Our immune system is pretty great. It helps us recover from injury and fight off deadly pathogens. However, sometimes the immune system does its job a little too well. In certain autoimmune diseases, immune cells can mistakenly recognize a part of our own body as a foreign invader and start attacking it. Depending on what type of tissue is being targeted, autoimmunity can lead to a variety of conditions including rheumatoid arthritis, celiac disease, and multiple sclerosis. Approximately 50 million Americans (20% of the population) have an autoimmune disease.
A study published this week in the Journal of Epidemiology and and Community Health looked at the relationship between autoimmune diseases and dementia. The researchers used health records of more than 1.8 million people in England who were hospitalized for an autoimmune condition between 1998 and 2012. They found that these patients were 20% more likely to be later hospitalized for dementia compared to controls. They identified 18 autoimmune diseases that were significantly associated with dementia. When they examined the type of dementia, the autoimmune patients were at the greatest risk for vascular dementia, with a 28% higher risk than normal. The increased risk for Alzheimer’s disease was relatively small at 6%.
This study is in line with several previous papers that hinted at a possible link between autoimmunity and dementia. It’s been shown that people with two common autoimmune diseases, type 1 diabetes and thyroid autoimmune disease, are at an increased risk of dementia. The mechanism for this connection remains unknown, but it raises the interesting question of whether dementia may be related to the immune system.
Additionally, the study supports the possible use of NSAIDs as a way to reduce the risk of dementia. NSAIDs (which include aspirin, ibuprofen, and naproxen) are some of the most commonly-used painkillers and can also be used to combat inflammation in autoimmune conditions. People who take NSAIDs tend to have a reduced risk of Alzheimer’s disease, suggesting that using these drugs to treat an overactive immune system could have cognitive benefits as well.
Many doctors have begun prescribing baby aspirins to their patients in the hopes of decreasing their risk of dementia as well as cardiovascular disease. However, caution is necessary when considering an NSAID regimen. It’s possible that for some people, NSAIDs could be doing more harm than good, as one study suggested that these drugs may reduce the risk of Alzheimer’s but increase the risk of vascular dementia. More research is needed before we can say conclusively whether NSAIDs may be beneficial for cognitive health.