Association of anticholinergic drug exposure with the risk of dementia among older adults in Japan: The LIFE Study.

Objectives: Several studies have investigated that anticholinergic drugs cause cognitive impairment. However, the risk of dementia associated with anticholinergics has not been extensively investigated in the super-aging society of Japan. We conducted this study to assess the association between anticholinergic drugs and the risk of dementia in older adults in Japan.

Methods: This nested case-control study used data from the Longevity Improvement & Fair Evidence Study, which includes claim data in Japan from 2014 to 2020. We included 66,478 cases of diagnosed dementia and 328,919 matched controls aged ≥65 years, matched by age, sex, municipality, and cohort entry year. Primary exposure was the total cumulative anticholinergic drugs prescribed from cohort entry date to event date or matched index date, which was the total standardized daily doses for each patient, calculated by adding the total dose of different types of anticholinergic drugs in each prescription, divided by the World Health Organization-defined daily dose values. Odds ratios for dementia associated with cumulative exposure to anticholinergic drugs were calculated using conditional logistic regression adjusted for confounding variables.

Results: The mean (standard deviation) age at index date was 84.3 (6.9), and the percentage of women was 62.1%. From cohort entry date to event date or matched index date, 18.8% of the case patients and 13.7% of the controls were prescribed at least one anticholinergic drug. In the multivariable-adjusted model, individuals with anticholinergic drugs prescribed had significantly higher odds of being diagnosed with dementia (adjusted odds ratio, 1.50 [95% confidence interval, 1.47-1.54]). Among specific types of anticholinergic drugs, a significant increase in risk was observed with the use of antidepressants, antiparkinsonian drugs, antipsychotics, and bladder antimuscarinics in a fully multivariable-adjusted model.

Conclusions: Several types of anticholinergic drugs used by older adults in Japan are associated with an increased risk of dementia. These findings suggest that the underlying risks should be considered alongside the benefits of prescribing anticholinergic drugs to this population.