Background: Attention has been focused on the increased risk of high cholesterol, but the effect of low cholesterol remains unclear and receives little attention. Method: The study cohort, 537,430 adults in Taiwan who went through a medical screening program between 1996 and 2008, was followed up for an average of 8.5 years for mortality and cancer incidence, with 18,745 deaths and 17,714 cancer cases identified. Low and very low cholesterol or LDL were defined as