[The prevalence of mild cognitive impairment among residents aged 55 or over in Chengdu area].

Objective: To study the prevalence of mild cognitive impairment (MCI) in the urban and the rural areas in Chengdu, Southwest China.

Methods: Residents aged 55 or over were selected by stratified random cluster sampling from 19 districts, cities, and counties of Chengdu area in Sichuan province. A two-stage survey was carried out.