Testosterone and androstanediol glucuronide among men in NHANES III.

Background: Most of the androgen replacement therapies were based on serum testosterone and without measurements of total androgen activities. Whether those with low testosterone also have low levels of androgen activity is largely unknown. We hence examined the association between testosterone and androstanediol glucuronide (AG), a reliable measure of androgen activity, in a nationally representative sample of US men.

Age at menarche and cardiovascular risk factors using Mendelian randomization in the Guangzhou Biobank Cohort Study.

Observational studies show earlier age at menarche associated with higher risk of cardiovascular disease although these studies could be confounded by childhood obesity or childhood socioeconomic position. We tested the hypothesis that earlier age at menarche is associated with poorer cardiovascular risk factors using a Mendelian randomization design. We conducted a Mendelian randomization study in a large Southern Chinese cohort, the Guangzhou Biobank Cohort Study (n=12,279), to clarify the causal role of menarche in cardiovascular disease risk factors including blood pressure, lipids, fasting glucose, adiposity and type 2 diabetes.

Exome-chip association analysis reveals an Asian-specific missense variant in PAX4 associated with type 2 diabetes in Chinese individuals.

Aims/hypothesis: Genome-wide association studies (GWASs) have identified many common type 2 diabetes-associated variants, mostly at the intronic or intergenic regions. Recent advancements of exome-array genotyping platforms have opened up a novel means for detecting the associations of low-frequency or rare coding variants with type 2 diabetes. We conducted an exomechip association analysis to identify additional type 2 diabetes susceptibility variants in the Chinese population.

Environment-wide association study to identify factors associated with hematocrit: evidence from the Guangzhou Biobank Cohort Study.

Purpose: In randomized controlled trials reducing high hematocrit (Hct) in patients with polycythemia vera protects against cardiovascular disease (CVD) events, whereas increasing Hct in anemia patients causes CVD events. Hct is influenced by environmental and lifestyle factors. Given limited knowledge concerning the drivers of Hct, we took an agnostic approach to identify drivers of Hct.

Genetically predicted 17beta-estradiol, cognitive function and depressive symptoms in women: A Mendelian randomization in the Guangzhou Biobank Cohort Study.

Objective: The role of estrogen in cognitive function and depressive symptoms is controversial due to discrepancies between results from randomized controlled trials (RCT) and observational studies. Mendelian randomization analysis may provide further insights concerning the role of estrogen in these outcomes as it assesses the effect of lifelong endogenous exposure but is less vulnerable to confounding than observational studies.

Method: We used separate sample instrumental variable analysis to estimate the association of log 17β estradiol with cognitive function (Delayed 10 word recall, and Mini Mental State Examination (MMSE)) and depressive symptoms (Geriatric Depression Scale (GDS)) in older Chinese women of the Guangzhou Biobank Cohort Study (GBCS, n=3086).

Genetically predicted 17beta-estradiol and cardiovascular risk factors in women: a Mendelian randomization analysis using young women in Hong Kong and older women in the Guangzhou Biobank Cohort Study.

Purpose: The role of estrogen in cardiovascular health remains contested with discrepancies between findings from randomized controlled trials and observational studies. Mendelian randomization, which assesses the effect of lifelong endogenous exposure, may help elucidate these discrepancies.

Methods: We used separate sample instrumental variable analysis to estimate the association of log 17β-estradiol with factors related to cardiovascular disease risk (systolic and diastolic blood pressure, lipids, fasting glucose, body mass index, waist hip ratio, and waist circumference) and Framingham score, a predictor of 10-year risk of ischemic heart disease events, in older Chinese women from the Guangzhou Biobank Cohort Study (GBCS, n = 3092).

A Mendelian randomization study of testosterone and cognition in men.

Testosterone replacement for older men is increasingly common, with some observations suggesting a protective effect on cognitive function. We examined the association of endogenous testosterone with cognitive function among older men in a Mendelian randomization study using a separate-sample instrumental variable (SSIV) analysis estimator to minimize confounding and reverse causality. A genetic score predicting testosterone was developed in 289 young Chinese men from Hong Kong, based on selected testosterone-related single nucleotide polymorphisms (rs10046, rs1008805 and rs1256031).

Stress across the life course and depression in a rapidly developing population: the Guangzhou Biobank Cohort Study.

Objective: The objective of this study was to examine the role of stress across the life course in the development of depression among older adults in a non-Western developing setting.

Methods: Multivariable linear and multinomial logistic regression were used in cross-sectional analyses of 9729 Chinese participants (mean age 60.2 years) from phase 3 of the Guangzhou Biobank Cohort Study (2006-2008) to investigate the association of childhood adversities and adulthood stressors with depression.

Nut Consumption and Cardiovascular Risk in Older Chinese: The Guangzhou Biobank Cohort Study.

Objectives: In Western contexts nut consumption is associated with better health. We examined the associations of nut consumption with cardiovascular disease risk in the non-Western setting of Southern China.

Methods: In the Guangzhou Biobank Cohort Study we used multivariable linear regression to examine the associations of baseline nut (mainly peanuts) consumption (none (n = 6688), <3 portions/week (n = 2596) and ≥3 portions/week (n = 2444)) with follow-up assessment of Framingham cardiovascular disease score (excluding smoking) and its components in older Chinese (≥50 years) (follow-up 57.

Fruit and vegetable consumption and cardiovascular risk factors in older Chinese: the Guangzhou biobank cohort study.

Objective: To examine the adjusted associations of fruit consumption and vegetable consumption with the Framingham score and its components in the non-Western setting of Southern China, considering health status.

Method: Linear regression was used to assess the cross-sectional associations of fruit and vegetable consumption with the Framingham score and its components, among 19,518 older Chinese (≥50 years) from the Guangzhou Biobank Cohort Study in Southern China (2003-2006), and whether these differed by health status.

Results: The association of fruit consumption with the Framingham score varied by health status (P-value<0.

Genetically predicted testosterone and systemic inflammation in men: a separate-sample Mendelian randomization analysis in older Chinese men.

Objectives: Observationally, testosterone is negatively associated with systemic inflammation, but this association is open to both residual confounding and reverse causality. Large-scale randomized controlled trials (RCTs), assessing exogenous effects, are presently unavailable. We examined the association of endogenous testosterone with well-established systemic inflammatory markers (white blood cell, granulocyte, lymphocyte and high-sensitivity C-reactive protein (hsCRP)) using a separate-sample Mendelian randomization analysis to minimize reverse causality.

Genetically predicted testosterone and electrocardiographic QT interval duration in Chinese: a Mendelian randomization analysis in the Guangzhou Biobank Cohort Study.

Background: QT interval prolongation, a predictor of cardiac arrhythmias, and elevated heart rate are associated with higher risk of cardiovascular mortality. Observationally testosterone is associated with shorter corrected QT interval and slower heart rate; however, the evidence is open to residual confounding and reverse causality. We examined the association of testosterone with electrocardiogram (ECG) parameters using a separate-sample instrumental variable (SSIV) estimator.

Genetically predicted 17β-estradiol and systemic inflammation in women: a separate-sample Mendelian randomisation analysis in the Guangzhou Biobank Cohort Study.

Background: Many chronic diseases are characterised by low-grade systemic inflammation. Oestrogens may promote immune response consistent with sex-specific patterns of diseases. In vitro culture and animal experiments suggest oestrogens are anti-inflammatory and might thereby protect against low-grade systemic inflammation.

Milk consumption and cardiovascular risk factors in older Chinese: the Guangzhou Biobank Cohort Study.

Background: Dairy products consumption is increasingly common globally. Most of the evidence concerning dairy products comes from observational studies in western populations which are inevitably open to confounding. To triangulate the evidence concerning dairy products, we examined the associations of whole cow's milk consumption with cardiovascular risk factors in a non-Western setting with a different pattern of milk consumption and cardiovascular diseases from Western populations.

Genetically predicted testosterone and cardiovascular risk factors in men: a Mendelian randomization analysis in the Guangzhou Biobank Cohort Study.

Background: Observationally lower testosterone is associated with an unhealthier cardiovascular (CVD) risk profile, but this association is open to confounding and reverse causality. The authors examined the association of testosterone with well-established cardiovascular disease (CVD) risk factors (blood pressure, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL)cholesterol and fasting glucose) and the Framingham score using a Mendelian randomization analysis with a separate-sample instrumental variable estimator.

Methods: To minimize reverse causality, a genetic score predicting testosterone was developed in 289 young Chinese men from Hong Kong, based on three selected testosterone-related single nucleotide polymorphisms (rs10046, rs1008805 and rs1256031).

Smoking cessation and carotid atherosclerosis: the Guangzhou Biobank Cohort Study--CVD.

Introduction: Smoking has been shown to be associated with carotid atherosclerosis in cross-sectional and prospective studies in Western populations. However, few studies have examined the reversal of risk resulting from quitting smoking, and the results are conflicting.

Methods: 959 men aged 50-85 years were randomly selected from phase III (2006-2007) of the Guangzhou Biobank Cohort Study into this cross-sectional study.

Alcohol sensitivity, alcohol use and hypertension in an older Chinese population: the Guangzhou Biobank Cohort Study.

Although the J-shaped association between alcohol consumption and blood pressure (BP) is well known, the effect of alcohol sensitivity on this relationship is less clear. We studied the association of alcohol sensitivity and alcohol use with BP and hypertension. This cross-sectional analysis included 19 335 older participants from the Guangzhou Biobank Cohort Study recruited from 2003 to 2006, using clinically measured BP and self-reported alcohol use and alcohol sensitivity.