Cognitive decline associated with anticholinergics, benzodiazepines and Z‐drugs: Findings from The Irish Longitudinal Study on Ageing (TILDA)

Aims To estimate the association between patterns of anticholinergic, benzodiazepine and Z‐drug medication use and change in cognitive function in middle‐aged and older adults. Methods This prospective cohort study used data from the first three waves of The Irish Longitudinal Study on Ageing (TILDA), including community‐dwelling adults aged ≥50 years followed for up to 4 years (n = 7027). Cognitive function was assessed using the Mini Mental State Examination, animal naming test and word recall tests. Regular medication use was self‐reported at baseline and follow‐up interviews at 2 and 4 years. Pharmacy dispensing claims for a subset (n = 2905) allowed assessment of medication use between interviews and cumulative dosage. Medication use at consecutive waves of TILDA was analysed in relation to change in cognitive function between waves. Results Strongly anticholinergic medications (Anticholinergic Cognitive Burden scale 3), benzodiazepines and Z‐drugs were reported by 7.3%, 5.8% and 5.1% of participants, respectively, at any time during the study. Adjusting for potential confounders, new anticholinergic use between interviews was associated with change in recall score (−1.09, 95% confidence interval −1.64, −0.53) over 2 years compared to non‐use, but not with MMSE (0.07; 95% CI −0.21, 0.34) or animal naming (−0.70; 95% CI −1.43, 0.03). The pharmacy claims analysis was consistent with this finding. Other hypothesised associations were not supported. Conclusions Except for new use of anticholinergic medications, no other findings supported a risk of cognitive decline over 2‐year periods in this middle‐aged and older cohort. Patients and prescribers should weigh this potential risk against potential benefits of commencing anticholinergic medications.