Major Change in Body Weight over 5 Years and Total Sleep Time: Investigation of Effect Modification by Sex and Obesity in a Large e-Cohort

We assessed the association of long-term weight change ≥5 kg with total sleep time (TST), investigating effect modification by sex and overweight/obesity. In a cross-sectional context, we studied 41,610 adults from the general population-based NutriNet-Santé e-cohort. A sleep questionnaire was self-administered in 2014. It included sleep logs for the estimation of average TST at night, and items for the calculation of major weight change as experienced over the previous 5 years. We fit multivariate polytomous logistic regression models. Overall, women with major weight loss had an increased likelihood of short TST (≤6 h) when compared with women with stable weight (OR = 1.15, 95% CI: 1.05–1.25). Individuals with major weight gain had an increased likelihood of short TST compared with their counterparts with stable weight (men: OR = 1.20, 95% CI: 1.05–1.37; women: OR = 1.24, 95% CI: 1.15–1.33). Men with major weight gain were less likely to report long TST compared with men with stable weight (OR = 0.83, 95% CI: 0.70–0.97). Overweight or obesity did not moderate the associations. The study advances knowledge in the fields of public health and nutrition by providing some evidence of a sex-specific association of major weight change with both short and long TST. These associations merit future investigation in a longitudinal context with repeated, objective measures of both weight and sleep time, while applying more stringent interaction test criteria and accounting for changes in health behaviors.