Brain Science

Autoimmune Diseases Linked to Increased Chance of Dementia

Autoimmune Diseases Linked to Increased Chance of Dementia about undefined
A year ago, 31 senior scientists presented "incontrovertible evidence" that inflammation-creating infections were a key cause of Alzheimer's disease and dementia. Now, another whole category of inflammatory diseases is implicated. New evidence suggests chronic inflammation from autoimmune diseases may also act as a trigger for dementia. In 2016, Professor Robert Richards from the University of Adelaide, Australia, submitted strong backing for the idea that the decline seen in neurodegenerative diseases is sometimes caused by persistent inflammation originating in an uncontrolled, overactive immune system.

MS Doubles The Risk of Dementia

Researchers from the University of Oxford analyzed records of nearly two million hospital admissions in England over a period of 14 years. Their report appears in the March 1, 2017 issue of Epidemiology & Community Health. They took into account 25 different autoimmune disorders, with the numbers in each group ranging from 1,019 for Goodpasture's syndrome (a rare lung and kidney disease) to more than 300,000 people with rheumatoid arthritis (RA). Seven million hospital patients admitted for other reasons acted as a control group. The findings were that 18 of the 25 autoimmune disorders showed significant positive associations with dementia, and people admitted to hospital with these disorders were 20% more likely to be admitted with dementia at a later date. The increased risk for selected autoimmune diseases for any form of dementia were:
  • Myxedema 20%
  • Psoriasis 29%
  • Pernicious anemia 31%
  • Thyrotoxicosis 31%
  • Lupus 46%
  • Polyarteritis nodosa 43%
  • Addison's disease 48%
  • Multiple Sclerosis 97%
Among people who already have MS, the risk of dementia is almost double. Equally interesting is the finding that people with rheumatoid arthritis have a 10% lower risk of dementia.

NSAIDs Lower Inflammation and Reduce Risk

Professor Michael Goldacre, who led the study, believes the reason for this finding is that people with RA commonly take non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen. These have been shown to protect against Alzheimer's in a number of studies. Another important finding was the strong link between autoimmune diseases and heart and circulatory disorders. The increased risk of being admitted to hospital at a later date was even higher than for dementia -- 53% for cardiovascular disease and 46% for stroke. These health problems are known to increase the risk of vascular dementia. When the Oxford researchers looked at different types of dementia, they found that people with autoimmune diseases had a 29% increased risk of vascular dementia but only a 6% increased risk of Alzheimer's. Commenting on this finding, Dr. Colm Cunningham, a specialist in neurodegeneration and brain inflammation at Trinity College, Dublin said, "It's striking that increased risk for vascular dementia exceeds that for Alzheimer's. The impact of autoimmune diseases on cardiovascular disease may be the key common link." In the opinion of Dr. Rudolph Tanzi, Professor of Neurology at Harvard Medical School, "The results are very compelling and support the notion that neurovascular damage and inflammation are key drivers of risk for Alzheimer's disease." James Hendrix, director of the global science initiative for the Alzheimer's Association, observes that the link between autoimmune diseases and vascular dementia is "something new" and could implicate chronic inflammation as a possible cause of progressive dementia. When asked about how best to control inflammation, Professor Goldacre emphasized the importance of a healthy diet and regular exercise.

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