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- Pukkala, Eero, et al.
(author)
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Nordic biological specimen banks as basis for studies of cancer causes and control - more than 2 million sample donors, 25 million person years and 100 000 prospective cancers
- 2007
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In: Acta Oncologica. - : Informa UK Limited. - 1651-226X .- 0284-186X. ; 46:3, s. 286-307
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Journal article (peer-reviewed)abstract
- The Nordic countries have a long tradition of large-scale biobanking and comprehensive, population-based health data registries linkable on unique personal identifiers, enabling follow-up studies spanning many decades. Joint Nordic biobank-based studies provide unique opportunities for longitudinal molecular epidemiological research. The purpose of the present paper is to describe the possibilities for such joint studies, by describing some of the major Nordic biobank cohorts with a standardised calculation of the cancer incidence in these cohorts. Altogether two million donors have since 1966 donated more than four million biological samples, stored at -20 degrees C to -135 degrees C, to 17 biobank cohorts in Finland, Iceland, Norway and Sweden. As a result of joint database handling principles, the accuracy of personal identifiers and completeness of follow-up for vital status in all participating biobanks was improved. Thereafter, the cancer incidence was determined using follow-up through the national cancer registries. Biobanks based on random samples of population typically showed slightly lower cancer incidence rates than the general population, presumably due to better participation rates among health-conscious subjects. On the other hand, biobanks including samples for viral screening or clinical testing showed 1.5 to 2.1 fold increased incidence of cancer. This excess was very high immediately after sampling, but for some cancer sites remained elevated for years after clinical sampling. So far, more than 100 000 malignant neoplasms have occurred after sample donation, and the annual increase of the cancer cases in these cohorts is about 10 000. The estimates on the population-representativity of the biobanks will assist in interpretation of generalizability of results of future studies based on these samples, and the systematic tabulations of numbers of cancer cases will serve in study power estimations. The present paper summarizes optimal study designs of biobank-based studies of cancer.
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| 2. |
- Dahlström, Lisen Arnheim, et al.
(author)
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Prospective seroepidemiologic study of human papillomavirus and other risk factors in cervical cancer
- 2011
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In: Cancer Epidemiology, Biomarkers and Prevention. - 1055-9965 .- 1538-7755. ; 20:12, s. 2541-2550
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Journal article (peer-reviewed)abstract
- Background: Several sexually transmitted infections (STI) have been reported to interact with human papillomavirus (HPV) in the etiology of cervical cancer. A large cohort study is required to obtain a both unbiased and stable estimate of their effects. Methods: Four major biobanks in the Nordic Countries containing samples from about 1,000,000 subjects were linked with nation-wide cancer registries. Serum samples from 604 women with invasive cervical cancer (ICC) diagnosed on average 10 years after sampling and 2,980 matched control women were retrieved and analyzed with serology for key STI. Results: Exposure to HPV16 was the strongest risk factor for cervical cancer [ OR = 2.4; 95% confidence interval (CI), 2.0-3.0], particularly for squamous cell carcinoma (OR = 2.9; 95% CI, 2.2-3.7). HPV18 was strongly associated with increased risk for adenocarcinoma (OR = 2.3; 95% CI, 1.3-4.1). Baseline seropositivity for HPV16 did not confer any increased risk for HPV18 DNA-positive cancer and conversely HPV18 seropositivity had no association with HPV16 DNA-positive cancers. HPV6 had no effect on its own (OR = 1.1; 95% CI, 0.9-1.3), but had an antagonistic effect on the risk conferred by HPV16 (P < 0.01). Herpes simplex virus 2 had little or no association (OR = 1.1; 95% CI, 0.8-1.4). Previous exposure to Chlamydia trachomatis, as indicated by serum antibodies, had a strongly increased risk for cervical cancer (OR = 1.9; 95% CI, 1.5-2.3). Conclusions: A large prospective study has assessed the role of different STIs in cervical cancer. Impact: Prospective evidence supports cofactor role of some STI in cervical cancer. Cancer Epidemiol Biomarkers Prev; 20(12); 2541-50. (C) 2011 AACR.
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| 3. |
- Kapeu, Aline Simen, et al.
(author)
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Is Smoking an Independent Risk Factor for Invasive Cervical Cancer? A Nested Case-Control Study Within Nordic Biobanks
- 2009
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In: American Journal of Epidemiology. - Baltimore, Md. : Oxford University Press (OUP). - 0002-9262 .- 1476-6256. ; 169:4, s. 480-488
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Journal article (peer-reviewed)abstract
- The strong correlation between smoking and exposure to oncogenic human papillomaviruses (HPVs) has made it difficult to verify the independent role of smoking in cervical carcinogenesis. Thus, the authors evaluated this role. Five large Nordic serum banks containing samples from more than 1,000,000 subjects were linked with nationwide cancer registries (1973-2003). Serum samples were retrieved from 588 women who developed invasive cervical cancer and 2,861 matched controls. The samples were analyzed for cotinine (a biomarker of tobacco exposure) and antibodies to HPV types 16 and 18, herpes simplex virus type 2, and Chlamydia trachomatis. Smoking was associated with the risk of squamous cell carcinoma (SCC) among HPV16- and/or HPV18-seropositive heavy smokers (odds ratio = 2.7, 95% confidence interval: 1.7, 4.3). A similar risk of SCC (odds ratio = 3.2, 95% confidence interval: 2.6, 4.0) was found in heavy smokers after adjustment for HPV16/18 antibodies. The point estimates increased with increasing age at diagnosis and increasing cotinine level. This study confirms that smoking is an independent risk factor for cervical cancer/SCC in women infected with oncogenic HPVs. These findings emphasize the importance of cervical cancer prevention among women exposed to tobacco smoke.
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