Body Mass, Vitamin D and Alcohol Intake, Lactose Intolerance, and Television Watching Influence Bone Mineral Density of Young, Healthy Canadian Women

Objective: To report bone mineral density (BMD) in young, reportedly healthy Canadian women and to determine whether lifestyle factors that have been associated with bone health in older women are also associated with BMD in young women. Method: We recruited a convenience sample of 52 female undergraduate students in the Applied Human Nutrition program at the University of Guelph, Ontario, Canada. BMD was measured at the femoral neck, lumbar spine (L1 to L4), and whole body using a Discovery Wi (Hologic Inc.) dual-energy x-ray absorptiometer. Subjects completed a questionnaire to collect demographics, medical history, physical activity levels, and dietary habits; in addition, a subset of subjects (n = 31) completed a food frequency questionnaire to collect data on calcium and vitamin D intake. BMD data were examined using T- and Z-score classifications established by the World Health Organization (WHO); multiple regression analysis was used to predict BMD with biological and lifestyle variables. Results: Mean BMD measured at the femoral neck, lumbar spine, and whole body was 0.863 +/- 0.11, 1.019 +/- 0.09, and 1.085 +/- 0.07 g/cm(2), respectively. Body mass and body mass index were significantly positively correlated with BMD at all 3 sites. Television watching, lactose intolerance, number of alcoholic drinks consumed per week, and age were used to develop a linear regression model to predict whole-body BMD (r(2) = 0.727, p < 0.001). Conclusions: Based on criteria established by the WHO, women in this group presented with lower than expected BMD.