The cardiovascular benefit of statins is anything but news. But a very large retrospective study from Taiwan may bring the utility of these drugs to an entirely new level--it appears that the use of high dose statins cut the risk of senile dementia in older people. And by a lot.
And if there is one area where medical progress is sorely needed, it's Alzheimer's Disease. Because, despite being the target of vast amounts of research, all we really have is a vast amount of failures.
Treating Alzheimer's is bad enough (and the treatments for it are plenty bad). But preventing it? With the exception of taking steps to reduce vascular dementia (due to strokes)--forget it. Every vaccine, therapeutic or preventative, has been a total bomb.
Statins have been suspected of both increasing and decreasing dementia. Ironically, one reason that this study was conducted was to see whether cognitive dysfunction was a possible side effect of statins.
It didn't exactly turn out that way.
In a presentation to the 2013 meeting of the European Society of Cardiology, Dr. Tin-Tse Lin and Dr. Min-Tsun Liao of the National Taiwan University Hospital reported that not only didn't statins adversely impact cognitive function, but they had a significant protective effect .
Lin and colleagues used a database of one million people covered by Taiwan's national health insurance program. From this sample, about 57,000 people (aged 65+) with no history of senile dementia were selected during the period of 1997-1998. About 15,000 of these participants were taking statins.
During the 4.5 year follow-up period, about 5,500 people developed non-vascular senile dementia (not caused by strokes or blockages). And the data from this group are fascinating.
As shown in Figure 1, there was a substantial and dose-dependent difference in the number of dementia cases for participants who took statins--the higher the dose, the lower the risk of dementia. Also, the more potent statins showed a larger effect than the less potent, which in effect, strengthens this dose response trend (which is already impressive).
Figure 1: Dose Response of Statins (Source:http://www.theheart.org/article/1578833.do). For clarity, hazard ratios (given in the report) were converted to percent reduction: 1.0 minus HR times 100 = percent reduction.
For example, for rosuvastatin (Crestor), the low, medium and high dose groups showed a reduction in the incidence of dementia by 63, 87, and 87(!) percent, respectively.)
The relationship between the potency of the particular statin and protection against dementia is similarly interesting (Figure 2, below).
There is clearly a relationship between the inherent potency of the statins (at equivalent doses) and their effect. For comparison, the low-dose group is used as an example). The potent statins (atorvastatin and rosuvastatin) clearly outperform the less potent statins (e.g., lovastatin) in reduction of dementia.
Figure 2. Correlation of statin potency (low dose) with percentage of dementia reduction . Rosuvastatin is arbitrarily assigned 100 for reference purposes.
Of course, as a retrospective study (albeit a very good one), there are built-in limitations. It cannot prove that statin use will protect you against senile dementia--only that there is a strong association between the two. Cause and effect can only be determined by a prospective controlled study--something that will surely be done now.
This is far from definitive, but given the huge number of participants, the robust dose response, and the relationship between the strength of the statin and the magnitude of the response, it would seem that they are onto something here.
And when you add the fact that non-vascular-related dementia was excluded from the data, suggesting that the is more going on here than statins acting as lipid-lowering agents, it gets even more intriguing.
It is doubtful that high dose statin therapy for seniors will become standard practice anytime soon, but these results are certainly intriguing. Anything that can help combat Alzheimer's--perhaps the most devastating of all diseases--would be an enormous medical advance.