This introductory text gives an exceptionally clear and well organized account of epidemiologic concepts and methods, emphasizing the sequence of reasoning from different types of data that lead to inferences about the etiology or natural history of disease.

Foundations of Epidemiology

Epidemiology and the web of causation: Has anyone seen the spider?

Objective. —To assess health-related quality of life (HRQOL) in men treated for clinically localized prostate cancer. Design. —A cross-sectional analysis of HRQOL after treatment with radical prostatectomy, pelvic irradiation, or observation alone for clinically localized prostatic adenocarcinoma, and in age-matched comparison patients. Setting. —A large managed care population in California. Subjects. —A total of 528 men, including 214 treated for clinically localized prostate cancer (41 with evidence of metastatic disease were excluded from this analysis) and 273 age-matched, ZIP code—matched comparison patients without prostate cancer. Cancer patients were analyzed in three treatment groups: radical prostatectomy (n=98), primary pelvic irradiation (n=56), and observation alone (n=60). Main Outcome Measures. —General HRQOL was measured with the RAND 36-Item Health Survey 1.0. Cancer-specific HRQOL was measured with the CAncer Rehabilitation Evaluation System—Short Form and the Functional Assessment of Cancer Therapy—General form. Disease-targeted quality of life was measured with a new instrument assessing function and bother in three organ systems: sexual, urinary, and bowel. Results. —No differences among treatment groups were seen in comparisons of general HRQOL. Significant differences among treatment groups were seen in both function and bother in the prostate-targeted measures of sexual, urinary, and bowel domains. When cancer patients were compared with men of similar age without prostate cancer, differences were seen in the sexual, urinary, and bowel function and bother but not in general HRQOL measures. Although cancer-free men were found not to have full potency or continence, prostate cancer patients treated with surgery or radiation reported significantly worse sexual, urinary, and bowel function than men without cancer. Men who had undergone nerve-sparing prostatectomy did not differ from those who had undergone standard prostatectomy, but the power to detect a difference was low. Conclusions. —Although no differences were seen in general HRQOL, three disease-targeted domains were found to differ significantly among the treatment groups and comparison patients. Even after controlling for the sexual and urinary dysfunction experienced by older men without cancer, those receiving therapeutic interventions for their prostate cancer were found to have poorer disease-targeted HRQOL. We conclude that in addition to general HRQOL, disease-targeted measures must be used to assess outcomes of care in men treated for localized prostate cancer. ( JAMA . 1995;273:129-135)

Quality-of-life Outcomes in Men Treated for Localized Prostate Cancer

Reliability of the Center for Epidemiologic Studies Depression Scale, a 20-item symptom checklist, is examined using data from a sample of community respondents containing Anglos (254), Blacks (270), and Mexican Americans (181). Although the survey response rate was lower for Mexican Americans, quality of the data provided by this group was not significantly different from that for Anglos or Blacks. That is, there were no differences among these groups in terms of missing data or internal consistency reliabilty (as measured by Cronbach's alpha and Spearman-Brown split halves). Factor-analytic results also demonstrate the same general structure of responses among the three groups.

Reliability of the CES-D Scale in different ethnic contexts.

Ecological studies have been evaluated in epidemiological contexts in terms of the "ecological fallacy." Although the empirical evidence for a lack of comparability between correlations derived from ecological- and individual-level analyses is compelling, the conceptual meaning of the ecological fallacy remains problematic. This paper argues that issues in cross-level inference can be usefully conceptualized as validity problems, problems not peculiar to ecological-level analyses. Such an approach increases the recognition of both potential inference problems in individual-level studies and the unique contributions of ecological variables. This, in turn, expands the terrain for the location of causes for disease and interventions to improve the public's health.

https://ajph.aphapublications.org/doi/pdfplus/10.2105/AJPH.84.5.819

The fallacy of the ecological fallacy: the potential misuse of a concept and the consequences.

This classic text presents the basic principles of epidemiology. It includes coverage of epidemiologic concepts, measurements of morbidity and mortality, sources of data on community health, selected indices of health, descriptive epidemiology, analytic studies, prophylactic and therapeutic trials, screening in the detection of disease, population dynamics and health, epidemiologic aspects of infectious disease, occupational epidemiology, selected statistical topics, and more.

Judith S. Mausner

Papers

Epidemiology;: An introductory text