M. K. Javaid1, S. R. Shore*1, P. Taylor*2, C. Gale*1, F. O’Callaghan*1, N. K. Arden*1, K. M. Godfrey*1, C. Cooper1, &. The Princess Anne Hospital Study Group*1. 1MRC Environmental Epidemiology Unit, University of Southampton, Southampton, United Kingdom, 2Medical Physics and Bioengineering, Southampton Univeristy Hospitals NHS Trust, Southampton, United Kingdom.
Osteoporotic fractures are a significant burden to society in the UK. Peak bone mass is a major determinant of bone strength in later life and epidemiological studies suggest that intrauterine and early postnatal environments influence skeletal trajectory and peak bone mass accrual. The aim of this study was to identify the specific maternal and neonatal determinants of bone mass in later childhood.
211 children (113 boys) were studied at age nine years. Their mothers anthropometry, diet and lifestyle had been characterized prospectively and the children were measured at birth. Now aged nine years, the children had their bone mass measured using DXA.
Boys were significantly taller (p=0.004) and had greater bone mass (p=0.002) than the girls. At nine years, birthweight remained a strong predictor of whole body bone mineral content (WBBMC) (r=0.40, p<0.001); lean mass (r=0.35, p<0.001) and fat mass (r=0.21, p=0.02) in both boys and girls. Lower maternal social class and educational attainment, smoking during late pregnancy, reduced prepregnant weight and height, and lower maternal fat stores during late pregnancy were significantly (p<0.05) associated with lower childhood WBBMC.
There were also strong positive associations between childhood WBBMC and umbilical venous calcium (p=0.002) and albumin (p=0.008) concentration. In contrast, umbilical venous phosphate, alkaline phosphate and creatinine did not predicted childhood WBBMC. In multivariate analyses, maternal smoking, socioeconomic status and fat stores were no longer associated with childhood WBBMC when umbilical calcium concentration was taken into account; male sex and tall maternal stature remained independent predictors of WBBMC.
These results suggest that umbilical venous calcium concentration is an important correlate of the trajectory of skeletal growth during the first nine years of postnatal life. The capacity to maintain a materno-fetal calcium gradient might be the physiological mechanism through which maternal smoking and nutrition adversely influence skeletal development in the offspring.