Gender differences in cognitive impairment among the old and the oldest-old in China

Aim To examine gender differences in the prevalence of cognitive impairment across two age cohorts in China: the old (aged 65-79 years) and the oldest-old (aged 80-116 years). Methods The Chinese Longitudinal Healthy Longevity Survey with waves from 2008 to 2011 was used (N = 13 586). Regression analysis was used to model the gender effects on baseline cognitive function and onset of cognitive impairment. Independent variables included demographics, socioeconomic status (SES), social network, leisure activities and functional disabilities. Results Among the oldest-old, women (32.9%) were twice as likely as men (15.7%) to have cognitive impairment. For the old, women (2.2%) were only slightly more likely than men (1.9%). Regression models showed the oldest-old women having a significantly higher risk of cognitive impairment than men (P < 0.001), even after adjusting for independent variables. No significant gender differences were found among the old cohort. SES, social network and leisure activities appeared to affect gender differences, especially among the oldest-old. Of the independent variables examined, the gender effects were reduced the most when incorporating SES for both age cohorts. Conclusions For the oldest-old, gender differences in cognitive impairment could be due to differences in SES between men and women. The old cohort showed no statistically significant gender difference at this time; however, we should follow this old cohort for their future potential gender differences in the prevalence of cognitive impairment. Geriatr Gerontol Int 2019; 19: 586-592.