Pubertal growth as reflected by simultaneous changes in bone mineral content and serum alkaline phosphatase

Bone mineral content and total serum alkaline phosphatase were measured simultaneously in 230 normal children and adolescents aged 7-20 years. The bone mineral content showed almost no variation from the age of 7 to 13 in boys a,d 7 to 11 in girls. Thereafter a sharp increase was seen in both sexes with a highly significant sex difference between the mean values. Bone mineral content showed a fairly high correlation with age, height, weight, and surface area in boys. Before the time of the growth spurt, however, these variables were poorly correlated or not correlated at all. Concentrations of total serum alkaline phosphatase increased up to the age of 14 in boys and 11 in girls. Thereafter a rapid fall was seen in both sexes, the mean levels being significantly higher in boys. The fall approximated adult levels in boys by the age of 20 and in girls by 18. A significant negative correlation between bone mineral content and serum alkaline phosphatase was seen both in boys (r=0.71, p less than 0.001) and in girls (r=0.79, p less than 0.001).