Detailed information about this study is given elsewhere 33. In brief, the French Study on the Persian Gulf War and its Health Consequences is a cross-sectional study with an exhaustive aim which included all civilians and military personnel serving in the Persian Gulf from August 1990 to July 1991. The addresses of 10,478 French troops who served in the Gulf during the period from August 1990 through July 1991 were identified, based on data transmitted by military staff, and 5,666 participated in the study after receiving two reminders. The participation rate was 54% and varied by branch of service (56% in the Army, 55% in the Air Force, and 43% in the Navy).

Data collection was based on a 12-page self-administered postal questionnaire, accompanied by an explanatory letter stating the objectives of our study and a consent form, was developed on the basis of information published in the French authorities' reports and with reference to questionnaires used in PGWV morbidity studies. The questionnaire, tested on a sample of the target population, requested details of disorders requiring medical consultation, miscarriage or stillbirth, and the number of children born before and after the conflict. If a child presented a disease, his or her year of birth, gender, and detailed illnesses were requested. The notion of infertility was inferred from the following specific disorders: infertility or sperm abnormalities. The questionnaire also explored (i) socio-demographic characteristics (gender, age), (ii) military history (service branch, rank, military status on completion of the questionnaire), (iii) living conditions, and self-reported exposures during the Persian Gulf mission (sandstorms, smoke from oil well fires, chemical or bacteriological alerts, vaccinations, medication, and pesticides) of the PGWVs, and (iv) diseases and symptoms before, during, and after the mission. Hospitalization after the mission for one of the 49 symptoms of the Hopkins Symptom Checklist 34 was also reported.

On reception, the questionnaires were made anonymous, coded by an epidemiologist (CV) [ICD-10 35], keyboarded, and analyzed. Birth defects presented by PGWV offspring were grouped for analysis based on the classification system used in the European Registry of Congenital Anomalies (EUROCAT) 36.

We used Stata™ statistical software for all analyses. All p values are two sided, and we took values less than 0.05 to indicate statistical significance.

First, a descriptive analysis was conducted on PGWV: i) living conditions and exposures during the mission; ii) self-reported infertility disorders and miscarriage that appeared after the PGW mission.

Secondly, as data on healthy children were not available (except for the number of children), we decided to perform a case-control study nested within the cohort to determine the effect of PGW exposures on the risk of a father conceiving a child with a birth defect after the war. The date of birth had to be later than nine months after the end of the PGW mission for a child to be considered as having been conceived after the war. A case was defined as a man having had at least one child conceived after the PGW mission and presenting at least one birth defect. Two controls were selected for each case. A control was defined as a man of the same age as the case (± 1 year) who had never had a child with a birth defect but who had had at least one child after the PGW mission. Fathers having had at least one child with a birth defect before the PGW were excluded from this analysis. To minimize recall bias, a control should have reported one hospitalization for at least one symptom of the Hopkins Symptom Checklist 34 after the mission. PGW exposure odds-ratios were estimated by conditional logistic regression and then adjusted for service branch, rank, and military status.

Finally, the study provides a description of children born to PGWVs after the Gulf War. Major anomalies were described as Maconochie et al reported 27. Minor anomalies were coded and specified. As no national registry on birth defects has been developed in France, PGWV children's birth defect rates were compared to the 10-year incidence rate of birth defects among children conceived from 1991 to 2000, as described by the Paris Registry of Congenital Malformations 37. The Paris Registry rate was considered as the reference rate among the population. The confidence interval of the PGWV children's birth defect rate was estimated according to a Poisson distribution. The incidence ratio was calculated by dividing the PGWV children's birth defect rate by the reference rate.

The National Commission of Data Processing and Civil Liberty approved this investigation, in conformity with article 15, paragraph 3 of the Law of January 6, 1978, concerning data processing, files, and civil liberty.

Most of the 5,666 subjects who completed the questionnaire were male (99.5%), with an average age of 41 years (SD: 6 years) at the time of completion of the survey, and 71% of respondents were still in service. Considering the sample size of female veterans, the results are presented below by gender.

The mean age of the 28 women who completed the questionnaire was 44 years (37 to 57 years). They served mainly in military health services (n = 14) and in the Air Force (n = 12). One woman served in the Navy and one in the Army. Six women reported at least one miscarriage after the mission. Nine women reported having at least one child after the mission (total of 25 babies), ranging from 1 to 4 children. No birth defect was reported in children born after the mission.

The main characteristics of the 5,638 male veterans are presented in Table 1. Respondents served mainly in the Army or the Air Force and were servicemen. The respondents' age varied according to service: 63% of Army veterans, 52% of Navy veterans, and 28% of Air Force veterans were less than 40 years old (p < 0,001).

The health of live born children and birth defects are described in 5,183 children conceived after the PGW mission. Incidence of pre-term delivery reported in children conceived after the PGW mission was 104.2/10,000 live births [95% CI: 78.3–135.9]. Only 140 babies conceived after the PGW mission presented at least one birth defect (270.1/10,000 live births [95% CI: 227.2–318.7]). Eight babies presented two malformations. These associations were not specific.

The different major birth defects of babies conceived after the Gulf War mission are presented in Table 4.