Impact of Obesity on Biochemical Parameters and the Association Between NAFLD and Type 2 Diabetes Mellitus: A Retrospective Study

Abstract

Background: Non-alcoholic fatty liver disease (NAFLD), now termed metabolic dysfunction-associated steatotic liver disease (MASLD), is strongly associated with obesity, insulin resistance and type 2 diabetes mellitus (T2DM). Obesity and T2DM may contribute to hepatic steatosis, abnormal liver enzymes and atherogenic dyslipidemia. However, the relationship between obesity, biochemical abnormalities and NAFLD among patients with T2DM requires further characterization in routine clinical settings. Objective: To evaluate the impact of obesity on liver function tests (LFTs) and lipid profile and to assess the biochemical association between NAFLD and T2DM among obese patients attending SLCMC and SPNH, Khagaria. Methods: This retrospective observational study was conducted at SLCMC and SPNH, Khagaria, using medical records from 1 June to 15 September. A total of 1050 patients with obesity and T2DM were included. Demographic characteristics, body mass index (BMI), duration of diabetes, glycemic parameters, liver function tests and lipid profile were retrieved from medical records. NAFLD was identified based on documented hepatic steatosis on abdominal ultrasonography after exclusion of significant alcohol use and other major causes of liver disease. Patients were categorized into NAFLD and non-NAFLD groups. Statistical analysis was performed using SPSS version 26.0. Continuous variables were expressed as mean ± SD and categorical variables as frequencies and percentages. Student's t-test, chi-square test and Pearson correlation were used as appropriate. A p-value <0.05 was considered statistically significant. Results: Of the 1050 obese patients with T2DM, 618 (58.9%) had NAFLD and 432 (41.1%) did not. Patients with NAFLD had significantly higher BMI, waist circumference, HbA1c, ALT, AST, triglycerides and LDL-C and lower HDL-C than patients without NAFLD (p<0.001 for most comparisons). ALT, triglycerides and LDL-C increased progressively with increasing obesity class, whereas HDL-C decreased significantly. NAFLD prevalence was 52.4%, 61.3% and 69.8% among patients with class I, class II and class III obesity, respectively (p<0.001). BMI showed significant positive correlations with ALT (r=0.38), triglycerides (r=0.42), LDL-C (r=0.29) and HbA1c (r=0.31), while showing an inverse correlation with HDL-C (r=-0.35). Conclusion: Among obese individuals with T2DM, NAFLD was common and was associated with a more adverse biochemical profile, including higher aminotransferases, triglycerides, LDL-C and HbA1c and lower HDL-C. Increasing obesity severity was associated with greater NAFLD prevalence and metabolic abnormalities. Routine assessment of hepatic and metabolic parameters may facilitate earlier identification of patients at increased risk of MASLD-related liver disease. Keywords: NAFLD; MASLD; obesity; type 2 diabetes mellitus; liver function tests; lipid profile; triglycerides; ALT; dyslipidemia.