STATIN THERAPY IS ASSOCIATED WITH REDUCED NEUROPATHOLOGIC CHANGES OF ALZHEIMER DISEASE

To the Editor:

Li et al. referred to direct evidence of statin effects on the brain reducing Alzheimer disease (AD).¹ What they show are neither “direct” nor “effects,” but associations. This study failed to heed critiques of previous AD statin links.²

Patients who took statins have had lower rates of AD or associated autopsy changes¹ but this means little. Similarly, people who took hormone replacement therapy (HRT) also had sharply lower AD rates³ (and mechanisms supported potential benefit)⁴ but with randomization providing a comparable control group, HRT significantly increased dementia.⁵

Better educated people—who have greatly lowered rates of AD irrespective of medications⁶—are more likely to receive preventive medicines like HRT and statins, creating the appearance of a protective connection. Moreover, in the case of statins, low low density lipoprotein (LDL) and low cholesterol have been linked to more neurodegeneration⁷ and preclude statin use. This again could explain lower rates of AD in statin users. (Statin users have higher LDL before and often despite statin therapy.)

In theory, statins could even be harmful, since studies have repeatedly shown that more potent statins, which may better combat the high LDL that motivated their use, lose the beneficial link to AD. One possible reason is that LDL transports vital antioxidants including coenzyme Q10, which have been shown to …