Longer sleep duration (≥5 h) is independently associated with a lower risk of newly-onset cancer in middle-aged and elderly adults, particularly in those with depression.
Longer sleep duration was associated with a reduced risk of incident cancer in middle-aged and older adults.
The association between sleep duration and cancer risk was nonlinear, with an inflection point at 5.0 hours of sleep per night.
The protective effect of longer sleep duration on cancer risk was more pronounced among individuals with depression.
Subgroup analyses revealed heterogeneity in the protective effect of sleep duration across different population characteristics.
Kaplan-Meier survival curves were used alongside Cox regression to evaluate the relationship between sleep duration and cancer risk.
This research followed nearly 9,400 middle-aged and older adults in China for a median of 9 years to examine whether how long people sleep is related to their likelihood of developing cancer. Over the study period, about 3% of participants were newly diagnosed with cancer. The researchers found that people who slept 5 or more hours per night had an 18% lower risk of developing cancer compared to those who slept less, and when looking at overall sleep duration as a continuous measure, longer sleep was associated with a 35% lower cancer risk after accounting for other factors. The relationship between sleep and cancer risk was not a simple straight line — there was a threshold effect at 5 hours of sleep per night. Sleeping less than 5 hours did not appear to offer the same protective benefit, while sleeping 5 or more hours was clearly associated with reduced cancer risk. This protective effect appeared especially strong among people who also had depression, as well as among men, urban residents, non-hypertensive individuals, and smokers. This research suggests that adequate sleep may play a meaningful role in cancer prevention, particularly for vulnerable groups such as those experiencing depression. The findings highlight sleep health as a potentially modifiable factor worth attention in public health efforts around cancer prevention, though as an observational study it cannot prove that sleep changes directly cause differences in cancer rates.
Meng J, Mu B, Yang Y, He Y, Yang Z, Hoffman R, et al.. (2026). Sleep Duration and Depression as Predictors of Cancer Incidence in Middle-aged and Older Adults: A Longitudinal Analysis from the China Health and Retirement Longitudinal Study (CHARLS).. In vivo (Athens, Greece). https://doi.org/10.21873/invivo.14258