Observational studyJournal of translational medicine2026
Optimal nap timing and body mass index: beyond duration.
Observational study in Journal of translational medicine, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT03036592 (MTNR1B SNP*Food Timing Interaction on Glucose Control in a Late Eater Mediterranean Population), which is not on this map. Cited by 1 paper.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
MTNR1B SNP*Food Timing Interaction on Glucose Control in a Late Eater Mediterranean Population
Who cites it
1 citing paper in PubMed.
- Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors.
Funding
Abstract
backgroundOverweight and obesity continue to rise globally, and sleep has emerged as an important behavioral determinant of body weight. While nighttime sleep has been widely studied, the role of daytime napping-especially nap timing-remains unclear. Existing research relies on clock time, which may not reflect individual rhythms. This study investigates whether nap timing referenced to daily events is associated with BMI in two adult populations of habitual nappers (Spain and Brazil). Secondary aims included the association of nap duration and weekend-weekday differences in nap timing and duration with BMI.
methodsHabitual nappers (n = 3550) aged 18-65 years were studied. Nap timing was calculated relative to wake time and lunch time. As secondary analyses, nap duration and weekend-weekday differences in nap timing (nap jet lag) and in nap duration were evaluated. Linear regression and restricted cubic spline models were applied.
resultsBMI and excess weight prevalence were similar between countries. Compared with Spaniards, Brazilians showed earlier naps (by >2 h), longer weekend naps (by 13 min), and greater nap jet lag (by 23 min) (all p < 0.001). Despite these differences, no significant interactions by country were observed in nap-BMI associations, and data were pooled. Nap timing relative to wake and lunch displayed L-shaped associations with BMI: the highest BMI corresponded to early naps (~3h after waking and ~2h before lunch), whereas the lowest BMI (i.e. the inflection points) occurred when naps were 7h18min after wake (β = -0.48 kg/m
conclusionsFindings highlight nap timing as a novel behavioral factor associated with BMI, warranting further longitudinal research to explore its potential causal role.
trial registrationClinicalTrials.gov NCT03036592 (ONTIME-MT).
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