Introduction: Dyslipidemia remains a central modifiable driver of atherosclerotic cardiovascular disease (ASCVD) and is frequently observed in both Type 2 Diabetes Mellitus (T2DM) and hypothyroidism. Each condition independently alters lipid metabolism through mechanisms involving insulin resistance, impaired lipoprotein clearance, and thyroid-regulated hepatic lipid pathways. However, limited evidence exists on the combined metabolic burden when these disorders coexist, particularly within diverse populations (American Diabetes Association, 2024; American Thyroid Association, 2023).
Objective: To evaluate whether coexistence of T2DM and hypothyroidism produces an additive or synergistic deterioration in lipid biomarkers, thereby amplifying cardiovascular risk beyond the individual disease effects.
Methods: A cross-sectional study of 280 adults categorized into four groups (n = 70 each)—T2DM only, hypothyroidism only, T2DM + hypothyroidism, and healthy controls—was conducted. Fasting lipid parameters (TC, TG, HDL-C, LDL-C) were measured using standardized enzymatic assays. Intergroup comparisons were performed using ANOVA followed by Tukey’s post hoc test; significance was set at p < 0.001.
Results: Participants with coexisting T2DM + hypothyroidism exhibited the most adverse lipid abnormalities, with significantly higher levels of TC (245 ± 32 mg/dL), TG (210 ± 28 mg/dL), and LDL-C (165 ± 25 mg/dL), along with markedly reduced HDL-C (32 ± 6 mg/dL), compared with all other groups (p < 0.001). The magnitude of dyslipidemia exceeded the expected additive effect of the two conditions, indicating a potential synergistic metabolic disruption.
Conclusion: Coexistence of T2DM and hypothyroidism leads to disproportionately severe dyslipidemia, underscoring the importance of integrated endocrine and cardiovascular risk management. Early screening for thyroid dysfunction in individuals with T2DM—and vice versa—may allow for targeted therapeutic strategies that mitigate ASCVD risk. Longitudinal and mechanistic studies are warranted to further elucidate the pathways driving this synergistic interaction.
