For someone taking a statin, the risk for a heart attack or stroke drops by about 20% for each 39-point reduction in bad cholesterol. Under the new guidelines, anyone 21 or older with an LDL level of 190 or higher should take a statin drug.or someone taking a statin, the risk for a heart attack or stroke drops by about 20% for each 39-point reduction in bad cholesterol. Under the new guidelines, anyone 21 or older with an LDL level of 190 or higher should take a statin drug.