Xiang Qian Lao

Reliability and validity of the IPAQ-Chinese: the Guangzhou Biobank Cohort study.

INTRODUCTION Valid measurements of self-reported physical activity are very limited in Chinese populations, especially the elderly. Therefore, we examined the validity and reliability of the Chinese version of the International Physical Activity Questionnaire (IPAQ-C) in older Chinese people. METHODS Two hundred twenty-four older adults (66.1% women, 33.9% men, mean age 65.2 +/- 5.7 yr) were randomly selected from the Guangzhou Biobank Cohort Study, a prospective cohort of older Chinese in Southern China. To examine the test-retest reliability, the participants completed the IPAQ-C twice during a 7-d interval. The criterion validity of the IPAQ-C was tested with pedometry. RESULTS Good reliability was observed between the repeated IPAQ-C, with intraclass correlation coefficients (ICC) ranging from 0.81 to 0.89. Total activity measured by IPAQ-C correlated moderately with the pedometer-measured steps (partial r = 0.33 adjusted for sex, age, and education; P < 0.001). The walking domain of IPAQ-C was strongly associated with the number of steps (partial r = 0.58, P < 0.001), but there were no significant associations between other activity domains of the IPAQ-C and the pedometer data. CONCLUSION This is the first reported validation study of an international standardized questionnaire (IPAQ-C) in older Chinese adults. Our study shows that the IPAQ-C is adequately valid and reliable for assessing total physical activity and that it may be a useful instrument for generating internationally comparable data on physical activity in this population.

Age of menarche and the metabolic syndrome in China.

Objectives: In western populations, young age of menarche is associated with increased cardiovascular risk. Little is known about the potential impact of menarche on the metabolic syndrome (as a proxy for cardiovascular risk) in rapidly economically developing populations where age of menarche is falling. We sought to determine the relation between age of menarche and the metabolic syndrome in a rapidly developing Chinese population. Methods: We carried out a retrospective historical cohort study of 7349 women from the Guangzhou Biobank Cohort Study, China, enrolled in 2003–2004. Cardiovascular risk factors were obtained from physical examination; age of menarche was obtained from self-report. The main outcome measure was the metabolic syndrome and its components. Results: Adjusted for age, education, and number of pregnancies, young age of menarche (<12.5 years) compared with age of menarche ≥14.5 years was associated with a higher risk of the metabolic syndrome (odds ratio = 1.49; 95% confidence interval = 1.22–1.82), central obesity (1.35; 1.10–1.65), raised blood pressure (1.34; 1.09–1.65), raised fasting glucose (1.40; 1.15–1.71), and higher triglyceride levels (1.36; 1.12–1.67). Further adjustment by waist circumference attenuated these effects, but the odds ratios remained elevated. Conclusions: Earlier age of menarche experienced by younger women in China today, now 12.5 years on average in urban populations, may contribute to an increase in the metabolic syndrome and thereby an increase in cardiovascular disease as these women age. These results further highlight the importance of childhood antecedents of adulthood disease.

Hypertension prevalence, awareness, treatment, control, and associated factors in adults in southern China.

BACKGROUND Hypertension is the most important risk factor for cardiovascular diseases. Little information exists on the status of hypertension among southern Chinese. We therefore investigated the hypertension prevalence, awareness, treatment, control, and associated factors in a southern Chinese population with 85 million residents. METHODS Stratified multistage cluster sampling with probability proportional to size method was used in this survey. A representative sample of 13,889 residents aged 20 years or above with completed questionnaire and blood pressure (BP) measurement was obtained. BP was measured in accordance with the 1999 World Health Organization/International Society of Hypertension Guidelines. Information related to history of diagnosis and treatment of hypertension was collected through questionnaire. RESULTS The prevalence of hypertension in this population was 20.5% (16.5%, 24.4%), which translated to 9.8 million adults suffering from hypertension in Guangdong province. The urban population had higher prevalence of hypertension than the rural population (25.1 vs. 16.1%). The prevalence of awareness, treatment, and control of hypertension in hypertensive patients living in urban regions were 42.8, 37.9, and 13.5%, respectively, which were higher than those in rural regions (the corresponding figures were 17.6, 10.4, and 3.4%, respectively). Nearly 50% urban adults and 80% rural adults did not measure their BP in the last 12 months. Frequency of BP measurement was associated with both awareness and treatment. CONCLUSIONS Hypertension was prevalent in southern China. The prevalence of awareness, treatment, and control of hypertension is low. Urgent strategies are needed to improve prevention, detection, and treatment of hypertension in this large Chinese population.

Lymphocyte DNA damage in cigarette factory workers measured by the Comet assay

To investigate whether there were separate and combined effects of occupational exposure to tobacco dust and smoking on lymphocyte DNA damage, 148 workers from a cigarette manufacturing factory (107 occupationally exposed to tobacco dust from the production department and 41 unexposed controls who were managerial workers) were included in the study. The Tail Moment (TM) of Comet assay was used to measure DNA damage. The two groups had similar mean age, mean duration of work and smoking prevalence. The exposed workers had a larger TM than that of the controls (mean+/-S.D.: 43.43+/-13. 77 vs. 38.89+/-8.98, p<0.05). Smokers had significantly larger TM than non-smokers (47.25+/-14.02 vs. 38.90+/-10.75, p<0.001). Analysis of variance after adjustment for age and gender showed that occupational exposure and smoking had a significant and independent effect on Tail Moment (p=0.025 and p=0.002, respectively) and there was a significant positive two way interaction between the two factors (p=0.019). Age and gender had no significant effect on TM. The present study suggests that smoking and tobacco dust exposure can induce lymphocyte DNA damage and there is a synergistic effect of tobacco dust exposure and smoking on DNA damage.

Short-term effects of the 2008 cold spell on mortality in three subtropical cities in Guangdong Province, China.

Background: Few studies have been conducted to investigate the impact of extreme cold events on mortality in subtropical regions. Objective: In the present study we aimed to investigate the effects of the 2008 cold spell on mortality and the possibility of mortality displacement in three subtropical cities in China. Methods: Daily mortality, air pollution, and weather data were collected from 2006 to 2009 in Guangzhou, Nanxiong (no air pollutants), and Taishan. We used a polynomial distributed lag model (DLM) to analyze the relationship between the 2008 cold spell and mortality. To observe the mortality displacement of the cold spell, we estimated the cumulative effects at lag0, lag0–6, lag0–13, lag0–20, and lag0–27 separately. Results: During the 2008 cold spell, the cumulative risk of nonaccidental mortality increased significantly in Guangzhou [relative risk (RR) = 1.60; 95% CI: 1.19, 2.14] and Taishan (RR = 1.60; 95% CI: 1.06, 2.40) when lagged up to 4 weeks after the cold spell ended. Estimated effects at lag0–27 were more pronounced for males than for females, for respiratory mortality than for cardiovascular mortality, and for the elderly (≥ 75 years of age) than for those 0–64 years of age. Most of the cumulative RRs increased with longer lag times in Guangzhou and Taishan. However, in Nanxiong, the trend with cumulative RRs was less consistent, and we observed no statistically significant associations at lag0–27. Conclusion: We found associations between the 2008 cold spell and increased mortality in the three subtropical cities of China. The lag effect structure of the cold spell varied with location and the type of mortality, and evidence of short-term mortality displacement was inconsistent. These findings suggest that extreme cold is an important public health problem in subtropical regions.

Parity and the metabolic syndrome in older Chinese women: the Guangzhou Biobank Cohort Study

Objective  To examine whether parity or gravidity contributes to the development of the metabolic syndrome (MS).

Smoking, smoking cessation and inflammatory markers in older Chinese men: The Guangzhou Biobank Cohort Study

AIMS Smoking increases the risk of cardiovascular disease and inflammation plays a key role in the process of atherosclerosis. We therefore study the role of smoking and smoking cessation on the levels of inflammatory markers, C-reactive protein (CRP) and white blood cell (WBC) count, in older Chinese men. METHODS This cross-sectional analysis included 2999 men aged 50-85 years who received a medical check-up including measurement of fasting plasma vascular risk factors. Information on smoking status, socioeconomic and lifestyle factors was collected by standardized interview. RESULTS After adjustment for potential confounders, both CRP and WBC increased linearly across never, former and current smokers (both p<0.01). The odds ratios of elevated CRP and WBC (upper tertiles) were also increased across never, former and current smokers (both p<0.01). Dose-response relationships were observed among current smokers. Compared to current smokers, the odds ratios of elevated CRP and WBC and means of CRP and WBC declined with longer duration of smoking cessation (all p<0.01). CONCLUSIONS Smoking is associated with increased CRP and WBC levels, and smoking cessation is associated with the reduction of the increase, confirming the benefits of quitting. Inflammation may be a potential mechanism by which smoking promotes atherosclerotic disease.

The effect of heat waves on mortality and effect modifiers in four communities of Guangdong Province, China

BACKGROUND Heat waves have been reported to be associated with increased mortality; however, fewer studies have examined the effect modification by heat wave characteristics, individual characteristics and community characteristics. METHODS This study investigated the effect of extreme heat on mortality in 2 urban and 2 rural communities in Guangdong Province, China during 2006-2010. The effect of extreme heat was divided into two parts: main effect due to high temperature and added effect due to prolonged heat for several consecutive days. A distributed lag non-linear model was used to calculate the relative risk with consideration of lag days and potential confounding factors. Separate models were further fit by individual characteristics (cause of death, age and gender) and heat wave characteristics (intensity, duration and timing), and potential effect modification of community characteristics was examined using a meta-regression, such as educational levels, percentage of the elderly, Gross Regional Domestic Product (GDP). RESULTS The overall main effects (ER=8.2%, 95% CI: 3.4%, 13.2%) were greater than the added effects (ER=0.0%, 95% CI: -3.8%, 4.0%) on the current day. The main effect peaked at lag0-2, and was higher for the two rural areas compared to the two cities, for respiratory compared to cardiovascular mortality, for those ≥75 years old and for females. The modifying effects of heat wave characteristics and community characteristics on mortality were not statistically significant. CONCLUSION This study suggests the effects of extreme heat were mainly driven by high temperature, which can be modified by some individual characteristics.

The prevalence of metabolic syndrome and cardiovascular risk factors in adults in southern China

BackgroundThe metabolic syndrome has been shown to increase the incidence of cardiovascular disease. Little information exists on the prevalence of the metabolic syndrome for southern Chinese. We therefore investigate the prevalence of the metabolic syndrome in a southern Chinese population with 85 million residents.MethodsThe Guangdong Nutrition and Health Survey 2002 is a cross-sectional survey designed to assess the health and nutritional status of 85 million residents in Guangdong province located in southern China. Stratified multistage random sampling method was applied in this survey and a provincial representative sample of 6,468 residents aged 20 years or above was obtained in the present study. The participants received a full medical check-up including measurement of blood pressure, obesity indices, fasting lipids and glucose levels. Data describing socioeconomic and lifestyle factors was also collected through interview. Metabolic syndrome was defined in accordance with the International Diabetes Federation criteria.ResultsThe prevalence of metabolic syndrome was 7.30%, translating into a total of 4.0 million residents aged 20 years or above having the condition in this southern Chinese population. The urban population had higher prevalence of the syndrome than the rural population (10.57% vs 4.30%). Females had a higher prevalence of metabolic syndrome than males (8.99% vs 5.27%). More than 60% of the adults had at least one component of the metabolic syndrome.ConclusionsOur results indicate that a large proportion of southern Chinese adults have the metabolic syndrome and associated risk factors. The metabolic syndrome has become an important public health problem in China. These findings emphasize the urgent need to develop population level strategies for the prevention, detection, and treatment of cardiovascular risk in China.

Height, Its Components, and Cardiovascular Risk Among Older Chinese: A Cross-Sectional Analysis of the Guangzhou Biobank Cohort Study

OBJECTIVES Better childhood conditions, inferred from height and specifically leg length, are usually protective against ischemic heart disease and its risk factors in Western countries. In other geoethnic populations, height is less clearly protective, casting doubt on there being a biological etiology. To clarify the role of childhood conditions, we examined the associations of height and its components with cardiovascular risk among older Chinese people. METHODS We used multivariable regression to examine the associations of height and its components with blood pressure, lipid profile, and diabetes in 10413 older Chinese adults (mean age=64.6 years). RESULTS After we adjusted for age, gender, socioeconomic status, and lifestyle habits, greater sitting height was associated with diabetes and dyslipidemia. Longer legs were associated with lower pulse pressure and lower low-density lipoprotein cholesterol. CONCLUSIONS We provide indirect anthropometric evidence for the role of pre-pubertal and pubertal exposures on cardiovascular risk. Pubertal exposures are stronger than are prepubertal exposures but may be influenced by osteoporotic decline in old age. Further research should establish whether the observed relations are ethnically specific or relate to the stage or trajectory of socioeconomic development.