CLINICAL STUDIES Non-alcoholic fatty liver disease prevalence among school-aged children and adolescents in Iran and its association with biochemical and anthropometric measures Seyed-Moayed Alavian 1 , Amir-Hooshang Mohammad-Alizadeh 2 , Farzaneh Esna-Ashari 3 , Gelayol Ardalan 4 and Behzad Hajarizadeh 5 1 Baqiyatallah Research Center for Gastroenterology and Liver Diseases (BRCGL), Baqiyatallah University of Medical Sciences, Tehran Hepatitis Center, Tehran, Iran 2 The Research Center for Gastroenterology and Liver Disease, Shaheed Beheshti University of Medical Sciences, Tehran, Iran 3 Department of Community and Preventive Medicine, Shaheed Beheshti University of Medical Sciences, Tehran, Iran 4 MPH, Ministry of Health and Medical Education, Tehran, Iran 5 Secretariat of Applied Research, Deputy for Health, Tehran Hepatitis Center, Tehran, Iran Keywords adolescents – children – Iran – non-alcoholic fatty liver – ultrasonography Correspondence Seyed-Moayed Alavian, Baqiyatallah Research Center for Gastroenterology and Liver Diseases (BRCGL), Tehran Hepatitis Center, Baqiyatallah University of Medical Sciences, PO Box 14155/ 3651, Tehran, Iran Tel/Fax: 198 21 81264070 e-mail: alavian@thc.ir Received 9 January 2008 Accepted 14 April 2008 DOI:10.1111/j.1478-3231.2008.01790.x Abstract Objective: To investigate the prevalence of non-alcoholic fatty liver disease (NAFLD) as well as the determination of associated metabolic abnormalities in Iranian school-aged children and adolescents. Method: Data were obtained from 966 children aged 7–18 years in Iran by a cross-sectional survey in 2007. These children were subjected to a complete anthropometric and laboratory measure- ment and abdominal ultrasonography for liver echogenicity and size. A ques- tionnaire was also used to obtain information on demographical and medical history, dietary habit, alcohol consumption and cigarette smoking. Results: Fatty liver was diagnosed by ultrasound in 7.1% of children. The prevalence of elevated alanine aminotransferase (ALT) was 1.8%. NAFLD was significantly more com- mon in the older group (12.5 against 3.5%, P o 0.0001). The odds ratios (OR) (95% confidence interval) for NAFLD in children having elevated ALT, high fasting insulin, total cholesterol, low density lipoprotein (LDL) cholesterol, triglyceride and insulin resistance (IR) were 10.9 (3.9–30.4), 2.8 (1.6–4.8), 2.8 (1.5–5.1), 2.8 (1.5–5.3), 2.5 (1.3–4.8) and 4.4 (1.6–12.3) respectively. Therefore, NAFLD was significantly associated with increasing age, ALT, fasting insulin, total cholesterol, LDL cholesterol, triglyceride and IR. In multiple logistic regression analysis, ALT (OR = 1.2; P o 0.01), total cholesterol (OR = 1.01; P o 0.01) and waist circumfer- ence (OR = 1.14, P o 0.0001) were independent metabolic factors predictive of NAFLD after adjustment for other variables. Conclusion: There was a strong relationship between NAFLD and the abnormal metabolic variables in children. It will be very useful if children are assessed for variables such as waist circumference, fasting blood sugar, fasting insulin and serum lipid profile in order to screen those susceptible to NAFLD. Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in USA (1, 2). The disorder is being recognized increasingly in the paediatric popu- lation (3, 4). Children with NAFLD are almost uni- formly obese and asymptomatic and, except for the presence of hepatomegaly, the disease may be difficult to recognize. In most instances, an incidental finding of abnormal serum aminotransferase leads to the diagnosis of fatty liver or NAFLD in adults and children (5). The histopathological features of NAFLD include steatosis that is primarily macrovesicular, inflammation that is usually mild and variable degrees of fibrosis (6). The prognosis is excellent for individuals with stea- tosis alone, but worsens for individuals with increased fibrosis. The condition may progress to cirrhosis in up to 5% of individuals based on adult studies (1). The actual prevalence of NAFLD remains unknown, because of the lack of population-based studies and reliable non-invasive screening tools (5). Liver International (2008) c  2008 The Authors. Journal compilation c  2008 Blackwell Munksgaard Liver International ISSN 1478-3223