Gender differences in the heritability of musculoskeletal and body composition parameters in mother-daughter and mother-son pairs.

Bone mass and body composition traits are genetically programmed, but the timing and gender and site specificities of their heritability are unclear. Mother-child correlations of bone mineral density (BMD) and bone mineral content, lean mass, and fat mass were studied in 169 premenopausal mothers and their 239 children. Heritability estimates of lean mass, fat mass, BMD, and area were derived for each gender and pubertal stage. There were significant correlations for most densitometry-derived variables at the spine, hip, femoral neck (FN), and total body (r=0.192-0.388) in mother-postmenarcheal daughter pairs, for bone areas at all sites in early puberty (r=0.229-0.508) and for volumetric-derived density at FN and spine (r=0.238-0.368) in mother-son pairs. Fat mass correlations were significant in both genders after puberty (r=0.299-0.324) and lean mass in postmenarcheal girls only (r = 0.299). Heritability estimates varied between 21% and 37% for mother-daughter and 18% and 35% for mother-son pairs for density-derived variables and between 26% and 40% for body composition variables. Maternal inheritance of bone traits is expressed in early-pubertal boys for several skeletal site traits but consistently involves most site traits in girls and boys by late puberty. Body composition inheritance is more variable.