Charlie Zhong<\/b><\/strong><\/p>\n<\/div>\n The findings highlight the \u201ccomplex\u201d association between sleep and cancer, Charlie Zhong, PhD, MPH,<\/b> principal scientist in epidemiology research at American Cancer Society, and colleagues wrote.<\/p>\n
\u201cAsk your patients about their sleep habits,\u201d Zhong told Healio.<\/p>\n
Poor sleep common<\/h2>\n Poor sleep health affects approximately a third of adults in the U.S., according to study background.<\/p>\n
They may sleep too little, too much, or have poor quality of sleep. National Sleep Foundation recommends 7 to 9 hours of sleep per night for adults.<\/p>\n
Prior research has shown that poor sleep health is associated with increased cardiovascular disease, morbidity and mortality, as well as with certain malignancies, including breast, colon and lung cancers.<\/p>\n
\u201cCancer is sometimes a misnomer,\u201d Zhong said. \u201cIt\u2019s hundreds, if not thousands, of different diseases. Some behaviors are protective for one cancer, but increase risk for another. This makes it important to have large studies where we can look at individual cancers.\u201d<\/p>\n
Zhong and colleagues conducted a pooled meta-analysis of seven prospective cohorts to evaluate the impact sleep has on cancer development.<\/p>\n
The investigation included 918,100 individuals (median age, 58 years; range, 34-99; 65% women).<\/p>\n
The association between sleep duration and quality, and cancer incidence, both overall and for 29 specific types, served as the primary endpoint.<\/p>\n
Researchers categorized short sleep as less than 7 hours per day, long sleep as more than 9 hours, and restless sleep and trouble sleep as those reporting those issues more than once per week.<\/p>\n
Different risks for different cancers<\/h2>\n Individuals who reported short sleep had a significantly lower risk for overall cancers (HR = 0.98; 95% CI, 0.97-0.99), breast cancer (HR = 0.97; 95% CI, 0.94-1.00), skin (HR = 0.94; 95% CI, 0.88-1.00) and lung cancer (HR = 0.97; 95% CI, 0.94-1.00).<\/p>\n
\u201cWhen it comes to breast, prostate, and some of the more hormone-driven cancers, there is some evidence that short sleep might have a protective association,\u201d Zhong said. \u201cGenerally, the less that you\u2019re exposed to estrogen, the less risk you have of getting breast cancer. It seems short sleep may have some effect in disrupting your hormonal balance.\u201d<\/p>\n
Conversely, short sleep significantly increased the risk for cancers of the small intestine (HR = 1.22; 95% CI, 1.02-1.45), head and neck (HR = 1.08; 95% CI, 1.01-1.17), and acute myeloid leumkemia (HR = 1.14; 95% CI,1.00-1.30).<\/p>\n
Long sleep had associations with elevated risk for several cancers, though none were statistically significant. <\/p>\n
Individuals who reported restless sleep had a significantly higher risk for hepatocellular carcinoma (HR = 1.31; 95% CI, 1.03-1.67), but a significantly lower risk for breast cancer (HR = 0.95; 95% CI, 0.9-0.99). Restless sleep also had an association with lower rectal cancer risk (HR = 0.78; 95% CI, 0.63-0.96), but those data only included two cohorts. <\/p>\n
Researchers did not observe any association between trouble sleeping and cancer risk.<\/p>\n
Zhong acknowledged study limitations, including patients self-reporting their sleep habits.<\/p>\n
Researchers plan to add eight additional cohorts into their meta-analysis to develop a \u201cclearer picture\u201d of these findings, Zhong added.<\/p>\n
\u201cAt the moment, only about 5% of participants reported long sleep,\u201d Zhong said. There has always been this assumption that short sleep is bad, but more studies are showing that longer sleep may be worse.\u201d<\/p>\n
Future investigations are needed to understand why short sleep duration and\/or disrupted sleep may lower risk for some cancer.<\/p>\n
\u201cTiming of sleep also is really important,\u201d Zhong said. \u201cIt\u2019s not just how much you sleep, it\u2019s if you\u2019re also going to sleep at an appropriate time, with consistency, and if that aligns to your body\u2019s appropriate time.\u201d<\/p>\n
These studies can be difficult to conduct, but technology could revolutionize the research.<\/p>\n
\u201cThere are a lot of wearables and nearables,\u201d Zhong said. \u201cEverything from watches, rings, even beds that tracks your sleep. All these data are being collected, and if we could tap into it, and get those more objective measures, that would be amazing.\u201d<\/p>\n
For more information:<\/h2>\n Charlie Zhong, PhD, MPH,<\/b> can be reached at charlie.zhong@cancer.org.<\/p>\n\n
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Published by:<\/span>\n
Sources\/Disclosures<\/h3>\n Source: <\/h2>\n Zhong C, et al. Abstract 5047. Presented at: American Association for Cancer Research Annual Meeting; April 17-22, 2026; San Diego.<\/p>\n
Reference:<\/h2>\n\n
Disclosures: <\/strong>
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