Association between education and blood lipid levels as income increases over a decade: a cohort study

The causal effects of intelligence and fluid intelligence on Parkinson's disease: a Mendelian randomization study

Background

Parkinson's disease (PD) is a chronic neurodegenerative disease that affects the central nervous system, primarily the motor nervous system, and occurs most often in older adults. A large number of studies have shown that high intelligence leads to an increased risk of PD. However, whether there is a causal relationship between intelligence on PD has not yet been reported.

Methods

In this study, Mendelian randomization (MR) analysis was performed with intelligence (ebi-a-GCST006250) and fluid intelligence score (ukb-b-5238) as exposure factors and PD (ieu-b-7) as an outcome, which the datasets were mined from the IEU OpenGWAS database. MR analysis was performed through 3 methods [MR Egger, weighted median, inverse variance weighted (IVW)], of which IVW was the primary method. In addition, the reliability of the results of the MR analysis was assessed via the heterogeneity test, the horizontal polytropy test, and Leave-One-Out (LOO). Finally, based on gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, the genes corresponding to intelligence and fluid intelligence score related to SNPs were enriched for functional features and pathways.

Results

The results of MR analysis suggested that elevated intelligence indicators can increase the risk of PD [p = 0.015, Odd Ratio (OR) = 1.316]. Meanwhile, fluid intelligence score was causally associated with the PD (p = 0.035), which was a risk factor (OR = 1.142). The reliability of the results of MR analysis was demonstrated by sensitivity analysis. Finally, the results of GO enrichment analysis for 87 genes corresponding to intelligence related SNPs mainly included regulation of synapse organization, developmental cell growth, etc. These genes were enriched in the synaptic vessel cycle, polycomb expressive complex in KEGG. Similarly, 44 genes corresponding to SNPs associated with fluid intelligence score were used for enrichment analysis. Based on the GO database, these genes were mainly enriched in regulation of developmental growth, negative regulation of neuron projection development, etc. In KEGG, 44 genes corresponding to SNPs associated with fluid intelligence score were enriched in signaling pathways including Alzheimer's disease, the cellular senescence, etc.

Conclusion

The causal relationships between intelligence and fluid intelligence scores, and PD were demonstrated through MR analysis, providing an important reference and evidence for the study of PD.

Excessive Consumption of Alcoholic Beverages and Extremely High Levels of High-Density Lipoprotein Cholesterol (HALP) in the ELSA-Brasil Cohort Baseline

BACKGROUND

It has already been established that the consumption of alcoholic beverages increases high-density lipoprotein cholesterol (HDL-C) levels in dose-response.

METHODS AND RESULTS

A cross-sectional analysis was carried out with 6132 participants of both sexes aged between 35 and 74 years, who were active and retired workers from six Brazilian states. Heavy drinkers were categorized by sex: men > 210 g/week and women > 140 g/week; moderate drinkers: men ≤ 209 g/week and women ≤ 139 g/week. The HDL-C level was dichotomized into normal (40 mg/dL-82.9 mg/dL) and extremely high (≥83 mg/dL). We used binary logistic regression to assess associations between baseline alcohol intake and HDL-C, which were adjusted for sex, age, income, physical activity, kilocalories and body mass index (BMI), and we found an positive association between extremely high HDL-C and the excessive consumption of alcoholic beverages. These participants were mostly women with a high income, lower waist circumference, kilocalorie consumption and also a higher consumption in all categories of alcoholic beverages.

CONCLUSION

Excessive alcohol consumption was associated with a higher probability of extremely high HDL-C.

Intelligence, education level, and risk of Parkinson's disease in European populations: A Mendelian randomization study

Background: A high level of education or intelligence (IQ) is reported to be a risk factor for Parkinson's disease (PD). The purpose of this study was to systematically examine the causal relationships between IQ, educational attainment (EA), cognitive performance, and PD. Methods: We used summary statistics from genome-wide association studies on IQ, EA, cognitive performance, and PD. Four genome-wide association study (GWAS) data for PD were used to comprehensively explore the causal relationship, including PD GWAS (regardless of sex), age at onset of PD GWAS, male with PD GWAS, and female with PD GWAS data. We conducted a two sample Mendelian randomization (MR) study using the inverse-variance weighted (IVW), weighted median, simple mode, and weighted mode methods to evaluate the causal association between these factors. MR-Egger and MR-PRESSO were used for sensitivity analysis to test and correct horizontal pleiotropy. Multivariate MR (MVMR) was also used to account for the covariation between IQ, EA, and cognition, as well as to explore potential mediating factors. Results: Genetically predicted higher IQ was associated with an increased risk of PD in the entire population, regardless of gender. In the analyses using the IVW method, the odds ratio was 1.37 (p = 0.0064). Men with a higher IQ, more years of education, or stronger cognitive ability are more likely to develop PD compared to women. MVMR showed that adjusting for education and cognition largely attenuated the association between IQ and PD, suggesting that education and cognition may mediate the effect of IQ on PD. Conclusion: This study provides genetic support for the causal link between higher IQ and an increased risk of PD.

Lipoprotein Profile in Populations from Regions of the Russian Federation: ESSE-RF Study

This study aimed to describe the dyslipidemia prevalence and pattern among adult populations from different regions (n = 13) of the Russian Federation (RF). Randomly selected samples (n = 22,258, aged 25-64) were studied according to the ESSE-RF protocol. Lipoprotein parameters were estimated by routine methods. Statistical analyses were performed using R software (v.3.5.1). The overall dyslipidemia prevalence was 76.1% (76.9/75.3% for men/women). In women, total cholesterol (TC) and low-density lipoprotein (LDL)-C levels gradually increased with age (from 4.72 to 5.93 and from 2.76 to 3.79 mmol/L, respectively); in men, they reached a maximum by 45-54 (5.55 and 3.55 mmol/L, respectively) and then decreased. No differences in high-density lipoprotein (HDL)-C in men of different ages were found, but slight decreases in HDL-C and apo AI were observed in women by 55-64 years. No pronounced associations between education and lipid levels in men were observed; higher-educated women showed significantly better lipoprotein profiles. Similar associations between lipids and income level were detected. Women from rural areas had higher TC and triglycerides than urban residents. Regardless of sex, rural residents had higher HDL-C and apo AI, and reduced apo B/apo AI. Conclusion: Information on the peculiarities of dyslipidemia prevalence and lipoprotein profile depending on sex, age, residential place, and socioeconomic status is useful for assessing the global ASCVD risk, and for risk modeling based on national data.

Lipids, Anthropometric Measures, Smoking and Physical Activity Mediate the Causal Pathway From Education to Breast Cancer in Women: A Mendelian Randomization Study

Purpose

We aimed to investigate whether obtaining a higher level of education was causally associated with lower breast cancer risk and to identify the causal mechanism linking them.

Methods

The main data analysis used publicly available summary-level data from 2 large genome-wide association study consortia. Mendelian randomization (MR) analysis used 65 genetic variants derived from the Social Science Genetic Association Consortium as instrumental variables for years of schooling. The outcomes from the Breast Cancer Association Consortium (BCAC) were the overall breast cancer risk (122,977 cases/105,974 controls in women) and the two subtypes: estrogen receptor (ER)-positive breast cancer and ER-negative breast cancer. Fixed and random effects inverse variance weighted methods were used to estimate the causal effects, along with other additional MR methods for sensitivity analyses.

Results

Results showed that each additional standard deviation of 4.2 years of education was causally associated with a 27% lower risk of ER-negative breast cancer (odds ratio, 0.73; 95% confidence interval, 0.64–0.84; p-value < 0.001). This finding was consistent with the results of the sensitivity analyses. Physical activities can help improve the protective effect of education against breast cancer, with relatively large mediation proportions. Education increases the risk of ER-positive breast cancer due to alterations in high-density lipoprotein level, triglyceride level, height, waist-to-hip ratio, body mass index, and smoking status, with relative medium mediation proportions. Other mediators including low-density lipoprotein, hip circumference, number of cigarettes smoked per day, time spent performing light physical activity, and performing vigorous physical activity for > 10 minutes explain a small part of the causal effect of education on the risk of developing breast cancer, and their mediation proportion is approximately 1%.

Conclusion

A low level of education is a causal risk factor in the development of breast cancer as it is associated with poor lipid profile, obesity, smoking, and types of physical activity.

Association of a Total Cholesterol Polygenic Score with Cholesterol Levels and Pathological Biomarkers across the Alzheimer's Disease Spectrum

Midlife hypercholesterolemia is a well-known risk factor for sporadic Alzheimer's disease (AD), and like AD, it is highly influenced by genetics with heritability estimates of 32-63%. We thus hypothesized that genetics underlying peripheral blood total cholesterol (TC) levels could influence the risk of developing AD. We created a weighted polygenic score (TC-PGS) using summary data from a meta-analysis of TC genome-wide association studies for evaluation in three independent AD-related cohorts spanning pre-clinical, clinical, and pathophysiologically proved AD. APOE-ε4 variant was purposely included in the analysis as it represents an already well-established genetic risk factor for both AD and circulating TC. We could vastly improve the performance of the score when considering p-value thresholds for inclusion in the score, sex, and statin use. This optimized score (p-value threshold of 1 × 10^-6 for inclusion in the score) explained 18.2% of the variance in TC levels in statin free females compared to 6.9% in the entire sample and improved prediction of hypercholesterolemia (receiver operator characteristics analysis revealed area under the curve increase from 70.8% to 80.5%). The TC-PGS was further evaluated for association with AD risk and pathology. We found no association between the TC-PGS and either of the AD hallmark pathologies, assessed by cerebrospinal fluid levels of Aβ-42, p-Tau, and t-Tau, and 18F-NAV4694 and 18F-AV-1451 positron emission tomography. Similarly, we found no association with the risk of developing amyloid pathology or becoming cognitively impaired in individuals with amyloid pathology.

Factors associated with elevated low-density lipoprotein cholesterol levels among hill tribe people aged 30 years and over in Thailand: a cross-sectional study

Background

Low-density lipoprotein cholesterol (LDL-C) is one of the most important types of cholesterol and has an impact on health. Certain lifestyle and dietary habits in different populations may leads to increased levels of LDL-C, particularly among those with poor education and economic statuses, such as hill tribe people in Thailand. This study aimed to estimate the prevalence of and determine the factors associated with high LDL-C levels among hill tribe people in northern Thailand.

Methods

A cross-sectional study was performed to gather information from six main hill tribe populations: Akha, Lahu, Hmong, Yao, Karen, and Lisu. Individuals who were aged over 30 years and living in 30 selected hill tribe villages were invited to participate in the study. A validated questionnaire and 5-mL blood specimens were used to obtain data. Correlation analyses, chi-square tests, t-tests, and logistic regression were used to detect correlations and associations.

Results

A total of 2552 participants were recruited into the study; 65.9% were females, and 64.1% were aged younger than 60 years old. Approximately 69.6% of participants had abnormal LDL-C levels; 33.6% had above-optimal levels, 24.3% had borderline high levels, 8.0% had high levels, and 3.7% had very high levels. A total of 17.4% of participants had low high-density lipoprotein cholesterol (HDL-C) and high LDL-C levels, while 14.9% had high triglyceride and LDL-C levels. After controlling for sex, age, religion, education, annual family income, and marital status in the multivariate model, three variables were found to be associated with high LDL-C levels: occupation, the amount of lard used in daily cooking, and glycated hemoglobin (HbA1c). Those who were working as agriculturalists had a 1.34-fold greater chance of having abnormal LDL-C than traders and others (95% CI = 1.09–1.34). Those who used moderate and high quantities of lard in their daily cooking had a 1.45-fold (95% CI = 1.15–1.82) and 1.31-fold (95% CI = 1.04–1.68) greater likelihood of having abnormal LDL-C levels than those who used low quantities, respectively. Those who had abnormal HbA1c levels were less likely to develop abnormal LDL-C levels than those who had normal HbA1c levels (AOR = 0.69, 95% CI = 0.51–92).

Conclusions

Effective public health programs that do not conflict with the cultures of hill tribes are urgently needed, particularly programs encouraging the use of small quantities of lard for daily cooking practices.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10577-3.

Heart rate, intelligence in adolescence, and Parkinson's disease later in life

To investigate whether physical and cognitive fitness measured in late adolescence was associated with future risk of Parkinson’s disease (PD). The cohort included 1,259,485 Swedish men with physical fitness, body mass index (BMI), resting heart rate (RHR), blood pressure, intelligence quotient (IQ), and stress resilience measured at the age of 17–20 in relation to conscription. Incident cases of PD were ascertained from the Swedish Patient Register. Hazard ratios were estimated from Cox models, after controlling for multiple confounders. We further performed Mendelian randomization (MR) analyses to assess the causality of the associations, using GWAS summary statistics with > 800,000 individuals. During follow-up, we identified 1,034 cases of PD (mean age at diagnosis = 53). Men with an RHR > 100 beats per minute had a higher risk of PD compared to men with an RHR of 60–100 beats per minute (HR = 1.47; 95% CI = 1.08–1.99). Men with IQ above the highest tertile had a higher risk of PD compared to men with an IQ below the lowest tertile (HR = 1.46; 95% CI = 1.19–1.79). We found no association for physical fitness, BMI, blood pressure, or stress resilience. A causal relationship was suggested by the MR analysis between IQ and PD, but not between RHR and PD. RHR and IQ in late adolescence were associated with a higher risk of PD diagnosed at relatively young age. The association of IQ with PD is likely causal, whereas the association of RHR with PD suggests that altered cardiac autonomic function might start before 20 years of age in PD.

Childhood Maternal School Leaving Age (Level of Education) and Risk Markers of Metabolic Syndrome in Mid-Adulthood: Results from the 1958 British Birth Cohort

PURPOSE

The aim of this study is to investigate the relationship between childhood maternal level of education (CMLE) and changes in anthropometric and laboratory risk markers of metabolic syndrome (MetS) in mid-adulthood using results from the 1958 British Birth Cohort Study.

DESIGN

Cohort study.

PARTICIPANTS

A total of 9376 study samples consisting of subjects that participated in the biomedical survey of the national child development study (NCDS) carried out between 2002 and 2004 were used for the analysis.

MAIN OUTCOME MEASURES

Five risk markers of MetS: (i) HDL-cholesterol (ii) triglyceride (iii) blood pressure (BP) including systolic (SBP) and diastolic (DBP) (iv) waist circumference (WC) and (v) glycated haemoglobin (HbA1c).

METHODS

The NCDS or the 1958 British birth cohort data deposited in the UK data service by the centre for longitudinal studies were used for analyses. Ordinary least squares regression was used to determine unit changes in the outcome variables given CMLE.

RESULTS

The estimates for unadjusted regression analysis of individual risk markers indicated a significant relationship between CMLE and alterations in the five risk markers of MetS (HDL-cholesterol, triglyceride, WC, HbA1c, and BP) in midlife. After adjustment for birth and lifestyle characteristics/health behaviours, the relationship between CMLE and the risk markers was attenuated for HDL-cholesterol, triglycerides, and HbA1c but remained significant for WC 0.70 (95% confidence interval (CI) 0.065-1.30, p<0.001) and SBP 1.48 (95% CI 0.48-2.47 p<0.001).

CONCLUSION

There was a positive association between lower CMLE and the risk of MetS using the NCDS data. Lifestyle characteristics may be influential determinants of MetS risk in mid-adulthood.