Background: Sleep disorders are increasingly being characterized in modern society as contributing to a host of serious medical problems, including higher cardiometabolic risk and obesity. Changes to the microbial community in the human gut have been reportedly associated with many of these cardiometabolic outcomes.

Objective: Determine whether sleep length is associated with gut microbiota and cardiometabolic outcomes.

Methods: In this study, we investigated the impact of sleep length on the gut microbiota in a large cohort of 655 participants of African descent, aged 25-45, from Ghana, South Africa (SA), Jamaica, and the United States (US). Using subjectively measured sleep data, participants were classified into 3 sleep groups: short (<7hrs), normal (79hrs), and long (≥9hrs). Objectively measured sleep data are being analyzed. 16S rRNA gene sequencing was used to analyze gut microbial composition.

Results: Forty-seven percent of US participants were classified as short sleepers, conversely 88% of SA participants as long sleepers. The gut microbiota profiles of participants with both short and long-sleep durations significantly differed when compared to normal sleep duration participants. “Long sleepers” had significantly lower BMI and age than short and normal sleepers. “Short sleepers” in the SA cohort had significantly higher triglyceride levels when compared to short and normal sleepers.

Conclusions: These results suggest that sleep length may be associated with the gut microbiota and suggest a causal pathway between impaired sleep and chronic inflammation. Future research should focus on understanding the impact of altering microbially produced metabolites on cardiometabolic risk.