Association of habitual sleep duration and its trajectory with the risk of cancer according to sex and body mass index in a population-based cohort
Menée à partir des données d'une étude chinoise, cette étude analyse l'association entre la durée du sommeil et le risque de cancer en fonction du sexe
Background: The relationship between sleep duration and cancer in China remains inconclusive. The authors investigated the association between sleep duration and cancer from both static and dynamic perspectives. Methods: This study was based on the China Health and Retirement Longitudinal Study. We first tested the hazard ratios (HRs) with 95% confidence intervals (CIs) between baseline sleep duration and incident cancer using Cox proportional hazards regression analysis. Sleep duration trajectories from 2011 to 2015 were identified using group-based trajectory modeling to examine the subsequent risk of incident cancer from 2015 to 2018 using Cox proportional hazards regression model. Results: The risk of incident cancer increased by 69% (HR, 1.69; 95% CI, 1.19–2.39) in individuals who slept for <7 h per day (vs. 7 to ≤8 h), 41% (HR, 1.41; 95% CI, 1.01–1.95) in those who slept for <6 h per night (vs. 6 to ≤8 h), and 60% (HR, 1.60; 95% CI, 1.01–2.55) in those who did not take any naps during the day (vs. >60 min). Stratified by sex and body mass index, the risk of cancer was evident among women with night sleep of <6 h (vs. 6–8 h). However, the duration of <7 h of total sleep among men and overweight individuals was associated with cancer risk. Moreover, individuals with a short night sleep duration but no napping had a higher risk of cancer. Furthermore, cancer risk was only observed in individuals with short stable trajectory of night sleep (HR, 2.01; 95% CI, 1.07–3.80) and among women with short stable trajectory of total sleep (HR, 2.26; 95% CI, 1.13–4.52). Conclusions: Cancer incidence risk was observed in participants with sleep duration of <7 h and among women with short stable sleep trajectory. Short nights and total sleep duration were both associated with a high risk of incident cancer, but varied by sex. Interestingly, cancer risk was restricted to women with short stable sleep trajectory.