en Endocrinology Endocrinology Original Article Original Article <span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="line-height:14.3pt"><b><i><span style="color:blue">Background</span></i></b><i><span style="color:blue">:</span></i> Hypothyroidism can play an important role in the development of non-alcoholic fatty liver disease (NAFLD). This study compared the thyroid function tests in overweight and obese children and adolescents with and without NAFLD.</span><br> <span style="line-height:14.3pt"><b><i><span style="color:blue">Methods:</span></i></b> This case-control study was conducted on 100 children and adolescents<b> </b>aged 4-18 years who referred to the endocrinology clinic of Amirkola Children&#39;s Hospital, Babol, Iran in 2021. 42 obese and overweight children with NAFLD were considered as case group and 56 persons without NAFLD as control group. They were selected after physical examination and body mass index (BMI) assessment. Then, TSH, T4, FBS, lipid profile, 25(OH) vit D3 (VD), AST and ALT levels were measured. Abdominal ultrasound was performed to survey fatty liver. T-test and Chi-score were used for analysis and p< 0.05 was considered significant.</span><br> <span style="line-height:14.3pt"><b><i><span style="color:blue">Results:</span></i></b> The mean age in both group was 11.63&plusmn;2.55 and 10.07&plusmn;2.61 years, respectively (P=0.004). Hypothyroidism was not seen in the groups. Two groups in terms of mean TSH (P=0.92), T4 (P=0.87), FBS (P=0.33), cholesterol (P=0.44), LDL (P=0.35), VD (P=0.07) had no significant difference. However, difference was found between the two groups in terms of the mean level of AST (P=0.003), ALT (P=0.001), TG (P=0.02), HDL (P=0.01) and BMI (P<0.001).&nbsp; </span><br> <span style="line-height:14.3pt"><b><i><span style="color:blue">Conclusion</span></i></b><i><span style="color:blue">:</span></i> This study showed that the mean level of thyroid hormones in both groups did not have significant difference and hypothyroidism was not seen. Other studies with larger sample size and longer periods of time are suggested. </span></span></span><br> &nbsp; Thyroid function test, Non-alcoholic fatty liver, adolescence, Obesity, Overweight. 623 628 http://caspjim.com/browse.php?a_code=A-10-1423-5&slc_lang=en&sid=1 Armineh Barzegar arminehbarzegar97@gmail.com 100319475328460049936 100319475328460049936 No Student Research Committee, Health Research Institute, Babol University of Medical Sciences, Babol, IR Iran Morteza Alijanpour m.alijanpour@yahoo.com 100319475328460049937 100319475328460049937 Yes Non-Communicable Pediatric Diseases Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, IR Iran. Mohammadreza Esmaeeli esmaeilidooki@yahoo.com 100319475328460049938 100319475328460049938 No Non-Communicable Pediatric Diseases Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, IR Iran. Soraya Khafri khafri@yahoo.com 100319475328460049939 100319475328460049939 No Infertility and Reproductive Health Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, IR Iran. Haj Ghorban Nooreddini nooreddini@gmail.com 100319475328460049940 100319475328460049940 No The Clinical Research Development Unit of Amirkola Children's Hospital, Babol University of Medical Sciences, Babol, IR Iran. Mohammad Pournasrollah pornasrollah@yahoo.com 100319475328460049941 100319475328460049941 No The Clinical Research Development Unit of Amirkola Children's Hospital, Babol University of Medical Sciences, Babol, IR Iran. Pouria Alijanpour pouria.alijanpour@yahoo.com 100319475328460049942 100319475328460049942 No Student of Research Committee, School of Health Management & Information Science, Shiraz University of Medical Sciences, Shiraz, Iran.