Work

Birth weight and risk of testicular cancer

Year: 2007

Type: letter

Abstract: Dear Prof. zur Hausen, We read with great interest the meta-analysis of birth weight and testicular cancer published recently in the International Journal of Cancer.1 As there is currently interest in the relationship between perinatal factors and risk of testicular cancer, the meta-analysis was certainly timely. The conclusion of the study, however, that “A U-shaped association was observed between birth weight and the risk for testicular cancer.” is questionable. The meta-analysis included both a study published by Akre et al.2 and a study by Richiardi et al.3 Since the latter study is an update of the former, the former study should have been excluded from the analysis. The dual inclusion effectively increased the weighting of the risk estimates attributable to this population at the expense of the other studies considered. If the study by Akre et al.2 is excluded from the meta-analysis, the overall estimate for low birth weight, compared to normal birth weight, in relation to testicular cancer risk becomes 1.15 (95% confidence interval (CI): 0.98, 1.35; I2 = 57%). In addition, given the excess heterogeneity, one may be inclined to use a random effects, rather than fixed effects, model which gives an overall odds ratio of 1.29 (95% CI: 0.97, 1.72; Figure 1). Exclusion of the earlier study2 from the high birth weight analysis provides an odds ratio of 1.09 (95% CI: 0.99, 1.20; I2 = 34%) using a fixed effects model and 1.10 (95% CI: 0.96, 1.26; Figure 2) using a random effects model. In light of the lack of statistical significance in the reanalyses, we do not believe that the literature currently endorses a conclusion of a “U-shaped association” between birth weight and testicular cancer risk. It is, perhaps, more prudent to conclude that an association between these 2 variables remains tenuous, as stated in another recent meta-analysis of low birth weight and testicular cancer risk.4 Comparison of low vs. normal birth weight and risk of testicular cancer. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.] Comparison of high vs. normal birth weight and risk of testicular cancer. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.] Yours sincerely, Michael B. Cook*, Lorenzo Richiardi , Katherine A. McGlynn*.

Source: International Journal of Cancer

DOI: 10.1002/ijc.23129

Authors: Michael B. Cook, Lorenzo Richiardi, Katherine A. McGlynn

Institutions: United States Department of Health and Human Services, National Institutes of Health, National Cancer Institute, Division of Cancer Epidemiology and Genetics, University of Turin

Language: English

Topic: Testicular diseases and treatments

Subfield: Surgery

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: bronze

Funder: National Institutes of Health