Growth, bone maturation, and biochemical changes in Brazilian children from two different socioeconomic groups.

A study of blood biochemistry related to skeletal growth in 900 Brazilian children aged 7 to 17 yr is reported. Two groups were studied, a privileged and underprivileged sample. Anthropometry and measures of bone maturation in the control group were comparable with American and British standards. Underprivileged children showed growth impairment and delay in bone maturation. No signs of rickets were found in either group. Plasma calcium, magnesium, vitamin D, and total protein did not differ in the two groups of Brazilian children. Plasma alkaline phosphatase and inorganic phosphorus were abnormal in the underprivileged children. Alkaline-phosphatase activity and phosphorus levels did not fall towards adult levels after the predicted age of the adolescent spurt for underprivileged children. Menarche was delayed in the underprivileged girls.