International perspective on military exposure data sources, applications, and opportunities for collaboration.

Military personnel may be exposed to a range of hazards. The assessment, documentation and reporting of military exposure information are important steps to guide health protection, services, and research to support actively serving members and veterans. In 2021, a Working Group of researchers from veteran and defense administrations across the Five Eyes countries (Australia, Canada, New Zealand, the United Kingdom, and the United States) was established to examine large military exposure data sources available in each country, their applications, and opportunities to leverage information across administrations and internationally. We provide a brief summary of this work here to highlight some successful examples of data applications and to elicit interest in this evolving area of exposure science.

Cohort study of workers at a New Zealand agrochemical plant to assess the effect of dioxin exposure on mortality.

OBJECTIVES: To describe how the exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) influenced mortality in a cohort of workers who were exposed more recently, and at lower levels, than other cohorts of trichlorophenol process workers. DESIGN: A cohort study. SETTING: An agrochemical plant in New Zealand PARTICIPANTS: 1,599 men and women working between 1 January 1969 and 1 November 1988 at a plant producing the herbicide 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) with TCDD as a contaminant. Cumulative TCDD exposure was estimated for each individual in the study by a toxicokinetic model. PRIMARY OUTCOME MEASURES: Calculation of cause-specific standardised mortality ratios (SMRs) and 95% confidence intervals (95% CI's) compared those never and ever exposed to TCDD. Dose-response trends were assessed firstly through SMRs stratified in quartiles of cumulative TCCD exposure, and secondly with a proportional hazards model. RESULTS: The model intercept of 5.1 ppt of TCDD was consistent with background TCDD concentrations in New Zealand among older members of the population. Exposed workers had non-significant increases in all-cancer deaths (SMR=1.08, 95% CI 0.86 to 1.34), non-Hodgkin lymphoma (SMR=1.57, 95% CI: 0.32 to 4.59), soft tissue sarcoma (one death) (SMR=2.38, 95% CI: 0.06 to 13.26), diabetes (SMR=1.27, 95% CI: 0.55 to 2.50) and ischaemic heart disease (SMR=1.21, 95% CI: 0.96 to 1.50). Lung cancer deaths (SMR=0.95, 95% CI: 0.56 to 1.53) were fewer than expected. Neither the stratified SMR nor the proportional hazard analysis showed a dose-response relationship. CONCLUSION: There was no evidence of an increase in risk for 'all cancers', any specific cancer and no systematic trend in cancer risk with TCDD exposure. This argues against the carcinogenicity of TCDD at lower levels of exposure.

Does daily exposure to whole-body vibration and mechanical shock relate to the prevalence of low back and neck pain in a rural workforce?

OBJECTIVES: To determine whether whole-body vibration (WBV) and mechanical shock exposure from quad bike use are associated with the prevalence of neck and low back pain (LBP) in New Zealand farmers and rural workers. METHODS: Full-day WBV and mechanical shock exposures were gathered from 130 farmers and rural workers. Participants were surveyed for a history of neck or LBP in the past 7 days and in the past 12 months. Anthropometric, personal, and workplace data were also gathered. RESULTS: Physical exposures (mechanical shocks), employee status, and low levels of workplace satisfaction are all significantly associated with the 12-month prevalence of LBP in this rural workforce that regularly use quad bikes. Both vibration and mechanical shock exposure were strongly associated with 12-month prevalence of neck pain. The 7-day prevalence of neck pain showed a non-significant association with mechanical shock and vibration. CONCLUSIONS: Knowledge of these findings will be valuable information for those who teach and advise on safe driving techniques for such vehicles in the rural workplace where reduction of physical exposures and injury rates is of high importance.

Exposure to whole-body vibration and mechanical shock: a field study of quad bike use in agriculture.

OBJECTIVES: The purpose of this study was to determine exposure to whole-body vibration (WBV) and mechanical shock in rural workers who use quad bikes and to explore how personal, physical, and workplace characteristics influence exposure. METHODS: A seat pad mounted triaxial accelerometer and data logger recorded full workday vibration and shock data from 130 New Zealand rural workers. Personal, physical, and workplace characteristics were gathered using a modified version of the Whole Body Vibration Health Surveillance Questionnaire. WBVs and mechanical shocks were analysed in accordance with the International Standardization for Organization (ISO 2631-1 and ISO 2631-5) standards and are presented as vibration dose value (VDV) and mechanical shock (S(ed)) exposures. RESULTS: VDV(Z) consistently exceeded European Union (Guide to good practice on whole body vibration. Directive 2002/44/EC on minimum health and safety, European Commission Directorate General Employment, Social Affairs and Equal Opportunities. 2006) guideline exposure action thresholds with some workers exceeding exposure limit thresholds. Exposure to mechanical shock was also evident. Increasing age had the strongest (negative) association with vibration and shock exposure with body mass index (BMI) having a similar but weaker effect. Age, daily driving duration, dairy farming, and use of two rear shock absorbers created the strongest multivariate model explaining 33% of variance in VDV(Z). Only age and dairy farming combined to explain 17% of the variance for daily mechanical shock. Twelve-month prevalence for low back pain was highest at 57.7% and lowest for upper back pain (13.8%). CONCLUSIONS: Personal (age and BMI), physical (shock absorbers and velocity), and workplace characteristics (driving duration and dairy farming) suggest that a mix of engineered workplace and behavioural interventions is required to reduce this level of exposure to vibration and shock.

Mortality in workers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin at a trichlorophenol plant in New Zealand.

OBJECTIVE: We examined the overall mortality rates of 1599 workers employed between 1969 and 1988 at a New Zealand site, which manufactured trichlorophenol. METHODS: We developed exposure estimates for 2,3,7,8-tetrachlorodibenzo-p-dioxin from a serum dioxin evaluation and used standardized mortality ratios (SMR) and proportional hazards models to evaluate risk from exposure. RESULTS: Among exposed workers, deaths from total cancers (SMR = 1.1, 95% confidence intervals [CI]: 0.9-1.4), non-Hodgkin lymphoma (SMR = 1.6, 95% CI: 03-4.7), and ischemic heart disease (SMR = 1.1, 95% CI: 0.9-1.5) were slightly greater than expected, whereas deaths from lung cancer (SMR = 0.8, 95% CI: 0.4-1.5) were less than expected. We observed no significant trends with exposure levels. CONCLUSIONS: Although this study is small, we found no increasing trend of cancer or disease risk with increasing 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure with the possible exception of all cancers combined.

Mortality in employees at a New Zealand agrochemical manufacturing site.

BACKGROUND: Previous studies at the Dow AgroSciences (Formerly Ivon Watkins-Dow) plant in New Plymouth, New Zealand, had raised concerns about the cancer risk in a subset of workers at the site with potential exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin. As the plant had been involved in the synthesis and formulation of a wide range of agrochemicals and their feedstocks, we examined the mortality risk for all workers at the site. AIMS: To quantify the mortality hazards arising from employment at the Dow AgroSciences agrochemical production site in New Plymouth, New Zealand. METHODS: Workers employed between 1 January 1969 and 1 October 2003 were followed up to the end of 2004. Standardized mortality ratios (SMRs) were calculated using national mortality rates by employment duration, sex, period of hire and latency. RESULTS: A total of 1754 employees were followed during the study period and 247 deaths were observed. The all causes and all cancers SMRs were 0.97 (95% CI 0.85-1.10) and 1.01 (95% CI 0.80-1.27), respectively. Mortality due to all causes was higher for short-term workers (SMR 1.23, 95% CI 0.91-1.62) than long-term workers (SMR 0.92, 95% CI 0.80-1.06) and women had lower death rates than men. Analyses by latency and period of hire did not show any patterns consistent with an adverse impact of occupational exposures. CONCLUSIONS: The mortality experience of workers at the site was similar to the rest of New Zealand.

Chemical exposure among NZ farmers.

The objectives were to describe chemical use among farmers; to develop an exposure intensity score for three chemicals of interest: organophosphates (OPs), glyphosate (GP), and phenoxy herbicides (PHs). This was a cross-sectional study of a stratified random sample of farmers. Demographic, health and chemical use information were collected via questionnaire and an exposure level score developed. Within a sample of 586 farmers, 16 - 54% applied one or more of the chemicals. A high proportion of pastoral farmers used all the chemical types with 65% applying GP, 29% OPs and 19% PHs. Mean exposure scores were higher among women OP users, younger PH users, and arable farmers using PHs. This pesticide exposure score based on self-reported work practices among farmers can give an estimate of comparative annual exposure level. It can be used in analytical epidemiological studies and allows the identification of priority areas for intervention.

Obtaining health information from farmers: interviews versus postal questionnaires in a New Zealand case study.

PURPOSE: To compare the effectiveness of interviewer-led and postal surveys in gathering adequate health data for occupational health programmes among farmers. METHODS: Two cross-sectional studies of farmers from southern New Zealand were conducted. Farms were randomly selected from the public land valuation roll and all farmers and farm workers invited to participate in the farmers' health study. First, 477 farms were invited to participate in an interviewer administered questionnaire and health check; and second, a further 432 farms were selected and invited to participate in a self-administered postal survey. Both groups completed the same questionnaire. RESULTS: The response for the interviewer-led and postal surveys was 65.4 % and 51.6 % respectively. The 2 groups differed demographically, with fewer young farm workers in the postal survey, but were similar in all areas of health information collected, except that men in the interviewer-led survey were significantly more likely to have a psychological disturbance than men in the postal survey (chi ( 2 ) =5.06, df=1, p=0.024). CONCLUSIONS: Despite the interviewer-led survey having a higher response rate, the postal survey produced similar health data, which is adequate for planning occupational health programmes for farmers. Extra effort should be made to recruit younger farm workers in future research.

Noise-induced hearing loss and hearing conservation in mining.

BACKGROUND: Noise exposure is prevalent in mining, and as the prevalence of noise-induced hearing loss has not changed much in the past two decades, hearing conservation is an important issue. OBJECTIVES: To review the literature and highlight important developments in the field. METHODS: A review of the literature using OVID as the primary search engine, using the search terms as: noise, occupational; hearing loss, noise induced; ear protective devices; and mining. RESULTS: A total of 66 articles were found, but only 11 were in the English language and few were published in the past 10 years. This is disappointing, because neither noise exposure nor the consequent risk of noise-induced hearing loss seems to have changed much in the past 20 years. Noise is, however, a generic hazard, and this article reviews current best practice in prevention.

Noise exposure and hearing loss in agriculture: a survey of farmers and farm workers in the Southland region of New Zealand.

Farmers are known to be exposed to intermittent intense noise from a variety of sources, but long-term exposure and the resulting risk of hearing loss have not been well characterized. We studied a cross-sectional random sample of farms on which agricultural workers completed an audiometric test and questionnaire, and performed noise dosimetry on a subsample. Sixty-five percent of farms and a total of 586 workers participated. Noise on the subsample of 60 farms lay in a range between 84.8 to 86.8 dB(A) and hearing losses were consistent with this level of exposure. Age, driving tractors without cabs, and working with metal were important risk factors. Reported compliance with hearing protection was higher than that actually observed. The majority of farmers have a moderate risk of hearing loss, but a significant minority is at high risk. Elimination and isolation of noise sources are the control methods of choice, and if residual hearing protection is required, compliance must be improved.