Objective: To explore the associations between tea drinking and the incident risk of type 2 diabetes mellitus(T2 DM).
Methods: A dynamic prospective cohort study among a total of 27 841 diabetes-free permanent adult residents randomly selected from 2, 6 and 7 rural communities between 2006-2008, 2011-2012 and 2013-2014, respectively. Questionnaire survey, physical examination, and laboratory test were carried out among the participants. In 2018, we conducted a follow-up through the electronic health records of residents. Cox regression model were applied to explore the association between tea drinking and the incident risk of T2 DM and estimate the hazard ratio(HR), and its 95%CI.
Results: Among the 27 841 rural community residents in Deqing County, there were 10 726(38.53%) were tea drinkers, 8215 of which were green tea drinkers, accounting for 76.59%. Totally 883 new T2 DM incidents were identified until December 31, 2018, and the incidence density was 4.43 per 1000 person years(PYs). The incidence density was 4.07/1000 PYs in those with tea drinking habits and 4.71/1000 PYs in those without tea drinking habits, among which the incidence density was 3.79/1000 PYs in those with green tea drinking habits. After controlling for sex, age, education, farming, smoking, alcohol consumption, dietary preference, body mass index, hypertension, impaired fasting glucose, family history of diabetes, the risk of T2 DM among rural residents with tea drinking habits in Deqing County was 0.79 times higher than that among residents without tea drinking habits(HR=0.79, 95%CI 0.65-0.96), and the risk of T2 DM among residents with green tea drinking habits was 0.72 times higher than that among residents without tea drinking habits(HR=0.72, 95%CI 0.58-0.89). However, no significant associations were found between other kinds of tea and the risk of T2 DM, nor the amount of green tea to drink.
Conclusion: Drinking green tea may reduce the risk of T2 DM among adult population in rural China.
Keywords: prospective cohort study; tea; type 2 diabetes mellitus.