The key facts

  • Data from more than 400,000 UK Biobank participants were analyzed; about 54,000 had at least one cardiometabolic disease
  • Sleep was assessed based on five self-reported characteristics: duration, chronotype, insomnia, snoring, and daytime sleepiness
  • The link between sleep and brain structure was stronger in people with these diseases than in those without them

What the study showed

In people with type 2 diabetes, heart disease, or a prior stroke, healthier sleep was associated with better cognitive test results and greater brain volume. This is reported by Gazeta.Ru citing a study by the Karolinska Institute published in the journal Journal of the American Heart Association.

How the study was conducted

The scientists analyzed data from more than 400,000 participants of the UK Biobank project. About 54,000 of them had at least one cardiometabolic disease, and brain MRI scans were available for nearly 35,000 participants. Sleep was assessed based on five characteristics reported by the volunteers themselves: duration, chronotype, insomnia, snoring, and daytime sleepiness. This assessment was then compared with cognitive performance and brain structure.

Key findings

Among people with cardiometabolic diseases, participants with healthier sleep performed slightly better on tasks measuring general cognitive ability, problem-solving, and information processing speed. They also showed greater total brain volume as well as greater gray and white matter volumes. According to the study, the link between sleep characteristics and brain structure was more pronounced in people with diabetes, heart disease, or stroke than in those without these conditions. Since the sleep assessment was based on participants' self-reports, this refers to an observed association rather than a proven causal effect — a nuance not specifically discussed in the publication. Earlier, as Gazeta.Ru notes, neuroscientists found outhow much bright light the brain needs for protection against dementia.