Heavy metal exposure and women’s endocrine–metabolic disorders: An integrative review of PCOS, thyroid dysfunction, metabolic syndrome, and type 2 diabetes

Abstract

Cadmium (Cd), lead (Pb), mercury (Hg), and arsenic (As) are persistent environmental contaminants that can accumulate in human tissues and exert long-term biological effects. Although the acute toxicity of these metals is well established, increasing attention has focused on the effects of chronic, low-level exposure in the general population. These metals may disrupt endocrine and metabolic regulation through mechanisms including oxidative stress, mitochondrial dysfunction, immune activation, and interference with hormonal signaling pathways.

These mechanisms are relevant to endocrine and metabolic disorders affecting women, including polycystic ovary syndrome (PCOS), thyroid dysfunction, metabolic syndrome, and type 2 diabetes mellitus (T2DM). Hormonal transitions across the female life course may also influence responses to environmental exposures and disease expression.

This narrative review synthesizes epidemiological and mechanistic evidence published primarily between 2016 and 2024 and evaluates the relationships between exposure to Cd, Pb, Hg, and As and endocrine and metabolic disorders in women. Arsenic demonstrates the most consistent association with insulin resistance and T2DM. Cadmium has been associated with ovarian dysfunction, oxidative imbalance, and PCOS-related endocrine abnormalities. Lead and cadmium have also been linked to alterations in thyroid hormone levels, thyroid antibodies, and hypothyroid status. Findings regarding mercury remain less consistent.

Overall, current evidence supports a biologically plausible association between heavy metal exposure and the risk of endocrine and metabolic disorders in women. However, most available studies are observational. Longitudinal studies, standardized exposure assessments, and women-centered study designs are needed to clarify causal relationships and inform prevention strategies.

Keywords: Heavy metals, environmental exposure, polycystic ovary syndrome, thyroid dysfunction, metabolic syndrome, type 2 diabetes mellitus, women’s health