Abstract 009: Plain Water and Total Beverage Intakes and Risk of Type 2 Diabetes in Young and Middle-aged Women

Introduction: Some caloric beverages (e.g., sugar-sweetened beverage and fruit juice) have been associated with an elevated risk of type 2 diabetes; therefore, substitution of these caloric beverages with non-caloric beverages such as plain water may be important for diabetes prevention. Few previous studies have examined the association between plain water or total beverage intake and risk of type 2 diabetes. Methods: We followed 82,900 women, aged 27-45 years and free of diabetes, cardiovascular disease and cancer at baseline, from 1991 to 2007. Diet, including various beverages, was assessed by food frequency questionnaires and updated every four years. Incident type 2 diabetes cases were confirmed by supplementary questionnaires. Cox proportional hazard models were used to calculate relative risks (RRs) and corresponding 95% confidence intervals (CIs), and we estimated the effect of “substituting” a serving of one beverage for another by including both as continuous variables in the same multivariable model. The difference in their beta coefficients and their variances and covariance were used to estimate the RR and 95% CI for the substitution effect. Results: During 1,294,196 person-years of follow-up, we documented 2,980 incident T2DM cases. After adjustment for age and body mass index, compared with the reference group (<1 glass/d), the relative risks (RRs) and 95% confidence intervals (CIs) of type 2 diabetes according to categories of plain water consumption were 0.91 (0.81-1.02) for 1 glass/d, 0.91 (0.82-1.01) for 2-3 glasses/d, 0.98 (0.87-1.11) for 4-5 glasses/d, and 1.02 (0.89-1.18) for 6 or more glasses/d (P-for-trend=0.51). Further adjustment for other diabetes risk factors did not substantially alter the RRs. We estimated that substituting one serving/d of plain water for one serving/d of sugar-sweetened beverage or fruit juice was associated with a 10% (95% CI, 6%-13%) and 13% (95% CI, 7%-18%) lower risk of type 2 diabetes, respectively. In this cohort, no association was found for total beverage intake and risk of type 2 diabetes: compared with women who drank less than 6 servings/d of total beverage, the RRs (95% CIs) were 0.97 (0.87-1.09), 0.98 (0.88-1.10), 1.01 (0.89-11.5), and 0.99 (0.86-1.14) for women drank 6-8, 8-10, 10-12, and ≥12 servings/d of total beverages (P-for-trend=0.83). Conclusions: Increasing consumption of water per se was not associated with risk of type 2 diabetes, but substituting plain water for sugar-sweetened beverage or fruit juice was associated with a significantly lower risk of type 2 diabetes.