Persistent elevation of plasma insulin levels is associated with increased cardiovascular risk in children and young adults. The Bogalusa Heart Study.

BACKGROUND

Hyperinsulinemia has been considered to be a potent cardiovascular risk factor. The present investigation examines persistently elevated fasting insulin levels from childhood to young adulthood and its influence on cardiovascular risk factors.

METHODS AND RESULTS

A longitudinal cohort was constructed from two cross-sectional surveys in a community-based population over an 8-year period: 1606 individuals (39% were black) aged 5 to 23 years participated in the first survey. Stability in rankings (persistence) of insulin levels was shown by the presence of significant correlations between year 1 and year 8 values (r=.23 to .36, P<.0001), with a greater magnitude in older subjects. Compared with subjects with levels of insulin consistently in the lowest quartile, those with levels always in the highest quartile showed higher (P<.001) levels of body mass index (+9 kg/m2), triglycerides (+58 mg/dL), LDL cholesterol (+11 mg/dL), VLDL cholesterol (+8 mg/dL), glucose (+9 mg/dL), systolic blood pressure (+7 mm Hg), and diastolic blood pressure (+3 mm Hg); lower (P<.001) levels of HDL cholesterol (-4 mg/dL): and higher (P<.05) prevalence of parental history of diabetes (3.3-fold) and hypertension (1.2-fold). There were 739 young adults aged 20 to 31 years at follow-up. As adults, individuals with consistently elevated insulin versus those with consistently decreased insulin had increased (P<.05) prevalence of obesity (36-fold), hypertension (2.5-fold), and dyslipidemia (3-fold), which was attributed to both baseline insulin and change of insulin from baseline to follow-up. In addition, clustering of these risk factors was stronger (P<.05) in adults with persistent insulin elevation.

CONCLUSIONS

Elevated insulin levels persist from childhood through young adulthood, resulting in a clinically relevant adverse cardiovascular risk profile in young adults.