Bone mineral density and accelerometer-determined habitual physical activity and inactivity in Postmenopausal Women

Abstract

BACKGROUND: In postmenopausal women, physical activity appears to be important in preventing loss of bone mineral density (BMD) and osteoporosis and thus contributes to the reduction of fracture risk. OBJECTIVE: This cross sectional study aimed to investigate the differences in habitual physical activity, physical inactivity and meeting physical activity recommendations between women with normal femoral BMD and women with osteopenia. METHODS: Out of the ninety-two postmenopausal women analyzed in this study, 72.8% women had normal femoral BMD and 27.2% women were osteopenic. Their BMD and body composition were measured using Dual Energy X-ray Absorptiometry. The region of interest was the total proximal femur. Seven days of physical activity were objectively assessed by using the ActiGraph GT1M accelerometer. Daily activity and inactivity logs were used for the participants to self record their times (minutes) when the accelerometer was worn and follow activity and inactivity patterns. RESULTS: Women with normal BMD spent significantly more hours/day being active than women with osteopenia. On the other hand, women with osteopenia perform significantly more household related PA. According to the physical inactivity analysis, women with osteopenia spent significantly more minutes/week while doing different mental activities (reading, doing crossword puzzles, etc.) in a sitting position than women with normal BMD. CONCLUSIONS: In conclusion, the results of this study show the differences in physical activity and physical inactivity in women with different femoral BMD. © František Chmelik, 2011.