Abstract
The objective of this study is to conduct a meta-analysis of published and unpublished studies that examine the association between Agent Orange (AO) exposure and the risk of spina bifida. Relevant studies were identified through a computerized literature search of Medline and Embase from 1966 to 2008; a review of the reference list of retrieved articles and conference proceedings; and by contacting researchers for unpublished studies. Both fixed-effects and random-effects models were used to pool the results of individual studies. The Cochrane Q test and index of heterogeneity (I 2) were used to evaluate heterogeneity, and a funnel plot and Egger’s test were used to evaluate publication bias. Seven studies, including two Vietnamese and five non-Vietnamese studies, involving 330 cases and 134,884 non-cases were included in the meta-analysis. The overall relative risk (RR) for spina bifida associated with paternal exposure to AO was 2.02 (95% confidence interval [CI]: 1.48–2.74), with no statistical evidence of heterogeneity across studies. Non-Vietnamese studies showed a slightly higher summary RR (RR = 2.22; 95% CI: 1.38–3.56) than Vietnamese studies (RR = 1.92 95% CI: 1.29–2.86). When analyzed separately, the overall association was statistically significant for the three case–control studies (Summary Odds Ratio = 2.25, 95% CI: 1.31–3.86) and the cross sectional study (RR = 1.97, 95% CI: 1.31–2.96), but not for the three cohort studies (RR: 2.11; 95% CI: 0.78–5.73). Paternal exposure to AO appears to be associated with a statistically increased risk of spina bifida.
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Abbreviations
- AO:
-
Agent Orange
- CDC:
-
Centers for disease control and prevention
- CI:
-
Confidence interval
- EOI:
-
Exposure opportunity index
- OR:
-
Odds ratio
- RR:
-
Relative risk
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Ngo, A.D., Taylor, R. & Roberts, C.L. Paternal exposure to Agent Orange and spina bifida: a meta-analysis. Eur J Epidemiol 25, 37–44 (2010). https://doi.org/10.1007/s10654-009-9401-4
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DOI: https://doi.org/10.1007/s10654-009-9401-4