Is Insulin Resistance the Driver or the Outcome of Diabetes Mellitus? A Critical Review

Insulin resistance (IR) and Type 2 diabetes mellitus (DM) are intricately related metabolic conditions that significantly contribute to the global health burden. IR is characterized by chronic hyperglycemia that triggers a cascade of metabolic dysfunctions, including alterations in insulin signaling and the promotion of IR via inflammatory pathways. Concurrently, IR intensifies the progression of DM, resulting in a vicious cycle of metabolic decline and hyperglycemia. This review critically evaluates whether IR is a cause, an effect, or both in the pathogenesis of DM. This study seeks to clarify the causal relationship between IR and DM by integrating mechanistic insights, clinical data, and recent epidemiological studies. However, emerging evidence suggests that IR can be both a cause and an effect in DM, depending on the stage and type of the disease. Public health implications play an important part in the prevention of DM, particularly in developing regions where the prevalence of DM is escalating. Early detection of IR, lifestyle interventions, and therapeutic strategies, coupled with digital health initiatives and urban design, present unique avenues for addressing this worldwide health challenge. Future research must address these gaps in causal inference by undertaking long-term studies, adopting standardized definitions, and implementing precision medicine applications via multiomics approaches. Recognition of IR as both a driver and consequence of diabetes emphasizes the urgent necessity for targeted and comprehensive strategies that address its progression and root causes across different populations.