Structural model for osteoporosis preventing behavior in postmenopausal women

Background. Osteoporosis prevention behaviors (OPBs) can prevent and delay bone deterioration; dual-energy X-ray absorptiometry (DXA) scan can identify osteoporosis and provide personal osteoporosis risk information that may promote prevention behaviors. Objectives: This study was designed to estimate relationships between receiving personal knowledge of bone mineral density (gained through DXA scan), general knowledge of osteoporosis, health beliefs, and the two OPBs of calcium intake and weight-bearing exercise in healthy postmenopausal women 50 to 65 years. Methods: In this longitudinal, randomized clinical trial (including covariates), receipt of personal DXA information was manipulated by random assignment to the experimental or control group. The remaining antecedent and outcome variable measures were collected by questionnaire at three time points (initial [T1; pre-DXA], 6 months [T2], 12 months [T3]) and by bone density assessment from 203 women over an 18-month period in 2001-2003. Results: The experimental manipulation (DXA results) had a direct positive effect (beta =.23, p <.05) on calcium intake at T2, and indirectly at T3 through T2. Women in the experimental group who were informed they had osteopenia or osteoporosis had a greater T1-T2 change in daily calcium intake than those with normal bone density (P =.23, p <.05). However, providing DXA results did not relate to change in exercise. Health beliefs and general osteoporosis knowledge predicted initial calcium and exercise levels; there was tentative evidence that susceptibility beliefs partially mediate between DXA results and change in calcium intake. Discussion: Personal knowledge of DXA results was related significantly to increases in calcium intake in postmenopausal women, but not to exercise. Directions for further study are discussed.