Sex differences in bone mineral content and bone geometry accrual: a review of the Paediatric Bone Mineral Accural Study (1991-2017).

CONTEXT: Girls' and boys' growth patterns differ in timing and tempo, and they have different lifestyles with regards to diet and physical activity. These factors have all been linked with bone mineral accrual. OBJECTIVE: To identify the associations of boys' and girls' growth, maturation, and lifestyle choices relating to parameters of bone geometry and mineral accrual. METHODS: Between 1991 and 1993, 251 children aged 8-15 years were recruited into a mixed-longitudinal cohort study (The Paediatric Bone Mineral Accrual Study (PBMAS)) and followed repeatedly over 26 years. RESULTS: It was found that girls matured approximately two years earlier than boys (11.8 vs. 13.4 years) but on average were shorter, had less lean mass and had greater fat mass (p < 0.05). There was a dissociation between the growth of bone and its mineralisation in both sexes. Boys had greater bone mass and bone geometry (p < 0.05). Both a healthy childhood diet and high levels of physical activity were associated with improved bone parameters. CONCLUSIONS: Most, but not all, of the sex differences observed, were explained by height and lean mass differences. The importance of diet and physical activity on obtaining optimal bone mass during adolescence in both sexes was also paramount.