{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,25]],"date-time":"2026-01-25T02:52:57Z","timestamp":1769309577010,"version":"3.49.0"},"reference-count":35,"publisher":"BMJ","issue":"3","funder":[{"DOI":"10.13039\/100008730","name":"The Norwegian Cancer Society","doi-asserted-by":"crossref","id":[{"id":"10.13039\/100008730","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Open"],"accepted":{"date-parts":[[2018,2,8]]},"published-print":{"date-parts":[[2018,3]]},"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Bladder cancer (BC) (including renal pelvis, ureter and urethra) is one of the most common urogenital cancers and the fourth most frequent cancer in men in the USA. In Norway, the incidence of BC has increased over the last decades. The age-standardised incidence rates per 100 000 for 2011-2015 were 53.7 in men and 16.5 in women. Compared to the 5-year period 2006\u20132010, the percentage increase in incidence was 6.1% in men and 12.3% in women. The recurrence rate of BC is over 50%, the highest recurrence rate of any malignancy. Smoking and occupational exposure to aromatic amines are recognised as the major risk factors. Recently, low-serum level of 25-hydroxy vitamin D (25(OH)D) and obesity have been suggested to increase the BC risk, and leptin, which is important in weight regulation, may be involved in bladder carcinogenesis. More knowledge on potential risk factors for BC is necessary for planning and implementing primary prevention measures.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods and analyses<\/jats:title>\n                    <jats:p>Cohort and nested case\u2013control studies will be carried out using the population-based Janus Serum Bank Cohort consisting of prediagnostic sera, clinical measurement data (body height and weight, body surface area and weight change over time, blood pressure, cholesterol and triglycerides) and self-reported information on lifestyle factors (smoking, physical activity). Participants were followed from cohort inclusion (1972\u20132003) through 2014. The cohort will be linked to the Cancer Registry of Norway (cancer data), the National Cause of Death Registry (date and cause of death), National Population Registry (vital status) and Statistic Norway (education and occupation). Serum samples will be analysed for 25(OH)D, vitamin D binding protein, leptin, albumin, calcium and parathyroid hormone. Cox regression and conditional logistic regression models and mediation analysis will be used to estimate association between the exposures and BC.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Ethics and dissemination<\/jats:title>\n                    <jats:p>The study has been approved by the Regional Committee for Medical Research Ethics and is funded by the Norwegian Cancer Society. Results will be published in peer-reviewed journals, at scientific conferences and through press releases.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/bmjopen-2017-019309","type":"journal-article","created":{"date-parts":[[2018,3,30]],"date-time":"2018-03-30T09:25:23Z","timestamp":1522401923000},"page":"e019309","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":7,"title":["Vitamin D, obesity and leptin in relation to bladder cancer incidence and survival: prospective protocol study"],"prefix":"10.1136","volume":"8","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4511-5173","authenticated-orcid":false,"given":"Randi Elin","family":"Gislefoss","sequence":"first","affiliation":[{"name":"Department of Research, Cancer Registry of Norway, Oslo, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1964-5410","authenticated-orcid":false,"given":"Jo Steinson","family":"Stenehjem","sequence":"additional","affiliation":[{"name":"Department of Research, Cancer Registry of Norway, Oslo, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Helga Helseth","family":"Hektoen","sequence":"additional","affiliation":[{"name":"Department of Research, Cancer Registry of Norway, Oslo, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bettina Kulle","family":"Andreassen","sequence":"additional","affiliation":[{"name":"Department of Research, Cancer Registry of Norway, Oslo, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hilde","family":"Langseth","sequence":"additional","affiliation":[{"name":"Department of Research, Cancer Registry of Norway, Oslo, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Karol","family":"Axcrona","sequence":"additional","affiliation":[{"name":"Department of Urology, Akershus University Hospital, L\u00f8renskog, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Elisabete","family":"Weiderpass","sequence":"additional","affiliation":[{"name":"Department of Research, Cancer Registry of Norway, Oslo, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alison","family":"Mondul","sequence":"additional","affiliation":[{"name":"School of Public Health, University of Michigan, Ann Arbor, Michigan, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Trude Eid","family":"Robsahm","sequence":"additional","affiliation":[{"name":"Department of Research, Cancer Registry of Norway, Oslo, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[2018,3,30]]},"reference":[{"key":"2025121220264760000_8.3.e019309.1","doi-asserted-by":"publisher","DOI":"10.3322\/caac.21332"},{"key":"2025121220264760000_8.3.e019309.2","doi-asserted-by":"publisher","DOI":"10.1016\/j.eururo.2014.01.006"},{"key":"2025121220264760000_8.3.e019309.3","doi-asserted-by":"publisher","DOI":"10.1001\/jama.2011.1142"},{"key":"2025121220264760000_8.3.e019309.4","doi-asserted-by":"crossref","first-page":"1256","DOI":"10.1097\/01.smj.0000247266.10393.72","article-title":"An updated review of the literature: risk factors for bladder cancer with focus on occupational exposures","volume":"99","author":"Olfert","year":"2006","journal-title":"South Med J"},{"key":"2025121220264760000_8.3.e019309.5","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1293\/tox.24.25","article-title":"Enhanced urinary bladder, liver and colon carcinogenesis in Zucker diabetic fatty rats in a multiorgan carcinogenesis bioassay: evidence for mechanisms involving activation of PI3K signaling and impairment of p53 on urinary bladder carcinogenesis","volume":"24","author":"Ishii","year":"2011","journal-title":"J Toxicol Pathol"},{"key":"2025121220264760000_8.3.e019309.6","doi-asserted-by":"publisher","DOI":"10.1016\/j.urology.2003.08.038"},{"key":"2025121220264760000_8.3.e019309.7","doi-asserted-by":"publisher","DOI":"10.1210\/jc.2008-1454"},{"key":"2025121220264760000_8.3.e019309.8","doi-asserted-by":"publisher","DOI":"10.1007\/s10552-004-1661-4"},{"key":"2025121220264760000_8.3.e019309.9","doi-asserted-by":"publisher","DOI":"10.1016\/j.annepidem.2007.12.001"},{"key":"2025121220264760000_8.3.e019309.10","unstructured":"Pike JW FD , Glorieux FH . 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