Physical activity level and incident type 2 diabetes among Chinese adults.

PURPOSE: The objective is to examine the association between physical activity level (PAL) and incident type 2 diabetes among middle-age and older Chinese men and women in urban China. METHODS: This prospective study included 6348 participants (age 35 to 74 yr) who were free of diabetes and cardiovascular disease at baseline. PAL was estimated on the basis of self-reported overall physical activity on a typical day. According to PAL, participants were classified into four groups: sedentary (PAL, 1.00-1.39), low active (PAL, 1.40-1.59), active (PAL, 1.60-1.89), and very active (PAL, >1.89). The association of PAL with incident diabetes was examined by Cox proportional hazards model. RESULTS: During 7.9 yr of follow-up (50,293 person-years), 478 incident cases of type 2 diabetes were identified. After adjustment for age, sex, geographic region, educational level, smoking, alcohol use, and family history of diabetes, the HR (95% CI) values for type 2 diabetes across increasing categories of PAL were 1.00 (reference), 0.82 (0.62-1.09), 0.63 (0.47-0.83), and 0.47 (0.36-0.61), respectively (P for trend <0.0001). Additional adjustment for baseline body mass index or waist circumference attenuated the magnitude of risk reduction, but it remained significant. The inverse association between PAL and risk of incident diabetes was persistent in subgroup analyses according to age, sex, hypertension, smoking, body mass index, waist circumference, and fasting plasma glucose level. CONCLUSIONS: Higher PAL is associated with substantial reduction in risk of type 2 diabetes. Our findings suggest the importance of a physically active lifestyle in the prevention of diabetes.

Exhaled carbon monoxide and its associations with smoking, indoor household air pollution and chronic respiratory diseases among 512,000 Chinese adults.

BACKGROUND: Exhaled carbon monoxide (COex) level is positively associated with tobacco smoking and exposure to smoke from biomass/coal burning. Relatively little is known about its determinants in China despite the population having a high prevalence of smoking and use of biomass/coal. METHODS: The China Kadoorie Biobank includes 512,000 participants aged 30-79 years recruited from 10 diverse regions. We used linear regression and logistic regression methods to assess the associations of COex level with smoking, exposures to indoor household air pollution and prevalent chronic respiratory conditions among never smokers, both overall and by seasons, regions and smoking status. RESULTS: The overall COex level (ppm) was much higher in current smokers than in never smokers (men: 11.5 vs 3.7; women: 9.3 vs 3.2). Among current smokers, it was higher among those who smoked more and inhaled more deeply. Among never smokers, mean COex was positively associated with levels of exposures to passive smoking and to biomass/coal burning, especially in rural areas and during winter. The odds ratios (OR) and 95% confidence interval (CI) of air flow obstruction (FEV1/FVC ratio<0.7) for never smokers with COex at 7-14 and ≥14 ppm, compared with those having COex<7, were 1.38 (1.31-1.45) and 1.65 (1.52-1.80), respectively (Ptrend<0.001). Prevalence of other self-reported chronic respiratory conditions was also higher among people with elevated COex (P<0.05). CONCLUSION: In adult Chinese, COex can be used as a biomarker for assessing current smoking and overall exposure to indoor household air pollution in combination with questionnaires.

[Relationship between physical activity and the incidence of metabolic syndrome in Chinese adults: a prospective cohort study].

OBJECTIVE: To investigate the association between physical activity (PA) and the incidence of metabolic syndrome (MS) in Chinese adults. METHODS: Data on PA and other variables were obtained at the baseline examination of China Multi-center study of Cardiovascular Epidemiology in 1998 and of International Collaborative study of Cardiovascular Disease in Asia(InterASIA) during 2000 - 2001. Follow-up study was conducted in 2007 - 2008. A total of 11 512 Chinese adults aged 35 - 74 years (5563 men and 5949 women) were included in the final data analysis. Information on demographics, PA, smoking and alcohol consumption were obtained and components of MS were examined. Participants were divided into four groups according to quartile of total metabolic equivalent (MET) values per day. In addition, subjects were grouped into the following categories according to occupational PA: inactive, light, moderate and vigorous. Binary logistic model was used to examine the association between PA and the incidence of MS. RESULTS: A total of 2527 cases with MS were documented during an average following up of 8.1 years. The annual incidence rate of MS was 2.71% (2527/93 178.68). After multivariate logistic regression analysis, compared with participants with total PA volume < 32.0 MET×h×d(-1) (annual incidence rate was 3.19% (697/21 830.74)), the RR (95%CI) value of participants with total PA volume during 32.00 - 37.85, 37.86 - 52.29, and ≥ 52.30 MET×h×d(-1) was 1.05(0.92 - 1.19), 0.98(0.86 - 1.12), and 0.68(0.59 - 0.80), respectively (χ(2)trend = 34.23, P < 0.05), with corresponding annual incidence rates of 2.82% (690/24 504.25), 2.73% (661/24 179.36) and 2.11% (479/22 664.33). In addition, compared to inactive occupational PA (annual incidence rate was 2.76% (402/14 588.33)), the corresponding RR (95%CI) value was 0.80 (0.69 - 0.92), 0.70 (0.59 - 0.82), and 0.54 (0.45 - 0.65) (χ(2)trend = 42.34, P < 0.05), and the annual incidence rates were 2.86% (648/22 663.41), 2.40% (455/18 956.14) and 1.89% (344/18 173.86) in participants with light, moderate and vigorous occupational PA, respectively. CONCLUSION: Both increased total PA volume and occupational PA intensity are significantly associated with decreased risk of incidence of MS.