[Physical activity and bone mineral density in postmenopausal women]

To test the association of total and physical activity (PA) intensity levels with bone mineral density (BMD) and bone mineral content (BMC) in postmenopausal women.

315 postmenopausal women (50-70 y) were recruited for this cross-sectional study from community residents in Guangzhou, China. PA and related covariates including general characteristics and dietary intakes were assessed using a face-to-face interview. BMD and BMC were determined by a dual energy x-ray absorptiometry, at the whole body, lumbar spine (L1-AL4), total hip and its sub-sites.

The participants were tertiled according to metabolic equivalent (MET) of PA. Analysis of covariance showed that greater PA tended to correlated to better BMD and BMC at various sites. Mean (S) BMDs at the whole body were (1.045 +/- 0.008), (1.043 +/- 0.008), (1.068 +/- 0.008) g/cm2 in the tertile I, II and III of total PA. BMD was significantly higher in the tertile III than those in the tertile I (P = 0. 049) and II (P = 0.028). No significant difference was observed at other sites. Mean BMC was significantly higher in the of highest total PA group than those in the other two groups at total femur, femoral neck, shaft femur and ward's triangle (P = 0. 004-0. 042). The association was differed by PA intensity levels. BMD tended to be increased with less light-intensity PA, more moderate-intensity PA and moderate vigorous-intensity PA.

Greater total PA and moderate-intensity PA, and moderate vigorous-intensity PA might improve bone mass in postmenopausal women.