Cognitive changes are commonly observed in older adults following surgical procedures. There are concerns that exposure to general anesthesia (GA) may contribute to an increased risk of Alzheimer's disease.

Our study examined the associations between exposure to GA compared with regional anesthesia (RA) administered for elective surgical procedures and the development of dementia.

Population-based propensity matched retrospective cohort study.

Linked administrative databases were accessed from ICES (formerly called the Institute for Clinical Evaluative Services) in Ontario, Canada.

We included all community-dwelling individuals aged 66 and older who underwent one of five elective surgical procedures in Ontario, Canada, between April 1, 2007, and March 31, 2011.

Individuals with evidence of dementia preceding cohort entry were excluded. Individuals who received GA were matched within surgical procedures to those who received RA on age, sex, cohort entry year, and a propensity score to control for potential confounders.