Objectives: To evaluate the association between histamine-2 receptor antagonist (H2A) exposure and incident cognitive impairment in a community-based sample of African Americans.
Design: Five-year longitudinal observational study.
Participants: A sample of 1,558 community-dwelling African Americans aged 65 and older with no baseline cognitive impairment living in Indianapolis, Indiana.
Outcome measure: Incident cognitive impairment, defined as incident dementia, cognitive impairment without dementia, or poor cognitive performance, as determined using combined cognitive assessments that included the Community Screening Instrument for Dementia, a comprehensive clinical assessment including informant interview, and neuropsychological testing.
Exposure: Trained interviewers assessed the use of prescription and over-the-counter H2As using in-home inspection of medications and report of participants and informants.
Results: Incident cognitive impairment occurred in 275 (17.7%) participants. After controlling for age, education, baseline cognitive score, the use of anticholinergics, and history of diabetes mellitus and depression, continuous use of H2As was associated with greater risk of incident cognitive impairment than for nonusers (odds ratio=2.42; 95% confidence interval=1.17-5.04).
Conclusion: H2As might be a risk factor for the development of cognitive impairment in African Americans. This finding requires confirmation from future studies.