The importance of diversity in aging studies.

In conclusion, the Zhang et al. (2021) study and the diverse cohort of older Chinese study participants provide an important contribution to the growing knowledge regarding sleep duration and cognitive impairment. The World Health Organization projects the total number of people with dementia worldwide to reach 82 million in 2030, nearly doubling to 152 million by 2050 (Jia, 2020). The current study noted that among individuals with primary and above education, excessive sleep duration was linked to cognitive impairment (Zhang et al., 2021). Zhang and colleagues' (2021) article in the current issue examined links between sleep and cognitive impairment among 3,692 community-dwelling older Chinese participants from a 3-year longitudinal study. [Extracted from the article]