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CORRESPONDENCE
Author reply: Meta-analysis of stress-related factors in cancer
Andrew Steptoe, Yoichi Chida, Mark Hamer and Jane Wardle
We share many of the concerns expressed by Coyne and colleagues about the standard of scientific research in this field. As we emphasized in our Review,1
many published studies are of poor quality, due to an insufficient number of cases (resulting in low statistical power) and limited controls, and we agree that publication biases are often likely to bea factor. Nonetheless, we take issue with several aspects of this critique.
Coyne et al. appear to have misunderstood the nature of systematic reviews and meta-analyses. This technique of aggregating data is based on specified procedures and pre-defined criteriafor identifying published articles.2 All studies that fulfill these criteria mustbe included. Coyne et al. suggest that some published studies should have been excluded from the meta-analyses, but it is improper to pick and choose studies for inclusion in relation to the investigators preconceptions. We took methodological quality into account by defining quality criteria, rating each study, and doing sub-analyses of only high-quality studies.1
The combined hazard ratios for the high-quality studies were similar to those of the complete dataset (Figure 2 and Figure 31), and did not show signs of publication bias. This makes it difficult to conclude, as Coyne et al. do, that inclusion of...