Objective: To assess the association of physical activity with bone mass in premenarche girls.
Methods: Bone mineral density (BMD) and bone mineral content (BMC) at the whole body, femoral neck, Ward triangle and L1-L4 spine were measured using dual-energy X-ray absorptiometry (DXA) in 194 premenarche girls (10 +/- 1, year). Physical activity and dietary calcium intakes were assessed by using frequency questionnaire and diary.
Results: It was found that BMD and BMC were significantly and positively associated with weight-bearing physical activities (WBPA) (P < 0.01), total physical activities (TPA) (P < 0.01) rather than non-weight-bearing physical activity (P > 0.05) at all the studied bone sites (P < 0.01). Both BMC and BMD were tending to a better increase of WBPA. When WBPA increases from 227 to 415 (kcal/d), mean BMC and BMD were increased in 17.5%-29.0% and 8.8%-17.1%, respectively.
Conclusion: It should be helpful for premenarche girls to improve bone mass by increasing physical activities, especially weight-bearing physical activities.