Background: Cancer epidemiology has been criticized for producing false-positive associations. The present analysis investigates the frequency of and factors contributing to false-positive findings in cancer epidemiology.
Methods: The International Agency for Research on Cancer (IARC) Monographs Group 3 agents were examined to identify potential false-positive findings. Frequency estimates for their occurrence were calculated. Comments of the Working Groups on study quality were recorded for studies with potential false-positives. These were used to determine how many of such studies were criticized for each of the study quality factors that are suspected to contribute to false-positive results.
Results: Of 509 agents in group 3, 37 agents were found to have potential false-positive associations in the studies reviewed in their respective IARC monograph(s). The overall frequency of potential false-positives among these agents was between 0.03 and 0.10. The individual frequencies ranged from 0.01 to 0.40. The potential false-positive findings were produced by 162 studies. The most common factors contributing to potential false-positive findings were confounding and exposure misclassification.
Conclusions: The frequency estimates we have obtained do not suggest that epidemiology is grossly flooded by false-positive findings. The factors for which studies with potential false-positives were most often criticized were factors that are sometimes difficult to address in cancer epidemiologic research and can bias an effect estimate toward or away from the null.
Impact: The low frequency of false-positives in cancer epidemiology restores faith in epidemiologic procedures, making epidemiologic findings a useful guide for public health care measures.
©2012 AACR.