New research indicates that sleep duration alone does not increase the risk of developing cancer of the digestive system when diet, exercise and other health-promoting factors are controlled for. A researcher says that this finding is encouraging and underscores the importance of examining various factors affecting health in context.
Poor sleep generally harms health and has been repeatedly linked to cardiovascular disease, diabetes and various types of cancer, but a new study reveals that sleep duration is not an independent risk factor for developing cancer of the digestive system.
The findings are encouraging, since they demonstrate that maintaining a healthy diet, exercising regularly and quitting smoking can still effectively reduce the risk of cancer even if sleep duration is shorter or longer than normal.
“Sleep duration may not be as crucial to the risk of developing cancer of the digestive system as many researchers previously thought. This is encouraging news. Our study also enhances understanding of how various factors related to health interact and influence various health outcomes,” explains Christian Benedict, Associate Professor and sleep researcher, Department of Pharmaceutical Biosciences, Uppsala University, Sweden.
The research has been published in BMC Medicine.
Health data from more than 400,000 people
The researchers explored the relationships between sleep duration, diet and the risk of developing cancer of the digestive system, encompassing oral and throat cancer to the intestines and related organs such as the liver and kidneys.
They analysed data from 406,584 participants obtained from the UK Biobank, a comprehensive database containing detailed information on health and lifestyle.
The researchers categorised participants based on their sleep duration: less than six hours per night, seven to eight hours per night and more than nine hours per night.
In addition, they assessed participants’ daily intake of dietary fibre, fruit, vegetables and meat, categorising them on a scale from 0 (least healthy) to 3 (healthiest).
The researchers examined health registry records over an average of 12.6 years, determining which participants developed cancer of the digestive system.
The participants ranged in age from 38 to 73 years, and 54% were women.
“Diet and exercise are crucial in reducing the risk of developing cancer, but this study aimed to elucidate the role of sleep duration,” says Christian Benedict.
Poor diet and sleep deprivation increase risk of cancer
The findings indicate that healthier eating habits were associated with lower risk of developing cancer of the digestive system, consistent with previous research.
The study also showed that an increased risk of cancer of the digestive system was associated with both sleeping less than seven hours per night (9% increase) and more than nine hours per night (14% increase).
The researchers also assessed whether the protective effects of a healthy diet could counteract the negative effects of short or long sleep duration. They found that, if individuals maintained a healthy diet, aberrant sleep duration did not affect the risk of developing cancer.
“This is encouraging news, since it demonstrates that, although short and long sleep duration are associated with an increased risk of cancer, this can be mitigated by adhering to a healthy diet and regularly exercising,” notes Christian Benedict.
Sleep deprivation leads to unhealthy behaviour
Christian Benedict explains that the results suggest that the negative effect of short or long sleep duration on the risk of developing cancer of the digestive system probably does not result from the duration of sleep itself but rather the behaviour associated with short or long sleep duration, such as neglecting regular exercise and not maintaining a healthy diet.
The premise is that short or long sleep duration triggers unhealthy behaviour that can promote cancer.
“Poor sleep is known to increase the risk of diabetes, which can then increase the risk of cancer. In addition, people deprived of sleep tend to have more risky behaviour, such as consuming unhealthy foods in larger quantities, smoking and drinking more alcohol. All these factors can contribute to developing cancer of the digestive system,” says Christian Benedict.
He elaborates that these studies are crucial since they help to provide a nuanced understanding of what is healthy and what is unhealthy.
“People’s health results from complex interaction of various lifestyle factors. Sleep patterns and diet are two important factors, but so are physical activity, social interaction, environmental factors such as local pollution concentrations and others. Minimising the risk of disease requires considering all these factors. Many factors interact in intricate ways, creating difficulty in isolating the effects of any single factor. Sleep may not directly influence the risk of cancer of the digestive system, but it influences many other health outcomes,” concludes Christian Benedict.
