Dementia, whether from Alzheimer's disease or other causes, is a difficult diagnosis for patients and families. There is no known cause of Alzheimer's and no successful treatments so far. New research from the University of East Anglia might hint at a possible factor in developing dementia.
Researchers there studied patients who had a diagnosis of dementia and found a correlation between the use of anticholinergic (AC) medications and dementia. AC medications, which include antidepressants, allergy medications, and drugs for overactive bladder and Parkinson's, block the neurotransmitter acetylcholine. There has been previous research into anticholinergic medications, and slow healing from brain injury as well as dementia and the connection seems reliable, but it's not well understood how it's happening.
In the most recent research, the team of scientists had access to the medical records of 40,770 patients aged over 65 who had been diagnosed with dementia and compared them to the records of 283,933 similarly aged healthy controls. More than 27 million prescriptions were analyzed. Their results pointed to a connection between dementia and patients who used AC drugs for Parkinson's disease, depression, and bladder conditions.
The study looked at other medications that block acetylcholine, including anti-histamines and drugs prescribed for abdominal spasms but found no increased incidence of dementia in patients who took AC medications for allergies or cramps. The effect was long-term as well. Patients who had taken AC antidepressants were found to have higher rates of dementia, even if the drugs had been used decades before a dementia diagnosis.
The team crunched the data to get even more detail, finding that the patients who took larger amounts of AC antidepressants, bladder medications, and Parkinson's drugs were also the ones who had the highest incidence of dementia. The work is the largest and most detailed study to date into the relationship between dementia and acetylcholine limiting prescriptions. By using a database of medical records and prescription records from the Clinical Practice Research Datalink, the team was able to get a sample that is reasonably representative of age, sex, and ethnicity in Great Britain.
Dr. George Savva from UEA's School of Health Sciences was the lead author and explained, "More than 50 million people worldwide are affected by dementia, and this number is estimated to be 132 million by 2050. Developing strategies to prevent dementia is, therefore, a global priority. We studied patients with a new dementia diagnosis and looked at what anticholinergic medication they were prescribed between four and 20 years prior to being diagnosed. We found that people who had been diagnosed with dementia were up to 30 percent more likely to have been prescribed specific classes of anticholinergic medications. And the association with dementia increases with greater exposure to these types of medication. This research is really important because there are an estimated 350 million people affected globally by depression, and bladder conditions requiring treatment are estimated to affect over 13 percent of men and 30 percent of women in the UK and US."
Check out the video for more information on this research.