Association of urinary levels of trace metals with type 2 diabetes and obesity in postmenopausal women in Korea: A community-based cohort study

Several toxic metals have been associated with metabolic diseases like obesity and diabetes mellitus (DM) in humans. However, knowledge regarding the influence of many trace elements, especially in combination with essential elements is limited. This study aims to address this research gap by investigating the associations of both non-essential and essential inorganic trace elements in urine with DM and obesity, employing a group of postmenopausal women (n = 851) from the Korean Genome and Epidemiology Study (KoGES) cohort. Urine samples were collected during 2017–2018, and were analyzed for 19 trace elements using inductively coupled plasma–mass spectrometry and an automatic mercury analyzer. Outcomes of interest were metabolic diseases (DM and obesity) and DM-related traits (insulin resistance and β-cell function). After adjustment of covariates, such as age, alcohol consumption, smoking status, educational level, and daily energy intake, urinary Zn, Ni, Tl, and U levels were associated with the prevalence of DM and homeostatic model assessment (HOMA) for insulin resistance (IR) in the postmenopausal women. In the whole mixture model, however, no significant association was observed for the prevalence of DM. Urinary levels of Zn were negatively associated with HOMA of β-cell function (HOMA-β), positively correlated with HbA1c levels, HOMA-IR, and prevalent DM. In addition, urinary Zn, Co, Tl, and Cs were positively associated with obesity (body mass index ≥25 kg/m²). The present observation shows that several individual elements and their mixtures may be associated with the prevalence of DM, IR, or obesity.