Poor sleep may be fuelling the global rise in under-50s being diagnosed with cancer, according to two large studies. The number of younger people diagnosed with the disease has increased by almost 80% in three decades, with worldwide cases of early-onset cancer rising from 1.82 million in 1990 to 3.26 million in 2019. Cancer deaths among people in their 40s, 30s, or younger have also increased by 27%.
Research Findings
Research presented at the American Society of Clinical Oncology’s annual meeting in Chicago suggests irregular sleeping patterns in younger people may be a contributing factor. Two studies led by MD Anderson Cancer Center in Houston, Texas, analysed health data for more than 18 million adults in the US aged between 18 and 50.
Researchers found that people with poor sleeping patterns were more likely to develop early-onset bowel, breast, uterine, or ovarian cancer. In some cases, under-50s diagnosed with insomnia were three times more likely to develop cancer within five years.
“These findings suggest that sleep disruption may represent a clinically relevant, potentially modifiable risk factor in early-onset cancer risk stratification and warrants further investigation,” the researchers stated.
Global Health Priority
Identifying the causes of rising cancer rates among younger adults has become a global health priority. More than 1 million under-50s die from cancer each year, according to research published in BMJ Oncology.
Experts not involved in the studies welcomed the findings but emphasised the need for further research to better understand the link between insomnia and early-onset cancer.
Expert Opinions
Claire Coughlan, clinical lead at Bowel Cancer UK, noted that while bowel cancer is still more common in over-50s, there is growing global evidence of increasing cases in younger people. “We don’t know exactly why this is yet, but researchers currently believe it may be due to genetics and lifestyle factors,” she said. “This study’s conclusion that insomnia may be a potential risk factor in early-onset colorectal cancer could go some way to helping us understand the reasons behind this increase.”
Dr David Garley, a GP and director of the Better Sleep Clinic in Bristol, England, said the impact of insomnia on cancer risk was of “growing interest” but cautioned that the studies had identified an association rather than proof of causation. “There are possible causes from the physiology that arises from poor sleep, but also the fact that when sleep-deprived it’s difficult to live a healthy life – there is more drinking, more obesity, less exercise, more smoking etc – and these may be what causes any possible increased risk,” he explained.
Megan Winter, health information manager at Cancer Research UK, stated: “These studies explore whether there could be a link between insomnia and some types of cancer in people under 50, but more research is needed, particularly looking at people over longer periods of time, before we can draw any conclusions.” She added that people could reduce their cancer risk by not smoking, maintaining a healthy weight, and staying safe in the sun.
