A three-country study on the components of the metabolic syndrome in youths: the BIG Study.

OBJECTIVES: This study aimed to assess the prevalence of components of the metabolic syndrome (MetS) among representative samples of children and adolescents from Brazil, Iran and Germany (BIG study).

METHODS: We report the data of a total number of 4 473 children (mean age 7.7 years; 2 218 boys,) and 6 800 adolescents (mean age 12.6 years; 3 409 boys) who participated in three large national studies. Anthropometric measures, blood pressure (BP) and lipid profile were assessed, fasting plasma glucose was determined in German and Iranian participants.

RESULTS: With few exceptions, the mean of the components of the metabolic syndrome was higher in boys than in girls. The main ethnic differences were the high prevalence of low HDL-C levels in Iranian and Brazilian youths compared with German youths (34% vs.7%, respectively, p<0.05) and of increased triglycerides (10% vs. 1%, respectively, p<0.05). Furthermore the prevalence of high BP was lowest (<1%) in Iranian than in Brazilian and German children (6%). Both in children and adolescents, the prevalence of the MetS was significantly higher in Iranian than in German children (1% vs.0.1%, respectively, p<0.05) and adolescents (2% vs.0.5%, respectively, p<0.05). TG to HDL-C ratio had significant correlations with waist circumference and body mass index in Iranian and German children of both genders; these correlations were significant among both genders of adolescents in the three ethnic groups.

CONCLUSION: While the prevalence of abdominal adiposity was nearly similar, Iranian and Brazilian youths had considerably higher prevalence of dyslipidemia than German youths. Future longitudinal studies should seek the clinical importance of these ethnic differences.