THE ADVENT of the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or statins, has brought a phenomenal advance to pharmacologic disease prevention. Not only has long-term therapy with these agents revolutionized the prevention of acute myocardial infarction and stroke through effective control of hyperlipidemia,1,2 but it also seems to reduce the risk of osteoporosis3 and, now, Alzheimer disease (AD). In this issue of the ARCHIVES, Wolozin and colleagues4 report the results of a large observational study demonstrating the association of statin therapy with a 60% to 73% lower prevalence rate of AD. If this association turns out to be causal, it could represent an important breakthrough in the search for a medication that could prevent or arrest the most common form of dementia. However, for the statistical association to be considered causal, we must have evidence for a plausible biological mechanism for the preventive effect, and plausible alternative explanations for the statistical association must be ruled out.
Haley RW, Dietschy JM. Is There a Connection Between the Concentration of Cholesterol Circulating in Plasma and the Rate of Neuritic Plaque Formation in Alzheimer Disease?. Arch Neurol. 2000;57(10):1410-1412. doi:10.1001/archneur.57.10.1410