Peter M. Rabinowitz

Proximity to Pollution Sources and Risk of Amphibian Limb Malformation

The cause of limb deformities in wild amphibian populations remains unclear, even though the apparent increase in prevalence of this condition may have implications for human health. Few studies have simultaneously assessed the effect of multiple exposures on the risk of limb deformities. In a cross-sectional survey of 5,264 hylid and ranid metamorphs in 42 Vermont wetlands, we assessed independent risk factors for nontraumatic limb malformation. The rate of nontraumatic limb malformation varied by location from 0 to 10.2%. Analysis of a subsample did not demonstrate any evidence of infection with the parasite Ribeiroia. We used geographic information system (GIS) land-use/land-cover data to validate field observations of land use in the proximity of study wetlands. In a multiple logistic regression model that included land use as well as developmental stage, genus, and water-quality measures, proximity to agricultural land use was associated with an increased risk of limb malformation (odds ratio = 2.26; 95% confidence interval, 1.42–3.58; p < 0.001). The overall discriminant power of the statistical model was high (C = 0.79). These findings from one of the largest systematic surveys to date provide support for the role of chemical toxicants in the development of amphibian limb malformation and demonstrate the value of an epidemiologic approach to this problem.

Proximity to Natural Gas Wells and Reported Health Status: Results of a Household Survey in Washington County, Pennsylvania

Background: Little is known about the environmental and public health impact of unconventional natural gas extraction activities, including hydraulic fracturing, that occur near residential areas. Objectives: Our aim was to assess the relationship between household proximity to natural gas wells and reported health symptoms. Methods: We conducted a hypothesis-generating health symptom survey of 492 persons in 180 randomly selected households with ground-fed wells in an area of active natural gas drilling. Gas well proximity for each household was compared with the prevalence and frequency of reported dermal, respiratory, gastrointestinal, cardiovascular, and neurological symptoms. Results: The number of reported health symptoms per person was higher among residents living < 1 km (mean ± SD, 3.27 ± 3.72) compared with > 2 km from the nearest gas well (mean ± SD, 1.60 ± 2.14; p = 0.0002). In a model that adjusted for age, sex, household education, smoking, awareness of environmental risk, work type, and animals in house, reported skin conditions were more common in households < 1 km compared with > 2 km from the nearest gas well (odds ratio = 4.1; 95% CI: 1.4, 12.3; p = 0.01). Upper respiratory symptoms were also more frequently reported in persons living in households < 1 km from gas wells (39%) compared with households 1–2 km or > 2 km from the nearest well (31 and 18%, respectively) (p = 0.004). No equivalent correlation was found between well proximity and other reported groups of respiratory, neurological, cardiovascular, or gastrointestinal conditions. Conclusion: Although these results should be viewed as hypothesis generating, and the population studied was limited to households with a ground-fed water supply, proximity of natural gas wells may be associated with the prevalence of health symptoms including dermal and respiratory conditions in residents living near natural gas extraction activities. Further study of these associations, including the role of specific air and water exposures, is warranted. Citation: Rabinowitz PM, Slizovskiy IB, Lamers V, Trufan SJ, Holford TR, Dziura JD, Peduzzi PN, Kane MJ, Reif JS, Weiss TR, Stowe MH. 2015. Proximity to natural gas wells and reported health status: results of a household survey in Washington County, Pennsylvania. Environ Health Perspect 123:21–26; http://dx.doi.org/10.1289/ehp.1307732

Antioxidant status and hearing function in noise-exposed workers.

The cellular antioxidant system appears to protect cochlear hair cells from oxidative stress due to noise and aging. The role of individual metabolic variables remains poorly understood, however. We examined the role of a number of metabolic factors on human cochlear function in noise-exposed individuals. In 58 factory workers we measured audiometry and distortion product otoacoustic emissions prior to a workshift. Simultaneously we measured levels of vitamin E, vitamin C, and polymorphism status for two metabolic genes related to glutathione S-transferase function (GSTM1 and GSTT1). Age and total noise exposure were predictive of hearing status. Vitamin E levels were negatively correlated with hearing function, and this effect was partly explained by an increase in vitamin E levels with age. No effect was found for vitamin C. Individuals possessing the GSTM1 gene had significantly better high frequency otoacoustic emissions compared to GSTM1 null individuals. The protective effect of GSTM1 was present even after adjusting for age, race, sex, and years of noise exposure. GSTT1 did not exhibit a similarly protective effect. While the cross-sectional nature of the study precludes drawing conclusions about causation, these data suggest that GSTM1, an antioxidant enzyme which is found in the mammalian cochlea, may play a protective role in humans against hair cell damage due to noise or aging.

Occupational Noise-induced Hearing Loss: Acoem Task Force on Occupational Hearing Loss

Noise-induced hearing loss (NIHL) continues to be one of the most prevalent occupational conditions and occurs across a wide spectrum of industries. Occupational hearing loss is preventable through a hierarchy of controls, which prioritize the use of engineering controls over administrative controls and personal protective equipment. The occupational and environmental medicine (OEM) physician works with management, safety, industrial hygiene, engineering, and human resources to insure that all components of hearing loss prevention programs are in place.1 The OEM physician should emphasize to employers the critical importance of preventing hearing loss through controls and periodic performance audits rather than just conducting audiometric testing. Nevertheless, audiometric testing, besides documenting the permanent loss of hearing, can be of value in the identification of hearing loss at a time when early preventive intervention is possible. The American College of Occupational and Environmental Medicine (ACOEM) believes that OEM physicians should understand a worker’s noise exposure history and become proficient in the early detection and prevention of NIHL.

Animals as Sentinels of Bioterrorism Agents

Pets, wildlife, or livestock could provide early warning.

Do ambient noise exposure levels predict hearing loss in a modern industrial cohort

Background: Much of what is known about the exposure–response relationship between occupational noise exposures and hearing loss comes from cross-sectional studies conducted before the widespread implementation of workplace hearing conservation programmes. Little is known about the current relationship of ambient noise exposure measurements to hearing loss risk. Aim: To examine the relationship between rates of high frequency hearing loss and measured levels of noise exposure in a modern industrial workforce. Methods: Ten-year hearing loss rates were determined for 6217 employees of an aluminium manufacturing company. Industrial hygiene and human resources records allowed for reconstruction of individual noise exposures. Hearing loss rates were compared to ANSI 3.44 predictions based on age and noise exposure. Associations between hearing loss, noise exposure, and covariate risk factors were assessed using multivariate regression. Results: Workers in higher ambient noise jobs tended to experience less high frequency hearing loss than co-workers exposed at lower noise levels. This trend was also seen in stratified analyses of white males and non-hunters. At higher noise exposure levels, the magnitude of hearing loss was less than predicted by ANSI 3.44 formulae. There was no indication that a healthy worker effect could explain these findings. The majority of 10 dB standard threshold shifts (STS) occurred in workers whose calculated ambient noise exposures were less than or equal to 85 dBA. Conclusions: In this modern industrial cohort, hearing conservation efforts appear to be reducing hearing loss rates, especially at higher ambient noise levels. This could be related to differential use of hearing protection. The greatest burden of preventable occupational hearing loss was found in workers whose noise exposure averaged 85 dBA or less. To further reduce rates of occupational hearing loss, hearing conservation programmes may require innovative approaches targeting workers with noise exposures close to 85 dBA.

Toward Proof of Concept of a One Health Approach to Disease Prediction and Control

A One Health approach considers the role of changing environments with regard to infectious and chronic disease risks affecting humans and nonhuman animals. Recent disease emergence events have lent support to a One Health approach. In 2010, the Stone Mountain Working Group on One Health Proof of Concept assembled and evaluated the evidence regarding proof of concept of the One Health approach to disease prediction and control. Aspects examined included the feasibility of integrating human, animal, and environmental health and whether such integration could improve disease prediction and control efforts. They found evidence to support each of these concepts but also identified the need for greater incorporation of environmental and ecosystem factors into disease assessments and interventions. The findings of the Working Group argue for larger controlled studies to evaluate the comparative effectiveness of the One Health approach.

Acute inhalation injury

Recent events have underscored the importance of proper diagnosis and management of patients with inhalation injury. Clinicians who care for individuals who have sustained inhalation damage to their respiratory tract need to take a careful exposure history and be alert to possibilities of delayed effects and clinical deterioration. Although supportive care and prevention remain the cornerstone of current approaches to this condition, better understanding of the mechanisms of cellular injury and repair may lead to improved treatments in the future.

Comparison of ARIMA and Random Forest time series models for prediction of avian influenza H5N1 outbreaks

BackgroundTime series models can play an important role in disease prediction. Incidence data can be used to predict the future occurrence of disease events. Developments in modeling approaches provide an opportunity to compare different time series models for predictive power.ResultsWe applied ARIMA and Random Forest time series models to incidence data of outbreaks of highly pathogenic avian influenza (H5N1) in Egypt, available through the online EMPRES-I system. We found that the Random Forest model outperformed the ARIMA model in predictive ability. Furthermore, we found that the Random Forest model is effective for predicting outbreaks of H5N1 in Egypt.ConclusionsRandom Forest time series modeling provides enhanced predictive ability over existing time series models for the prediction of infectious disease outbreaks. This result, along with those showing the concordance between bird and human outbreaks (Rabinowitz et al. 2012), provides a new approach to predicting these dangerous outbreaks in bird populations based on existing, freely available data. Our analysis uncovers the time-series structure of outbreak severity for highly pathogenic avain influenza (H5N1) in Egypt.

Trends in the prevalence of hearing loss among young adults entering an industrial workforce 1985 to 2004

Objectives: Studies have suggested that hearing loss due to recreational noise exposure may be on the rise among adolescents and young adults. This study examines whether the hearing status of young US adults entering an industrial workforce has worsened over the past 20 yr. Design: The baseline audiograms of 2526 individuals ages 17 to 25 beginning employment at a multisite US corporation between 1985 and 2004 were analyzed to determine the yearly prevalence of hearing loss. Results: Approximately 16% of the young adults in the sample had high frequency hearing loss (defined as hearing thresholds greater than 15 dB in either ear at 3,4, or 6 kHz). In a linear regression model, this prevalence decreased over the 20-yr period (odds ratio (OR) = 0.96, 95% confidence interval (CI): 0.94, 0.99). Almost 20% of subjects had audiometric “notches” consistent with noise exposure; this rate remained constant over the 20 yr, as did the prevalence (5%) of low frequency hearing loss. Conclusions: These results indicate that despite concern about widespread recreational noise exposures, the prevalence of hearing loss among a group of young US adults has not significantly increased over the past two decades.