Multiple chemical sensitivity syndrome - Symptom prevalence and risk factors in a military population

Objective: To assess the prevalence of and risk factors for self-reported s ymptoms suggestive of multiple chemical sensitivities/idiopathic environmen tal intolerance (MCS/IEI) in Persian Gulf War (PGW) veterans from Iowa and a comparison group of PGW-era military personnel. Methods: A population-based sample of Iowa military personnel was surveyed using a cross-sectional telephone interview. Study participants were random ly drawn from 1 of 4 domains: PGW active duty, PGW National Guard/Reserve, non-PGW active duty, and non-PGW National Guard/Reserve. A complex sample s urvey design was used selecting participants from the following substrata: age, sex, race, rank, and military branch. The criteria for MCS/IEI were de veloped using expert consensus and the medical literature. Results: A total of 3695 study participants (76% of those eligible) complet ed the telephone survey. The prevalence of symptoms suggestive of MCS/IEI i n all participants was 3.4%. Veterans of the PGW reported a significantly h igher prevalence of symptoms suggestive of MCS/IEI than did non-PGW militar y personnel (5.4% vs 2.6%); greater sensitivity to organic chemicals, vehic le exhaust, cosmetics, and smog; and more lifestyle changes. The following risk factors for MCS/IEI were identified with univariate analysis: deployme nt to the Persian Gulf, age (>25 years), female sex, receiving a physician diagnosis of MCS, previous professional psychiatric treatment, previous psy chotropic medication use, current psychiatric illness, and a low level of p reparedness. Multiple logistic regression analysis identified several indep endent risk factors for MCS/IEI, including deployment to the Persian Gulf, age, sex, rank, branch of service, previous professional psychiatric treatm ent, and current mental illness. Conclusions: Self-reported symptoms suggestive of MCS/IEI are relatively fr equent in a military population and are more common among PGW veterans than comparable controls. Reported chemical sensitivities and accompanying beha vioral changes were also frequent. After adjusting for age, sex, and traini ng preparedness, previous professional psychiatric treatment and previous p sychotropic medication use (before deployment) showed a robust association with symptoms suggestive of MCS.