Long nightly fasting duration was a risk factor for colorectal cancer, especially among individuals over 60 years old, while long nightly sleep duration was protective in Guangzhou older residents.
Each 1-hour increment in nightly fasting duration was associated with a 9.5% higher risk of colorectal cancer.
The association between longer nightly fasting duration and higher CRC risk was limited to individuals over 60 years of age.
Each 1-hour increment in nightly sleep duration was associated with a 15.2% lower risk of colorectal cancer.
Earlier dinner time, later breakfast time, and later bedtime were each independently associated with higher colorectal cancer risk.
After exclusions, 197,507 individuals were included in the final analytic sample, with 351 CRC cases, 1,384 precancerous lesions, and 195,772 negative results.
Multivariable logistic regression, subgroup analyses, and sensitivity analyses were used to evaluate the associations between nightly fasting/sleep duration and CRC risk.
This research suggests that the timing of meals and sleep may be linked to colorectal cancer (CRC) risk in older adults. Using data from nearly 200,000 community-dwelling older residents in Guangzhou, China, researchers found that people who went longer between their last meal of the day (dinner) and their first meal the next day (breakfast) had a higher risk of being diagnosed with CRC. Specifically, each additional hour of nightly fasting was associated with about a 9.5% increase in CRC risk, and this effect was particularly pronounced in people over age 60. In contrast, each additional hour of nightly sleep was associated with about a 15% lower risk of CRC. The study also found that eating dinner earlier, eating breakfast later, and going to bed later were each independently associated with higher CRC risk, which aligns with the overall pattern that a longer overnight fasting window may be harmful. These patterns held up after accounting for other known risk factors through statistical adjustment, as well as in sensitivity and subgroup analyses. This research suggests that everyday lifestyle habits around meal timing and sleep could play a role in colorectal cancer risk, particularly for older adults. The findings point toward maintaining adequate sleep and being mindful of the gap between the last meal at night and the first meal in the morning as potentially worthwhile habits for CRC prevention. Because this was a cross-sectional study (a snapshot in time rather than a follow-up over years), it cannot establish that these habits directly cause or prevent cancer, and further research would be needed to confirm these relationships.
Huang P, Zeng B, Li S, Zhang K, Li C, Liang Y, et al.. (2026). Exploratory Analysis of Association of Nightly Fasting and Sleep Durations with Colorectal Cancer Risk in Chinese Community-Dwelling Older Adults: A Cross-Sectional Study.. Nutrients. https://doi.org/10.3390/nu18050861