Napping, sleep apnea, and cognitive function: cross-sectional results from the U.S. POINTER-zzz sleep ancillary study.

BACKGROUND

The relationship between the duration of napping and cognitive function is unclear. We examine this association by analyzing baseline data from the US POINTER-zzz Sleep Ancillary Study.

METHODS

This study evaluates sleep assessments obtained via home apnea-screening device, wrist actigraphy, and sleep diaries among 686 older adult participants. Naps were defined as sleep periods with at least 30 continuous minutes outside of the primary period of sleep or the longest sleep duration. We conducted linear regression analyses to test the association between napping minutes and baseline global cognitive function and its domains, including executive function, episodic memory, and processing speed. We also examined whether the association between duration of napping and cognitive function outcomes differed by the presence (n = 223) or absence of sleep apnea (n = 463).

RESULTS

For the total sample, greater minutes of napping were associated with decreased processing speed [β = -0.0973 (95% CI = -0.1664, -0.0282)]. The interaction analyses between sleep apnea and napping did not reach statistical significance, providing no evidence that sleep apnea modifies the association between napping and cognition in the total sample. Greater minutes of napping were associated with poor executive function in participants with sleep apnea and who were in an under-represented ethno-racial group [β = -0.2493 (95% CI = -0.4943, -0.0042)].

CONCLUSIONS

Study findings are exploratory and suggest that it may be important to detect and treat sleep apnea for possible cognitive benefits, especially in certain subgroups of older adults.

CLINICAL TRIAL REGISTRATION NUMBER: NCT03688126; https://clinicaltrials.gov/ct2/show/NCT03688126.