Association of physical activity and the metabolic syndrome in children and adolescents: CASPIAN Study.

BACKGROUND/AIM: To determine the association of physical activity and the metabolic syndrome in a large national-representative sample of children. METHODS: This study was performed in 2003-2004 on 4,811 school students aged 6-18 years, selected by multi-stage random cluster sampling from six provinces in Iran. We assessed the level of physical activity using a standardized questionnaire, and categorized it to the tertiles. The metabolic syndrome was defined based on criteria analogous to those of the Adult Treatment Panel III. RESULTS: The participants comprised 2,248 boys and 2,563 girls with a mean age of 12.07 +/- 3.2 years. In all age groups, boys were more physically active than girls. The metabolic syndrome was detected in 14.1% of participants, and its prevalence was higher in those subjects in the 1st, 2nd and 3rd tertiles of physical activity, respectively (15.1 vs.14.2 and 13.1%, respectively, p <0.05). This difference was seen in boys, while no difference was found between girls in the 2nd and 3rd tertiles of physical activity. Physical activity was linked to a cluster of factors consisting of high-density lipoprotein-cholesterol and waist circumference, followed by triglycerides in boys, and of triglycerides, waist circumference and blood pressure in girls. In both genders, before and after adjustment for age and body mass index, low levels of physical activity significantly increased the risk of having the metabolic syndrome [in boys: OR: 1.8, 95% CI: 1.1, 2.1; and in girls, OR: 1.6 (1.1, 1.9)]. CONCLUSION: We found an association between physical activity and the metabolic syndrome, which was independent of body mass index and age. Children should be encouraged to have greater physical activity.

Blood pressure and its influencing factors in a national representative sample of Iranian children and adolescents: the CASPIAN Study.

BACKGROUND: This study was performed to determine the blood pressure (BP) percentile curves by height, as well as to assess the prevalence of high BP and its influencing factors among children in the first national survey in this field in Iran. DESIGN: A multicentre national cross-sectional survey. METHODS: This study was performed in 23 provinces among a representative sample of 21,111 students aged 6-18 years. RESULTS: Age and sex-specific percentile curves of systolic and diastolic BP were obtained by height. A comparison of the values obtained corresponding to the 90th percentiles with the Second Task Force cut-offs showed that the BP values and trends were relatively similar in both studies. The overall prevalence of systolic, diastolic as well as systolic or diastolic hypertension according to the Second Task Force study 95th percentile cut-off points were 4.2, 5.4 and 7.7%, respectively, without a significant sex difference. A history of low birthweight, overweight, taller height, the consumption of solid hydrogenated fat, as well as the frequency of fast food consumption increased the risk of both systolic and diastolic hypertension. Male sex, large waist, and low education of the mother were the risks for systolic hypertension, whereas the risk of diastolic hypertension rose with living in an urban area, attending public school, low physical activity level, having a housewife mother, and a positive family history of obesity, especially in the parents. CONCLUSION: Considering the effect of modifiable environmental factors on the childrens' BP, encouraging breast feeding and a healthy lifestyle may have an important effect on public health.