Tak-Sun Yu

Adverse effects of low-level air pollution on the respiratory health of schoolchildren in Hong Kong.

To evaluate the respiratory effects of long-term exposure to air pollution, schoolchildren (ages 8 to 12 years) from two districts in Hong Kong with contrasting air quality were studied. Parents of 1660 children completed questionnaires on respiratory symptoms, and 1294 children had their ventilatory function tested with a spirometer. After adjustment for relevant covariates, children living in the more polluted district had increased odds ratios for frequent cough (1.74), frequent sputum (1.87), chronic sputum (1.84), and doctor-diagnosed asthma (1.98). Children of both sexes in the more polluted district had significantly poorer lung function, and the differences among girls were more marked. The study provides additional evidence for the adverse effects of long-term exposure to relatively low-level air pollution.

Effects of ambient air pollution on lung function growth in Chinese schoolchildren

OBJECTIVE To evaluate the adverse effect of exposure to air pollution on lung function growth in school-aged children. METHODS A cohort of 1983 children from three districts in Guangzhou, China was followed-up for 6 months. The children performed pulmonary function tests twice, and their parents reported the childs respiratory symptoms by self-administered questionnaires in both surveys. RESULTS The annual mean concentrations of air pollutants for the past 5 years for particulate matter less than 10 microns in diameter (PM(10)), nitrogen (NO(2)), and sulfur dioxide (SO(2)) were respectively: 96.1 microg/m(3), 76.0 microg/m(3), and 65.7 microg/m(3) in the highly-polluted district (HPD), 80.3 microg/m(3), 67.6 mug/m(3), and 54.5 microg/m(3) in the moderately-polluted district (MPD), and 80.0 microg/m(3), 48.1 microg/m(3), and 52.2 microg/m(3) in the least-polluted district (LPD). After adjustment for potential confounders, significant deficits were found in the annual growth rates of forced expiratory flows at 25% (FEF(25)), and between 25% and 75% (FEF(25-75)) in boys and FEF(25) in girls (In boys, for FEF(25), -0.136 l/s, p = 0.008 in MPD and -0.153 l/s, p = 0.004 in HPD, respectively; for FEF(25-75), -0.176 l/s, p = 0.013 in MPD and -0.167 l/s, p = 0.021 in HPD, respectively. In girls, for FEF(25), -0.123 l/s, p = 0.043 in HPD), using LPD as the reference. Deficits in the annual growth rate of forced expiratory volume in 1 s (FEV(1)) were also negatively associated with air pollution in boys (-0.063 L, p = 0.032 in HPD). CONCLUSIONS The study adds more evidence that exposure to air pollution has adverse effects on lung function growth in schoolchildren.

Determinants of perceived occupational stress among Chinese offshore oil workers

This is the first comprehensive study to explore the determinants of perceived sources of occupational stress among workers in the rapidly expanding Chinese offshore oil industry. In this study we surveyed 561 Chinese workers in a state-owned oil company using a questionnaire that measured occupational stress and Type A personality behaviour (TABP), social support and other socio-demographic data. Occupational stress was assessed by the Occupational Stress Scale, adapted from the questionnaire developed in previous studies (Cooper & Sutherland, 1987; Sutherland & Cooper, 1996). Using factor analyses, we identified nine sources of stress: ‘interface between job and family/social life’; ‘career and achievement’; ‘safety’; ‘management problems and relationship with workmates’; ‘physical environment of workplace’; ‘living environment’; ‘managerial role’; ‘ergonomics’; and ‘organizational structure’. We performed hierarchical regression analyses on each source of stress with variables reflecting socio-demographic characteristics, TABP and social support. Better-educated workers perceived more stress from the interface between their job and family or social life and career achievement, but less stress from ergonomics. Type A workers perceived more stress from career achievement and the living environment. Social support was significantly associated with four sources of stress. Workers with different job titles perceived stress from different sources. Our findings imply that, in the stress management of offshore oil workers, different strategies and methods could be applied to different occupational groups, and to workers with different personalities and socio-demographic characteristics.

Environmental tobacco smoke exposure and Chinese schoolchildren's respiratory health: a prospective cohort study.

BACKGROUND Although China is the most coveted cigarette market worldwide, few studies have examined the longitudinal effects of environmental tobacco smoke (ETS) on health. PURPOSE To examine the relationship between exposure to ETS and respiratory health in Chinese schoolchildren. METHODS The study subjects included 1718 children, who were never-smokers, aged 10.05±0.86 years and asthma-free at baseline. The children performed spirometric tests in 2006 and 18 months later. Parents reported the childrens respiratory symptoms and illnesses, ETS exposure, and other related information by self-administered survey at both assessment points. The data were analyzed in 2010. RESULTS Significant exposure-response relationships were found between ETS exposure and coughing at night (p for trend<0.001); sneezing (p for trend=0.031); and sneezing with itchy, watery eyes (p for trend=0.006) in the first survey, and coughing at night (p for trend=0.019); phlegm without a cold (p for trend<0.001); and sneezing (p for trend=0.036) in the second survey. Compared with those who reported no ETS exposure in either survey, children who had a high ETS exposure level (>5 cigarettes/day) in either survey had lower growth rates in forced expiratory flow between 25% and 75% of forced vital capacity (FEF(25-75); β= -0.104, p=0.020) and forced expiratory flow at 25% of forced vital capacity (FEF(25); β= -0.077, p=0.027). A monotonic exposure-response effect was observed between ETS exposure and the deficits in the growth rate of FEF(25) and FEF(25-75.) CONCLUSIONS Exposure to ETS increased the risks of respiratory symptoms in Chinese school-aged children and was associated with impaired lung function growth. A dose-response relationship was observed for the latter effect.

Recent Trends of Stroke Mortality in Hong Kong: Age, Period, Cohort Analyses and the Implications

This study describes the time trend of cerebrovascular disease (CVD) mortality during the period 1976–1995 in Hong Kong and explores the period and birth cohort effects using Poisson regression models with correction for overdispersion of data. A clear downward trend was observed for age-adjusted CVD mortality rate in both sexes. It decreased from 84 per 100,000 to 41 per 100,000 among men (a 51% drop), and from 56 per 100,000 to 35 per 100,000 among women (a 38% drop). The rate of decline was in general greater in the second decade and among males, resulting in a significant downward trend for the male-to-female rate ratio. Both the period of death and the birth cohort showed a significant effect on the reduction in mortality rates, but the latter seemed to have a more substantial influence. However, an increasing trend was observed among younger males in the second decade, and the protective cohort effect seemed to be waning for the more recent cohorts in both sexes. Closer monitoring of the situation in the next years is warranted.

Influence of occupational stress on mental health among Chinese off-shore oil workers.

Aim: To explore the influence of occupational stress on mental health in off-shore oil production. Methods: A cross-sectional survey was conducted among 561 Chinese off-shore oil workers. The workers were invited to fill in a self-administered questionnaire exploring their socio-demographic characteristics, occupational stress levels, and 12-item general health questionnaire. A hierarchical multiple regression procedure was used to assess the effects of occupational stress on mental health. Results: After controlling for age, educational level, marital status and years of off-shore work, poor mental health was found to have a significant positive association with seven of the nine identified sources of occupational stress. They were: conflict between job and family/social life, poor development of career and achievement at work, safety problems at work, management problems and poor relationship with others at work, poor physical environment of the work place, uncomfortable ergonomic factors at work, and poor organizational structure at work. All of these occupational stress sources together explained 19.9% of the total variance. Conclusions: The results confirmed that occupational stress was a major risk factor for poor mental health among Chinese off-shore oil workers. Reducing or eliminating occupational stressors at work would benefit workers’ mental health.

Nutrition and children's respiratory health in Guangzhou, China

OBJECTIVE To investigate the role of nutrition in childrens respiratory health in subjects participating in a study on air pollution and respiratory health. STUDY DESIGN Cross-sectional survey. METHODS The relationships between consumption of fresh fruit, vegetables and milk and pulmonary function (forced expiratory volume in 1 s, FEV(1)) and respiratory symptoms (phlegm with cold, phlegm without cold, cough with cold, and cough without cold) were examined in 2228 children (age 10.07+/-0.86 years) in Guangzhou, China. RESULTS A positive association was found between consumption of leafy vegetables and lung function in children. Subjects with the highest consumption of leafy vegetables had significant higher FEV(1) values than subjects who ate leafy vegetables less than once per week (1.68 l vs 1.56 l; P=0.047). Children with high consumption of fresh fruit and milk had higher lung function values than children with low consumption, although the differences were not statistically significant. Milk consumption was a protective factor for phlegm with cold, cough with cold, and cough without cold [odds ratio (OR) 0.62, 95% confidence interval (CI) 0.39-0.97; OR 0.53, 95% CI 0.36-0.79; OR 0.43, 95% CI 0.21-0.92, respectively, in the highest intake group]. Consumption of vegetables was a protective factor for cough with cold (P for trend=0.003) and cough without cold (P for trend=0.028). Consumption of fresh fruit was marginally associated with reduced prevalence of respiratory symptoms. CONCLUSIONS This study suggests that dietary nutrients are important protective factors for childrens respiratory health. Following-up these children may provide more evidence to confirm these associations.

Socioeconomic correlates of infant mortality in Hong Kong, 1979—93

Although Hong Kongs infant mortality is among the lowest in the world, there may still be subgroups in the population with unusually high and possibly avoidable mortality rates. We conducted an ecological study on the relationship between socioeconomic deprivation and infant mortality in Hong Kong by using government data from three periods: 1979—83, 1984—88 and 1989—93. The study population comprised all infant births in 65 modified districts in Hong Kong in the period 1979—93. Infant, neonatal and post-neonatal mortality rates (IMRs, NMRs and PNMRs) were used as the health indicators. An F score was derived from highly correlated socioeconomic variables by factor analysis and used as a summary index of socioeconomic status. In 1979—83, socioeconomic deprivation was found to be significantly associated with high IMRs and high NMRs in both sexes, while in 1984—88 this association was observed only in baby girls. None of the observed associations were significant in 1989—93. Overall, the territorys infant mortality rates fell from 10.2 per thousand live births in 1979—83 to 5.6 per thousand live births in 1989—93. Individual-based studies are needed to ascertain whether this apparent disappearance of the socioeconomic relationship with infant and neonatal mortality is real.