[Meta-analysis of epidemiologic studies].
BACKGROUND
A metaanalysis is often performed if risk assessment with available epidemiological data is not sensible. The results of these analyses serve mainly to quantify the risk of weak associations.


METHODS
In this paper we describe methodologic issues of this approach with emphasis on the difference between metaanalysis from published data and from individual patient records. As an example we discuss studies on oral contraceptives and breast cancer. Limits of metaanalysis from published data are given.


CONCLUSIONS
Although metaanalysis with individual data may be cost- and time-consuming their results are more reliable.
Blettner
M
M
Deutsches Krebsforschungszentrum, Abteilung Epidemiologie, Heidelberg.
Sauerbrei
W
W
D001943:Breast Neoplasms / Q000139:chemically induced / Q000453:epidemiology; D003276:Contraceptives, Oral / Q000009:adverse effects; D016021:Epidemiologic Studies; D005260:Female; D006801:Humans; D015201:Meta-Analysis as Topic; D012306:Risk
D003276:Contraceptives, Oral