Abstract
BACKGROUND: The microbiota-gut-brain axis underlies the pathogenesis of sleep disorders. The dietary index for gut microbiota (DI-GM) is an innovative diet quality metric related to gut microbiota diversity, with higher scores indicating a healthier gut microbiome. This study aimed to investigate its association with sleep duration. METHODS: This cross-sectional study analyzed the National Health and Nutrition Examination Survey (NHANES) data from 2005 to 2018, involving 25,439 participants aged ≥20 years. The DI-GM score was calculated utilizing dietary recall data, encompassing both beneficial (BGMS) and unfavorable (UGMS) to gut microbiota score. Sleep duration was assessed via the question: "How much sleep do you usually get at night on weekdays or workdays?" and categorized as short (<7 h per night), optimal (7-8 h per night), and long (>8 h per night). Multivariable weighted linear and logistic regression models were performed to determine the association between DI-GM and sleep duration. Secondary analyses included restricted cubic splines (RCS) and subgroup analyses. RESULTS: In the fully adjusted model, a higher DI-GM score was associated with longer sleep duration (β =0.03, 95 % confidence interval [CI]: 0.01-0.04, P < 0.001), as was a higher BGMS (β =0.04, 95 % CI: 0.02-0.06, P < 0.001). Using optimal sleep as the reference category, both higher DI-GM score and BGMS were significantly associated with lower odds of short sleep (DI-GM: odds ratio [OR] =0.96, 95 % CI: 0.93-0.99, P = 0.010; BGMS: OR =0.93, 95 % CI: 0.89-0.96, P < 0.001). RCS revealed nonlinear associations between DI-GM and both outcomes, while BGMS exhibited linear patterns. Subgroup analyses confirmed consistent associations across demographic, lifestyle, and health strata, with significant effect modification by race/ethnicity (P = 0.015 for sleep duration; 0.016 for short sleep) and physical activity (P = 0.033 and 0.007, respectively). CONCLUSIONS: Higher DI-GM scores were associated with longer sleep duration, underscoring the potential of gut microbiota-targeted diets for sleep health.