Tea drinking and bone mineral density in older women

Abstract

Background: High caffeine intake is reportedly a risk factor for reduced bone mineral density (BMD) in women. Most studies, however, are from populations in which coffee drinking predominates and is the major caffeine source. Tea contains caffeine but also has other nutrients, such as flavonoids, that may influence bone mass in different ways. Objective: We examined the relation between tea drinking and BMD in older women in Britain, where tea drinking is common. Methods: We measured BMD at the lumbar spine, femoral neck, greater trochanter, and Ward's triangle in 1256 free-living women aged 65–76 y in Cambridge, United Kingdom. Tea drinking was assessed by self-completed questionnaire and women were categorized as tea drinkers or non–tea drinkers. Results: There were 1134 tea drinkers (90.3%) and 122 non–tea drinkers (9.7%). Compared with non–tea drinkers, tea drinkers had significantly greater (≈5%) mean BMD measurements, adjusted for age and body mass index, at the lumbar spine (0.033 g/cm²; P = 0.03), greater trochanter (0.028 g/cm²; P = 0.004), and Ward's triangle (0.025 g/cm²; P = 0.02). Differences at the femoral neck (0.013 g/cm²) were not significant. These findings were independent of smoking status, use of hormone replacement therapy, coffee drinking, and whether milk was added to tea. Conclusions: Older women who drank tea had higher BMD measurements than did those who did not drink tea. Nutrients found in tea, such as flavonoids, may influence BMD. Tea drinking may protect against osteoporosis in older women.