Background: Unawareness of cognitive deficit in people with dementia (PwD) has wide clinical implications, impacting on help-seeking behavior, treatment compliance, and patient safety. Most studies on unawareness among PwD have been conducted in small clinical samples. This study investigated the frequency of unawareness of memory impairment in dementia, exploring regional differences and sociodemographic and health status correlates in large population-based surveys.

Methods: Community samples (total n = 15,022) from three world regions (Latin America, China, and India) were obtained using cross-sectional population-based surveys. Out of these, 897 (5.97%) PwD with memory impairment were identified using standardized interviews, diagnostic algorithms (DSM-IV or 10/66 criteria), and neuropsychological memory assessment. Unawareness of memory deficits was ascertained from the participants’ subjective report. The frequency of unawareness was calculated for each region and associations with demographic variables and health status were investigated using prevalence ratios and Poisson regressions.

Results: Regional differences in frequency of unawareness were found, from 63% in China to 81% in India. Unawareness was associated with depression in China and Latin America, dementia severity in India and Latin America, and education and socioeconomic level in Latin America.

Conclusions: Unawareness of memory impairment in PwD varies across international regions. Our data support the notion that unawareness should be seen not only as a common neurobiological feature of dementia, increasing with severity of dementia, but also as a phenomenon influenced by social and cultural factors.