Secular trends in the national prevalence of overweight and obesity during 2007-2009 in 6-year-old Iranian children

BACKGROUND: This study aimed to determine the secular trends in the national prevalence of overweight and obesity among 6-year-old Iranian children, and to compare the results in Northern, Central and Southern parts of the country. METHODS: The data were collected as part of a routine and mandatory national screening program on children entering elementary schools in 2007, 2008 and 2009. RESULTS: The study population comprised 2,600,065 children including 862,433 in 2007, 782,244 in 2008 and 955,388 in 2009. Of total children 12.8%, 13.5% and 10.9% were overweight in 2007, 2008 and 2009, respectively (P > 0.05). The corresponding figures for obesity were 3.4%, 3.5% and 3.4%, respectively (P > 0.05). In all surveys, the prevalence of overweight was higher in Southern region than in the other two regions. P for trend was not significant for prevalence rates of overweight and obesity in any of the regions. CONCLUSIONS: To the best of our knowledge, this study was the first of its kind in presenting the nationwide trend of overweight and obesity in young children living in a developing country. It showed a considerably high prevalence of overweight and obesity, but with a constant rate in three years. The higher prevalence of overweight in Southern region than in Central and Northern regions might be related to the lower socioeconomic position of this population. At a very young age, children's lifestyle is more under control of parents. Primordial and primary prevention efforts against the overweight epidemic can be effective and shall be further strengthened.