence using genetic markers. Prev Med 2019; 129:105866. [PMID: 31698308 PMCID: PMC6913517 DOI: 10.1016/j.ypmed.2019.105866] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 09/09/2019] [Accepted: 10/11/2019] [Indexed: 01/07/2023]
Abstract
Education is strongly correlated with health outcomes in older adulthood. Whether the impact of education expansion improves health remains unclear due to a lack of clarity over the causal relationship. Previous health research within the social sciences has tended to use specific activities of daily living or self-reported health status. This study uses a broader and objective health measure - allostatic load (AL) - to take into consideration the exposures that accumulate throughout the life course. This paper applies a Mendelian Randomization (MR) approach to identify causality in relation to education on health as measured by AL. Using the Health and Retirement Study 2008 (N=3935), we adopt a polygenic score built from genetic variants associated with years of education. To test whether our analyses violate the exclusion assumption, we further run MR Egger regressions to test for bias from pleiotropy. We also explore the potential pathways between education and AL, including smoking, drinking, marital length, health insurance, etc. Using this genetic instrument, we find a 0.3 unit (19% of a standard deviation) reduction in AL per year of schooling. The effect is mainly driven by BMI and Hba1c. Smoking and marital stability are two potential pathways that also causally influenced by education. If our main and sensitivity analyses are valid, the results find support that a higher level of education is causally related to better health in older adulthood.
Collapse
Affiliation(s)
- Xuejie Ding
- Department of Sociology, University of Oxford, United Kingdom of Great Britain and Northern Ireland; Nuffield College, United Kingdom of Great Britain and Northern Ireland.
| | - Nicola Barban
- University of Essex, Institute for Social and Economic Research (ISER), United Kingdom of Great Britain and Northern Ireland
| | - Melinda C Mills
- Department of Sociology, University of Oxford, United Kingdom of Great Britain and Northern Ireland; Nuffield College, United Kingdom of Great Britain and Northern Ireland; Leverhulme Centre for Demographic Science, University of Oxford, United Kingdom of Great Britain and Northern Ireland
| |
Collapse
|
35
|
Gill D, Efstathiadou A, Cawood K, Tzoulaki I, Dehghan A. Education protects against coronary heart disease and stroke independently of cognitive function: evidence from Mendelian randomization. Int J Epidemiol 2019; 48:1468-1477. [PMID: 31562522 PMCID: PMC6857750 DOI: 10.1093/ije/dyz200] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2019] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND There is evidence that education protects against cardiovascular disease. However, it is not known whether such an effect is independent of cognition. METHODS We performed two-sample Mendelian randomization (MR) analyses to investigate the effect of education and cognition, respectively, on risk of CHD and ischaemic stroke. Additionally, we used multivariable MR to adjust for the effects of cognition and education in the respective analyses to measure the effects of these traits independently of each other. RESULTS In unadjusted MR, there was evidence that education is causally associated with both CHD and stroke risk [CHD: odds ratio (OR) 0.65 per 1-standard deviation (SD; 3.6 years) increase in education; 95% confidence interval (CI) 0.61-0.70, stroke: OR 0.77; 95% CI 0.69-0.86]. This effect persisted after adjusting for cognition in multivariable MR (CHD: OR 0.76; 95% CI 0.65-0.89, stroke OR 0.74; 95% CI 0.59-0.92). Cognition had an apparent effect on CHD risk in unadjusted MR (OR per 1-SD increase 0.80; 95% CI 0.74-0.85), however after adjusting for education this was no longer observed (OR 1.03; 95% CI 0.86-1.25). Cognition did not have any notable effect on the risk of developing ischaemic stroke, with (OR 0.97; 95% CI 0.87-1.08) or without adjustment for education (OR 1.04; 95% CI 0.79-1.36). CONCLUSIONS This study provides evidence to support that education protects against CHD and ischaemic stroke risk independently of cognition, but does not provide evidence to support that cognition protects against CHD and stroke risk independently of education. These findings could have implications for education and health policy.
Collapse
Affiliation(s)
- Dipender Gill
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
| | - Anthoula Efstathiadou
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
| | | | - Ioanna Tzoulaki
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
- Medical Research Council–Public Health England Centre for Environment, School of Public Health, Imperial College London, London, UK
- Department of Hygiene and Epidemiology, University of Ioannina Medical School, Ioannina, Greece
| | - Abbas Dehghan
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
- Medical Research Council–Public Health England Centre for Environment, School of Public Health, Imperial College London, London, UK
| |
Collapse
|
36
|
Davies NM, Hill WD, Anderson EL, Sanderson E, Deary IJ, Davey Smith G. Multivariable two-sample Mendelian randomization estimates of the effects of intelligence and education on health. eLife 2019; 8:e43990. [PMID: 31526476 PMCID: PMC6748790 DOI: 10.7554/elife.43990] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 07/08/2019] [Indexed: 11/16/2022] Open
Abstract
Intelligence and education are predictive of better physical and mental health, socioeconomic position (SEP), and longevity. However, these associations are insufficient to prove that intelligence and/or education cause these outcomes. Intelligence and education are phenotypically and genetically correlated, which makes it difficult to elucidate causal relationships. We used univariate and multivariable Mendelian randomization to estimate the total and direct effects of intelligence and educational attainment on mental and physical health, measures of socioeconomic position, and longevity. Both intelligence and education had beneficial total effects. Higher intelligence had positive direct effects on income and alcohol consumption, and negative direct effects on moderate and vigorous physical activity. Higher educational attainment had positive direct effects on income, alcohol consumption, and vigorous physical activity, and negative direct effects on smoking, BMI and sedentary behaviour. If the Mendelian randomization assumptions hold, these findings suggest that both intelligence and education affect health.
Collapse
Affiliation(s)
- Neil Martin Davies
- Medical Research Council Integrative Epidemiology UnitUniversity of BristolBristolUnited Kingdom
- Bristol Medical SchoolUniversity of BristolBristolUnited Kingdom
| | - W David Hill
- Centre for Cognitive Ageing and Cognitive EpidemiologyUniversity of EdinburghEdinburghUnited Kingdom
- Department of PsychologyUniversity of EdinburghEdinburghUnited Kingdom
| | - Emma L Anderson
- Medical Research Council Integrative Epidemiology UnitUniversity of BristolBristolUnited Kingdom
- Bristol Medical SchoolUniversity of BristolBristolUnited Kingdom
| | - Eleanor Sanderson
- Medical Research Council Integrative Epidemiology UnitUniversity of BristolBristolUnited Kingdom
- Bristol Medical SchoolUniversity of BristolBristolUnited Kingdom
| | - Ian J Deary
- Centre for Cognitive Ageing and Cognitive EpidemiologyUniversity of EdinburghEdinburghUnited Kingdom
- Department of PsychologyUniversity of EdinburghEdinburghUnited Kingdom
| | - George Davey Smith
- Medical Research Council Integrative Epidemiology UnitUniversity of BristolBristolUnited Kingdom
- Bristol Medical SchoolUniversity of BristolBristolUnited Kingdom
| |
Collapse
|