The Effect of Cumulative Anticholinergic Use on the Cognitive Function of Older Adults: Results from the Personality and Total Health (PATH) through Life Study

Background: Multiple comorbidities are common in older adults, resulting in polypharmacy that often includes medications with anticholinergic properties. These medications have multiple side effects, which are more pronounced in the older population. This study examined the association between the use of anticholinergics and changes in the cognitive function of older adults. Methods: The study population consisted of 2,222 individuals aged 65-69 years at baseline from the Personality and Total Health (PATH) Through Life Study in Australia. Medication data were obtained from the Pharmaceutical Benefits Scheme (PBS). Cognitive measures were obtained from neuropsychological battery assessment. Exposure to cumulative anticholinergic use was quantified to a total standardized daily dose (TSDD). The association between change in cognitive measures between baseline and 4-year follow-up, and cumulative use of anticholinergic was assessed through generalized linear models. Results: During the study period, 18.6% (n = 413) of participants filled at least one prescription for anticholinergics. Compared to those not on anticholinergics, participants on anticholinergics were more likely to be woman (62.7% compared to 45.1%) and spent lesser time engaging in vigorous physical activity (0.4 h/week compared to 0.9 h/week). Cumulative use of anticholinergic resulting in a TSDD exceeding 1,095 was significantly associated with poorer performance in Trail Making Test Part B (Model 1: ß = 5.77, Model 2: ß = 5.33, Model 3: ß = 8.32, p <. 01), indicating impairment in processing speed. Conclusions: In our study, except for speed of processing, other cognitive domains measured were not affected by cumulative anticholinergic use over a 4-year period.