To determine the contribution of various risk factors to quantitative ultrasound parameters in a sample of women, and to develop a tool to assess osteopenia risk, with a view to targeted early intervention.
A local center comprising a fitness center, conference center, and administrative offices for various businesses and sports.
A convenience sample of 187 Caucasian women who volunteered as part of a free public health screening initiative.
A questionnaire was designed to collect data on history of osteoporosis, current physical activity, calcium, alcohol and caffeine intakes, smoking, and various reproductive measures. Historical physical activity data were also collected, and lifetime energy expenditure and impact scores were calculated. Quantitative ultrasound was performed on the left calcaneus. Odds ratios (ORs) were calculated to determine the odds of being osteopenic (T-score ≤−1 SD) against not being osteopenic (T-score >−1SD), due to exposure to the aforementioned risk factors.
Significant ORs were obtained for age (OR: 1.042; 95% CI: 1.016-1.068), current physical activity (≥3 times/wk; OR: 0.320; 95% CI: 0.140-0.732), and lifetime energy expenditure score (OR: 0.957; 95% CI: 0.926-0.989). A regression model based on age and current physical activity correctly identified 57% of women with or without osteopenia.
Although the model we developed was not sensitive or specific enough to assess osteopenic risk accurately, the results show that frequency of physical activity, independent of age, is an important lifestyle factor to consider when quantifying osteopenic risk.
From the *MRC/UCT Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, UCT School of Health Sciences, and the †Biostatistics Unit, MRC, Cape Town, South Africa.
Received for publication July 2004; accepted March 2005.
Reprints: Lisa Micklesfield, PhD, MRC/UCT Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Private Bag, Rondebosch 7700 South Africa (e-mail: email@example.com).