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.

Anthropometric markers for detection of the metabolic syndrome in adolescents.

OBJECTIVES: This study aimed to estimate, in a large group of Algerian adolescents, the prevalence of the metabolic syndrome (MetS), using four definitions (by Cook, De Ferranti, Viner and the IDF), and to test the validity of unique thresholds of waist circumference, waist/height ratio and BMI in screening for the MetS regardless of the definition used. SUBJECTS AND METHODS: A total of 1100 adolescent students, aged 12-18 y, were randomly selected from schools and classrooms in the city of Constantine; all had anthropometric measurements taken and 989 had blood tests. RESULTS: Prevalences of the MetS were: 2.6% for boys and 0.6% for girls by the Cook definition; 4.0% for boys and 2.0% for girls by the De Ferranti definition; 0.7% for boys and 0% for girls by the Viner definition; and 1.3% for boys and 0.5% for girls by the 2007 IDF definition. Prevalences ranged from 3.7% to 13.0% in obese adolescents. Unique thresholds, independent of gender, age and height, of 80cm for waist circumference, 0.50 for waist/height ratio and 25kg/m(2) for BMI had sensitivities of 72-100%, 67-100% and 72-100%, respectively, and specificities of 74-78%, 74-86% and 74-78%, respectively, depending on the MetS definition used. CONCLUSION: The MetS is present in Algerian adolescents and the prevalence is especially high in obese young people. Our thresholds for waist circumference, waist/height ratio and BMI for screening for the MetS should now be tested in other adolescent populations.

Arterial hypertension in overweight and obese Algerian adolescents: role of abdominal adiposity.

OBJECTIVE: This study aimed to estimate the prevalence of hypertension in Algerian overweight and obese adolescents to assess the risk factors associated with hypertension and an increase in arterial stiffness. SUBJECTS AND METHODS: This cross-sectional study included 305 adolescents (133 boys and 172 girls) aged 12-19 years, who were either overweight or obese (IOTF criteria). Their body weight, height, BMI, waist circumference (WC), WC-to-height ratio and blood pressure were also measured. RESULTS: Hypertension and prehypertension were found in 19.7 and 16.1%, respectively, of the study population, with significantly more hypertensives among the obese than among the overweight adolescents. The prevalence of hypertension was also twice as high in boys as in girls (27.1% vs 14%; P=0.004), and WC and WC-to-height ratios were significantly higher in hypertensives than in normotensives. The risk of hypertension was also significantly higher in boys and associated with WC, independent of age and severity of weight excess (whether overweight or obese). Mean pulse pressure (PP) was significantly higher in boys versus girls, in obese versus overweight adolescents and in hypertensives versus normotensives, and was correlated with WC and WC-to-height ratio. PP >45 mmHg was associated with WC and hypertension only in boys, independent of age. CONCLUSION: The prevalence of hypertension is high in overweight and obese adolescents, and higher in boys than in girls. Hypertension and arterial stiffness, as determined by high PP levels, were associated with abdominal adiposity. It is recommended that prehypertension be identified in overweight adolescents and that lifestyle changes be made to avoid its evolution towards obesity and hypertension.