INS and Alzheimer disease: Potential concerns over the use of statins to treat AD have been raised by the findings that: 1] brain cholesterol levels are reduced in AD [370]; 2] reductions in neuronal cholesterol lead to impaired insulin signaling and energy metabolism [49]; and 3] cognitive impairment can occur with chronic statin use [379-382] and following its discontinuation, cognitive function may be restored [380, 382].