United Kingdom has analyzed the link between a certain class of drugs and the risk of dementia called anticholinergics.
Their effect is to help relax or contract muscles, and doctors can prescribe them to help treat bladder conditions, gastrointestinal problems, and some of the symptoms of Parkinson’s disease.
In their new study, which looked at data from tens of thousands of participants, the researchers concluded that anticholinergics may increase a person’s risk of developing dementia.
The National Institute for Health Research funded this study, and the scientists published their findings yesterday in JAMA Internal Medicine.
An almost 50% increase in risk
For their study, lead researcher Prof. Carol Coupland and team analyzed the medical records of 58,769 people with dementia and 225,574 people without dementia. They were all 55 years old or above at baseline.
Among those with dementia, 63% were women and the average age was 82. For each person with dementia, the researchers found five control matches of the same age and sex and who attended the same general practice to receive medical care.
Prof. Coupland and colleagues sourced the data from the QResearch database and looked at medical records from between January 1, 2004 and January 31, 2016.
The researchers found that anticholinergic drugs in general were associated with a higher risk of dementia. More specifically, however, anticholinergic antidepressants, antipsychotic drugs, anti-Parkinson’s drugs, bladder drugs, and epilepsy drugs were associated with the highest increase in risk.
Among these, the most frequently prescribed drugs were antidepressants, anti-vertigo drugs, and bladder antimuscarinic drugs (for the treatment of overactive bladders).
These results remained even after the researchers controlled for confounding variables (or known risk factors for dementia), including body mass index (BMI), smoking status, alcohol use, cardiovascular problems, and the use of other medication, such as antihypertensive drugs.
All in all, the researchers concluded that people aged 55 or over who had taken strong anticholinergics on a daily basis for at least 3 years had an almost 50% higher chance of developing dementia than people who had not used this type of medication.
“This study provides further evidence that doctors should be careful when prescribing certain drugs that have anticholinergic properties,” explains study co-author Prof. Tom Dening.
“However,” he warns, “it’s important that [people] taking medications of this kind don’t just stop them abruptly, as this may be much more harmful. If [people] have concerns, then they should discuss them with their doctor to consider the pros and cons of the treatment they are receiving.”
However, they note that this is an observational study, so they cannot confirm whether the drugs are directly responsible for the increased risk of dementia.
The researchers add that doctors may have prescribed some of these drugs to their patients precisely for the treatment of very early dementia symptoms.
An anticholinergic agent is a substance that blocks the neurotransmitter acetylcholine in the central and the peripheral nervous system. These agents inhibit parasympathetic nerve impulses by selectively blocking the binding of the neurotransmitter acetylcholine to its receptor in nerve cells. The nerve fibers of the parasympathetic system are responsible for the involuntary movement of smooth muscles present in the gastrointestinal tract, urinary tract, lungs, and many other parts of the body. Anticholinergics are divided into three categories in accordance with their specific targets in the central and peripheral nervous system: antimuscarinic agents, ganglionic blockers, and neuromuscular blockers.