(expected number 17.0-30.3). Limitations of the study include the lack of data on mothers’ risk factors and possible exposures of the fathers in Vietnam, possible recall bias, and lack of verification of many of the reproductive effects reported by the veterans.
Cowan et al. (1997) examined routinely collected data on all live births in 135 military hospitals in 1991-1993 to compare the frequency of birth defects in children of active-duty Gulf War veterans and nondeployed active-duty veterans. Information on 33,998 infants born to Gulf War-deployed veterans (30,151 men and 3847 women) and 41,463 born to nondeployed veterans (32,638 men and 8825 women) was reviewed. The risk of any birth defect was 7.45% for deployed veterans and 7.59% for nondeployed veterans (RR 0.98, 95% CI 0.93-1.03). There was no significant association between service in the Gulf War and the risk of any birth defect for male veterans (OR 0.97, 95% CI 0.91-1.03) or female veterans (OR 1.07, 95% CI 0.94-1.22) after adjustment for mother’s age at delivery, race or ethnicity, and marital status of parent at the time of the Gulf War. The unadjusted risk of having an infant with severe birth defects was 1.03 (95% CI 0.92-1.15) for male active-duty veterans, 0.92 (95% CI 0.71-1.20) for female active-duty veterans, and 1.00 (95% CI 0.90-1.10) for men and women combined; the authors note that when the adjusted ORs were calculated, no associations were seen but did not provide the data. A limitation of the study is that it examined data only from live births to active-duty personnel in military hospitals.
After conducting a pilot study (Araneta et al. 2000) in Hawaii on birth-defects in the offspring of Gulf War veterans, Araneta et al. (2003) conducted an expanded study examining hospital records of births in 1989-1993 to military personnel in Arizona, Hawaii, Iowa, and selected counties of Arkansas, California, and Georgia. Data from the DMDC on people in military service in February 1991 were linked to data from state and county birth-defects surveillance programs to identify infants born to military personnel who served during the Gulf War. The researchers identified 11,961 infants born to Gulf War veterans (including 450 female veterans) and 33,052 infants born to Gulf War-era veterans (including 3966 female veterans). In infants conceived before and during the Gulf War, there was no significant difference in birth defects between those born to Gulf War veterans and those born to era veterans. In infants conceived after the war, the rate of hypospadias was significantly higher in male infants born to Gulf War mothers than to era mothers (RR 6.3, 95% CI 1.5-26.3, p = 0.015). The prevalence of congenital tricuspid valve insufficiency was higher in infants born to Gulf War male veterans than to era male veterans (RR 2.7, 95% CI 1.1-6.6, p = 0.039), as was the prevalence of aortic valve stenosis (RR 6.0, 95% CI 1.2-31.0, p = 0.026). A significant limitation on the interpretation of these findings is that comparisons were made for 26 birth-defect categories without correction for multiple comparisons; this raises the possibility that the statistical significance of the associations observed is due to chance (Ryan et al. 2004).
In a case-control study performed by Werler et al. (2005), birth records of infants born with the malformation hemifacial microsomia were examined to determine whether there was an association between Gulf War service of the parents and the birth defect. Hemifacial microsomia was identified in 232 cases from craniofacial clinics in 26 cities and matched to 832 controls by pediatrician and child’s age. Mothers of case subjects and controls were interviewed by telephone in 1996-2002 to identify pregnancy exposures, including military service, particularly in the Gulf War, of the mother or father 5-11 years before the child’s birth. Of the cases, four mothers and 30 fathers had served in the military, as had 10 control mothers and 100 control fathers; of those, four case parents (all in the Army) and 23 control parents (including nine in the Army) had served in the Gulf War. The risk associated with Army service overall was significant