Table 1

GRADE summary of findings for all outcomes

OutcomeNo. of studiesStudy designRisk of biasInconsistencyIndirectnessImprecisionPublication biasFactors than increase the certaintyNo. of patients and findingsCertainty
Congenital birth defect (CBD)10ObservationalVery serious*Not seriousSerious†Not seriousSerious‡NoneAlthough most studies are of small sample size, one study has a very large sample size (n=16 746), and its findings are both precise and consistent with the results of the remaining studies.Very low
Cancer15ObservationalVery serious§Not seriousSerious¶Not seriousSerious‡NoneThe total number of participants included in all the studies was 997. Some studies reported small significant increase in cancer incidence among exposed populations, and other studies (mainly ecological studies) reported ‘non-significant results’. The findings of one population-based study of 711 households were both precise and consistent with the results of the remaining studies.Very low
BCL-2 oncogene1ObservationalVery serious**Not seriousNot seriousSerious††Serious‡NoneThe total number of participants included in the study was 80 (low sample size). The study reported BCL-2 expression was found to be significantly higher among exposed populations.Very low
Immune system function3ObservationalVery serious‡‡Not seriousNot seriousNot seriousSerious‡NoneThe total number of participants included in all the studies was 365. All studies reported worse immune system function among exposed populations.Very low
Kidney failure1ObservationalVery serious§§Not seriousNot seriousSerious¶¶Serious‡NoneThe total number of participants included in the study was 26. The study found higher exposure among kidney failure patients than healthy controls.Very low
PTEN gene1ObservationalSerious***Not seriousSerious†††Serious‡‡‡Serious‡NoneThe total number of patients included in the study was 43. The study found that PTEN gene expression mean fold change was greater among the exposed group than the unexposed group.Very low
  • *All 10 studies were judged to have high risk of bias related to confounding, because none accounted for any confounders known to be associated with birth defects, including consanguinity, maternal age, maternal nutritional status (ie, folate deficiency) or exposure to other environmental teratogens.

  • †We judged the evidence to have serious indirectness as the studies that assessed CBD incidence did not directly measure uranium exposure. For the case–control studies, which did measure uranium concentrations in human biological samples, it was not known whether the source of uranium exposure came from natural or artificial sources (ie, conventional weapons used by the US or coalition forces in Iraq). One study, carried out in Fallujah, measured the isotopic ratio of uranium in participants’ samples and found that the uranium had an enriched, rather than depleted, isotopic signature.

  • ‡We suspect publication bias given that the sanctions played a role in limiting research publications on the health impacts of weaponised uranium in Iraq.

  • §All 15 studies were judged to have high risk of bias related to confounding. Five studies were rated high risk of bias in the domain ‘other sources of bias’. One study was potentially subject to recall bias or over-reporting.

  • ¶We judged the evidence to have serious indirectness as the studies that assessed cancer incidence did not directly measure uranium exposure. For the case–control studies that did measure uranium concentrations in human biological samples, it was not known whether the source of uranium exposure came from natural or artificial sources (ie, conventional weapons used by the US or coalition forces in Iraq).

  • **The study was rated high risk of bias due to lack of adjusting for confounding and reporting of adequate blinding.

  • ††The total number of patients included in the study was almost 80 (low sample size). The study reported BCL-2 expression was found to be significantly higher among exposed populations.

  • ‡‡All three of the studies were rated high risk of bias due to lack of adjusting for confounding and probably high risk of bias due to lack of reporting of adequate blinding.

  • §§The study was judged to have high risk of bias due to lack of adjusting for confounding and probably high risk of bias due to lack of reporting of adequate blinding.

  • ¶¶The study found higher exposure among kidney failure patients than healthy controls, but the sample size for the study was small (n=26).

  • ***The study was rated probably high risk of bias in the domains of exposure assessment and confounding.

  • †††The study did not directly measure uranium exposure.

  • ‡‡‡The total number of patients included in the study was 43 (low sample size).