Breast feeding and early adolescent behaviour, self-esteem and depression: Hong Kong's 'Children of 1997' birth cohort.

Objective: Breast feeding may contribute to neurological development and hence mental health. However, associations from Western populations are unclear, and most likely confounded by socioeconomic position (SEP), making evidence from other sociocultural settings valuable. We examined whether breast feeding was associated with early adolescent emotional and behavioural problems, self-esteem and depressive symptoms in a non-Western developed setting, where socioeconomic patterning of breast feeding differs from but other postnatal characteristics are similar to Western settings.

Androgen activity and markers of inflammation among men in NHANES III.

Objectives: Inflammation contributes to chronic diseases. Lower serum testosterone among men is associated with less inflammation, yet immune defense is thought to trade-off against reproduction with androgens adversely affecting immune function. Anti-androgens are effective at castrate levels of serum testosterone, suggesting serum testosterone may not capture all androgen activity.

Power and sample size calculations for Mendelian randomization studies using one genetic instrument.

Mendelian randomization, which is instrumental variable analysis using genetic variants as instruments, is an increasingly popular method of making causal inferences from observational studies. In order to design efficient Mendelian randomization studies, it is essential to calculate the sample sizes required. We present formulas for calculating the power of a Mendelian randomization study using one genetic instrument to detect an effect of a given size, and the minimum sample size required to detect effects for given levels of significance and power, using asymptotic statistical theory.

Alcohol intake and death from cancer in a prospective Chinese elderly cohort study in Hong Kong.

Background: In observational studies of Western populations, moderate alcohol use is usually associated with lower cancer mortality rates. However, moderate alcohol use (regular drinking of moderate amounts) is socially patterned. Evidence from other contexts can clarify such observations.

Grandparental education, parental education and child height: evidence from Hong Kong's "Children of 1997" birth cohort.

Purpose: Adult height is the sum of growth during fetal, infancy, childhood, and puberty, controlled by different biological factors. In long-term developed Western populations, height is positively associated with socioeconomic position, but less clearly so in recently developing populations. We aimed to elucidate socioeconomic influences on height at different growth phases.

Mode of delivery and adiposity: Hong Kong's "Children of 1997" birth cohort.

Purpose: To examine whether mode of delivery was associated with childhood adiposity in a developed non-Western context.

Methods: We used generalized estimating equations to estimate the association of mode of delivery (vaginal or cesarean) with body mass index (BMI) z-score and overweight (including obesity) from 3 months to 13 years, in 7809 term birth (94% follow-up) from a population-representative Chinese birth cohort, "Children of 1997." We used multiple imputation for missing data.

Moderate alcohol use and cardiovascular disease from Mendelian randomization.

Background: Observational studies show moderate alcohol use negatively associated with ischemic heart disease (IHD) and cardiovascular disease (CVD). However, healthier attributes among moderate users compared to never users may confound the apparent association. A potentially less biased way to examine the association is Mendelian randomization, using alcohol metabolizing genes which influence alcohol use.

Breastfeeding and adolescent blood pressure: evidence from Hong Kong's "Children of 1997" Birth Cohort.

Observationally, breastfeeding is associated with lower blood pressure in Western developed settings, whereas little association exists in developing settings. However, postnatal characteristics (e.g.

Testosterone therapy and cardiovascular events among men: a systematic review and meta-analysis of placebo-controlled randomized trials.

Background: Testosterone therapy is increasingly promoted. No randomized placebo-controlled trial has been implemented to assess the effect of testosterone therapy on cardiovascular events, although very high levels of androgens are thought to promote cardiovascular disease.

Methods: A systematic review and meta-analysis was conducted of placebo-controlled randomized trials of testosterone therapy among men lasting 12+ weeks reporting cardiovascular-related events.

Age-period-cohort projections of ischaemic heart disease mortality by socio-economic position in a rapidly transitioning Chinese population.

Background: With economic development and population aging, ischaemic heart disease (IHD) is becoming a leading cause of mortality with widening inequalities in China. To forewarn the trends in China we projected IHD trends in the most economically developed part of China, i.e.

Timing of solid food introduction and obesity: Hong Kong's "children of 1997" birth cohort.

Background: Some observational studies in Western settings show that early introduction of solid food is associated with subsequent obesity. However, introduction of solid food and obesity share social patterning. We examined the association of the timing of the introduction of solid food with BMI and overweight (including obesity) into adolescence in a developed non-Western setting, in which childhood obesity is less clearly socially patterned.

Are depressive symptoms associated with cardiovascular mortality among older Chinese: a cohort study of 64,000 people in Hong Kong?

Background: Depression was positively associated with cardiovascular disease (CVD) or mortality in previous studies. However, whether the observed association can be explained by health status is not clear.

Objectives: To study the association of depressive symptoms with CVD, stroke, and coronary heart disease (CHD) mortality in older Chinese in Hong Kong, and whether the associations varied by gender or health status.

The effect of statins on testosterone in men and women, a systematic review and meta-analysis of randomized controlled trials.

Background: Statins are extensively used for cardiovascular disease prevention. Statins reduce mortality rates more than other lipid-modulating drugs, although evidence from randomized controlled trials also suggests that statins unexpectedly increase the risk of diabetes and improve immune function. Physiologically, statins would be expected to lower androgens because statins inhibit production of the substrate for the local synthesis of androgens and statins' pleiotropic effects are somewhat similar to the physiological effects of lowering testosterone, so we hypothesized that statins lower testosterone.

The role of dairy products and milk in adolescent obesity: evidence from Hong Kong's "Children of 1997" birth cohort.

Background: Observational studies, mainly from Western populations, suggest dairy consumption is inversely associated with adiposity. However, in these populations the intake range is limited and both diet and obesity may share social patterning. Evidence from non-Western developed settings with different social patterning, is valuable in distinguishing whether observed associations are biologically mediated or socially confounded.

Is aldehyde dehydrogenase 2 a credible genetic instrument for alcohol use in Mendelian randomization analysis in Southern Chinese men?

Background: Mendelian randomization studies provide a means of assessing causal relations without interventions, but require valid genetic instruments. We assessed the credibility of aldehyde dehydrogenase 2 (ALDH2) as a genetic instrument for alcohol use in Southern Chinese men.

Methods: We genotyped the single nucleotide polymorphism rs671 of ALDH2 in 4867 men from the Guangzhou Biobank Cohort Study.

Lifetime growth and blood pressure in adolescence: Hong Kong's "Children of 1997" birth cohort.

Objectives: Blood pressure tracks from adolescence to adulthood and is positively associated with low birth weight and faster infant growth. Most observations are from Western populations; it is unclear whether these are biologically based or contextually specific. We examined the associations of growth with blood pressure in adolescence.

Alanine transaminase has opposite associations with death from diabetes and ischemic heart disease in NHANES III.

Purpose: Diabetes increases the risk of ischemic heart disease (IHD). Stringent control of diabetes does not reliably reduce cardiovascular events. Some global regions, such as East Asia, have low mortality rates from IHD and high rates of diabetes.

Breastfeeding, childhood milk consumption, and onset of puberty.

Objective: Early nutrition has been postulated as programming pubertal timing. Limited observational studies, mainly from Western settings, suggest puberty occurs later with breastfeeding and earlier with higher cow's milk (including infant formula) consumption. However, these observations may be socioeconomically confounded.

Trends in mortality from septicaemia and pneumonia with economic development: an age-period-cohort analysis.

Background: Hong Kong population has experienced drastic changes in its economic development in the 1940s. Taking advantage of Hong Kong's unique demographic and socioeconomic history, characterized by massive, punctuated migration waves from Southern China, and recent, rapid transition from a pre-industrialized society to the first ethnic Chinese community reaching "first world" status over the last 60 years (i.e.