To analyze the association between high-sensitivity C-reactive protein (hs-CRP) levels and cardiovascular risk factors in healthy school children, and to evaluate whether changes in body mass index (BMI) category throughout childhood affect hs-CRP levels.

We measured serum hs-CRP levels, lipid profile, insulin levels, and leptin levels in 683 prepubertal children and 748 adolescents. A total of 272 children participated in the study in both cohorts, prepubertal (baseline; age 6-8 years) and adolescents (follow-up; age 12-16 years).

Compared with their normal weight (NW) counterparts, hs-CRP levels were significantly higher in obese and overweight (OW) adolescents and obese prepubertal children. The highest hs-CRP levels were seen in children who were OW at baseline and at follow-up, and the lowest levels in those who transitioned from OW at baseline to NW at follow-up. High-density lipoprotein cholesterol and apolipoprotein A-I levels decreased across the hs-CRP tertile in both prepubertal children and adolescents, with significant differences (P < .001) in concentrations between the highest and lowest tertiles in 6- to 8-year-old boys and girls and in 12- to 16-year-old boys. The hs-CRP levels were also significantly associated with leptin levels in both prepubertal children and adolescents, with a significant increase across hs-CRP tertiles (P < .001).

The shift from OW to NW throughout childhood is associated with a decrease in hs-CRP level to below that observed in children who maintain NW throughout childhood. Leptin levels were strongly associated with hs-CRP levels in our population independent of BMI. Our findings suggest that an obesity-related chronic inflammatory state may be reversible by improving weight status.