Maintenance of Body Weight, Physical Activity and Calcium Intake Helps Preserve Bone Mass in Elderly Women

This prospective study focused on lifestyle factors and weight maintenance that may modulate the rate of bone loss at the weight-bearing proximal femur and non-weight-bearing distal radius in elderly women. Altogether 128 women of 134 subjects participated in this study with a mean follow-up time 3.9 years (range 2.9–5.3 years). The initially 60- to 65-year-old subjects were originally selected by their level of physical activity [high (PA⁺) and low (PA^–)] and calcium intake [high (Ca⁺) and low (Ca^–)], and the original groups were maintained in this study. Physical fitness and bone mineral content (BMC) decreased significantly at a similar rate in all four study groups without any statistically significant between-group difference. The mean change in the muscle strength of leg extensors was −3.3% (95% CI −5% to −1.5 %) at follow-up when including all individuals. The leg extension strength was still 9.2% (95% CI 2.7% to 16.1%) better in the PA⁺ groups compared with PA^– groups at follow-up. The mean change in the forearm flexion strength was −14% (95% CI −16.5% to −11.3%) at follow-up with no difference in the strength level between PA⁺ and PA^– groups. The mean change in the estimated oxygen uptake was −3.4% (95% CI −5.6% to −1.1%) at follow-up. The PA⁺ groups were still fitter, the between-group difference in the estimated oxygen uptake being 11.9% (95% CI 4.8% to 19.5%). The mean changes in BMC at follow-up were −2.1% (95% CI −3.0% to −1.2%) at the femoral neck, −1.9% (95% CI −3.2% to −0.5%) at the trochanter, and −12.4% (95% CI −15.4% to −9.4%) at the distal radius, indicating mean annual losses of 0.6% (95% CI 0.3% to 0.8%), 0.5% (95% CI 0.1% to 0.8%), and 3.2% (95% CI 2.4% to 4.0%), respectively. Decreased body weight was associated with higher bone loss in all measured bone sites. High calcium intake and better preservation of physical fitness were associated with a smaller decrease in femoral neck BMC. Received: 25 July 2000 / Accepted: 1 December 2000