Dietary glycaemic carbohydrate in relation to the metabolic syndrome in adolescents: comparison of different metabolic syndrome definitions
Aims: High dietary glycaemic carbohydrate, as measured by the dietary glycaemic index and glycaemic load has been associated with increased risk of the metabolic syndrome in adults, but limited research exists for younger populations. We aimed to evaluate associations between dietary glycaemic carbohydrate and insulin resistance or the prevalence of the metabolic syndrome defined by three different criteria in a population-based adolescent cohort.
Methods: Diet was assessed using 3 day food records in 769 adolescents aged 13-15 years participating in the Western Australian Pregnancy Cohort (Raine) Study. The metabolic syndrome was identified using age-specific adolescent definitions from the International Diabetes Federation, the National Cholesterol Education Program Adult Treatment Panel III and a population-derived 'high-risk' metabolic cluster algorithm. Presence of a high waist circumference was mandatory only in the International Diabetes Federation definition. Insulin resistance was measured using homeostasis model assessment (HOMA-IR).
Results: The prevalence of the metabolic syndrome as defined by the International Diabetes Federation and the Adult Treatment Panel III was 3.6 and 4.0%, respectively; 25.9% of subjects were classified into the high-risk cluster. Significantly increased odds oflnternational Diabetes Federation-defined metabolic syndrome were independently associated with a 20 unit glycaemicload increase (odds ratio 2.18; 95% confidence interval 1.26-3.78) and a 30 g carbohydrate increase (odds ratio 3.86; 95% confidence interval 1.80-8.28). No significant associations were observed when using the Adult Treatment Panel III, or the cluster-defined metabolic syndrome, or with HOMA-IR.
Conclusions: This study supports the concept that high dietary glycaemic carbohydrate is associated with a higher prevalence of the metabolic syndrome in adolescents. However, relationships vary according to the definition of the metabolic syndrome used, with waist circumference a potentially relevant factor.