TRACKING OF ELEVATED SYSTOLIC BLOOD-PRESSURE AMONG LEAN AND OVERWEIGHT ADOLESCENTS - THE MINNEAPOLIS CHILDRENS BLOOD-PRESSURE STUDY

Objective: To determine whether elevated blood pressure tracks to a gr eater degree in overweight than in lean children. Design: Prospective cohort study. Methods: We examined 758 adolescents (mean age 13.4 year s) who participated in a longitudinal study of blood pressure. The deg ree of tracking was examined by cross-classification of sex-specific t ertiles of systolic blood pressure (SBP) and body mass index determine d at baseline and 5 years later. Those children that were in the highe st tertile of SBP and body mass index were considered to be 'overweigh t with elevated blood pressure'. Those that were in the highest tertil e of SBP but lowest tertile of body mean index were considered to be ' lean with elevated blood pressure'. Results: Of those boys that were i nitially classified as lean with elevated blood pressure, 38% remained so classified compared with 54.6% of those that were initially classi fied as overweight with elevated blood pressure. Among the girls the r espective proportions were 48 and 44.2%. The subjects of each sex who were lean with elevated blood pressure were significantly shorter at b aseline than their overweight counterparts, and over the follow-up per iod experienced a greater mean increase in SBP than their overweight p eers. This difference was almost totally explained for the boys once t he difference in height change was taken into account. For the girls a difference of 5.9 mmHg remained after covariate adjustment for the ch ange in height. Conclusion: These results fail to support the hypothes is that blood pressure tracks differently in obese and in lean adolesc ents, particularly once differences in sexual maturation are considere d.