Lower levels of "bad" LDL cholesterol could mean a lower risk of dementia and Alzheimer's disease , a new study says. People with low-density lipoprotein, or LDL, cholesterol levels lower than 70 mg/dl had a 26% lower risk of dementia and 28% lower risk of Alzheimer's, compared to people with LDL levels above 130 mg/dl, researchers reported Tuesday in the Journal of Neurology, Neurosurgery & Psychiatry . Advertisement Statins taken to lower cholesterol also appeared to confer additional