Waist-to-height ratio and sedentary lifestyle as predictors of metabolic syndrome in children in Ecuador.

OBJECTIVE: To determine the predictors and prevalence of metabolic syndrome (MS) and the presence of vascular inflammation in apparently-normal children (10-15 years) of both sexes in Guayaquil, Ecuador.

STUDY DESIGN AND METHODS: We included 395 apparently-healthy students from a middle-income school in a cross-sectional survey. Informed consent was obtained from students and parents. Anthropometric measurements including blood pressure (BP), body mass index (BMI) and waist-to-height ratio (WHtR), and blood tests were recorded. Vascular inflammation parameters were assessed. Percentiles of the different parameters were used, and MS was defined according to National Cholesterol Education Program Adult Treatment Panel III criteria (NCEP-ATPIII). Waist circumference>P 75, blood pressure>P 90, glucose>100mg/dl, triglycerides>100mg/dl, HDL<45mg/dl. If 3 of the 5 criteria were present, this was considered MS.

RESULTS: The mean age was 12 years (186 boys, 209 girls). The overall prevalence of MS was 9.37% (6.33% in girls, 3.04% in boys). Sustained hypertension was detected in 6.6% of children and pre-hypertension in 7.1%. Obesity was found in 1.8% of subjects, and overweight in 15.2%. Triglycerides has a RR 2.34 (1.97-2.76); HOMA index has a RR 1.97(1.62-2.40); HDL cholesterol has a RR 1.84(1.58-2.13); Insulin level has a RR 1.53(1.40-1.67) and interleukin 6 has RR 1.83(1.20-2.79). Serum glucose, total cholesterol and LDL-Cholesterol had no association with the metabolic syndrome. HDL-Cholesterol<45mg/dl and triglyceride>100mg/dl were present in 70% of subjects with MS. The WHtR threshold≥0.5 was 100% sensitive in both sexes (67% specificity in boys and 69% in girls). There were significant associations between the WHtR and pre-hypertension and sedentary lifestyle (P<0.001 and P<0.003 respectively). A WHtR value of ≥0.50 indicated a 2.2-fold increased risk of MS compared with normal WHtR, and normal weight.

CONCLUSIONS: A WHtR≥0.5 was 100% sensitive in detecting MS in 10-15 year-old boys and girls in the normal or overweight range of the BMI. This assessment is a simple and practical tool for use in population-based studies of cardiovascular risk. When combined with pre-hypertension and a sedentary lifestyle, the WHtR is highly sensitive in predicting MS.