Department of Epidemiology, School of Public Health, Fudan University, Shanghai, China.
Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, TN, USA.
Int J Epidemiol. 2018 Dec 1;47(6):1887-1896. doi: 10.1093/ije/dyy173.
Epidemiological evidence on the association between tea consumption and the risk of type 2 diabetes (T2D) is inconsistent. This study prospectively investigated whether green tea drinking affects the risk of T2D.
This study included participants from the Shanghai Women's Health Study (N = 67 058) and the Shanghai Men's Health Study (N = 52 315) without diabetes at study enrolment. Details of tea consumption, including types and amounts, were collected at the baseline and follow-up survey. Incident T2D was identified through follow-up surveys. Plasma level of caffeine metabolite was measured in a nested case-control study involving 592 diabetes case-control pairs. Cox regression analysis, with tea drinking as a time-dependent variable and covariates adjusted for by a propensity score, was applied to estimate the hazard ratio (HR) and 95% confidence interval (CI) for T2D risk. Logistic regression analysis was applied to evaluate the association between caffeine metabolites and T2D risk.
Current green tea drinkers had an increased risk of T2D compared with non-current drinkers [HR = 1.20 (95% CI = 1.14-1.27)], and a dose-response relationship was observed for duration of drinking tea and the amount of tea consumed [P for trend <0.001]. The increased risk associated with green tea drinking was observed in both women and men, across the entire period of follow-up, with HR (95% CI) of 1.08 (0.97-1.19) within 5 years of follow-up, 1.22 (1.12-1.32) during the period of 5-10 years of follow-up and 1.16 (1.03-1.30) after 10 years of follow-up. This association did not vary significantly by body mass index, waist-to-hip circumference ratio or smoking status. Plasma level of caffeine was also associated with increased diabetes risk (P = 0.03), confirming the results based on self-reported tea drinking.
Green tea drinking was associated with an increased risk of T2D in Chinese adults. The mechanisms underlying the association need to be elucidated.
关于饮茶与 2 型糖尿病（T2D）风险之间关联的流行病学证据并不一致。本研究前瞻性调查了饮用绿茶是否会影响 T2D 的发病风险。
本研究纳入了上海女性健康研究（N=67058）和上海男性健康研究（N=52315）中无糖尿病的参与者。在基线和随访调查中收集了详细的饮茶情况，包括茶的种类和饮用量。通过随访调查确定了 T2D 的发病情况。在一项涉及 592 例糖尿病病例对照的嵌套病例对照研究中测量了血浆咖啡因代谢产物水平。应用 Cox 回归分析，以饮茶为时间依赖性变量，通过倾向评分调整协变量，估计 T2D 风险的风险比（HR）和 95%置信区间（CI）。应用 logistic 回归分析评估咖啡因代谢产物与 T2D 风险之间的关联。
与非当前饮茶者相比，当前饮用绿茶者发生 T2D 的风险增加[HR=1.20（95%CI=1.14-1.27）]，且饮茶时间和饮茶量呈剂量-反应关系[P 趋势<0.001]。这种与饮用绿茶相关的风险增加在女性和男性中均可见，在整个随访期间，5 年内随访的 HR（95%CI）为 1.08（0.97-1.19），5-10 年内为 1.22（1.12-1.32），10 年后为 1.16（1.03-1.30）。这种关联在 BMI、腰围-臀围比或吸烟状况方面没有显著差异。咖啡因的血浆水平也与糖尿病风险的增加相关（P=0.03），证实了基于自我报告的饮茶情况的结果。
在中国成年人中，饮用绿茶与 T2D 风险增加相关。需要阐明这种关联的潜在机制。
