Prevalence of General and Abdominal Obesity in a Nationally Representative Sample of Iranian Children and Adolescents: The CASPIAN-IV Study

BACKGROUND: Pediatric obesity is one of the predisposing risk factors for many non-communicable diseases. OBJECTIVES: The purpose of this study was to estimate the national prevalence of general and abdominal obesity among Iranian children and adolescents. PATIENTS AND METHODS: This cross-sectional nation-wide study was performed in 30 provinces in Iran among 14880 school students aged 6 – 18 years, selected by multistage random cluster sampling. The World Health Organization growth curve was used to categorize Body Mass Index (BMI). Obesity was defined as BMI equal to or higher than the age- and gender-specific 95(th) percentile; abdominal obesity was considered as waist-to-height ratio of more than 0.5. RESULTS: Data of 13486 out of 14880 invited students were complete (response rate of 90.6%). They consisted of 6543 girls and 75.6% urban residents, and had a mean age of 12.45 (95% CI: 12.40 - 12.51) years. The prevalence rate of general and abdominal obesity was 11.89% (13.58% of boys vs. 10.15% of girls) and 19.12% (20.41% of boys vs. 17.79% of girls), respectively. The highest frequency of obesity was found in the middle school students (13.87% general and 20.84% abdominal obesity). The highest prevalence of general obesity was found in Boushehr (19%) followed by Guilan and Mazandaran (18.3%, 18.3%), while the lowest prevalence was observed in Hormozgan (2.6%). The highest frequency of abdominal obesity was found in Mazandaran (30.2%), Ardabil (29.2%) and Tehran (27.9%). Provinces such as Sistan-Baloochestan (8.4%), Hormozagan (7.4%), and Kerman (11.4%) had the lowest prevalence of abdominal obesity. The Southern and South Eastern provinces had the lowest prevalence of general obesity (2.6% and 5.6%) and abdominal obesity (7.4% and 8.8%). Moreover, the highest prevalence of obesity was found in North and North West Iran by maximum frequency of 18.3% general obesity and 30.2% of abdominal obesity. CONCLUSIONS: The results showed a high prevalence of general and abdominal obesity among boys living in the Northern provinces of Iran. The present study provides insights that policy makers should consider action-oriented interventions for prevention and control of childhood obesity at national and sub-national level.