The relationship of serum alkaline phosphatase concentrations to sex maturity ratings in adolescents.

The relationship of serum alkaline phosphatase concentrations to sex maturity ratings, age sex, and race was studied in healthy prepubertal and adolescent patients. Previous data concerning SAP concentrations in adolescents have been age related and do not give primary consideration to biologic growth during adolescence. The highest mean concentrations for girls occurred at SMR 2 and for boys at SMR 3, coinciding in each instance with peak height velocity and thus correlating with presumed maximum osteoblastic activity during growth. With increasing SMR or age, the SAP levels in both sexes decreased markedly. Black boys had higher SAP concnetrations than white boys at SMRs 2, 3 and 4, whereas black girls had higher values than white girls only at SMR 4. This study demonstrates the value of correlating the enzyme activity with sex maturity ratings rather than with chronologic age.

Iron intake and transferrin saturation in adolescents.

The relationship of maturity, age, race, sex and income level to dietary intake and body stores of iron, as indicated by percent of transferrin saturation, was studied in healthy adolescents. Maturity rating, sex, and race were significant. Level of family income was not a significant factor. Both boys and girls increase the intake of iron as they mature, boys more than girls, and white adolescents slightly more than their black counterparts. Range of intakes was large, and there was no significant correlation between quantity of dietary iron and the percent of transferrin saturation. Norms for dietary intake of iron and percent of transferrin saturation, based on sex, race, and maturity, are presented for use by physicians and nutritionists.