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ABSTRACT: This study aimed to examine possible persisting peripheral neuropathy in a group who undertook fuel tank repairs on F-111 aircraft, relative to two contemporaneous comparison groups.
Vibration perception threshold (VPT) was tested using biothesiometry in 614 exposed personnel, compared with two unexposed groups (513 technical trades and 403 nontrades). Regression modeling was used to examine associations, adjusting for possible confounders.
We observed that 26% of participants had chronic persistent increased VPT in the great toe. In contrast, statistically significant higher VPT of the great toe was observed in the comparison groups; however, the effect was small, about 1/4 the magnitude of diabetes. Age, height, and diabetes were all significant and strong predictors in most models.
This study highlights chronic persisting peripheral neuropathy in a population of aircraft maintainers.
Journal of occupational and environmental medicine / American College of Occupational and Environmental Medicine 03/2011; 53(4):381-7. · 1.88 Impact Factor
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ABSTRACT: The purpose of the study was to examine possible persisting effects to color vision in a group from the Royal Australian Air Force who had exposure to formulations containing neurotoxins during F-111 fuel tank maintenance, relative to two contemporaneous comparison groups.
Color vision was tested in 512 exposed personnel, 458 technical-trade comparisons, and 330 non-technical comparisons using the Ishihara test plates and the Lanthony D-15 Desaturated Color disk arrangement test. Participants were excluded if they failed the Ishihara test as this indicates congenital color blindness. From the Lanthony results, the type of color deficient vision (CDV) was diagnosed, and additionally, the Bowman's color confusion index (CCI) was calculated. Regression models were used to examine whether there was an association between color vision deficiencies and F-111 fuel tank maintenance, adjusting for possible confounders.
The CCI ranged from 1 to 2.8 (median 1.2, quartiles 1.1, 1.4) in the 2,600 eyes tested. Forty five percent of all participants had blue-yellow CDV in at least one eye. Deficiencies of this nature are caused by environmental exposures. Logistic regression demonstrated statistically significant differences in CCI category in the exposed group versus technical group (odds ratio 1.7: 95% CI 1.3-2.0) and a blue-yellow confusion in the exposed group versus technical group (odds ratio 1.4: 95% CI 1.1-1.7). No differences were observed between the exposed group and the non-technical group.
The results indicate reduced color discrimination among the exposed subjects compared to one of two control groups. The findings may be due to previous exposure to solvents among the air force personnel.
Archiv für Gewerbepathologie und Gewerbehygiene 11/2010; 84(7):723-33. · 1.89 Impact Factor
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Maya Guest,
May Boggess,
John Attia,
Catherine D'Este,
Anthony Brown,
Richard Gibson,
Meredith Tavener,
Ian Gardner, Warren Harrex,
Keith Horsley,
James Ross
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ABSTRACT: We sought to examine hearing loss in a group from the Royal Australian Air Force who undertook fuel tank maintenance on F-111 aircraft, with exposure to formulations containing ototoxins, relative to two different comparison groups.
Using pure-tone audiometry, hearing thresholds were assessed in 614 exposed personnel, 513 technical-trade comparisons (different base, same job), and 403 non-technical comparisons (same base, different job). We calculated percentage loss of hearing (PLH) and used regression models to examine whether there was an association between PLH and F-111 fuel tank maintenance, adjusting for possible confounders. In addition, the difference between the observed hearing thresholds and the expected thresholds based on an otologically normal population (ISO-7029-2003) was determined.
The PLH ranged from nil to 96 (median 1.5, quartiles 0.3, 5.5). A logistic regression model showed no statistically significant difference in PLH among the three exposure groups (exposed vs. non-technical controls 1.1: 95% CI 0.7, 2.0 and exposed vs. technical OR 0.9: 95% CI 0.6, 1.3). The model also highlighted a number of other risk factors for PLH including age, tinnitus, smoking, depression, and use of depression medications. However, at all eight frequencies measured, all populations had lower than expected hearing thresholds based on published ISO-7029 medians.
Although there was no difference in PLH between the three exposure groups, the study did reveal a high degree of hearing loss between the 3 groups and a normal population.
American Journal of Industrial Medicine 11/2010; 53(11):1159-69. · 1.63 Impact Factor
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ABSTRACT: In Australia, four formal F-111 fuel tank deseal/reseal (DSRS) repair programs were implemented over more than two decades, each involving different processes and using a range of hazardous substances. However, health concerns were raised by a number of workers. The "Study of Health Outcomes in Aircraft Maintenance Personnel" was commissioned by the Australian Department of Defence to investigate potential adverse health outcomes as a result of being involved in the deseal/reseal processes.
To compare measures of sexual function in F-111 aircraft fuel tank DSRS maintenance workers, against two appropriate comparison groups.
Exposed and comparison participants completed a postal questionnaire which included general questions of health and health behavior, and two specific questions on sexual functioning. They also completed the International Index of Erectile Function (IIEF) questionnaire. Logistic regression was used to explore exposure status and outcome while adjusting for potential confounders.
The three outcomes of interest for this study were the proportion of participants with erectile dysfunction (ED) according to the IIEF, the proportion with self-reported loss of interest in sex, and the proportion with self-reported problems with sexual functioning.
Compared with each of the comparison groups, a larger proportion of the exposed group reported sexual problems and were classified as having ED according to the IIEF. In logistic regression, the odds of all three outcomes were higher for exposed participants relative to each comparison group and after adjustment for potentially confounding variables including anxiety and depression.
There was a consistent problem with sexual functioning in the exposed group that is not explained by anxiety and depression, and it appears related to DSRS activities.
Journal of Sexual Medicine 07/2009; 6(6):1569-78. · 3.55 Impact Factor
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ABSTRACT: A cancer incidence and mortality study was conducted in response to health concerns raised by workers from F-111 aircraft deseal/reseal fuel tank maintenance programs, to determine whether personnel exposed to deseal/reseal had an excess of cancers and mortality.
Number of deaths and cancers for individuals involved in F-111 DSRS activities were matched against two Air Force comparison groups. Analyses were weighted to adjust for differences in age, exposure period and rank.
Eight hundred seventy-three exposed, 7,577 comparison group one, and 9,408 comparison group two individuals were matched against death and cancer data, with 431 cancers and 431 deaths. Cancer incidence was higher in the exposed group, with marginally significant increases of 40-50% (cancer incidence rate ratio range 1.45-1.62). Exposed group mortality was significantly lower than both comparison groups, likely due to survivor bias in the exposed group (mortality rate ratio range 0.33-0.44).
On the balance of probabilities, there is an increased risk of cancer associated with participation in F-111 deseal/reseal activities.
American Journal of Industrial Medicine 02/2008; 51(1):16-23. · 1.63 Impact Factor
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Peter W Schofield,
Richard Gibson,
Meredith Tavener,
John R Attia,
Catherine D'Este,
Maya Guest,
Anthony M Brown,
Stephen J Lee,
Keith Horsley, Warren Harrex,
James Ross
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ABSTRACT: To contrast subjective and objective measures of neuropsychological health in F-111 aircraft Deseal/Reseal maintenance personnel, against two appropriate comparison groups.
Exposed and comparison participants completed a postal questionnaire which included a validated memory questionnaire and additional questions relating to possible cognitive symptoms. They also underwent a comprehensive neuropsychological assessment and screening for a past or current disturbance of mood. Multiple linear or logistic regression was conducted for each outcome using exposure group and potential confounders as explanatory variables.
There was a strong and consistent excess of self-reported cognitive problems among the exposed group relative to the comparison groups including a 2.8-4.3-fold increase in self-reported symptoms of forgetfulness, loss of concentration and difficulty finding the right word. On detailed neuropsychological testing, the exposed group performed significantly worse than comparisons on tests of psychomotor speed, executive functioning, and new learning/memory. These findings could not be accounted for by disturbances of mood or other potential confounders.
There was a strong and consistent increase in self-reported cognitive problems among the exposed, and small but significant exposure-specific differences on objective tests of cognitive functioning. The findings are consistent with the development of adverse neuropsychiatric changes related to occupational exposure to solvents.
NeuroToxicology 10/2006; 27(5):852-60. · 3.10 Impact Factor
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ABSTRACT: We sought to contrast mood disorder symptoms in F-111 aircraft Deseal/Reseal maintenance personnel with appropriate comparisons.
Participants completed a comprehensive health assessment, including measures of mood disorder, self-reported mood symptom questionnaire items, and review of anxiolytic and depression medication. Multiple logistic regression was conducted for each outcome using exposure group and potential confounders as explanatory variables.
There was high agreement between self-reported mood disturbance and objective tests. The exposed group was more likely to self-report previous diagnoses of depression/anxiety, had higher use of antidepressant medications, and had increased risk of diagnosis of depression/anxiety. Results were consistently strong against both comparison groups, with the exposed more likely to have mental distress and social dysfunction when compared with the Australian population.
There is robust evidence for an association between F-111 Deseal/Reseal exposure and impaired mental health.
Journal of Occupational and Environmental Medicine 08/2006; 48(7):682-91. · 2.06 Impact Factor
