Differences in proximal femur bone density over two centuries

The incidence of osteoporotic hip fractures in northern Europe has been increasing over the past few decades faster than the rate adjusted for increased life expectancy. One important factor that determines osteoporotic fracture risk is bone density. The restoration of a London church, during which skeletal material dating from 1729 to 1852 was recovered, gave us the opportunity to compare the rate of bone loss in the femora of these samples with that of present-day women. The rate of bone loss, as judged by dual energy X-ray absorptiometry, was significantly greater in modern-day women than in the women from two centuries ago, both pre-menopausally (p < 0.05) and post-menopausally (p < 0.01). The difference in bone loss in the Ward's triangle region between the Spitalfields samples and present-day women remained even when the assumed age at menopause was increased to 48 years or decreased to 42 years. The results suggest that differences in rates of bone loss over two centuries may partly account for the increasing incidence of hip fracture in modern-day women. Reasons for these differences are unclear, but one factor may be a lower degree of physical activity in present-day women.