Infant growth influences proximal femoral geometry in adulthood

The relationship between early growth and adult femoral geometry has not been studied previously. In 333 adults, we were able to show that infant weight predicts femoral width and cross-sectional moment of inertia but not femoral neck length. These results support the hypothesis that growth in early life leads to persisting differences in proximal femoral geometry.

Both femoral geometry and bone mass have been shown independently to predict both hip strength and fracture risk. Whereas growth during intrauterine and early postnatal life has been shown to influence adult bone mass, the relationship between growth in early life and adult femoral geometry has not been described previously.

We studied the relationship between growth during early life, adult hip geometry, and proximal femur bone mass in a sample of 333 men and women (60-75 years of age), for whom birth weight and weight at 1 year of age were recorded. Hip geometry was derived using Hip Structure Analysis software from proximal femur DXA scans (Hologic QDR 1000).

There were significant (p < 0.002) relationships between weight at age 1 year and measures of femoral width as well as intertrochanteric (IT) cross-sectional moment of inertia (CSMI), but not with femoral neck length. The relationships with measures of femoral width but not CSMI remained after adjusting for adult body weight and were independent of proximal femoral BMC.

These results support the hypothesis that different patterns of growth in utero and during the first year of life lead to persisting differences in proximal femoral geometry, thereby mediating in part the effects of early growth on risk of hip fracture in adulthood.