Relation between birth weight at term and growth rate, skeletal age, and cortical bone at 6-11 years.

There is an apparent link between fetal and childhood growth and puberty and risk for several degenerative diseases in adulthood. It is also important to consider associations between birth weight and indicators of growth and biological maturation during childhood and adolescence as potential explanations for associations between fetal growth and adult risk for disease. The present study examines the association between birth weight and (1) size attained and rate of growth in body size and cortical bone area of the second metacarpal (M II), and (2) skeletal age and rate of skeletal maturation in children 6-11 years of age. The sample included 127 boys and 105 girls of European ancestry, divided into two age groups, 6-8 years and 9-11 years. The relationship between birth weight and attained size (stature, mass, and the BMI), M II cortical area and skeletal age (SA, Tanner-Whitehouse method) during childhood was examined with correlational analyses. Observations on children measured on two occasions were converted to annual velocities, and correlations between birth weight and annual velocities were also calculated. Birth weight is significantly associated with stature and mass in boys and only with stature in girls 6-11 years of age, but is not related to the BMI, M II cortical area, or skeletal maturity. Birth weight is not significantly related to annual velocities of growth in stature, mass, the BMI and M II cortical area; to the annual increment in SA; and to weight gain from birth to the time of measurement (intervals of 6 to 11 years). The results emphasize a role of other influences than birth weight on growth rate, cortical area of M II, and skeletal maturation during childhood. Am. J. Hum. Biol. 11:505-511, 1999. Copyright 1999 Wiley-Liss, Inc.