Do statins increase dementia risk?
On 6 November 2007, Medical News Today published a report entitled Study Of Relationship Between Statins And Cognitive Decline. The abstract to that study is below. (I have the full text.)
What the study found was that the:
"Initial use of statins resulted in less cognitive decline in individuals, but continued use of a statin resulted in more cognitive decline."(emphasis added)
At first sight, this looks confusing. But only at first sight — for these results are easily explained.
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Szwast SJ, Hendrie HC, Lane KA, et al. Association of statin use with cognitive
decline in elderly African Americans.Neurology2007; 69: 1873-1880
ABSTRACT
Background: Previously reported associations between statin use and incident dementia or cognitive
decline have been inconsistent. We report the results from a 3-year prospective study on the
association of statin use on cognitive decline and incident dementia in elderly African Americans.
Methods: A community-based cohort of 1,146 African Americans aged 70 and older living in
Indianapolis, Indiana, was evaluated in 2001 and 2004. The instrument used for cognitive assessment
was the Community Screening Interview for Dementia (CSI-D). Cognitive decline was
defined as CSI-D scores measured at 2001 minus scores at 2004. Measurements of low-density
lipoprotein cholesterol (LDL-C) and C-reactive protein (CRP) were obtained from baseline blood
samples.
Results: Adjusting for age at baseline, gender, education, and the possession of ApoE _4 allele, baseline statin use was associated with less cognitive decline (p=.0177). There were no significant interactions of statin use when LDL-C and CRP were included. Logistic regression with the four independent variables showed that statin use may be associated with a reduction in incident dementia (OR _ =0.32; p _ =0.0673). Association with cognitive decline was less clear when investigating statin use over time. Significance remained only for those who discontinued prior to follow-up compared to continuous users or users who started after baseline.
Conclusions: The relationship between statin use and cognitive decline is complex and subjected to unknown confounders. This effect may not be associated with the cholesterol lowering or anti-inflammatory action of statins.
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COMMENT: This study found that taking statins slowed down the oncoming of dementia at first. But after a short initial benefit, cognitive decline and dementias such as Alzheimer's, speeded up in those taking statins. Right, let's look at what this really demonstrates.
Work in the 1950s found that as we get older, the level of cholesterol in our brains declines.[1] Later studies suggested that this decline may be the cause of brain disorders such as Alzheimer's.
In 1991, a paper discussing the relief of Alzheimer's Disease, asked that 'strategies for increasing the delivery of cholesterol to the brain should be identified' and recommended increasing fat intake.[2]
The Framingham Study added weight to this proposition when it examined the relationship between total cholesterol and cognitive performance.[3] Participants were 789 men and 1105 women who were free of dementia and stroke and who received biennial cholesterol checks over a 16- to 18-year surveillance period. Cognitive tests were administered four to six years after the surveillance period and consisted of measures of learning, memory, attention, concentration, abstract reasoning, concept formation, and organizational abilities.
The researchers found a significant linear association between the level of blood cholesterol and measures of verbal fluency, attention, concentration, abstract reasoning, and a composite score measuring multiple cognitive domains. Participants with 'desirable' cholesterol levels of less than 5.2 mmol/L (200 mg/dL) performed significantly less well than participants with cholesterol levels higher than 6.25 mmol/L (240 mg/dL). Dr. Penelope K. Elias from Boston University said that:
'It is not entirely surprising that lower cholesterol levels were associated with moderately lower levels of cognitive function, given [that] cholesterol is important in brain function.'
And Henry Lorin in his book, Alzheimer's Solved, shows that low cholesterol level is the main cause of Alzheimer's disease.[4]
The bottom line
This new study actually confirms the role of low cholesterol in Alzheimer's disease and in cognitive decline generally. And this is why:
Having a high cholesterol is associated with having good cognitive function and with being on a statin. Hence just after the beginning of statin therapy, these
people will still show a relatively good cognitive function.
If they continue with the statins, however, the detrimental effects of lower cholesterol on brain function will progressively show up.
This is exactly the pattern this study shows. And that is why those who started taking statins, then stopped, were in a better state than those who continued to take them.
In view of this evidence, why on earth is the government so keen to get everyone on cholesterol-lowering drugs?
References
1. Max Bürger. Altern und Krankheit als Problem der Biomorphose. 3rd Ed, Georg Thieme, Leipzig, 1957.
2. Corrigan FM, et al. Dietary supplementation with zinc sulphate, sodium selenite and fatty acids in early dementia of Alzheimer's Type II: Effects on lipids. J Nutr Med 1991; 2: 265-71.
3. Elias PK, et al. Serum Cholesterol and Cognitive Performance in the Framingham Heart Study. Psychosom Med 2005; 67:24-30.
4. Lorin, Henry. Alzheimer's Solved. BookSurge Publishing, 2006.
Last updated 7 November 2007
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