Association Between Trace Elements and Sleep Duration in Patients with Type 2 Diabetes Mellitus: Evidence from a...

Sleep disorders exert a significant influence on the overall quality of life, especially in diabetic patients. Hence, the identification of the risk factors causing sleep disorders is an important public health issue. The present research was conducted to investigate the relationship between sleep duration in type 2 diabetes and serum levels of heavy metals using data from the Non-Communicable Diseases (RaNCD) Cohort Study. In this study, 300 individuals, comprising type 2 diabetes mellitus (n = 150) and healthy control group (n = 150), were enrolled from the RaNCD cohort. The sleep duration of the study subjects was measured using the Pittsburgh Sleep Quality Index (PSQI) tool. Serum concentrations of toxic and essential metals, including arsenic (As), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), nickel (Ni), and zinc (Zn), were analysed using ICP-MS (Agilent 7900). The findings indicated that BMI and age were the only demographic parameters showing significant differences between diabetic patients and the control group (p < 0.05). Serum concentrations of As, Cr, Hg, Ni, and Cu were significantly higher in diabetic patients, while zinc (Zn) levels were elevated in the control group. Although no direct association was found between overall trace element concentrations and sleep duration, subgroup analysis using the Mann-Whitney test revealed that Cr and Hg levels were notably higher in specific diabetic subgroups. On the other hand, a nonlinear relationship was observed between the logarithm of Cr levels and sleep duration (P for non-linearity = 0.022), with Cr levels remaining stable in individuals sleeping less than 7 h and peaking among those with 7-8 h of sleep. Our study also presented a correlation of serum Hg and Cr with sleep duration. Higher levels of Hg were associated with unacceptable sleep duration, while Cr was positively associated with sleep duration in diabetic patients. These exploratory findings warrant further longitudinal studies to validate the observed associations and clarify the role of trace elements in sleep regulation across diverse populations.