To estimate the prevalence of metabolic syndrome (MS) and determine its association with white blood cell (WBC) count as a marker of low-grade systemic inflammation in children and adolescents in Korea.

We investigated the prevalence of MS and its association with WBC count in 928 children and adolescents. MS was defined as having 3 or more conditions based on the modified criteria of the National Cholesterol Education Program–Adult Treatment Panel III (NCEP-ATP III). The odds ratios (ORs) for MS were also calculated using multivariate logistic regression analysis across WBC count quartiles (Q1, <5200; Q2, 5200–6100; Q3, 6200–7200; and Q4, ≥7300cells/μL for boys; Q1, <5200; Q2, 5200–6000; Q3, 6100–7000; and Q4, ≥7100cells/μL for girls). The prevalence of MS in children and adolescents in Korea was 6.7% (8.5% in boys, 4.5% in girls, P<0.001). MS was more prevalent in overweight and obese children and adolescents in both boys and girls. The mean WBC counts continuously increased with each additional component of MS in both boys and girls. The ORs (95% CIs) for MS in each WBC quartile were 1.00, 1.56 (0.43–5.67), 4.47 (1.42–14.07), and 5.25 (1.71–16.07) in boys and 1.00, 1.05 (0.15–7.61), 2.89 (0.55–15.17), and 7.47 (1.61–36.67) in girls after adjusting for age, household income, and residential area.

In summary, this study shows that a substantial number of children and adolescents in Korea have MS, and elevated WBC count may be a surrogate marker for MS.