Alzheimer’s disease is a neurodegenerative disorder characterized by progressive memory loss, spatial disorientation, cognitive dysfunction, and behavioral changes. The major genetic risk factor for Alzheimer’s disease is a variant in the apolipoprotein E (APOE) gene called apolipoprotein E4 (APOE4). Findings from a new study suggest that use of anticholinergic drugs increases the risk of cognitive decline, especially among those who are APOE4 carriers.

Anticholinergic drugs are a widely prescribed class of drugs that work by blocking the activity of acetylcholine, a neurotransmitter. They are used to treat a wide range of conditions, including respiratory disorders, Parkinson’s disease, dizziness, allergies, and incontinence, among others.

The study included nearly 700 cognitively normal adults who were enrolled in the Alzheimer’s Disease Neuroimaging Initiative study. Participants provided information regarding regular (at least once a week for more than six months) use of anticholinergic drugs. The authors of the study assessed the participants' progression from normal cognitive function to mild cognitive impairment over a 10-year period and noted rates of decline in memory, executive function, and language. They also investigated whether participants who carried the APOE4 gene were at greater risk for decline.

Participants who took anticholinergic drugs were 42 percent more likely to progress to mild cognitive impairment during the 10-year period compared with participants who did not take the drugs. Participants who took the drugs and were APOE4 carriers had a more than twofold greater risk of decline.

These findings suggest that commonly prescribed anticholinergic drugs increase the risk of cognitive decline, especially among adults who carry the APOE4 gene. Careful consideration of drug choice among older adults is advised.

• Link to study abstract.

• Learn more about the APOE4 gene and Alzheimer’s disease risk in this clip featuring Dr. Dale Bredesen.