Association between fluctuations in blood cholesterol levels and the risk of suicide death in the general population

Objective: Suicide is a pressing global public health issue. While recent studies have explored the association between serum cholesterol levels and suicide risk, the association between cholesterol variability and suicide risk is not well characterized. Methods: This was a nationwide population-based cohort study using data from the Korean National Health Insurance Service database. A total of 1,983,701 patients with at least three measurements of TC between 2004 and 2009 were included. Participants were followed until death by suicide or the study's end in December 2021. Participants were categorized based on baseline TC or TC variability. TC variability was assessed using coefficient of variation (CV), variability independent of the mean (VIM), and average successive variability (ASV). Results: Over a median follow-up of 11 years, 5883 (0.3 %) patients died by suicide. Compared to subjects with TC <200 mg/dL, those with TC >= 240 mg/dL had a lower risk of suicide death (hazard ratio [HR]: 0.85, 95 % confidence interval [95 % CI]: 0.78-0.93). In the unadjusted model, the HR for suicide death in the highest quartile (Q4) compared to the lowest quartile (Q1) of TC variability was 1.36 (95 % CI: 1.26-1.46). After adjusting for potential confounders, high variability in TC levels was associated with a higher risk of suicide death (HR 1.27, 95 % CI: 1.18-1.37). When analyzed based on the combination of TC baseline and variability, the highest quartile of TC variability showed a higher rate of suicide death compared to the lowest quartile, regardless of baseline TC level. Conclusion: High TC variability and low TC levels were associated with an increased risk of suicide.