PubMed · 12317922
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H Yan. 1992. A comprehensive study on the age structure.. https://pubmed.ncbi.nlm.nih.gov/12317922/
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In Germany, neuroblastoma is the most frequent extracranial solid childhood tumour. Its properties made it seem an ideal candidate for screening. A German trial assessed the effect of screening at one year of age from 1995-2001 in a nationwide project. We present here the methods developed for the estimation of lead-time and overdiagnosis in this project. Follow up on 1.5 million screened children and 2.1 million control children is currently available until June 2002. Ascertainment of control cohort cases and false negative cases is complete up to this date. A method for determining an empirical lead-time distribution and overdiagnosis estimate from comparing the age specific incidences in the control group and the study group is presented. Lead-time leads to an excess of cases in the screening group at the screening age and cases missing at higher age. If more cases are observed at the screening age than can be explained by lead-time, the difference is attributed to overdiagnosis. The width of the screening age window and the empirical maximum lead-time have to be chosen from graphs. About 1.0/100000 cases (20 per cent of the possible cases) experienced lead-time while 6.8/100000 cases were overdiagnosed. The mean lead-time was estimated to be about 15 months. The number of cases who might benefit is much smaller than was expected before the study while the overdiagnosed group is much larger. The method is robust against the choices that have to be made in the estimation process.
Non-steroidal anti-inflammatory drugs (NSAIDs), including aspirin, seem to have chemopreventive properties against several types of cancer, particularly colon cancer. Persons with rheumatoid arthritis, an autoimmune disease for which NSAIDs are used commonly, have been reported to be at lower risk of colon cancer but at elevated risk of non-Hodgkin lymphoma (NHL), raising the possibility that NSAIDs may be a risk factor for NHL. We evaluated the association of use of NSAIDs, arthritis history, and risk of NHL in a prospective cohort of 27,290 postmenopausal women from the state of Iowa. The frequency of use of aspirin and of other NSAIDs excluding aspirin (e.g., ibuprofen), as well as a physician diagnosis of rheumatoid arthritis (RA) or osteoarthritis (OA), were self-reported on a questionnaire mailed in 1992. The incidence of NHL was ascertained through annual linkages to the Iowa SEER Cancer Registry. Relative risks (RR) and 95% confidence intervals (CI) were estimated using Cox proportional hazards regression. Through 7 years of follow-up, 131 cases of NHL were identified. Compared to women who did not use either aspirin or other non-aspirin NSAIDs, women using aspirin exclusively (RR = 1.71; 95% CI = 0.94-3.13), non-aspirin NSAIDs exclusively (RR = 2.39; 95% CI = 1.18-4.83), or both types of drugs (RR = 1.97; 95% CI = 1.06-3.68) were at increased risk of NHL. A diagnosis of RA (RR = 1.75; 95% CI = 1.09-2.79), but not OA (RR = 1.06; 95% CI = 0.67-1.68), was associated with risk of NHL, but the positive association of use of aspirin and other NSAIDs with NHL was independent of RA history. Multivariate adjustment for other NHL risk factors only attenuated slightly these associations, whereas exclusion of cases occurring during the first 2 years of follow-up strengthened the associations. These data suggest that use of NSAIDs, either aspirin or other non-aspirin NSAIDs, are associated positively with risk of NHL, and that this association is independent of RA history.