Associations between environmental exposures in the Middle East Area of Operations and pregnancy outcomes in Australian Defence Force veterans.

Military personnel deployed on operations may encounter a variety of hazards with the capacity to adversely affect reproductive health. This paper investigates the association between self-reported exposure to reproductive toxicants and adverse pregnancy outcomes in Australian Defence Force veterans who deployed to Iraq and Afghanistan during the period 2001-2009. Utilising the Middle East Area of Operations (MEAO) Census Study data set, descriptive analyses of participants' self-reported exposure were compared with the occupational environmental monitoring data taken at their reported deployment location. Univariate analyses assessed the significance of unadjusted associations between self-reported exposures and reproductive outcomes. There is no systematic or consistent relationship between deployment to the MEAO and adverse pregnancy outcomes. Overall, self-reported adverse reproductive outcomes were significantly increased in veterans who deployed to both Afghanistan and Iraq (p = 0.04) compared to those who only deployed to only one of those locations; particularly in women (p = 0.009). Miscarriage was the most likely of these (p = 0.008). These figures would benefit from being confirmed against medical records but are worthy of further study. In this historical cohort study, causal inference cannot be made due to absence of control groups to exclude sources of potential bias. Imprecision in the assessment of environmental hazards in the MEAO and other methodological constraints make it impossible to calculate precise estimates of risk. The results warrant continued investigation, especially when combined with previous findings related to pregnancy outcomes in this population, the importance of reproductive outcomes, and the potential emergence of new hazards.

Jet Fuel, Noise, and the Central Auditory Nervous System: A Literature Review.

Prompted by the continued prevalence of hearing related disabilities accepted as eligible for compensation and treatment under Australian Department of Veterans' Affairs legislation, a review of recent literature regarding possible causation mechanisms and thus, possible prevention strategies, is timely. The emerging thoughts on the effects of a combination of jet fuel and noise exposure on the central auditory nervous system (CANS) have relevance in the military aviation context because of the high exposures to solvents (including fuels) and unique noise hazards related to weapons systems and military aircraft. This literature review aimed to identify and analyze the current knowledge base of the effects of combined exposure to JP-8 jet fuel (or its aromatic solvent components) and noise on the CANS in human populations. We reviewed articles examining electrophysiological and behavioral measurement of the CANS following combined exposures to jet fuel (or its aromatic constituents) and noise. A total of 6 articles met the inclusion criteria for the review and their results are summarized. The articles considered in this review indicate that assessment of the CANS should be undertaken as part of a comprehensive test battery for military members exposed to both noise and solvents in the workplace.

The effect of prenatal exposure to a repeat high dose of toluene in the fetal rat.

Solvent abuse during pregnancy results in a clinical pattern of adverse outcomes including deafness. The aim of this project was to determine whether high doses of toluene for a short duration during pregnancy produced adverse outcomes in the fetal rat. Pregnant rats were given either 1250 mg/kg of toluene or peanut oil by gavage from gestation day 16-19. The study demonstrated that administration of toluene at the dose used did not result in significant maternal toxicity. However, some maternal renal pathology was noted. There was no significant difference in placental or fetal weights nor was there a significant difference in the number of external or skeletal malformations of fetuses between treatment and control groups. Treated fetuses had an increased frequency and severity of enlarged renal pelveses. A pattern of accelerated development in the upper mid-turn and sometimes apical turns in the treated fetal cochleas was observed. This accelerated development suggests that toluene may induce excessive cell death resulting in premature maturation of the cochlea.