Abstract
BACKGROUND: Genetic factors play an important role in metabolic disease susceptibility. Apolipoproteins E (APOE) and A1 (APOA1) are key regulators of lipid metabolism and have been individually associated with dyslipidemia and type 2 diabetes mellitus (T2DM). OBJECTIVE: This study aimed to examine the individual and combined associations of APOE (rs429358, rs7412) and APOA1 (rs5069) gene polymorphisms with obesity and T2DM. METHODS: A case-control study was conducted including 350 participants categorized into four groups: controls (n = 100), euglycemic obese individuals (n = 100), obese individuals with T2DM (n = 100), and non-obese individuals with T2DM (n = 50). Biochemical parameters, including lipid profiles and glycemic indices, were assessed. Genotyping was performed using TaqMan(®) SNP genotyping assays. RESULTS: Metabolic disturbances and dyslipidemia were observed across all patient groups, with the most pronounced abnormalities in obese individuals with T2DM. The APOE ε4 allele and ε4/ε4 genotype were significantly associated with obese T2DM compared with controls and euglycemic obese subjects. The APOA1 rs5069 A allele and AA genotype were associated with both obesity and T2DM. Spearman correlation analysis revealed a positive co-occurrence of APOE and APOA1 genotypes in euglycemic obese (ρ = 0.264, p = 0.008) and obese T2DM (ρ = 0.347, p < 0.001) groups, but not in non-obese T2DM individuals. However, in multivariate logistic regression models adjusted for age, sex, and BMI, the APOE × APOA1 interaction term did not reach statistical significance (p = 0.138). CONCLUSION: APOE ε4 and APOA1 rs5069 A alleles were independently associated with obesity-related T2DM. Although these variants demonstrated correlated distribution patterns in obese individuals, the formal gene-gene interaction on T2DM risk was not statistically significant after multivariable adjustment. These findings suggest that obesity may represent a metabolic context in which combined genetic associations are more evident, warranting further investigation in larger and well-powered cohorts.