In previous meta-analyses, tea consumption has been associated with lower incidence of type 2 diabetes. It is unclear, however, if tea is associated inversely over the entire range of intake. Therefore, we investigated the association between tea consumption and incidence of type 2 diabetes in a European population.
The EPIC-InterAct case-cohort study was conducted in 26 centers in 8 European countries and consists of a total of 12,403 incident type 2 diabetes cases and a stratified subcohort of 16,835 individuals from a total cohort of 340,234 participants with 3.99 million person-years of follow-up. Country-specific Hazard Ratios (HR) for incidence of type 2 diabetes were obtained after adjustment for lifestyle and dietary factors using a Cox regression adapted for a case-cohort design. Subsequently, country-specific HR were combined using a random effects meta-analysis. Tea consumption was studied as categorical variable (0, >0-<1, 1-<4, ≥4 cups/day). The dose-response of the association was further explored by restricted cubic spline regression. Country specific medians of tea consumption ranged from 0 cups/day in Spain to 4 cups/day in United Kingdom. Tea consumption was associated inversely with incidence of type 2 diabetes; the HR was 0.84 [95%CI 0.71, 1.00] when participants who drank ≥4 cups of tea per day were compared with non-drinkers (plinear trend = 0.04). Incidence of type 2 diabetes already tended to be lower with tea consumption of 1-<4 cups/day (HR = 0.93 [95%CI 0.81, 1.05]). Spline regression did not suggest a non-linear association (pnon-linearity = 0.20).
我们在8个欧洲国家的26个中心实施了EPIC互动案例的群组研究.该群组研究总共包含了12,403个2型糖尿病病例和16,835名受测者组成的抽样分层亚群组，这个抽样群组采集自由340,234名受测者组成且伴随399万人／年随访的群组。在调整生活方式和饮食因素后，我们通过运用适合个案－群组设计的Cox回归获得了国别化2型糖尿病发病率危险比（HR）。随后，我们采用随机效应Meta分析使国别化HR与之相结合。我们对作为分类变量的 茶叶消费量进行了研究（0，>0 - <1，1 -<4，≥4杯/天）。随后对相关剂量反应运用条件三次样条回归进行了进一步探讨。茶叶消费国别化中位数范围变化从西班牙每天消费0杯到英国每天消费4杯不等。茶叶消费量 与2型糖尿病患者发病率呈负相关; 与不饮茶者（plinear trend即线性趋势概率= 0.04）相比，当受测者每天喝茶超过4杯时，相关HR为0.84 [95％CI为0.71，1.00]。当每天喝茶在1杯到4杯之间时，2型糖尿病发病率已经趋于降低（HR = 0.93 [95％CI为0.81，1.05]）。样条回归不建议采纳相关非线性的部分（pnon-linearity即非线性概率= 0.20）。
A linear inverse association was observed between tea consumption and incidence of type 2 diabetes. People who drink at least 4 cups of tea per day may have a 16% lower risk of developing type 2 diabetes than non-tea drinkers.