Gn Thomas

The effects of air pollution on mortality in socially deprived urban areas in Hong Kong, China

Background Poverty is a major determinant of population health, but little is known about its role in modifying air pollution effects. Objectives We set out to examine whether people residing in socially deprived communities are at higher mortality risk from ambient air pollution. Methods This study included 209 tertiary planning units (TPUs), the smallest units for town planning in the Special Administrative Region of Hong Kong, China. The socioeconomic status of each TPU was measured by a social deprivation index (SDI) derived from the proportions of the population with a) unemployment, b) monthly household income < US

Satellite-Based Estimates of Long-Term Exposure to Fine Particles and Association with Mortality in Elderly Hong Kong Residents

250, c) no schooling at all, d) one-person household, e) never-married status, and f ) subtenancy, from the 2001 Population Census. TPUs were classified into three levels of SDI: low, middle, and high. We performed time-series analysis with Poisson regression to examine the association between changes in daily concentrations of ambient air pollution and daily number of deaths in each SDI group for the period from January 1996 to December 2002. We evaluated the differences in pollution effects between different SDI groups using a case-only approach with logistic regression. Results We found significant associations of nitrogen dioxide, sulfur dioxide, particulate matter with aerodynamic diameter < 10 μm, and ozone with all nonaccidental and cardiovascular mortality in areas of middle or high SDI (p < 0.05). Health outcomes, measured as all nonaccidental, cardiovascular, and respiratory mortality, in people residing in high SDI areas were more strongly associated with SO2 and NO2 compared with those in middle or low SDI areas. Conclusions Neighborhood socioeconomic deprivation increases mortality risks associated with air pollution.

Rimonabant for the Treatment of Obesity

Background A limited number of studies on long-term effects of particulate matter with aerodynamic diameter < 2.5 μm (PM2.5) on health suggest it can be an important cause of morbidity and mortality. In Asia where air quality is poor and deteriorating, local data on long-term effects of PM2.5 to support policy on air quality management are scarce. Objectives We assessed long-term effects of PM2.5 on the mortality in a single Asian city. Methods For 10–13 years, we followed up a cohort of 66,820 participants ≥ 65 years of age who were enrolled and interviewed in all 18 Elderly Health Centres of the Department of Health, Hong Kong, in 1998–2001. Their residential addresses were geocoded into x- and y-coordinates, and their proxy exposures to PM2.5 at their addresses in 1 × 1 km grids were estimated from the U.S. National Aeronautics and Space Administration (NASA) satellite data. We used Cox regression models to calculate hazard ratios (HRs) of mortality associated with PM2.5. Results Mortality HRs per 10-μg/m3 increase in PM2.5 were 1.14 (95% CI: 1.07, 1.22) for all natural causes, 1.22 (95% CI: 1.08, 1.39) for cardiovascular causes, 1.42 (95% CI: 1.16, 1.73) for ischemic heart disease, 1.24 (95% CI: 1.00, 1.53) for cerebrovascular disease, and 1.05 (95% CI: 0.90, 1.22) for respiratory causes. Conclusions Our methods in using NASA satellite data provide a readily accessible and affordable approach to estimation of a sufficient range of individual PM2.5 exposures in a single city. This approach can expand the capacity to conduct environmental accountability studies in areas with few measurements of fine particles. Citation Wong CM, Lai HK, Tsang H, Thach TQ, Thomas GN, Lam KB, Chan KP, Yang L, Lau AK, Ayres JG, Lee SY, Chan WM, Hedley AJ, Lam TH. 2015. Satellite-based estimates of long-term exposure to fine particles and association with mortality in elderly Hong Kong residents. Environ Health Perspect 123:1167–1172; http://dx.doi.org/10.1289/ehp.1408264

Association between raised blood pressure and dysglycemia in Hong Kong Chinese.

Obesity is a growing public health problem that is already reaching epidemic proportions and is increasingly encompassing young children and adolescents. Despite the increasing prevalence and the health risks associated with obesity, the pharmacotherapeutic options for treating obesity are limited. The endogenous cannabinoid or endocan-nabinoid system (ECS) was discovered in the early 1990s in relation to work on the action of components of marijuana. Central activation of the ECS promotes food ingestion. The endogenous cannabinoids exert their pharmacologic action through interaction with the specific receptors, CB(1) and CB(2). CB(1) receptors are located predominantly in the brain and peripherally in adipose tissue, liver, skeletal muscle and the gastrointestinal tract. In July 2006, European regulatory authorities approved the use of rimonabant, SR141716, a selective CB1 receptor antagonist, in obese patients (BMI > or =30kg/m(2), or >27kg/m(2) with complications). However, in June 2007, despite extensive clinical trial data, the FDAs Endocrine and Metabolic Drugs Advisory Committee (EMDAC) concluded that the safety of rimonabant had not been adequately demonstrated by the manufacturer Sanofi-Aventis; the full application was subsequently withdrawn. This review article provides evidence and outlines some patents for the use of rimonabant and potential safety concerns which still prevent its use in the single largest market for drugs of its kind.

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

OBJECTIVE—To investigate the association between raised blood pressure and dysglycemia. RESEARCH DESIGN AND METHODS—We studied the association between raised blood pressure and dysglycemia in 1,862 subjects in the Hong Kong Cardiovascular Risk Factor Prevalence Study cohort. We determined the factors predicting the development of diabetes and hypertension in 1,496 subjects who did not have either condition at baseline. RESULTS—Diabetes and hypertension were both related to age, obesity indexes, blood pressure, glucose, HDL cholesterol, and triglycerides. Of subjects with diabetes, 58% had raised blood pressure. Of subjects with hypertension, 56% had dysglycemia. BMI and blood glucose 2 h after a 75-g oral glucose load were independent predictors of new-onset diabetes. Age, systolic blood pressure, and 2-h glucose were independent predictors of new-onset hypertension. BMI, systolic blood pressure, and 2-h glucose were independent predictors of the development of diabetes and hypertension together. CONCLUSIONS—Diabetes and hypertension share common etiological factors. Patients with diabetes or hypertension should be screened and managed for the precursor of the other condition.

Is leg length a biomarker of childhood conditions in older Chinese women? The Guangzhou Biobank Cohort Study

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. Common carotid artery intima-media thickness (CCA-IMT) was measured by B-mode ultrasonography, and carotid artery plaques were identified. Major cardiovascular risk factors, including fasting triglyceride, low-density and high-density lipoprotein (LDL and HDL) cholesterol and glucose, and systolic and diastolic blood pressure, were assessed. Results CCA-IMT and the number of carotid plaque increased from never to former to current smokers (both p≤0.001). Among former smokers compared to current smokers, after adjustment for cigarette pack-years and other potential confounders, the adjusted ORs (95% CI) for quitting for 1–9, 10–19 and 20+ years were 0.77 (0.47 to 1.26), 0.45 (0.26 to 0.79) and 0.37 (0.17 to 0.77) for the presence of CCA atherosclerosis, and 0.69 (0.43 to 1.12), 0.47 (0.27 to 0.82) and 0.45 (0.23 to 0.96) for the presence of carotid plaques, respectively. Longer duration of quitting smoking was also significantly associated with decreasing risk of the severity of CCA atherosclerosis and carotid plaques (all p≤0.001). Conclusion Smoking cessation was beneficial in attenuating the risk of carotid atherosclerosis associated with cigarette smoking. The short duration of cessation in earlier studies is a likely explanation for the inconsistent results.

Cancer Mortality Risks from Long-term Exposure to Ambient Fine Particle

Objective: In developed western populations longer legs have been shown to be a biomarker of better early childhood conditions. It was hypothesised that in transitioning populations better childhood conditions may bring forward puberty and thus decrease leg length, counteracting the overall positive effect of a favourable childhood environment on leg growth. Design: Structural equation modelling was used to assess the interrelationship of age, education, father’s job, age of menarche and leg length in a cross-sectional sample of 7273 Chinese women aged at least 50 years from the Guangzhou Biobank Cohort Study. Results: Leg length had no significant association with education or father’s occupation on bivariable testing. After including age of menarche in the model, education was associated with longer legs (0.45 cm longer per 10 years of education, 95% CI 0.20 to 0.71). Education was also associated with younger age of menarche (1.21 years younger per 10 years of education, 95% CI 1.09 to 1.34), which was in turn associated with shorter legs (0.23 cm shorter per year of menarche earlier, 95% CI 0.18 to 0.27). Conclusions: In older Chinese women leg length is not a universal biomarker of childhood conditions, when proxied by her educational level and father’s occupation. Nutritionally driven epigenetic influences operating over generations may constrain growth in very recently developed populations. Given the impact of childhood conditions on health, and the dearth of long-term records outside the industrialised world, a greater understanding of the influences on growth in the developing world is required.

Study of the Effects of Total Flavonoids of Astragalus on Atherosclerosis Formation and Potential Mechanisms

Background: Few studies have assessed long-term effects of particulate matter (PM) with aerodynamic diameter < 2.5 μm (PM2.5) on mortality for causes of cancer other than the lung; we assessed the effects on multiple causes. In Hong Kong, most people live and work in urban or suburban areas with high-rise buildings. This facilitates the estimation of PM2.5 exposure of individuals, taking into account the height of residence above ground level for assessment of the long-term health effects with sufficient statistical power. Methods: We recruited 66,820 persons who were ≥65 in 1998 to 2001 and followed up for mortality outcomes until 2011. Annual concentrations of PM at their residential addresses were estimated using PM2.5 concentrations measured at fixed-site monitors, horizontal–vertical locations, and satellite data. We used Cox regression model to assess the HR of mortality for cancer per 10 μg/m3 increase of PM2.5. Results: PM2.5 was associated with increased risk of mortality for all causes of cancer [HR, 1.22 (95% CI, 1.11–1.34)] and for specific cause of cancer in upper digestive tract [1.42 (1.06–1.89)], digestive accessory organs [1.35 (1.06–1.71)] in all subjects; breast [1.80 (1.26–2.55)] in females; and lung [1.36 (1.05–1.77)] in males. Conclusions: Long-term exposures to PM2.5 are associated with elevated risks of cancer in various organs. Impact: This study is particularly timely in China, where compelling evidence is needed to support the pollution control policy to ameliorate the health damages associated with economic growth. Cancer Epidemiol Biomarkers Prev; 25(5); 839–45. ©2016 AACR.

Association of a genetic variant in the apolipoprotein A5 gene with the metabolic syndrome in Chinese

Astragalus mongholicus Bunge has long been used to treat cardiovascular disease in Chinese traditional medicine. However, its mechanisms are not fully understood. In this study, we explored potential mechanisms and protective effects of total flavonoids of Astragalus (TFA) on cardiovascular disease using in vitro experiments and diet-induced atherosclerotic rabbits. We identified six components and their proportion in TFA. The animal experiments showed that TFA significantly reduced plasma levels of total cholesterol and LDL cholesterol (P < 0.05 to 0.01), increased HDL cholesterol levels (P < 0.01), and reduced the aortic fatty streak area by 43.6 to 63.6% (P < 0.01). We also found that TFA scavenged superoxide and hydroxyl radicals and this effect increased with higher TFA concentration. In in vivo experiments, TFA effectively inhibited the free radical spectrum in the ischemia-reperfusion module. In conclusion, TFA was the active component of Astragalus mongholicus Bunge, which benefits cardiovascular disease attributing to the potent antioxidant activity to improve the atherosclerosis profile.

The Complex Associations Among Sleep Quality, Anxiety-Depression, and Quality of Life in Patients with Extreme Obesity

Objective  Single nucleotide polymorphisms (SNPs) in the apolipoprotein A5 gene (APOA5) are associated with hypertriglyceridaemia in our population. We studied the associations of SNPs in APOA5 with the metabolic syndrome (MetS) in the Hong Kong and Guangzhou Chinese.