Lower bone mass detected at femoral neck and lumbar spine in lower-weight vs normal-weight small-boned women.

Sixty-one nonsmoking, healthy, young, menstruating women aged 18 to 30 years generally considered at peak skeletal bone mass were screened for diseases and drugs known to adversely affect bone mineral density (BMD). Anthropometric measures, BMD of the lumbar spine (LS) and femoral neck (FN), exercise time, selected nutrient, and energy intake were compared. The women were categorized by frame size and body mass index (BMI), with the upper range for normal weight (NW) being BMI 23.0 to 25.9 (n=30) and lower weight (LW) being BMI 16.0-19.9 (n=31). Multivariate t tests, Pearson correlations, and independent sample t tests were used for statistical analysis. Ten of 21 in the LW group, all with small frames, had varying degrees of low BMD of the LS and/or FN. The amount of exercise time was greater in the NW group. Energy and nutrient intakes did not differ significantly between groups.