Introduction:
To investigate whether there is an association between nocturnal-daytime sleep patterns as well as social participation and memory-related categories of diseases in the middle-aged and elderly population in China.

Material and methods:
This study was based on data from the Peking University China Health and Aging Tracking Survey (CHARLS), and a total of 19,023 study participants were analyzed in the year 2018 according to the inclusion and exclusion criteria. Logistic regression models were used to explore the relationship between different night-time-daytime sleep patterns, social participation, and memory-related categories of disorders step by step with adjustments for different covariates, and the odds ratios (ORs) and 95% confidence intervals (95% Cl) were obtained.

Results:
Logistic regression models gradually adjusted for confounding with nighttime sleep duration >5 h and daytime sleep duration ≤30 min group, Going to a sport, social, or other club activity and social participation as the protective factors of memory-related class of diseases. Stratified analyses found that among males, people living in rural areas, and married people, the group with >5 h of nighttime sleep and ≤30 min of daytime sleep was a protective factor for memory-related classes of diseases. Among women, people living in urban areas, and married people, social participation was a protective factor for memory-related diseases.

Conclusions:
Nighttime sleep time >5 h, daytime sleep time ≤30 min group, and social participation are independent protective factors for memory-related class disorders in older adults. Keywords: sleep patterns, social participation, memory-related disorders, CHARLS, middle‐aged and older adults