Heavy metal toxicity and its impact on diabetes mellitus development: Focus on cadmium and arsenic

Diabetes mellitus, a chronic metabolic disorder characterized by impaired glucose metabolism and insulin resistance, has reached epidemic proportions worldwide. While genetic predisposition and lifestyle factors, such as diet and physical inactivity, have long been recognized as major contributors to the disease, recent studies have shed light on the role of environmental factors, particularly heavy metal exposure. Among these, cadmium and arsenic are two of the most concerning environmental toxicants, as they are widely distributed in the environment through industrial processes, contaminated water, food, and air pollution. Both metals have been shown to contribute to the development and progression of diabetes mellitus, particularly type 2 diabetes, through various biological mechanisms. Cadmium is known to induce oxidative stress, inflammation, and disrupt insulin signaling pathways, while arsenic exposure has been linked to pancreatic β-cell dysfunction and altered glucose homeostasis. Epidemiological studies have reported a significant association between chronic exposure to these metals and an increased risk of developing diabetes, with certain populations living in areas of high arsenic contamination showing elevated diabetes prevalence. Furthermore, evidence suggests that these heavy metals may exacerbate the complications of diabetes, including cardiovascular diseases, nephropathy, and neuropathy, by promoting further oxidative damage and endothelial dysfunction. This review synthesizes the current body of literature on the toxicological effects of cadmium and arsenic in the context of diabetes mellitus. Additionally, we highlight the gaps in knowledge and the need for more rigorous studies to assess the long-term impact of environmental heavy metal exposure on diabetes risk and progression. Given the widespread environmental contamination by these toxicants, understanding their role in metabolic diseases is crucial for public health interventions and prevention strategies.