Relationship of Tea Consumption and its Circulating Biomarkers with Longitudinal Bone Mineral Changes: A Prospective Cohort Study With Repeated Measurements.

BACKGROUND: Tea is a dietary source of flavan-3-ols, which may influence bone health, but prospective evidence linking tea intake and its circulating biomarkers with longitudinal bone mineral status remains limited. OBJECTIVE: To examine associations of tea consumption and its serum biomarkers with bone mineral status in Guangzhou Nutrition and Health Study (GNHS). METHODS: In 2,133 participants, whole-body, total hip, lumbar spine, and femoral neck bone mineral density (BMD) and bone mineral content (BMC) were measured using dual-energy X-ray absorptiometry at four repeated visits during a 13-year follow-up period. Baseline serum flavan-3-ols, including Epicatechin [EC], Epigallocatechin gallate [EGCG], Epicatechin gallate [ECG], Epigallocatechin [EGC], and Catechin, were quantified using UHPLC-MS/MS. Tea consumption was categorized as non-, low-, moderate-, or high-frequency. Multivariable linear mixed-effects models, including exposure × visit interactions, were used to evaluate visit-averaged bone mineral measures and longitudinal trajectories. RESULTS: Among 1,708 participants, significant tea consumption group × visit interactions were observed for whole-body, lumbar spine, and femoral neck BMD and whole-body BMC (P-interaction ranged from < 0.001 to 0.022). Moderate-frequency tea drinkers generally had the highest visit-averaged adjusted marginal mean Z-scores, including 0.107 (95% CI: 0.025, 0.190) for whole-body BMD, 0.090 (0.012, 0.168) for lumbar spine BMD, and 0.108 (0.029, 0.187) for femoral neck BMD (P-diff ranged from < 0.001 to 0.017 ). In analyses of serum tea biomarkers, higher biomarker categories were generally associated with more favorable bone mineral measures; however, the associations were not consistently linear, and several biomarkers showed non-monotonic patterns. Visit-averaged differences were most extensive across ECG and EGCG categories. CONCLUSIONS: Moderate-frequency tea consumption and higher categories of selected circulating tea biomarkers were associated with more favorable bone mineral status.