Plasma insulin-like growth factor 1 distribution and its relation to blood pressure in adolescents: the Bogalusa Heart Study.

The distribution of circulating insulin-like growth factor-1 (IGF-1) and its relationship to blood pressure was examined in a community study of 1073 biracial (black-white) adolescents aged 11 to 18 years. Girls of both races displayed higher levels of plasma IGF-1 than did their male counterparts (P < .01), independent of age and sexual maturation. In boys, IGF-1 was correlated positively with height (r = 0.37 P < .001), weight (r = 0.26, P < .001), Tanner stage (r = 0.31, P < .001), and age (r = 0.11, P < .05). Girls, on the other hand, showed an inverse association with age (r = -0.38, P < .001) and Tanner stage (r = -0.10, P < .05). Plasma IGF-1 was correlated positively with systolic blood pressure in boys of both races (r = 0.21 to 0.25, P < .01) and with diastolic blood pressure in white boys (r = 0.18, P < .05), but not in girls of either race. Boys with elevated levels of IGF-1 (>80th percentile) showed significantly higher blood pressure levels, especially during early to middle stages of puberty. Multivariate analysis revealed that IGF-1 was associated with systolic and diastolic blood pressure, independent of age, race, sexual maturation, height, weight, and insulin in boys. These results suggest that plasma IGF-1 may contribute to the regulation of blood pressure only in males during puberty.