Osteoporosis prevention in premenopausal women and children

Maximising peak bone mass, and reducing premenopausal bone loss are both potential approaches for the long-term prevention of osteoporosis and fracture. However, little is known about how to improve osteoporosis preventive behaviours in either premenopausal women or children. We performed a randomised controlled trial of individualised bone density feedback combined with either a leaflet or group education (the Osteoporosis Prevention and Self-management Course (( OPSMC)) in 467 healthy premenopausal women. Outcomes measured included changes in calcium intake; physical activity and fitness; BMD at the femoral neck and lumbar spine; osteoporosis knowledge and self-efficacy; and, maternal report of changing children's calcium intake and physical activity. Key findings were: ‚ÄöFeedback of low BMD resulted in a greater increase in femoral neck (but not lumbar spine) BMD compared to feedback of normal BMD (1.6% p.a. vs. 0.7% p.a., p=0.0001). ‚ÄöParticipation in the OPSMC had no greater effect on BMD than receiving a simple leaflet. ‚ÄöFemoral neck BMD change was associated with starting calcium supplements (1.3 % p.a, 95%CI +0.49, +2.17) and self-reported change in physical activity levels (0.7% p.a., 95%CI +0.22, +1.22). ‚ÄöBoth the OPSMC and feedback of low T-score were associated with long-term improvements in osteoporosis knowledge, but not self-efficacy. ‚ÄöMother's report of increasing their children's calcium intake was associated with receiving the OPSMC (OR 2.3, 95%CI 1.4,3.8) and feedback of a low T-score (OR 2.0, 95ToCI 1.2,3.3). We also performed a systematic review of the effects of calcium supplementation in children, which found that supplementation had effects only on total body bone mineral content (standardised mean difference (SMD) +0.14, 95% CI+0.01, +0.27) and upper limb BMD (SMD +0.14, 95%CI +0.04, +0.24). This small treatment effect, if applied to the peak incidence of childhood fractures, would result in a decrease in absolute risk of at most 0.2% p.a. in boys and 0.1% p.a. in girls. In conclusion, individualised BMD feedback combined with a minimal educational intervention is effective at increasing hip but not spine bone density in premenopausal women. The changes in behaviour through which this was mediated are potentially important in the prevention of other diseases, thus measuring BMD at a young age may have substantial public health benefits, particularly if these changes are sustained. The apparent effect of bone density feedback and the OPSMC delivered to mothers on osteoporosis preventive behaviours in their children could add to the public health benefits of such interventions. However, further research using objective measures of children's behaviour change is needed to confirm this finding. While it is possible that the small increase in BMD from calcium supplementation seen in the systematic review could reduce fracture risk in childhood, the public health impact of this appears small. Alternative methods of achieving osteoporosis preventive behaviours in children need further exploration.