[Association between tea drinking and stroke in adults in Zhejiang province: a prospective study].

Objective: To prospectively explore the association between tea drinking and incidence of stroke of adults of Zhejiang province. Methods: After excluding participants with heart disease, stroke, cancer and diabetes at baseline study, 53 916 participants aged 30-79 years in the China Kadoorie Biobank (CKB) study from Tongxiang were included for final analysis. Cox regression model was used to estimate the hazard ratio (HR) for the association of tea drinking with incident stroke. Results: The main type of drinking tea was black tea (79.78%), followed by green tea (20.08%). Of the 53 916 participants, the proportion of participants who drank tea at least once per week was 31.27%. The corresponding proportions for men and women were 60.24% and 10.30%, respectively. Among 391 512 person-years of the follow-up program (median 7.26 years), a total of 1 487 men and 1 769 women were diagnosed with stroke. After adjusting for socio-demographic status, lifestyle, BMI, waist circumference, and systolic blood pressure, HR for incident stroke decreased with the increase of daily average tea consumption amount (P=0.000 6). Compared with participants who did not drink tea weekly, the HRs for incident stroke in those consuming tea 0.1-, 3.0- and ≥5.0 g/d were 0.93 (95%CI: 0.85-1.00), 0.88 (95%CI: 0.77-0.99) and 0.79 (95%CI: 0.69-0.89), respectively. The HRs for incident stroke in smokers and non-smokers who consumed tea ≥5.0 g/d were 0.71 (95%CI: 0.59-0.86) and 0.97 (95%CI: 0.77-1.21), respectively, compared with current smokers and non-smokers who did not drink tea weekly (P=0.040 0). The corresponding HRs for alcohol drinkers and non-drinkers were 0.96 (95%CI: 0.76-1.22) and 0.70 (95%CI: 0.58-0.84), respectively (P=0.040 0). The corresponding HRs for central obese persons and non-central obese persons were 0.60 (95%CI: 0.44-0.81) and 0.86 (95%CI: 0.73-1.01), respectively (P=0.040 0). Conclusion: Tea drinking had an effect on reducing the possibility of incident stroke, especially among those who were current smokers, non-alcohol drinkers and central obese.

[Prospective study on the effect of BMI and waist circumference on diabetes of adults in Zhejiang province].

Objective: To explore the effect of BMI and waist circumference on diabetes of adults. Methods: After excluding participants with heart disease, stroke, cancer and diabetes at baseline study, 53 916 people aged 30-79 in the China Kadoorie Biobank (CKB) study from Tongxiang city of Zhejiang province were recruited. Cox regression model was used to estimate the hazards ratios (HR) for the associations of baseline BMI and waist circumference with incident diabetes. Results: Among 391 512 person-years of the follow-up program between 2004 and 2013 (median 7.26 years), a total of 944 men and 1 643 women were diagnosed as having diabetes. Compared to those with normal weight, after adjusting for known or potential factors, HR of both overweight and obesity in men for incident diabetes appeared as 2.72 (95%CI: 2.47-2.99) and 6.27 (95%CI: 5.33-7.36), respectively. The corresponding figures in women were 2.19 (95%CI: 2.04-2.36) and 3.78 (95%CI: 3.36-4.26). Compared to those with normal waist circumference, after adjusting for known or potential factors, HR of Ⅰgrade andⅡgrade in men for diabetes were 2.56 (95%CI: 2.22-2.95) and 4.66 (95%CI: 4.14-5.24), respectively. The corresponding figures in women were 1.99 (95%CI: 1.80-2.21) and 3.16 (95%CI: 2.90-3.44), respectively. Conclusions: Overweight, obesity and central obesity were all associated with the increased incident of diabetes. Strategies on diabetes prevention should include not only losing weight, but reducing waist circumference as well.

[Interaction between smoking and indoor air pollution on chronic obstructive pulmonary diseases].

Objective: To investigate the prevalence of chronic obstructive pulmonary diseases (COPD) in Tongxiang, Zhejiang province, and analyze the interaction between smoking and indoor air pollution on COPD. Methods: Townships of Chongfu, Zhouquan, Gaoqiao, Shimen, Wuzhen were randomly selected from Tongxiang. All the local people aged 30-79 years were asked to receive questionnaire survey, physical examination and pulmonary function testing. FEV1max/FVC max≤0.7 was the criterion of COPD diagnosis. Logistic regression model was used to analyze the relationship between smoking/indoor air pollution and COPD, multiplied interaction between smoking and indoor air pollution was evaluated, Excel table prepared by Andersson et al. was used to calculate the adding interaction. Results: The overall prevalence of COPD was 6.6%, and adjusted for age, educational level, occupation, marriage, income level, BMI, waist-to-hip and other factors, multivariate logistic regression analysis showed that males who had quit smoking, started smoking at age of <25 years had a high risk of COPD; females who smoked every day <15 g, inhaled smoke into mouth or throat had high risk of COPD. Interaction analysis showed that using fuel of firewood/charcoal/coal, briquettes for cooking and regular smoking had multiplied interaction on COPD. Use no chimney or exhaust system in cooking and regular smoking had adding interaction in females. Conclusion: The prevalence of COPD in Tongxiang was close to the national average level. Female smokers had higher risk for COPD than male smokers. Improving kitchen ventilation, using natural gas or fuel gas for cooking and active tobacco control would facilitate the prevention of COPD.