Epidemiology retrospective analysis

Gessner BD and Middaugh JP (1995) Paralytic shellfish poisoning in Alaska A 20-year retrospective analysis. American Journal of Epidemiology 141 766-770. Morbidity and Mortality Weekly Report (1991) Paralytic shellfish poisoning - Massachusetts and Alaska, 1990. MMWR 40 157-161. 

Table A-2. Summary of Epidemiological Information Concerning Human PCB Exposures Retrospective Analysis of... 

The first valuable epidemiological data on OP have been provided only recently by a retrospective analysis of biopsy-proven cases diagnosed in Iceland between 1984 and 2003 (28). This study took advantage from the fact that all pathology specimens in Iceland are evaluated at only two departments, thus allowing a comprehensive nationwide search for available cases. The mean annual incidence of OP was 1.97/100,000, with 1.10/100,000 for COP and 0.87/100,000 for secondary OP (28). Men and women were equally affected, at a mean age of 67 years. No relationship between OP occurrence and smoking has been demonstrated so far. 

Pratt PC, Vollmer RT, Miller JA Epidemiology of pulmonary lesions in nontextile and cotton textile workers—a retrospective autopsy analysis. Arch Environ Health 35 133-138, 1980... 

Even if there were no such limitations, epidemiologic analysis is retrospective study it cannot be depended upon for the detection and prevention of potential health hazards to the public. In comparison to epidemiologic studies, animal bioassays are short in duration, relatively inexpensive, easily perfomed under controlled conditions, and are reliable predictors for known human carcinogens. Therefore, from the point of view of identifying and preventing public health hazards, animal bioassay is an invaluable tool. 

Future studies on the adverse human health effects of PCBs will require more standardized methods of congener specific PCB analysis, the development of more sensitive techniques to determine subtle toxic effects caused by relatively low exposures to PCBs (e.g. environmental) and a more thorough knowledge of the interactive effects of PCBs with other environmental pollutants. The most appropriate indicators of the adverse health effects of PCBs and their role in carcinogenicity will be determined from the continuing epidemiological and retrospective studies on occipationally exposed workers. 

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