Although the relative risk (RR) for coronary heart disease (CHD) and cardiovascular disease (CVD) mortalities increase with serum total cholesterol (TC) level, all-cause mortality follows a U-curve.
According to Low Serum Cholesterol and Mortality: Which Is the Cause and Which Is the Effect?, certain illnesses that increase mortality lower TC levels. This is the Iribarren hypothesis.
According to Cholesterol and all-cause mortality in elderly people from the Honolulu Heart Program: a cohort study, TC that's low and is still low 20 years later results in a 64% increase in the RR for mortality relative to TC that's intermediate and is still intermediate 20 years later.
|Table 4 Relative risk for mortality based on change in cholesterol between examinations three and four|
Interestingly, TC that's low but is intermediate 20 years later results in a 30% increase in the RR for mortality, whereas TC that's low but is high 20 years later results in a 5% increase in the RR for mortality.
P.S. There's a false dichotomy for vitamin D level vs illness. Ditto for carbohydrates vs calories.