PD17-02 GREEN TEA INTAKE AND RISK OF INCIDENT KIDNEY STONES: A REPORT FROM THE SHANGHAI MEN’S AND WOMEN’S HEALTH STUDIES

Abstract

You have accessJournal of UrologyStone Disease: Medical & Dietary Therapy I1 Apr 2018PD17-02 GREEN TEA INTAKE AND RISK OF INCIDENT KIDNEY STONES: A REPORT FROM THE SHANGHAI MEN’S AND WOMEN’S HEALTH STUDIES Xiang Shu, Hui Cai, Yong-Bing Xiang, Honglan Li, Loren Lipworth, Nicole Miller, Wei Zheng, Xiao-Ou Shu, and Ryan Hsi Xiang ShuXiang Shu More articles by this author , Hui CaiHui Cai More articles by this author , Yong-Bing XiangYong-Bing Xiang More articles by this author , Honglan LiHonglan Li More articles by this author , Loren LipworthLoren Lipworth More articles by this author , Nicole MillerNicole Miller More articles by this author , Wei ZhengWei Zheng More articles by this author , Xiao-Ou ShuXiao-Ou Shu More articles by this author , and Ryan HsiRyan Hsi More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.964AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Tea intake may increase kidney stone risk as a source of dietary oxalate, but as a fluid it may also decrease risk. Previous studies investigating the association of tea intake and risk of stones have had mixed results. However, these studies primarily evaluated black tea, which has the highest oxalate content among different tea types. Green tea has inhibitory, antioxidative effects on calcium urinary stone formation in animal models. Our study objective was to investigate the association of green tea and incident kidney stones in two large prospective cohorts in Shanghai, China. METHODS We examined self-reported incident kidney stone risk in the Shanghai Men's Health Study (N=58,054 men; baseline age range 40-74) and the Shanghai Women's Health Study (N =69,166 women; baseline age range 40-70 years) who had no history of nephrolithiasis at study enrollment. Information on kidney stone history and tea intake was collected by in-person surveys. Multivariable Cox proportional hazards models were adjusted for baseline demographic variables, medical history, smoking history, total energy intake, and dietary intakes of non-tea oxalate, protein, potassium, magnesium, dietary calcium, supplemental calcium and vitamin C assessed using a validated food frequency questionnaire. RESULTS During 319,211 and 696,950 person-years of follow-up, respectively, 1,451 men and 1,202 women reported incident kidney stones. Nearly two-thirds of men and approximately one in four women were self-reported current tea drinkers. Green tea was the primary type consumed in both genders (95% in men and 88% in women). Current tea drinkers had lower incident stone risk than never/former tea drinkers (Men: HR=0.88, 95% CI 0.83-0.94; Women: HR=0.93, 95% CI 0.88-0.99). Compared to never/former tea drinkers, green tea intake was associated with lower risk among both men (HR=0.78, 95% CI 0.69-0.89) and women (HR=0.84, 95% CI 0.74-0.95). Compared to never/former tea drinkers, a stronger dose-response trend was observed for the amount of dried tea leaf consumed/month in men (HR=0.85, 95% CI 0.73-0.99 for <100g; HR=0.82, 95% CI 0.70-0.96 for 100-150g; HR=0.67, 95% CI 0.56-0.80 for>150g; ptrend <0.001) than in women (HR=0.89, 95% CI 0.77-1.02 for <100g; HR=0.82, 95% CI 0.63-1.06 for 100-150g; HR=0.87, 95% CI 0.70-1.08 for >150g; ptrend=0.038). CONCLUSIONS Green tea intake is associated with lower risk of incident kidney stones among the middle-aged and elderly urban Chinese. The benefit of tea intake for reducing stone risk is observed more strongly in men than in women. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e384 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Xiang Shu More articles by this author Hui Cai More articles by this author Yong-Bing Xiang More articles by this author Honglan Li More articles by this author Loren Lipworth More articles by this author Nicole Miller More articles by this author Wei Zheng More articles by this author Xiao-Ou Shu More articles by this author Ryan Hsi More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...