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

Abstract:

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.