Percent body fat and bone mass in healthy Canadian females 10 to 19 years of age.

The primary aim of the investigation was to assess the relationship between whole-body fat expressed as a percentage of body weight with whole-body bone mineral content relative to age and anthropometry. Sixty females between 10 and 19 years of age were recruited to this cross-sectional study, which included measurements of weight and height and whole-body fat and bone mineral content using dual-energy X-ray absorptiometry. To assess bone mineral content, data were expressed as a weight or standard deviation scores using age and bone area. Relationships between outcome variables were determined using multiple correlation analysis followed by multiple linear regression with age, weight, height, and fat as predictor variables for outcomes of bone mineral content and density. Correlation analysis indicated that whole-body fat expressed as a percent was significantly related to weight (p < 0.01), but was not related to age or bone mineral content or density unless bone mineral content was corrected to age or bone area using standard deviation scores. In addition, body fat was associated with bone area for age and height (p < 0.01). However, multiple linear regression yielded opposite results. When included in regression, body fat had a negative impact on bone mineral content (p = 0.003), mineral content corrected to bone area (p = 0.02), and bone density (p = 0.003), while age, weight, and height had positive impacts on these outcome measurements. The data suggest that for younger children, the relative influence of percent body fat will be greater and could be linked with suboptimal attainment of peak bone mass. The females in this study appeared to be within reference limits for percent body fat. However, greater amounts of body fat relative to weight could be a marker for lifestyles that do not support attainment of optimal peak bone mass.