Abstract 026: Biomarkers of Polyphenol Intakes and Risk of Type 2 Diabetes in Us Women
Objectives: To examine select urinary biomarkers of dietary polyphenol intakes in relation to incidence type 2 diabetes in U.S. women.
Design: Prospective nested case-control study.
Setting: The Nurses’ Health Study (NHS) and NHS II, United States.
Participants: During follow-up period of 2000-2008 in the NHS and 1995-2007 in the NHS II, a total of 1107 type 2 diabetes (T2D) cases were identified and confirmed among participants who provided blood samples in these two cohorts. A control was selected for each case and case-control pairs were matched on age at urine sample collection, race, fasting status, and use of hormone replacement therapy (NHS II only). Seven selected markers of polyphenols that can be reliably measured in urine (caffeic acid, ferulic acid, enterolactone, enterodiol, naringenin, quercetin, and isorhamnetin) were assayed by liquid chromatography.
Main outcome measures: Incident self-reported T2D cases were confirmed using a validated supplementary questionnaire.
Results: After multivariate adjustment of matching factors and demographic, lifestyle, and dietary variables, urinary levels of enterolactone were associated with lower risk of T2D. The odds ratio (OR) of T2D comparing extreme quartiles of enterolactone was 0.64 (95% confidence interval [CI]: 0.45, 0.91; P for trend = 0.007). Other markers were not associated with lower risk of T2D after multivariate adjustment. However, when we restricted the analysis to the early follow-up period (≤5 years) since urine sample collection, the sum of quercetin and isorhamnetin, markers of flavonol intakes, was significantly associated with a lower risk of diabetes (OR = 0.57; 95% CI, 0.35, 0.92; P for trend = 0.04). In contrast, no significant association was observed for these biomarkers in the follow-up period longer than 5 years (OR = 1.31; 95% CI, 0.78, 2.20; P for trend = 0.28), and the P value for interaction with follow-up length was 0.03. A similar pattern of association was observed for caffeic acid: the ORs (95% CIs) comparing extreme quartiles were 0.59 (0.37, 0.94) and 0.90 (0.53, 1.50) in early vs. late follow-up periods, respectively, although no significant interaction was observed (P = 0.63).
Conclusions: These results indicate that enterolactone, a biomarker of lignan intakes, is associated with lower risk of type 2 diabetes. In addition, levels of quercetin and isorhamnetin, as well as caffeic acid, are associated with a lower diabetes risk in early follow-up period, but not longer follow-up. Although these data suggest intakes of certain polyphenols may lower risk of diabetes, future investigations are needed to corroborate our observations.
- © 2013 by American Heart Association, Inc.