A genome-wide association study of bitter and sweet beverage consumption

Coffee Consumption and Cardiovascular Diseases: A Mendelian Randomization Study

Coffee consumption has been linked to a lower risk of cardiovascular disease in observational studies, but whether the associations are causal is not known. We conducted a Mendelian randomization investigation to assess the potential causal role of coffee consumption in cardiovascular disease. Twelve independent genetic variants were used to proxy coffee consumption. Summary-level data for the relations between the 12 genetic variants and cardiovascular diseases were taken from the UK Biobank with up to 35,979 cases and the FinnGen consortium with up to 17,325 cases. Genetic predisposition to higher coffee consumption was not associated with any of the 15 studied cardiovascular outcomes in univariable MR analysis. The odds ratio per 50% increase in genetically predicted coffee consumption ranged from 0.97 (95% confidence interval (CI), 0.63, 1.50) for intracerebral hemorrhage to 1.26 (95% CI, 1.00, 1.58) for deep vein thrombosis in the UK Biobank and from 0.86 (95% CI, 0.50, 1.49) for subarachnoid hemorrhage to 1.34 (95% CI, 0.81, 2.22) for intracerebral hemorrhage in FinnGen. The null findings remained in multivariable Mendelian randomization analyses adjusted for genetically predicted body mass index and smoking initiation, except for a suggestive positive association for intracerebral hemorrhage (odds ratio 1.91; 95% CI, 1.03, 3.54) in FinnGen. This Mendelian randomization study showed limited evidence that coffee consumption affects the risk of developing cardiovascular disease, suggesting that previous observational studies may have been confounded.

Genetic analysis of obstructive sleep apnoea discovers a strong association with cardiometabolic health

There is currently limited understanding of the genetic aetiology of obstructive sleep apnoea (OSA). We aimed to identify genetic loci associated with OSA risk, and to test if OSA and its comorbidities share a common genetic background.We conducted the first large-scale genome-wide association study of OSA using the FinnGen study (217 955 individuals) with 16 761 OSA patients identified using nationwide health registries.We estimated 0.08 (95% CI 0.06-0.11) heritability and identified five loci associated with OSA (p<5.0×10^-8): rs4837016 near GAPVD1 (GTPase activating protein and VPS9 domains 1), rs10928560 near CXCR4 (C-X-C motif chemokine receptor type 4), rs185932673 near CAMK1D (calcium/calmodulin-dependent protein kinase ID) and rs9937053 near FTO (fat mass and obesity-associated protein; a variant previously associated with body mass index (BMI)). In a BMI-adjusted analysis, an association was observed for rs10507084 near RMST/NEDD1 (rhabdomyosarcoma 2 associated transcript/NEDD1 γ-tubulin ring complex targeting factor). We found high genetic correlations between OSA and BMI (r_g=0.72 (95% CI 0.62-0.83)), and with comorbidities including hypertension, type 2 diabetes, coronary heart disease, stroke, depression, hypothyroidism, asthma and inflammatory rheumatic disease (r_g>0.30). The polygenic risk score for BMI showed 1.98-fold increased OSA risk between the highest and the lowest quintile, and Mendelian randomisation supported a causal relationship between BMI and OSA.Our findings support the causal link between obesity and OSA, and the joint genetic basis between OSA and comorbidities.

Modifiable Lifestyle Factors and Risk of Stroke: A Mendelian Randomization Analysis

BACKGROUND AND PURPOSE

Assessing whether modifiable risk factors are causally associated with stroke risk is important in planning public health measures, but determining causality can be difficult in epidemiological data. We evaluated whether modifiable lifestyle factors including educational attainment, smoking, and body mass index are causal risk factors for ischemic stroke and its subtypes and hemorrhagic stroke.

METHODS

We performed 2-sample and multivariable Mendelian randomization to assess the causal effect of 12 lifestyle factors on risk of stroke and whether these effects are independent.

RESULTS

Genetically predicted years of education was inversely associated with ischemic, large artery, and small vessel stroke, and intracerebral hemorrhage. Genetically predicted smoking, body mass index, and waist-hip ratio were associated with ischemic and large artery stroke. The effects of education, body mass index, and smoking on ischemic stroke were independent.

CONCLUSIONS

Our findings support the hypothesis that reduced education and increased smoking and obesity increase risk of ischemic, large artery, and small vessel stroke, suggesting that lifestyle modifications addressing these risk factors will reduce stroke risk.

Cardiovascular risk factors and lifestyle behaviours in relation to longevity: a Mendelian randomization study

BACKGROUND

The American Heart Association introduced the Life's Simple 7 initiative to improve cardiovascular health by modifying cardiovascular risk factors and lifestyle behaviours. It is unclear whether these risk factors are causally associated with longevity.

OBJECTIVES

This study aimed to investigate causal associations of Life's Simple 7 modifiable risk factors, as well as sleep and education, with longevity using the two-sample Mendelian randomization design.

METHODS

Instrumental variables for the modifiable risk factors were obtained from large-scale genome-wide association studies. Data on longevity beyond the 90^th survival percentile were extracted from a genome-wide association meta-analysis with 11,262 cases and 25,483 controls whose age at death or last contact was ≤ the 60^th survival percentile.

RESULTS

Risk factors associated with a lower odds of longevity included the following: genetic liability to type 2 diabetes (OR 0.88; 95% CI: 0.84;0.92), genetically predicted systolic and diastolic blood pressure (per 1-mmHg increase: 0.96; 0.94;0.97 and 0.95; 0.93;0.97), body mass index (per 1-SD increase: 0.80; 0.74;0.86), low-density lipoprotein cholesterol (per 1-SD increase: 0.75; 0.65;0.86) and smoking initiation (0.75; 0.66;0.85). Genetically increased high-density lipoprotein cholesterol (per 1-SD increase: 1.23; 1.08;1.41) and educational level (per 1-SD increase: 1.64; 1.45;1.86) were associated with a higher odds of longevity. Fasting glucose and other lifestyle factors were not significantly associated with longevity.

CONCLUSION

Most of the Life's Simple 7 modifiable risk factors are causally related to longevity. Prevention strategies should focus on modifying these risk factors and reducing education inequalities to improve cardiovascular health and longevity.

Coffee consumption and risk of breast cancer: A Mendelian randomization study

BACKGROUND

Observational studies have reported either null or weak protective associations for coffee consumption and risk of breast cancer.

METHODS

We conducted a two-sample Mendelian randomization (MR) analysis to evaluate the relationship between coffee consumption and breast cancer risk using 33 single-nucleotide polymorphisms (SNPs) associated with coffee consumption from a genome-wide association (GWA) study on 212,119 female UK Biobank participants of White British ancestry. Risk estimates for breast cancer were retrieved from publicly available GWA summary statistics from the Breast Cancer Association Consortium (BCAC) on 122,977 cases (of which 69,501 were estrogen receptor (ER)-positive, 21,468 ER-negative) and 105,974 controls of European ancestry. Random-effects inverse variance weighted (IVW) MR analyses were performed along with several sensitivity analyses to assess the impact of potential MR assumption violations.

RESULTS

One cup per day increase in genetically predicted coffee consumption in women was not associated with risk of total (IVW random-effects; odds ratio (OR): 0.91, 95% confidence intervals (CI): 0.80-1.02, P: 0.12, P for instrument heterogeneity: 7.17e-13), ER-positive (OR = 0.90, 95% CI: 0.79-1.02, P: 0.09) and ER-negative breast cancer (OR: 0.88, 95% CI: 0.75-1.03, P: 0.12). Null associations were also found in the sensitivity analyses using MR-Egger (total breast cancer; OR: 1.00, 95% CI: 0.80-1.25), weighted median (OR: 0.97, 95% CI: 0.89-1.05) and weighted mode (OR: 1.00, CI: 0.93-1.07).

CONCLUSIONS

The results of this large MR study do not support an association of genetically predicted coffee consumption on breast cancer risk, but we cannot rule out existence of a weak association.

Relationships between accelerometer-measured and multiple sclerosis: a 2-sample Mendelian randomization study

BACKGROUND

Observational studies suggest that physical activity (PA) can independently modify the risk of developing multiple sclerosis (MS).

OBJECTIVE

To investigate the causal effect of PA on MS by Mendelian randomization (MR) approaches.

METHODS

Through a genome-wide association study including 91,105 participants from UK Biobank, we obtained 5 single-nucleotide polymorphisms (SNPs) associated with accelerometer-measured PA (P < 5 × 10^-8). Summary-level data for MS were obtained from a meta-analysis, incorporating 14,802 subjects with MS and 26,703 healthy controls of European ancestry. MR analyses were performed using the inverse-variance-weighted method, weighted median estimator, and MR-PRESSO method. Additional analyses were further performed using MR-Egger intercept and Cochran's Q statistic to verify the robustness of our findings.

RESULTS

We failed to detect a causal effect of PA on MS (OR, 0.60; 95% confidence interval [CI], 0.30-1.20; P = 0.15) per in the random-effects IVW analysis. Additional MR methods yielded consistent results. MR-Egger regression suggested no evidence of horizontal pleiotropy (Intercept = 0.14, P = 0.21) and there seemed no substantial heterogeneity (I² = 29.8%, P = 0.22) among individual SNPs.

CONCLUSION

Our findings suggest that enhancing PA might not modify the risk of developing MS independent of established risk factors.

The Nuanced Metabolic Functions of Endogenous FGF21 Depend on the Nature of the Stimulus, Tissue Source, and Experimental Model

Fibroblast growth factor 21 (FGF21) is a hormone that is involved in the regulation of lipid, glucose, and energy metabolism. Pharmacological FGF21 administration promotes weight loss and improves insulin sensitivity in rodents, non-human primates, and humans. However, pharmacologic effects of FGF21 likely differ from its physiological effects. Endogenous FGF21 is produced by many cell types, including hepatocytes, white and brown adipocytes, skeletal and cardiac myocytes, and pancreatic beta cells, and acts on a diverse array of effector tissues such as the brain, white and brown adipose tissue, heart, and skeletal muscle. Different receptor expression patterns dictate FGF21 function in these target tissues, with the primary effect to coordinate responses to nutritional stress. Moreover, different nutritional stimuli tend to promote FGF21 expression from different tissues; i.e., fasting induces hepatic-derived FGF21, while feeding promotes white adipocyte-derived FGF21. Target tissue effects of FGF21 also depend on its capacity to enter the systemic circulation, which varies widely from known FGF21 tissue sources in response to various stimuli. Due to its association with obesity and non-alcoholic fatty liver disease, the metabolic effects of endogenously produced FGF21 during the pathogenesis of these conditions are not well known. In this review, we will highlight what is known about endogenous tissue-specific FGF21 expression and organ cross-talk that dictate its diverse physiological functions, with particular attention given to FGF21 responses to nutritional stress. The importance of the particular experimental design, cellular and animal models, and nutritional status in deciphering the diverse metabolic functions of endogenous FGF21 cannot be overstated.

Causal Association of Coffee Consumption and Total, Knee, Hip and Self-Reported Osteoarthritis: A Mendelian Randomization Study

BACKGROUND

The causal association between coffee consumption and the risk of OA is limited. This study was conducted to identify the potential causal effects of coffee consumption on total, knee, hip, and self-reported OA.

METHODS

Genome-wide association studies (GWAS) of OA were derived from the UK Biobank, comprising 50,508 participants of European ancestry (10,083 with cases and 40,425 controls), and genetic data for specific diagnosed knee OA (4462 cases and 17,885 controls), hip OA (12,625 cases and 50,898 controls), and self-reported OA (12,658 cases and 50,898 controls). Primary and secondary genetic instruments (11 SNPs and 8 SNPs) were selected as instrumental variants from GWAS among 375,833 and 91,462 participants. Two-sample Mendelian randomization (MR) analyses were performed to test the effects of the selected single nucleotide polymorphisms (SNPs) and the OA risk. The causal effects were primarily estimated using weighted median and inverse-variance weighted method with several sensitivity analyses.

RESULTS

The MR analyses suggested that genetically predicted 1% increase of coffee consumption was associated with an increased risk of overall OA (OR:1.009, 95% CI:1.003-1.016), knee OA (OR:1.023, 95% CI:1.009-1.038), self-reported OA (OR:1.007, 95% CI:1.003-1.011), but not hip OA (OR: 1.012, 95%CI:0.999-1.024) using primary genetic instruments. Similar results were found when using secondary genetic instruments that genetically predicted coffee consumption (cups/day). Additionally, the sensitivity analyses for leave-one-out methods supported a robust association between exposure traits and OA.

CONCLUSION

Our findings indicate that genetically predicted coffee consumption exerts a causal effect on total, knee, and self-reported OA risk, but not at the hip. Further research is required to unravel the role of coffee consumption in OA prevention.

Association of Cardiovascular Risk Factors and Lifestyle Behaviors With Hypertension

Hypertension is a major risk factor for cardiovascular disease and mortality. To identify targets for the prevention of hypertension and its associated disease burden, we used the 2-sample Mendelian randomization method to investigate the causal associations of 18 cardiovascular risk factors and lifestyle behaviors with hypertension. From European-descent genome-wide association studies, we selected genetic variants (P<5×10−8) for type 2 diabetes, fasting glucose, lipids, body mass index, smoking, alcohol and coffee consumption, physical activity, sleep duration, insomnia, and educational level. We extracted the genetic associations with hypertension from 2 European cohorts: the FinnGen Study (15 870 cases and 74 345 controls) and UK Biobank (54 358 cases and 408 652 controls). The inverse-variance weighted method was used as main analysis method. Genetically predicted triglycerides (pooled odds ratio [OR] per 1 SD, 1.17 [1.10–1.25]), body mass index (OR per 1 SD, 1.42 [1.37–1.48]), alcohol dependence (OR, 1.10 [1.06–1.13]), and insomnia (OR, 1.17 [1.13–1.20]) were associated with a higher odds of hypertension. Higher genetically predicted high-density lipoprotein cholesterol (OR per 1 SD, 0.88 [0.83–0.94]) and educational level (OR per 1 SD, 0.56 [0.54–0.59]) were associated with a lower odds of hypertension. Suggestive evidence was obtained for type 2 diabetes, smoking initiation and alcohol consumption with a higher hypertension odds, and longer sleep duration with a lower hypertension odds. This Mendelian randomization study identified high-density lipoprotein cholesterol, triglycerides, body mass index, alcohol dependence, insomnia, and educational level as causal risk factors for hypertension. This implicates that these modifiable risk factors are important targets in the prevention of hypertension.

Modifiable lifestyle factors and heart failure: A Mendelian randomization study

BACKGROUND

Lifestyle factors may be important targets in the prevention of heart failure. The current knowledge on the relationship between lifestyle factors and heart failure originates mostly from observational studies. The objective of this study was to investigate causal associations of multiple lifestyle factors with heart failure risk by using Mendelian randomization.

METHODS

We obtained summary statistics data for single nucleotide polymorphisms associated with the following 5 lifestyle factors at genome-wide significance in genome-wide association studies of European-descent individuals: smoking, alcohol consumption, coffee consumption, physical activity, and sleep duration. The corresponding data for heart failure were acquired from a genome-wide association study comprising 47,309 cases and 930,014 controls of European ancestry. For the primary analyses, we used the inverse-variance weighted method.

RESULTS

Genetic predisposition to smoking initiation (ever smoked regularly) was robustly associated with a higher odds of heart failure (odds ratio: 1.28; 99% CI: 1.21-1.35). Genetically predicted longer sleep duration was associated with a lower odds of heart failure (odds ratio per hour/day: 0.73; 99% CI: 0.60-0.89). We found no associations of alcohol consumption, coffee consumption, and physical activity with heart failure.

CONCLUSIONS

This Mendelian randomization study showed that smoking initiation increases heart failure risk, whereas longer sleep duration decreases the risk of heart failure. Sleep duration should be regarded as novel risk factor in heart failure prevention guidelines. The potential causal role of alcohol and coffee consumption and physical activity for heart failure warrants further investigation in future larger Mendelian randomization analyses.

Habitual coffee intake and risk for nonalcoholic fatty liver disease: a two-sample Mendelian randomization study

PURPOSE

Epidemiological studies support a protective role of habitual coffee and caffeine consumption against the risk of non-alcoholic fatty liver disease (NAFLD). We aimed to investigate the causal relationship between coffee intake and the risk of NAFLD.

METHODS

We performed a two-sample Mendelian randomization (MR) analysis using SNPs associated with habitual coffee intake in a published genome-wide association study (GWAS) as genetic instruments and summary-level data from a published GWAS of NAFLD (1122 cases and 399,900 healthy controls) in the UK Biobank. The causal relationship was estimated with the inverse weighted method using a 4-SNP and 6-SNP instrument based on the single largest non-UK Biobank GWAS (n = 91,462) and meta-analysis (n = 121,524) of GWAS data on habitual coffee intake, respectively. To maximize power, we also used up to 77 SNPs associated with coffee intake at a liberal significance level (p ≤ 1e-4) as instruments.

RESULTS

We observed a non-significant trend towards a causal protective effect of coffee intake on NAFLD based upon either the 4-SNP (OR: 0.76; 95% CI 0.51, 1.14, p = 0.19) or 6-SNP genetic instruments (OR: 0.77; 95% CI 0.48, 1.25, p = 0.29). The result also remains non-significant when using the more liberal 77-SNP instrument.

CONCLUSION

Our findings do not support a causal relationship between coffee intake and NAFLD risk. However, despite the largest-to-date sample size, the power of this study may be limited by the non-specificity and moderate effect size of the genetic alleles on coffee intake.

Habitual Coffee and Tea Consumption and Cardiometabolic Biomarkers in the UK Biobank: The Role of Beverage Types and Genetic Variation

BACKGROUND

Mechanisms linking habitual consumption of coffee and tea to the development of type 2 diabetes and cardiovascular diseases remain unclear.

OBJECTIVES

We leveraged dietary, genetic, and biomarker data collected from the UK Biobank to investigate the role of different varieties of coffee and tea in cardiometabolic health.

METHODS

We included data from ≤447,794 participants aged 37-73 y in 2006-2010 who provided a blood sample and completed questionnaires regarding sociodemographic factors, medical history, diet, and lifestyle. Multivariable linear regression was used to examine the association between coffee or tea consumption and blood concentrations of glycated hemoglobin, fasting glucose, total cholesterol, HDL cholesterol, LDL cholesterol, fasting triglycerides (TGs), apoA-1, apoB, lipoprotein-a, and C-reactive protein (CRP). Lifestyle and genetic factors affecting caffeine metabolism, responses, or intake were tested for interactions with beverage intake in relation to biomarker concentrations.

RESULTS

Compared with coffee nonconsumers, each additional cup of coffee was significantly associated with higher total cholesterol, HDL-cholesterol, and LDL-cholesterol concentrations and lower TG and CRP concentrations in both men and women (P-trend < 0.002). Higher consumption of espresso coffee (≥2 compared with 0 cups/d) was associated with higher LDL cholesterol in men (β: 0.110 mmol/L; 95% CI: 0.058, 0.163 mmol/L) and women (β: 0.161 mmol/L; 95% CI: 0.088, 0.234 mmol/L), whereas no substantial association was observed for instant coffee. Compared with tea nonconsumers, higher tea consumption was associated with lower total and LDL cholesterol and apoB and higher HDL cholesterol (P-trend < 0.002); these associations were similar for black and green tea. Associations were not modified by genetics.

CONCLUSIONS

In the UK Biobank, consumption of certain coffee brews such as espresso had unfavorable associations with blood lipids, whereas consumption of tea had favorable associations. Findings were not modified by genetic variants affecting caffeine metabolism, suggesting a role of noncaffeine constituents of these beverages in cardiometabolic health.

Recent Caffeine Drinking Associates with Cognitive Function in the UK Biobank

Clinical evidence points to the premise that caffeine may benefit cognition, but whether these findings extend to real life settings and amidst factors that impact caffeine metabolism is unclear. The aim of this study was to investigate the impact of recent caffeine drinking on cognitive ability while additionally accounting for lifestyle and genetic factors that impact caffeine metabolism. We included up to 434,900 UK Biobank participants aged 37–73 years, recruited in 2006–2010, who provided biological samples and completed touchscreen questionnaires regarding sociodemographic factors, medical history, lifestyle, and diet. Recent caffeine drinking (yes/no in the last hour) was recorded during a physical assessment. Participants completed at least one of four self-administered cognitive function tests using the touchscreen system: prospective memory (PM), pairs matching (Pairs), fluid intelligence (FI), and reaction time (RT). Multivariable regressions were used to examine the association between recent caffeine drinking and cognition test scores. We also tested interactions between recent caffeine drinking and a genetic caffeine-metabolism score (CMS) on cognitive function. Among white participants, recent caffeine drinking was associated with higher performance on RT but lower performance on FI, Pairs, and PM (p ≤ 0.004). Similar directions of associations for FI (p = 0.09), Pairs (p = 0.03), and PM (p = 0.34) were observed among non-white participants. No significant and consistent effect modification by age, sex, smoking, test time, habitual caffeine intake, or CMS was observed. Caffeine consumed shortly before tasks requiring shorter reaction times may improve task performance. Potential impairments in memory and reasoning tasks with recent caffeine drinking warrant further study.

Coffee consumption is not associated with risk of multiple sclerosis: A Mendelian randomization study

OBJECTIVE

. Coffee consumption has been suggested to decrease the risk of multiple sclerosis (MS). In this study, we aim to investigate the causal effect of coffee consumption on risk of MS by Mendelian randomization (MR) approaches.

METHODS

. Through a genome-wide association study including 375,833 participants from UK Biobank, we obtained single-nucleotide polymorphisms (SNPs) associated with habitual coffee consumption (P < 5 × 10^-8). Summary-level data for MS were obtained from a meta-analysis, incorporating 14,802 subjects with MS and 26,703 healthy controls of European ancestry, which was conducted by the International Multiple Sclerosis Genetics Consortium. MR analyses were performed using inverse-variance-weighted method, weighted median estimator, and MR-Egger regression. Additional analyses were further performed using MR-Egger intercept and Cochran's Q statistic to verify the robustness of our findings.

RESULTS

. Nine coffee-associated SNPs were selected as instrumental variables. We failed to detect a causal effect of coffee consumption on MS risk (odds ratio, 1,00; 95% confidence interval, 0.98-1.01; P = 0.48). In the main MR analysis. Consistent results were yielded in sensitivity analyses using the weighted median and MR-Egger methods, and no horizontal pleiotropy (P = 0.49) was identified.

CONCLUSION

. Our MR results indicated that coffee consumption might not be causally associated with risk of MS occurrence. Further well-designed genetic-epidemiological studies investigating the effect of coffee intake on the disease course, such as relapse and progression, are warranted.

Insights into the aetiology of snoring from observational and genetic investigations in the UK Biobank

Although snoring is common in the general population, its aetiology has been largely understudied. Here we report a genetic study on snoring (n ~ 408,000; snorers ~ 152,000) using data from the UK Biobank. We identify 42 genome-wide significant loci, with an SNP-based heritability estimate of ~10% on the liability scale. Genetic correlations with body mass index, alcohol intake, smoking, schizophrenia, anorexia nervosa and neuroticism are observed. Gene-based associations identify 173 genes, including DLEU7, MSRB3 and POC5, highlighting genes expressed in the brain, cerebellum, lungs, blood and oesophagus. We use polygenic scores (PGS) to predict recent snoring and probable obstructive sleep apnoea (OSA) in an independent Australian sample (n ~ 8000). Mendelian randomization analyses suggest a potential causal relationship between high BMI and snoring. Altogether, our results uncover insights into the aetiology of snoring as a complex sleep-related trait and its role in health and disease beyond it being a cardinal symptom of OSA.

Snoring is common in the population and tends to be more prevalent in older and/or male individuals. Here, the authors perform GWAS for habitual snoring, identify 41 genomic loci and explore potential causal relationships with anthropometric and cardiometabolic disease traits.

GWAS of 165,084 Japanese individuals identified nine loci associated with dietary habits

Dietary habits are important factors in our lifestyle, and confer both susceptibility to and protection from a variety of human diseases. We performed genome-wide association studies for 13 dietary habits including consumption of alcohol (ever versus never drinkers and drinks per week), beverages (coffee, green tea and milk) and foods (yoghurt, cheese, natto, tofu, fish, small whole fish, vegetables and meat) in Japanese individuals (n = 58,610-165,084) collected by BioBank Japan, the nationwide hospital-based genome cohort. Significant associations were found in nine genetic loci (MCL1-ENSA, GCKR, AGR3-AHR, ADH1B, ALDH1B1, ALDH1A1, ALDH2, CYP1A2-CSK and ADORA2A-AS1) for 13 dietary traits (P < 3.8 × 10^-9). Of these, ten associations between five loci and eight traits were new findings. Furthermore, a phenome-wide association study revealed that five of the dietary trait-associated loci have pleiotropic effects on multiple human complex diseases and clinical measurements. Our findings provide new insight into the genetics of habitual consumption.

Associations of Smoking and Alcohol and Coffee Intake with Fracture and Bone Mineral Density: A Mendelian Randomization Study

The causal associations of smoking and alcohol and coffee intake with fracture and bone mineral density are unknown. We investigated the associations using Mendelian randomization (MR). Summary-level data from UK Biobank for bone fractures (main outcome) (53,184 cases; 373,611 non-cases) and estimated bone mineral density (eBMD) (n = 426,824 individuals) were used. Single-nucleotide polymorphisms associated with smoking initiation (n = 378) and alcohol (n = 99) and coffee (n = 15) intake at the genome-wide significance threshold (P = 5 × 10^-8) were identified from published genome-wide association studies. Univariable and multivariable inverse-variance weighted, weighted median, MR-Egger, and MR-PRESSO methods were used for statistical analyses. Genetic predisposition to smoking initiation was associated with fracture but not eBMD. The odds ratio of fracture per one-unit increase in log odds of smoking was 1.09 (95% confidence interval 1.04, 1.15; P = 8.58 × 10^-4) after adjustment for alcohol intake in the multivariable MR analysis. The association remained in complementary analyses. Genetically predicted alcohol and coffee intake was not associated with fracture or eBMD. Nevertheless, genetic liability to alcohol dependence, based on variants in the ALD1B gene, was associated with fracture and lower eBMD. The odds ratio was 1.06 (95% confidence interval 1.01, 1.12; P = 0.018) per genetically predicted one-unit higher log odds of liability to alcohol dependence. This MR study strengthens the causal inference on an association between smoking and higher fracture risk but found no linear association of modestly higher alcohol and coffee intake with fracture or BMD. However, alcohol dependence may increase fracture risk.

Allelic Variation in Taste Genes Is Associated with Taste and Diet Preferences and Dental Caries

Taste and diet preferences are complex and influenced by both environmental and host traits while affecting both food selection and associated health outcomes. The present study genotyped 94 single nucleotide polymorphisms (SNPs) in previously reported taste and food intake related genes and assessed associations with taste threshold (TT) and preferred intensity (PT) of sweet, sour and bitter, food preferences, habitual diet intake, and caries status in healthy young Swedish men and women (n = 127). Polymorphisms in the GNAT3, SLC2A4, TAS1R1 and TAS1R2 genes were associated with variation in TT and PT for sweet taste as well as sweet food intake. Increasing PT for sweet was associated with increasing preference and intake of sugary foods. Similarly, increasing TT for sour was associated with increasing intake of sour foods, whereas the associations between food preference/intake and TT/PT for bitter was weak in this study group. Finally, allelic variation in the GNAT3, SLC2A2, SLC2A4, TAS1R1 and TAS1R2 genes was associated with caries status, whereas TT, PT and food preferences were not. It was concluded that variations in taste receptor, glucose transporter and gustducin encoding genes are related to taste perception, food preference and intake as well as the sugar-dependent caries disease.