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.