Healthy Sleep Mitigates the Association Between Cardiometabolic Disease and Poorer Cognitive and Brain Health

BACKGROUND: Cardiometabolic diseases (CMDs), including type 2 diabetes, heart disease, and stroke, are important risk factors for dementia. We examined whether healthy sleep can support cognitive and brain health in people with CMDs. METHODS: The study included data from 408 977 adults from the UK Biobank. CMDs were defined using medical records, medication use, and medical history. Sleep patterns were defined using a composite score incorporating sleep duration, chronotype, insomnia symptoms, snoring, and daytime sleepiness. A subsample (n=34 913) underwent brain magnetic resonance imaging; volumes of total brain, gray matter, white matter, hippocampus, and white matter hyperintensities were ascertained. Associations of joint CMD (yes/no) and sleep (healthy, intermediate, poor) status with global and domain-specific cognitive scores and brain magnetic resonance imaging measures were examined using linear regression models. RESULTS: At baseline, 54017 (13.2%) participants had at least one CMD. In joint exposure analysis, performance in global cognition (β=0.02 [95% CI, 0.01-0.05]), verbal/numeric reasoning (β=0.07 [95% CI, 0.01-0.12]), and processing speed (β=0.07 [95% CI, 0.04-0.10]) was significantly higher among individuals with CMDs and a healthy sleep pattern, compared with those with CMDs and a poor sleep pattern. Similarly, in neuroimaging analyses, participants with CMDs and a healthy versus poor sleep pattern showed significantly larger total brain volume (β=0.22 [95% CI, 0.08-0.35]), gray matter volume (β=0.23 [95% CI, 0.09-0.36]), and white matter volume (β=0.19 [95% CI, 0.05-0.33]). CONCLUSIONS: Healthy sleep may attenuate the associations of CMDs with poorer cognitive performance and markers of brain atrophy. The findings highlight sleep as a modifiable factor that may support cognitive and brain health in individuals with CMDs.