Could poor sleep be one of the factors fueling the global rise in cancer cases among young people? Two large studies presented over the weekend at the annual meeting of the American Society of Clinical Oncology in Chicago, the world’s leading cancer conference, point to a possible link between sleep disorders and an increased risk of being diagnosed with cancer before age 50. The findings warrant special attention in Israel because of disrupted sleep during the war years.
In recent years, the rise in cancer rates among young people has become one of the most troubling questions in medicine. The number of young people diagnosed with cancer rose by nearly 80% over three decades, from 1.82 million cases worldwide in 1990 to 3.26 million in 2019. During the same period, cancer deaths among people in their 40s, 30s and even younger rose by 27%. The reasons for the increase remain unclear, and researchers are examining a range of possible factors, including diet, obesity, reduced physical activity, environmental exposure, smoking and alcohol. The new studies now add sleep quality to that list.
Threefold higher risk of breast cancer
The two studies, led by researchers at MD Anderson Cancer Center in Houston, one of the world’s leading cancer centers, analyzed health data from more than 18 million U.S. adults ages 18 to 50. The researchers found that people with poor sleep patterns were at higher risk of developing cancer at a young age, particularly colon, breast, uterine and ovarian cancers.
The detailed findings are especially troubling: Women diagnosed with insomnia were three times more likely to develop breast cancer within five years. Their risk of uterine cancer was twice as high, and their risk of ovarian cancer was 60% higher. Among both men and women, the average risk of colon cancer at a young age was 85% higher. Researchers said sleep disruption may be a clinically significant and potentially modifiable risk factor in assessing cancer risk at a young age, and that the findings require further study.
According to a study published three years ago in the leading journal BMJ Oncology, more than 1 million people under 50 die of cancer each year worldwide, and efforts to understand the causes of rising cancer rates among young people have become a global health priority.
A link, not proof
Experts who were not involved in the studies responded cautiously. Claire Coughlan, clinical lead at Bowel Cancer UK, said colon cancer is still more common among people 50 and older, but evidence is accumulating worldwide that cases among younger people are rising. She said experts still do not know exactly why cases are rising, but insomnia as a possible risk factor for early-onset bowel cancer may help explain the trend and warrants further study.
Dr. David Garley, a family physician and director of the Better Sleep Clinic in Bristol, England, stressed that the studies found an association only and did not prove that sleep disruption causes cancer. He said there could be several explanations for the link. Garley said lack of sleep can make healthy living harder, contributing to more alcohol use, obesity, reduced physical activity and smoking, which may raise risk. He added that sleep helps restore the immune system, while poor sleep may increase vulnerability to cancer-related processes. He also noted the reverse could be true: undiagnosed cancer itself may alter sleep patterns.
Megan Winter, health information manager at Cancer Research UK, emphasized that more research is needed, especially studies that follow people over time, before clear conclusions can be drawn.
The Israeli angle
Prof. Amir Onn, head of research and development in oncological pulmonary medicine at Sheba Medical Center, who is attending ASCO in Chicago, said the findings fit into the broader phenomenon of rising cancer rates among young people, which is also evident in Israel. “The phenomenon does exist,” he said, while adding a caveat: “The direct link between sleep disorders and cancer is still unclear. We do not know what mechanism causes this: the acceleration of cancer processes and weakening of the immune system at young ages.”
Prof. Amir Onn Photo: Sheba websiteHe said one reason the findings are drawing attention is that they involve a relatively young population. “Risk factors such as smoking and exposure to carcinogens can cause cancer after decades of exposure,” he explained. “Here, the mechanism is different because these are young people, and the observation requires research attention.”
Onn suggested viewing sleep disorders as part of a broader picture of stress, lifestyle and additional risk factors that accumulate at young ages. “We have known for years that any factor that worsens stress may be linked to biological processes that can also affect cancer risk,” he said. “This is especially concerning in light of what has been happening in Israel in recent years, and in the context of rising additional risk factors such as smoking and weight gain.”
For now, the message to the public is not that anyone who sleeps poorly should fear cancer, but that sleep is an important part of overall health. The proven ways to reduce cancer risk remain unchanged: avoiding smoking, maintaining a healthy weight, exercising, eating a balanced diet and protecting against excessive sun exposure.
- Eitan Gefen is a guest of Oncotest at the ASCO conference in Chicago. Oncotest is not involved in the content.
First published: 20:23, 05.30.26