Cardiovascular Risk, Total Sleep Time Independently Associated With Cognitive Decline
A combination of less sleep and high cardiovascular disease risk tended to be associated with greater decline in executive function.
Hannah Maybrier
Data presented at the 2022 SLEEP Annual Meeting, June 4-8, in Charlotte, North Carolina, showed that cardiovascular disease (CVD) risk and average total sleep time (TST) were independently associated with cognitive decline, with evidence also suggesting that sleep duration reduces CVD.1
Led by Hannah Maybrier, university fellow, Washington University in St. Louis, the analysis evaluated the mediating and moderating effects of CVD risk on the relationship between sleep duration and longitudinal change in executive function (EF) and executive memory (EM). In a cohort of 332 individuals, average TST across 2 to 6 nights was estimated using single-channel EEG at baseline, while CVD was estimated using the abbreviated Framingham Heart Score approximately 1-year post-baseline.
EF subtests measured semantic fluency, working memory, and task switching. EM subtests measured verbal associative memory, narrative episodic memory, and list learning. After evaluating EM composite scores per year up to 7 years post-baseline, greater TST was shown to be linearly associated with reduced CVD (ß = –.157; P = .006). Additionally, quadratic effects of TST on EF (ß = –.105; P = .002) and EM (ß = –.203; P = .007) were also observed.
Covariates of the analysis included age, gender, global cognition, apnea-hypopnea index, and Alzheimer disease (AD) biomarkers which were the ratio of phosphorylated tau 181 to amyloid-ß42. Individuals with the lowest TST were associated with a greater reduction in EF; the highest TST was related to a greater reduction in EF and EM. CVD mediated EF and EM (P <.05); however, the effects were nonsignificant when age (P = .08) and AD biomarkers were included (P = .10). Individuals who had less sleep with high CVD tended to be associated with a greater decline in EF, although CVD did not moderate the effects of TST on EM (ß = .07; P = .254).
Previous literature has shown that high and low sleep durations are associated with reduced EF and EM, although causal pathways have not been identified. A 2019 study investigated whether objective short sleep duration increases the risk of all-cause mortality associated with coexisting cognitive impairment and cardiometabolic conditions. A total of 1524 adults from the Penn State Adult Cohort underwent neuropsychological testing to ascertain cognitive impairment and a clinical history and physical examination to ascertain stage 2 hypertension, type 2 diabetes, heart disease, and stroke.2
Multivariable-adjusted Cox proportional hazard models (HR) showed that the risk of all-cause mortality associated with cardiometabolic conditions (n = 864) and possible vascular cognitive impairment (n = 122) (HR, 1.79 [95% CI, 1.28-2.51] and HR, 1.79 [95% CI, 2.66-6.05] respectively) was significantly increased in those who slept less than 6 hours at baseline, while it was negligible in those who slept at least 6 hours (HR, 1.44 [95% CI, 0.99-2.09], HR, 1.44 [95% CI, 0.99-2.09], and HR, 1.41 [95% CI, 0.70-2.83], respectively).2
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