Adjusted odds ratios under nondifferential misclassification: Application to prostate cancer

The high prevalence of unsuspected prostate cancer among middle aged and el derly men is unique among cancers. With their uncertain natural history, un suspected prostate cancer cases may be misclassified into control groups in which they can obscure the identification of prostate cancer risk factors in case-control studies. Assuming that the exposure experience of diagnosed and of unsuspected prostate cancers is the same (nondifferential misclassi fication), case-control odds ratios are biased toward the null, which may p rovide a rationale for reexamining findings in negative case-control studie s of prostate cancer. This article reviews the evidence supporting a high p revalence of prostate cancer and describes formulae that can be used to adj ust for misclassification bias in completed case-control studies and to est imate required sample sizes in proposed studies., CLIN EPIDEMIOL 52;2:129-1 36, 1999. (C) 1999 Elsevier Science Inc.