Circadian disturbances linked to increased risk for incident cancer
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Key takeaways:
- Morningness-Eveningness Questionnaire scores and the hazard for incident cancer are related to each other in a U-shaped curve.
- A score higher or lower than the median of 63 signaled a higher hazard.
HONOLULU — Adults faced a higher risk for incident cancer if their Morningness-Eveningness Questionnaire score deviated from the median score, signaling circadian disturbances, according to research presented at the CHEST Annual Meeting.
“Alterations in sleep and sleep timing [can] stress biological systems and influence malignancy risk,” Tetyana Kendzerska, MD, PhD, associate professor of medicine and clinical director of the sleep center at University of Ottawa, said during the presentation. “Evidence on the relationship between [morning-evening] chronotype and cancer is limited.”
In a retrospective cohort study, Kendzerska and colleagues assessed 1,888 adults (median age, 54 years; 47.1% men) in Ontario, Canada, who completed the Morningness-Eveningness Questionnaire (MEQ) between 2010 and 2015 and did not have cancer at baseline to find out how the morning-evening chronotype is linked to incident cancer through multivariable Cox cause-specific regression.
Researchers followed these adults until death or March 31, 2020, and used the Ontario Cancer Registry to figure out their cancer status.
Of the total cohort, the median MEQ score was 63, with a majority (65.7%) of adults classified as having morning chronotypes (≥ 59), followed by 30.6% with intermediate chronotypes (42-58) and 3.7% with evening chronotypes (≤ 41).
During median follow-up of 6.9 years, 120 (6.7%) adults received a cancer diagnosis, according to researchers.
After controlling for age, sex, BMI, apnea-hypopnea index, mean oxygen saturation, total sleep time, sleep onset latency, alcohol use disorder and Charlson comorbidity index, researchers observed that a MEQ score above or below 63 — represented by a U-shaped curve — was linked to a higher adjusted hazard ratio for incident cancer.
Kendzerska said the greatest statistically significant effect was seen when comparing adults with a MEQ score of 78 to those with the median score of 63 (adjusted HR = 1.84; 95% CI, 1.08-3.16).
“The U-shaped curve noted in malignancy risk may reflect deviations from a standard circadian tendency with a natural alert period during light hours,” Kendzerska said.
When reflecting on the above findings, it is important to consider the study’s limitations including unmeasured confounding, its design and the idea that MEQ may not fully mirror circadian rhythm, according to Kendzerska.
“This study provides further stimulus to prompt additional research on circadian disturbances in cancer and to establish possible therapeutic mechanisms,” Kendzerska said.