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 85 years (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.