Effects of Tea Consumption on Renal Function in a Metropolitan Chinese Population: The Guangzhou Biobank Cohort Study

Objective: Green tea consumption has been associated with many prophylactic health benefits. This study examined for the first time associations between tea consumption and renal function in a Chinese population. Design and Methods: Cross-sectional baseline data including demographics, and lifestyle and weekly consumption of green, black, and oolong tea were analyzed from 12,428 ambulatory subjects aged 50 to 85years (67.3% female) that were randomly selected from the membership list of a community social and welfare association in Guangzhou, China. Intervention: Associations between tea consumption and renal function were assessed using regression analyses to adjust for potential confounding factors. Main Outcome Measure: Renal function was assessed using the estimated glomerular filtration rate (eGFR) and in a subcohort of 1,910 participants using a spot urinary albumin-to-creatinine ratio. Results: Six thousand eight hundred and seventy-two participants drank at least 1 type of tea. Oolong tea consumption was negatively associated with eGFR (β-coefficient -0.019, P = .025), but in a gender-stratified analysis this was not the case. In men, black tea was positively associated with eGFR (β-coefficient 0.037, P = .013), but not in women (β-coefficient -0.002, P = .856). Otherwise, no statistically significant consistent associations between the measures of renal function and consumption of green tea, black tea, or oolong tea individually or total tea consumption were identified. Conclusion: Overall there was no clear evidence to suggest any consistent association between renal function and tea consumption in this large population-based study of older Chinese individuals.