Comparison of noncardiovascular and cardiovascular mortality related to low serum cholesterol among males and females

Background: Contrary to popular belief, no study to date has provided evidence regarding the effect of low cholesterol level on extended overall survival. Objectives: The aim of the current study was to examine the possible relationship between low serum cholesterol (< 160 mg/dL) and mortality from cardiovascular diseases (CVDs) and non-CVDs in males and females. Methods: This observational, prospective, cohort study included 19 different large-scale dynamic cohort studies in Italian populations, followed-up for 9 years. The Cox proportional hazard ratio (HR) was measured to analyze the data. The associations were presented as HRs with 95% confidence intervals. Results: The results showed that 1906 deaths (males, 1439 and females, 467; total non-CVD, 1214 and total CVD, 692) occurred during the 9-year follow-up. Total mortality for non-CVD was almost twice (1.76) higher than that of CVD. There was a significant inverse association between low serum cholesterol and non-CVD mortality in males, unlike females. The association of low cholesterol level with non-CVD mortality was more significant than CVD mortality among males (non-CVD: HR, 2.06; 95% CI, 1.54 - 2.74 vs. CVD: HR, 0.81; 95% CI, 0.54 - 1.22). However, an insignificant association was found between both non-CVD and CVD mortalities and low serum cholesterol among females (non-CVD: HR, 1.52; 95% CI, 0.91 - 2.50 vs. CVD: HR, 1.56; 95% CI, 0.72 - 3.38). Conclusions: The findings indicated an inverse association between low serum cholesterol and high non-CVD mortality versus CVD mortality. Therefore, non-CVD mortality rate was higher than CVD mortality in males and lower in females at minimum cholesterol level.