{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T15:46:11Z","timestamp":1791992771548,"version":"4.4.0"},"reference-count":31,"publisher":"American Medical Association (AMA)","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JAMA Surg"],"abstract":"\n Importance<\/jats:title>\n Obesity is associated with elevated risks for multiple cancers. How bariatric surgery influences these risks across age and sex is insufficiently understood.<\/jats:p>\n <\/jats:sec>\n \n Objective<\/jats:title>\n To evaluate the association between bariatric surgery and obesity-related cancer (breast, endometrial, ovarian, esophageal adenocarcinoma, liver, pancreatic, colon, rectal, kidney, and multiple myeloma) and whether this association varies by age and sex.<\/jats:p>\n <\/jats:sec>\n \n Design, Setting, and Participants<\/jats:title>\n This population-based cohort study within the Nordic Obesity Surgery Cohort (NordOSCo) included individuals aged 18 to 59 years with an obesity record in Denmark, Finland, or Sweden from 1992 to 2023. Prospectively collected data on exposure, outcomes, and confounders were obtained from well-maintained national registries. Follow-up continued until cancer diagnosis, death, emigration, or December 31, 2023. These data were analyzed from December 2025 to April 2026.<\/jats:p>\n <\/jats:sec>\n \n Exposure<\/jats:title>\n Bariatric surgery vs no surgery among individuals with obesity.<\/jats:p>\n <\/jats:sec>\n \n Main Outcomes and Measures<\/jats:title>\n The primary outcome was incidence of obesity-related cancers. Risks were compared using crude and multivariable-adjusted incidence rate ratios (aIRR) with 95% CIs derived from Poisson regression adjusted for age, sex, calendar year, country, and obesity- and lifestyle-related comorbidities. Effect modification by age group (18-39 vs 40-59 years) and sex (female vs male) was evaluated using interaction terms.<\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n Among 784\u202f105 individuals with obesity (569\u202f266 women [73%] and 214\u202f839 men [27%]), 99\u202f614 underwent bariatric surgery. Surgery was associated with a lower risk of obesity-related cancer overall (aIRR, 0.81; 95% CI, 0.77-0.85). The magnitude of risk reduction did not differ by age group (individuals aged 18 to 39 years: aIRR, 0.80; 95% CI, 0.72-0.88 and individuals aged 40 to 59 years: aIRR, 0.81; 95% CI, 0.78-0.86) (\n P<\/jats:italic>\n for interaction\u2009=\u2009.88). Associations for non\u2013sex-specific cancers were similar in men and women (\n P<\/jats:italic>\n for interaction\u2009=\u2009.50). For individual cancers, the strongest inverse associations were observed for liver cancer (aIRR, 0.49; 95% CI, 0.34-0.70), endometrial cancer (aIRR, 0.51; 95% CI, 0.45-0.59), and ovarian cancer (aIRR, 0.73; 95% CI, 0.60-0.87). In contrast, pancreatic cancer risk was increased after surgery, particularly among younger adults (aIRR, 2.21; 95% CI, 1.44-3.39;\n P<\/jats:italic>\n \u2009=\u2009.01).\n <\/jats:p>\n <\/jats:sec>\n \n Conclusions and Relevance<\/jats:title>\n In this study, bariatric surgery was associated with a lower long-term risk of obesity-related cancers, with similar associations across age groups and sexes. These findings suggest that the long-term oncologic benefits of bariatric surgery apply broadly across age groups and sexes, supporting equitable access to bariatric surgery for patients with obesity.<\/jats:p>\n <\/jats:sec>","DOI":"10.1001\/jamasurg.2026.4798","type":"journal-article","created":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T15:00:32Z","timestamp":1791990032000},"source":"Crossref","is-referenced-by-count":0,"title":["Bariatric Surgery and Risk of Obesity-Related Cancer by Age and Sex"],"prefix":"10.1001","author":[{"given":"Cecilia","family":"Radkiewicz","sequence":"first","affiliation":[{"name":"Upper Gastrointestinal Surgery, Department of Molecular Medicine and Surgery, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden"},{"name":"Department of Surgery and Oncology, Capio Sankt G\u00f6rans Hospital, Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Giola","family":"Santoni","sequence":"additional","affiliation":[{"name":"Upper Gastrointestinal Surgery, Department of Molecular Medicine and Surgery, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joonas H.","family":"Kauppila","sequence":"additional","affiliation":[{"name":"Upper Gastrointestinal Surgery, Department of Molecular Medicine and Surgery, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden"},{"name":"Department of Surgery, Oulu University Hospital and University of Oulu, Oulu, Finland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eivind","family":"Ness-Jensen","sequence":"additional","affiliation":[{"name":"Upper Gastrointestinal Surgery, Department of Molecular Medicine and Surgery, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden"},{"name":"HUNT Research Center, Department of Public Health and Nursing, NTNU, Norwegian University of Science and Technology, Trondheim\/Levanger, Norway"},{"name":"Medical Department, Levanger Hospital, Nord-Tr\u00f8ndelag Hospital Trust, Levanger, Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"My","family":"von Euler-Chelpin","sequence":"additional","affiliation":[{"name":"Department of Public Health, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dag","family":"Holmberg","sequence":"additional","affiliation":[{"name":"Upper Gastrointestinal Surgery, Department of Molecular Medicine and Surgery, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jesper","family":"Lagergren","sequence":"additional","affiliation":[{"name":"Upper Gastrointestinal Surgery, Department of Molecular Medicine and Surgery, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden"},{"name":"School of Cancer and Pharmaceutical Sciences, King\u2019s College London, and Guy\u2019s and St Thomas\u2019 NHS Foundation Trust, London, United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"10","published-online":{"date-parts":[[2026,10,14]]},"reference":[{"issue":"3","key":"soi260072r1","doi-asserted-by":"publisher","DOI":"10.1093\/jncics\/pkz038","article-title":"40 years of change in age- and stage-specific cancer incidence rates in US women and men.","volume":"3","author":"Kehm","year":"2019","journal-title":"J Natl Cancer Inst Cancer Spectr"},{"issue":"3","key":"soi260072r2","doi-asserted-by":"publisher","first-page":"e137","DOI":"10.1016\/S2468-2667(18)30267-6","article-title":"Emerging cancer trends among young adults in the USA: analysis of a population-based cancer registry.","volume":"4","author":"Sung","year":"2019","journal-title":"Lancet Public Health"},{"issue":"20","key":"soi260072r3","doi-asserted-by":"publisher","first-page":"4553","DOI":"10.1002\/cncr.33050","article-title":"Emerging cancer incidence trends in Canada: the growing burden of young adult cancers.","volume":"126","author":"Heer","year":"2020","journal-title":"Cancer"},{"issue":"10","key":"soi260072r4","doi-asserted-by":"publisher","first-page":"1374","DOI":"10.1038\/s41416-022-01704-x","article-title":"Incidence trends for twelve cancers in younger adults-a rapid review.","volume":"126","author":"di Martino","year":"2022","journal-title":"Br J Cancer"},{"issue":"24","key":"soi260072r5","doi-asserted-by":"publisher","first-page":"2662","DOI":"10.1200\/JCO.21.02708","article-title":"Practical considerations in diagnosing and managing early-onset GI cancers.","volume":"40","author":"Lumish","year":"2022","journal-title":"J Clin Oncol"},{"issue":"10","key":"soi260072r6","doi-asserted-by":"publisher","first-page":"656","DOI":"10.1038\/s41571-022-00672-8","article-title":"Is early-onset cancer an emerging global epidemic? 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