Metabolic syndrome in adolescents: definition based on regression of IDF adult cut-off points.

OBJECTIVES: The objective of this study was to derive a sex- and age-specific definition of the metabolic syndrome (MetS) and its abnormalities for adolescents.

STUDY DESIGN: This is a cross-sectional study.

METHODS: A total of 1100 adolescent students, aged 12-18 y, were randomly selected from schools and classrooms in the city of Constantine, Algeria; all had anthropometric measurements taken, and 989 had blood tests. Gender-specific growth curves for components of the MetS were derived, using the LMS (lambda-mu-sigma) method, and the percentiles corresponding to the thresholds of the MetS components proposed for adults by the International Diabetes Federation (IDF) were identified.

RESULTS: The prevalence of the MetS using this new definition was 4.3% for boys and 3.7% for girls (P = 0.64). Overall, a high waist circumference was the most frequent of the syndrome components, but the frequency was much higher in girls than that in boys, 33.6% and 6.9%, respectively. In contrast, a high systolic blood pressure was seen in 26.8% of the boys and only 11.4% of the girls. The prevalence of the MetS was higher among adolescents with a body mass index (BMI) ≥95th percentile of the study population, 28.8%, against 9.8% in adolescents with a BMI between the 95th and 85th percentile and 1.8% in those with a BMI <85th percentile (P < 0.0001).

CONCLUSION: MetS during adolescence requires more studies to establish a consensus definition. For clinical practice, we propose a simplified definition for boys and girls based on regression of IDF adult cut-off points. This definition should be tested in further studies with other adolescent populations.