Abstract 848: Sleep behaviors and risk of lung cancer in the UK Biobank
Authors: Wang Xiaoyan , Zong Xiaoyu , Li Na , Govindan Ramaswamy , Colditz Graham , Cao Yin 
Published: July 2021

Abstract
Background. Lung cancer is the second most common malignancy and the leading causes of cancer death in both men and women in the United States. Cross-sectional studies on sleep disorders showed that sleep apnea and nocturnal hypoxemia are associated with an increased risk of lung cancer. Studies on sleep patterns are largely limited to sleep duration, snoring, insomnia and narcolepsy, in which short or long sleep duration, insomnia and narcolepsy are associated with an increased lung cancer risk. However, the association with other sleep patterns such as chronotype has not yet been investigated and the joint collective impact of sleep behaviors on lung cancer risk remains undetermined. In this study, we examined the association of six sleep behaviors with risk of lung cancer overall and among subgroups defined by smoking status and sex.
Methods. A total of 410,252 UK Biobank participants free of lung cancer aged 37-73 years recruited in 2006-2010 were included. Lung cancer cases were identified from cancer registry or death records up to September 2020. Self-reported sleep behaviors (chronotype, duration, daytime nap, snoring, insomnia, and narcolepsy) were collected at study baseline. Multivariable Cox proportional hazard regression was used to estimate the hazard ratio (HR) and 95% confidence interval (CIs) for each sleep behavior and risk of lung cancer. A composite unhealthy sleep score (0-3) was further developed by summing the individual score of three unhealthy sleep behaviors: evening chronotype, sleep &lt;7 or &gt;8 h/day, and usual daytime nap, with higher scores indicating a higher-risk sleep pattern. Stratified analyses jointly by smoking status (never vs. ever) and sex were conducted.
Results. During up to 13.6 years of follow up with 4,693,213 person-years, a total of 2,897 lung cancer cases were documented. Compared with individuals with morning chronotype, participants with evening chronotype had an 11% increased risk of lung cancer (HR: 1.11, 95%CI: 0.98-1.26). Those who slept &lt;7 or &gt;8 h/day had 9-25% increased risk compared with individuals who slept 7-8 hours. Compared with those who never took daytime nap, participants with usual nap had an 14% increased lung cancer risk (HR: 1.14, 95%CI: 1.00-1.30). Snoring, insomnia and narcolepsy were not associated with lung cancer risk. Compared with participants without any of high-risk sleep behavior (evening chronotype, sleep &lt;7 or &gt;8 h/day, and usual daytime nap), those with 1 high-risk behavior had 12% (HR: 1.12, 95%CI: 1.04-1.21) increased risk of lung cancer, and individuals with 2 or 3 high-risk sleep behaviors had a 30% (HR: 1.30, 95%CI: 1.15-1.47) increased risk of lung cancer (Ptrend &lt; 0.001). Such association was similarly observed among male and female smokers, but was slightly stronger in male never smokers compared to females.
Conclusion. Unhealthy sleep behaviors including evening chronotype, sleep &lt;7 or &gt;8 hours per day, and usual daytime nap was associated with increased risk of lung cancer.
Citation Format: Xiaoyan Wang, Xiaoyu Zong, Na Li, Ramaswamy Govindan, Graham Colditz, Yin Cao. Sleep behaviors and risk of lung cancer in the UK Biobank [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 848.