Modifiable and nonmodifiable factors associated with osteoporosis in postmenopausal women: Results from the Third National Health and Nutrition Examination Survey, 1988-1994

We wished to study the relationship between modifiable and nonmodifiable fa ctors that were correlated with osteoporosis using a national sample of wom en aged 50 years and older who have never been on hormone replacement thera py (HRT). We used a cross-sectional study design with a nationally represen tative sample with a detailed clinical examination and a home interview. Be tween 1988 and 1994, 1953 postmenopausal women who had never been on HRT, a ged 50 years and older, were examined as part of the Third National Health and Nutrition Examination Survey (NHANES III). Mexican Americans and non-Hi spanic blacks were oversampled to produce reliable estimates for these grou ps. Bone density measurements of four proximal femur sites were assessed by using x-ray absorptiometry (DEXA). A DEXA measurement at any single femur site indicated osteoporosis if it was >2.5 standard deviations (SD) below t he reference mean of 20-29-year-old women. The study demonstrated that nume rous factors, both modifiable and nonmodifiable, were significantly related to the prevalence of osteoporosis. The modifiable factors identified were participation in physical activity (three to five times per week) and body mass index (BMI). Nonmodifiable factors included age, race, and mother's hi story. With the aging population, osteoporosis is a growing concern for the medical community. It is suggested that educational strategies are needed to increase awareness of factors that contribute to maintaining bone health among postmenopausal women. Emphasis may be placed on maintaining regular physical activity.