Pubertal timing is causal for diminished lower areal bone mineral density (aBMD) in a skeletal site-and sex-specific manner that tracks throughout life, potentially impacting later risk for osteoporosis, a recent study found. Researchers constructed sex-specific polygenic risk scores (GRS) consisting of 333 genetic variants associated with later puberty in children in the Bone Mineral Density in Childhood Study (BMDCS), consisting of a longitudinal cohort with up to 7 assessments (n=933) and a cross-sectional cohort (n=486). These GRS were tested for associations with age- and sex-specific aBMD Z-scores at the lumbar spine (LS), femoral neck (FN), total hip, and distal radius, accounting for clinical covariates using sex-stratified linear mixed models. They found:

• The puberty-delaying GRS was associated with later puberty and lower LS-aBMD in the BMDCS in both sexes (combined beta [SE]=-0.078 [0.024]).
• The puberty-delaying genetic instrument also supported a causal association with lower LS-aBMD and FN-aBMD in adults of both sexes.