Serum estradiol is associated with volumetric BMD and modulates the impact of physical activity on bone size at the age of peak bone mass: a study in healthy male siblings.

This study investigates determinants of peak bone mass (PBM) in healthy men, focusing on effects and interactions of parameters reflecting mechanical loading and sex steroids. Healthy male siblings (n = 677; 25-45 yr) were recruited in a cross-sectional, population-based study. Physical activity score was assessed by a self-reported questionnaire.