age, they found an 11% increase overall and 14% increase in cardiovascular disease mortality per 1 mg/dL per year drop in total cholesterol levels. The researchers attributed this phenomenon to the fact that people with severe chronic diseases or cancer tend to have below-normal cholesterol levels. [ 72 ] This explanation is not supported by the Vorarlberg Health Monitoring and Promotion Programme, in which men of all ages and women over 50 with very low cholesterol were likely to die of cancer, liver diseases, and mental diseases. This result indicates the low-cholesterol effect occurs even among younger respondents, contradicting the previous assessment among cohorts of older people that this is a proxy or marker for frailty occurring with age. [ 73 ] Abnormally low levels of cholesterol are termed hypocholesterolemia . Research into the causes of this state is relatively limited, but some studies suggest a link with depression , cancer , and cerebral hemorrhage . In general, the low cholesterol levels seem to be a consequence, rather than a cause, of an underlying illness. [ 53 ] A genetic defect in cholesterol synthesis causes Smith-Lemli-Opitz syndrome , which is often associated with low plasma cholesterol levels. The American Heart Association recommends testing cholesterol every five years for people aged 20 years or older. [ 76 ] A separate set of American Heart Association guidelines issued in 2013 indicates that patients taking statin medications should have their cholesterol tested 4–12 weeks after their first dose and then every 3–12 months