The Chilean harmonized cognitive assessment protocol (Chile-Cog): study design

Due to rapid population aging, the number of Chileans with dementia is estimated to triple by 2050. Measurement of multiple cognitive domains in population-based surveys that facilitate studies of associations between earlier experiences and cognition among older populations are rare. The purpose of this paper is to describe the survey protocol (Chile-Cog) for assessment of cognitive function in a sample of Chileans ages 60 and above. Chile’s distinctively high life expectancy and educational attainment relative to other Latin American countries, and its rapid transition from a middle- to a high-income economy, make it a valuable setting for studying life-course influences on cognitive health at older ages. The sample for the Chile-Cog was drawn from the longitudinal Chilean Social Protection Survey (SPS) in 2019 and it is nationally representative of individuals aged 60 and above. The survey protocol consists of in-person interviews to assess multiple cognitive domains, including orientation, immediate and delayed memory, attention, language, visuospatial ability, and executive function. In addition, interviews were conducted with individuals knowledgeable about the respondents’ health and daily activities. A sample of 2,033 respondents aged 60 and above in 2019 was interviewed, representing a 73% response rate. The informant sample included 1,778 participants. Most missing information in the cognitive evaluations resulted from respondents’ hearing, visual, and other physical limitations and/or inability to read or write, refusal, or not knowing the answer. Associations between cognitive function and age, sex, and education are similar to findings of the other studies using the Harmonized Cognitive Assessment Protocol (HCAP). Chile-Cog is a significant advancement in assessing cognitive functioning among older Chileans. The linkage to earlier waves of the SPS provides a wealth of individual-level longitudinal data that will improve understanding of life course determinants of cognitive health among older Chileans, and harmonization with other studies will facilitate cross-national comparisons of cognitive function.