Cholesterol and dementia risk – the evidence
Recent reviews have concluded that high midlife total serum cholesterol is associated with an increased risk of any dementia and of Alzheimer’s disease [1,2]. While there are some studies that have not found this association, the majority of studies show that high midlife cholesterol increases the risk of later developing dementia by around 2 times.
A meta-analysis of studies measuring cholesterol at late life and following participants over a few years found no association between late life cholesterol and dementia risk [2]. Another study found that a decrease in cholesterol level from midlife to late life was associated with an increased risk of Alzheimer’s disease [3]. Cholesterol levels may decline in the preclinical stages of Alzheimer’s [1,2].
Several studies have shown reduced risk of dementia in those treated with statins, but a meta-analysis found only a small non-significant benefit [4].
How does cholesterol impact on dementia risk?
Some epidemiological and experimental studies suggest the cellular cholesterol level to be involved in the pathogenesis of AD [4]. High cholesterol levels may accelerate the production of beta amyloid [4]. Autopsy findings indicated that low midlife total cholesterol was associated with a lower number of plaques and tangles [1].
References
- Kivipelto M & Solomon A. Cholesterol as a risk factor for Alzheimer’s disease – epidemiological evidence. Acta Neurol Scand, 2006, 114(Suppl. 185):50-57.
- Anstey KJ, et al. Cholesterol as a risk factor for dementia and cognitive decline: a systematic review of prospective studies with meta-analysis. Am J Geriatr Psychiatry, 2008, 16:343-354.
- Stewart R, et al. Twenty-six-year change in total cholesterol levels and incident dementia: the Honolulu-Asia Aging Study. Arch Neurol, 2007, 64:103-107.
- Zhou B, et al. Prevention and treatment of dementia or Alzheimer’s disease by statins: a meta-analysis. Dement Geriatr Cogn Disord, 2007, 23:194-201.
