Especially in older people who are at high risk of developing Alzheimer’s disease.
Depression, urinary incontinence, seasonal allergies: the most prescribed drugs are the most at risk
Anticholinergic drugs block the action of acetylcholine, a chemical messenger that controls a range of automatic bodily functions and plays a vital role in memory and attention. Doctors prescribe these drugs for various conditions. Including urinary incontinence, overactive bladder, chronic obstructive pulmonary disease (COPD), seasonal allergies and depression.
However, over the past decade there has been growing evidence that anticholinergics may increase the risk of dementia in older adults. Researchers at the University of California, San Diego have now linked anticholinergics to mild cognitive impairment, which can lead to dementia, including Alzheimer’s disease.
The increased risk was particularly pronounced in people who had biomarkers of Alzheimer’s disease in their cerebrospinal fluid and in those who had an increased genetic risk of developing the disease. This interaction between anticholinergic drugs and biomarkers of Alzheimer’s risk is doubly effective. In the first case, biomarkers for Alzheimer’s disease indicate that the degeneration begins in a small region of the brain called the basal forebrain, which produces acetylcholine. Then, in the second case, anticholinergic drugs further deplete the brain’s acetylcholine stores. This combined effect has a very significant impact on a person’s thinking and memory.
A 47% increase in the risk of cognitive impairment
The study involved 688 people who participated in the Alzheimer’s Disease Neuroimaging Initiative. The participants had an average age of 74, and none showed signs of cognitive or memory problems at the start of the study. A third of them were taking at least one type of medication, with an average of 4.7 anticholinergic drugs per person. There were no differences in genetic risk factors between people taking anticholinergics and those not taking them.
However, depressive symptoms, total number of medications and heart problems were greater in people taking anticholinergics. So these variables were taken into account in all subsequent analyses. From the start of the study, participants took annual cognitive tests for up to 10 years.
Among those taking at least one anticholinergic, there was an overall 47% increased risk of mild cognitive impairment compared to those taking none. Those taking these drugs and who were genetically at risk of developing Alzheimer’s disease were more than 2.5 times more likely to develop mild cognitive impairment than those who were not taking the drugs and were not genetically at risk . Participants who had Alzheimer’s biomarkers in their cerebrospinal fluid at the start of the study and who were taking anticholinergics were almost 5 times more likely to show signs of mild cognitive impairment.
The results of the study are published in the journal Neurology.