RESUMEN
BACKGROUND/OBJECTIVES: The aim of the present study was to investigate the relationship between tea drinking and gallstones, specifically to evaluate the amount and time of tea consumption by gender. SUBJECTS/METHODS: A total of 14,555 eligible adults receiving health examinations were included. The participants were divided into three subgroups with tea consumption of none, <240/day and ≥240 ml/day. We defined 120 ml for each traditional Chinese teapot as a "cup," and the variable "cup-year" was obtained by multiplying the cups per day by the years of tea consumption. Based on the findings of abdominal ultrasound examination, gallstones was defined by the presence of movable or gravity-dependent intraluminal hyperechoic foci that attenuated ultrasound transmission. RESULTS: Among the participants, 1040 (7.1%) had gallstones. In multivariate analysis, the inverse relationship between tea drinking habit and gallstones was significant (OR = 0.807; 95% CI = 0.685-0.951, p = 0.010). Daily consumption of 1-240 ml (OR = 0.741; 95% CI = 0.584-0.941, p = 0.014), but not ≥240 ml, was associated with reduced risk of gallstones. In addition, the 1-19 cup-year group had significantly lower associated risk of gallstones (OR = 0.677; 95% CI = 0.534-0.857, p = 0.001), while the ≥19 cup-year group did not. By gender, subjects with tea consumption of 1-19 cup-year exhibited a low associated risk of gallstones in both males (OR = 0.678; 95% CI = 0.504-0.913, p = 0.010) and females (OR = 0.671; 95% CI = 0.453-0.994, p = 0.047), while subjects with ≥19 cup-years did not. CONCLUSIONS: Appropriate tea drinking if less than 240 ml/day or 19 cup-years was associated with a decreased risk of gallstones in both genders.