Could unhealthy sleep habits cause cancer?

By Katie Campbell

            A recently published study has shown a potential connection between the sleep habits of men in China and development of cancer. The researchers, based at the Huanzhong University of Science and Technology in Wuhan, China studied a cohort of approximately 27,000 retired factory workers. They investigated the independent and combined impacts of three sleep habits: working night shifts, daytime napping, and length of nighttime sleep through a self-report questionnaire.

            The authors report that individuals who worked night shifts for more than 20 years, did not habitually nap during the day, and slept for more than ten hours per night had an increased risk of cancer. Individually, men who worked night shifts for over 20 years had a 27% higher prevalence of cancer; and that those who did not nap in the daytime had double the risk of cancer as compared to men who took a 1 to 30 minute nap. They also mention that individuals who exhibited two of these behaviors had a 43% increased risk of cancer, and were twice as likely to die from cancer compared to individuals with none of these habits. Interestingly, no such relationships were observed in women.

            Though these results appear to support research indicating the importance of regular sleep schedules, the authors of the study recognize that their results may be biased due to the self-report style questionnaire and short-term follow-up. Overall, a longer-term prospective study should be done, but this study adds to the monumental evidence supporting healthy lifestyles.


Taylor & Francis. "Male sleep habits may increase risk of cancer." ScienceDaily. ScienceDaily, 4 November 2016. <>.