CROSS-SECTIONAL ASSOCIATIONS AMONG NUTRIENT INTAKES AND BONE MINERAL DENSITY IN POSTMENOPAUSAL WOMEN

Abstract

The association of dietary nutrient intakes with bone mineral density (BMD) is controversial. The purpose of this study was to determine cross-sectional associations between average dietary intake of a variety of nutrients and BMD in 244 healthy, nonsmoking postmenopausal women, 40–66 y of age and enrolled at baseline in the Bone, Estrogen and Strength Training Study. BMD was measured at 5 sites (lumbar spine L2-L4, trochanter, femur neck, Ward's triangle and total body) using dual energy X-ray absorptiometry (DXA). Nutrient intakes were assessed using 3-day diet records (Minnesota Nutrient Data System). Unadjusted and energy-adjusted means of nutrient intakes were determined. Regression models were calculated using each BMD site as the dependent variable and nutrients as the independent variables. Covariates included in the models were y past menopause, body mass index (BMI), hormone replacement therapy (HRT) use, and total energy intake. Descriptive statistics showed that women, on average, weighed 68 kg, had 38% fat, and had a 3 y history of HRT use. Iron and magnesium were significantly associated with greater BMD at all sites (p < 0.03). Energy, protein, calcium, zinc, vitamin A, fiber, vitamin D, phosphorus, and potassium were positively and fat was negatively associated with BMD, though varying by bone sites. Models with covariates included predicted 9–13% of baseline BMD. Nutrients are significant predictors of BMD even after accounting for covariates. The significance of the role of iron on BMD is unknown and needs to be explored in future studies. Supported by NIH AR39559 and Mission Pharmacal