YEAR-TO-YEAR VARIABILITY OF CHOLESTEROL LEVELS IN A PEDIATRIC PRACTICE

Objectives: To study the impact of the variability of blood cholesterol levels, which are known to vary spontaneously. The impact of this variability on screening for hypercholesterolemia according to National Cholesterol. Education Program (NCEP) guidelines was reviewed in a private pediatric practice. Design: Retrospective chart review. Setting: Private pediatric practice. Patients: Children (N=646) aged 3 to 19 years. Intervention: Cholesterol measurements at a mean interval of 19 months between visits. Main Outcome Measures: Year-to-year change in cholesterol levels according to NCEP guidelines, regression to the mean, age, pubertal status, body mass index, hematocrit, interval between measurements, and season of the year were assessed for their contribution to cholesterol level variability. Results: Cholesterol level varied significantly with both age (P<.001) and pubertal status (P<.01) with children aged 9 to 12 years; prepubertal children had the highest levels. Visit-to-visit consistency of NCEP classification was poorer for younger children than for older children (K=0.21 for 3- to 6-year-olds, 0.39 for 6- to l0-year-olds, and 0.44 for those older than 10 years). Of children with initial total cholesterol levels of 5.17 mmoVL (200 mg/dL) or greater, only 40% continued to have high levels at follow-up. A child with an initial cholesterolvalue of 5.17 mmoVL(ZOO mg/dL) showed an average decline of 0.34 mmoVL (13 mg/dL) at follow-up by regression analysis. Conclusion: Year-to-year variability in total cholesterol'level has a significant impact on the stability of NCEP classification.