A case-control follow-up study for disease-specific mortality.
Case-control studies often rely on subjects to report their own screening or exposure information: this information is often obtained from cases after the event of interest has occurred. This is problematic for mortality outcomes, because dead subjects cannot report the desired information. To avoid this problem, Weiss and Lazovich (1996, American Journal of Epidemiology 143, 319-322) proposed obtaining exposure or screening information from potential cases, i.e., subjects diagnosed with disease, at the time of disease diagnosis, and also from a referent series. The design is best viewed as a new scheme for sampling from a cohort. I review estimation of the effects of time-varying screening or exposure in cohort studies, using a new factorization. I then show how this factorization, together with ignorability assumptions, allows valid estimation from these new designs. Even when the sampling fraction of nondiseased subjects is unknown, causal risk ratios are estimable if diagnosis is rare in the cohort. I illustrate and compare conventional and new methods with data from the Health Insurance Plan study.
Joffe
Marshall M
MM
Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, 602 Blockley Hall, 423 Guardian Dr., Philadelphia, Pennsylvania 19104-6021, USA. mjoffe@cceb.upenn.edu
D000328:Adult; D001943:Breast Neoplasms / Q000175:diagnosis / Q000401:mortality*; D016022:Case-Control Studies; D015984:Causality; D015986:Confounding Factors, Epidemiologic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008403:Mass Screening; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic; D012107:Research Design; D012306:Risk; D012494:Sampling Studies; D013997:Time Factors; D016896:Treatment Outcome