Role of toxic and essential elements in sleep duration of patients with cardiovascular diseases

Sleep disorders are a common aspect of cardiovascular diseases (CVDs) that can negatively impact a patient's quality of life, trigger coronary events, accelerate disease progression, and influence patient survival. This study aimed to investigate the relationship between essential and toxic elements with sleep duration among CVD patients. The study utilized cross-sectional data from 150 patients with CVDs (n = 150) from the Ravansar Non-Communicable Disease (RaNCD) Cohort Study. Serum concentrations of zinc (Zn), copper (Cu), Iron (Fe), arsenic (As), mercury (Hg), and nickel (Ni) were measured using a gas chromatography-mass spectrometry. The prevalence of short-sleep duration (< 7 h), normal sleep duration (7-8 h), and long-sleep duration (> 8 h) were 36%, 10.6%, and 53.3%, respectively. No significant differences were found among the three sleep duration categories in terms of serum concentrations of toxic and essential elements. The adjusted regression model showed that ORs for sleep duration across Zn quartiles Q1, Q2, Q3, and Q4 were 1.00 (reference), 0.32 (95% CI, 0.11-0.84), 0.31 (97.1% CI 0.11-0.81), and 0.33 (98.7% CI 0.12-0.88), respectively (p for trend = 0.006). Our findings suggest a significant relationship between serum zinc levels and sleep duration, with higher zinc concentrations being associated with optimal sleep duration.