Tea consumption and incidence of type 2 diabetes in Europe: the EPIC-InterAct case-cohort study.

BACKGROUND 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. METHODOLOGY/PRINCIPAL FINDINGS 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 (p(linear 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 (p(non-linearity) = 0.20). CONCLUSIONS/SIGNIFICANCE 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.

Journal Article; Research Support, Non-U.S. Gov't;

The EPIC-InterAct project was funded by the European Union (Integrated Project LSHM-CT-2006-037197 in the Framework Program 6 of the European Community). In addition, EPIC-InterAct investigators acknowledge funding from the following agencies:-DLvdA, AMWS, and HBBdM: Dutch Ministry of Public Health, Welfare and Sports (VWS), Netherlands Cancer Registry (NKR), LK Research Funds, Dutch Prevention Funds, Dutch ZON (Zorg Onderzoek Nederland), World Cancer Research Fund (WCRF), Statistics Netherlands (The Netherlands); EA and AB: Health Research Fund (FIS), Regional Governments of Andalucı´a, Basque Country, Murcia and Navarra, ISCIII RETIC (RD06/0020) (Spain); JWJB and IS: Verification of diabetes cases was additionally funded by NL Agency grant IGE05012 and an Incentive Grant from the Board of the UMC Utrecht; AM: Compagnia di San Paolo; MDC: Health Research Fund (FIS) of the Spanish Ministry of Health; Murcia Regional Government (Nu 6236), and CIBER Epidemiologı´a y Salud Pu´ blica (CIBERESP), Spain; FC: Cancer Research UK; AT, JH, CCD, and KO: Danish Cancer Society; OR: Va¨sterbotten County Council; PWF: Swedish Research Council, Novo Nordisk, Swedish Diabetes Association, Swedish Heart-Lung Foundation; JRQ: Regional Government of the Principality of Asturias (Spain); PN and LG: Swedish Research Council; RT: AIRE-ONLUS Ragusa, AVIS-Ragusa, Sicilian Regional Government; KTK: Medical Research Council UK, Cancer Research UK. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.