Suicide remains a major public health challenge worldwide. According to the World Health Organization, suicides account for approximately 720,000 deaths each year [1]. Identifying and addressing high-risk groups is essential for suicide prevention. Individuals with diabetes represent one such vulnerable population. Diabetes imposes a significant psychological burden due to the continuous demands of self-care and disease management. As a result, patients with diabetes often struggle to maintain lifestyle changes and adhere to medical treatments, all of which can increase the risk of suicide [[2], [3], [4], [5]]. A recent study has shown that individuals with diabetes are more than twice as likely to experience suicidal thoughts than those without diabetes [2]. Meta-analyses have confirmed that diabetes significantly increases suicide risk [3]. Therefore, finding ways to predict and prevent death by suicide among patients with diabetes is crucial for public health.

Among modifiable risk factors for suicide, smoking plays a critical role. Smoking has been identified as the strongest predictor of death among patients with type 2 diabetes (T2D) [6]. Compared to non-smokers with diabetes, smokers with diabetes are more prone to serious health complications such as heart disease, kidney disease, and neuropathy, which can exacerbate the psychological burden of living with diabetes [[7], [8], [9]]. In the general population, studies have shown that smokers have a significantly higher risk of suicide than never-smokers [[10], [11], [12], [13]]. However, the association between smoking and suicide risk in patients with diabetes remains poorly understood. This represents a critical gap, given the elevated risk of both physical and mental health complications in this population. Understanding the link between smoking and suicide mortality in patients with diabetes could significantly contribute to the prediction and prevention of suicide in this population.

This nationwide retrospective cohort study aimed to evaluate the association between smoking status and suicide mortality in patients with T2D. Participants were categorized based on current smoking status, intensity, and duration to examine their relationships with suicide death. The aim of this study was to improve our understanding of this association, thus supporting targeted prevention efforts and enhanced patient care for individuals with T2D.