DIETARY CALCIUM, PROTEIN, AND PHOSPHORUS ARE RELATED TO BONE-MINERAL DENSITY AND CONTENT IN YOUNG-WOMEN

Background: Dietary factors have been implicated in modifying bone hea lth, although the results remain controversial, particularly in young women. Objective: The objective of the study was to determine relation s of selected dietary factors and anthropometric measurements to bone mineral density (BMD) of the spine, femoral neck, trochanter, Ward's t riangle, radius, and total body and the bone mineral content (BMC) of the spine, radius, and total body. Design: The study was a cross-secti onal analysis of 215 women aged 18-31 y. Results: Weight, height, and lean mass were correlated with bone mineral measures at every site (r = 0.17-0.78). Postmenarcheal age (years since onset of menses) was pos itively correlated with total-body BMD and BMC, radius BMD and BMC, an d spine BMC, and negatively correlated with Ward's triangle BMD. Radiu s BMD was correlated with protein, calcium, and phosphorus intakes, an d spine BMD and BMC were correlated with energy, protein, calcium, and phosphorus intakes. These correlations remained significant when post menarcheal age, lean mass, and fat mass were controlled. A pattern eme rged in multiple regression analyses that showed a complex relation am ong calcium, protein or phosphorus, and the calcium-protein or calcium -phosphorus ratio and spine or total-body BMC and BMD. All 3 Variables (calcium, protein or phosphorus, and calcium-protein or calcium-phosp horus ratio) were required in the model for significance. Conclusions: Anthropometric measures were predictors of bone mass. A single ratio of calcium to phosphorus or protein did not optimize bone mass across the range of calcium intakes.