Sleep Duration Modifies the Association of Alternate Mediterranean Diet Score with Metabolic Syndrome in Mid-Life Women in Mexico

Adherence to a Mediterranean diet and better sleep health have independently been associated with a lower risk of metabolic syndrome (MetS), however, their combined effect has rarely been considered. To examine whether sleep duration modifies the association between adherence to the alternate Mediterranean (aMed) diet and MetS among mid-life Mexican women. The analytic sample consisted of 410 women with a mean age of 48.2±6.1 years participating in the Early Life Exposure in Mexico to ENvironmental Toxicants (ELEMENT) study. Diet was assessed with a validated food frequency questionnaire (FFQ). The mean daily sleep duration was measured with 7-day wrist actigraphy (Actigraph GTX-BT). MetS was defined based on the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI) criteria. Multivariable logistic regression models were employed to estimate the association between higher adherence to the aMed diet and MetS, and between sleep duration and MetS, each controlling for age, socioeconomic status, and moderate-to-vigorous physical activity (MVPA). To assess the potential modifying role of sleep duration, stratified analysis by sleep status was conducted, where participants were categorized as having adequate sleep (≥7 hours/day) or inadequate sleep (<7 hours/day) on average across the week. Statistical interaction was also tested in a logistic model. MetS was identified in 49.8% of participants, and 56.6% had an average sleep duration of less than 7 hours per day. Neither higher adherence to the aMed diet nor sleep duration was associated with MetS. However, the stratified analysis showed that among women with inadequate sleep, higher adherence to the aMed diet was related to 16% lower odds of MetS (OR: 0.84, 95% CI: 0.69 - 0.99; P for interaction=0.09). Associations between diet and MetS were only observed in the presence of inadequate sleep duration, suggesting a potential interaction that warrants further investigation through longitudinal research.