Total serum cholesterol in mid-life is consistently associated with increased risk of dementia but this association is not seen in late life, with some studies reporting significant lowering of cholesterol levels before the onset of dementia. Reducing cholesterol with statin drugs reduces risk of heart disease and stroke, but does not seem to affect risk of developing dementia. Genes influencing cholesterol metabolism, such as apolipoprotein E and J also influence risk for dementia.