Peripubertal estrogen levels and physical activity affect femur geometry in young adult women

Summary The growing skeleton is particularly responsive to exercise around the time of puberty, suggesting a possible role for estrogen in mechanical adaptation in young women. We assessed femoral neck strength index at age 17 in young women with varying adolescent physical activity levels and E2 levels in the first 3 years after menarche. The results indicate that both E2 levels in the first year after menarche and adolescent physical activity are positively associated with bone strength in young adulthood, such that hormone levels may modify human osteogenic responses to exercise.