Pleural determinants of restrictive lung function and respiratory symptoms in an asbestos-exposed population.

To further define the relationship between asbestos-induced pleural fibrosis and restrictive lung function, we investigated the pleural determinants of respiratory symptoms and restrictive physiology in 1,211 sheet metal workers. We evaluated the relationship between specific components of pleural fibrosis (costophrenic angle involvement, diaphragmatic plaques, width and length of pleural fibrosis, pleural calcification, and the type of fibrosis-circumscribed plaque or diffuse pleural thickening) and both forced vital capacity and respiratory symptoms. We found that costophrenic angle involvement, the width and length of pleural fibrosis, and the presence of either circumscribed plaque or diffuse pleural thickening were each significantly associated with a lower FVC. No consistent relationship was observed between FVC and either diaphragmatic plaques or pleural calcification. However, since the pleural abnormalities were highly collinear, none of these abnormalities alone or in combination predicted the reduction in FVC significantly better than a model that included circumscribed plaques and diffuse pleural thickening. We also investigated the relationship of each component of pleural fibrosis with cough, dyspnea, and chest pain. After controlling for appropriate confounders, a trend toward significance was observed between increased width and length of fibrosis and dyspnea with exertion. Otherwise, these pleural abnormalities were not consistently related to any of the three respiratory symptoms. Our results indicate that although pleural plaques and diffuse pleural thickening and their components are independently associated with a lower FVC, these components of pleural fibrosis do not substantially improve the previously defined relationship between FVC and both circumscribed plaques and diffuse pleural thickening. In addition, a trend toward significance was observed between the width and length of the pleural abnormality and dyspnea while hurrying.

Occupational exposure of water-plant operators to high concentrations of radon-222 gas.

Water-plant operators may be exposed to high airborne radon-222 (222Rn) concentrations created when 222Rn gas transfers from water to air during the water treatment processes. To evaluate this hazard, we placed yearlong alpha-track radon detectors in 31 water plants. The geometric mean of the annual average airborne 222Rn concentrations was 3.4 pCi L-1 (126 Bq m-3), with a maximum of 133 pCi L-1 (4921 Bq m-3). We assessed the short-term temporal variability of 222Rn by monitoring four water plants continuously for a 3- to 6-day period. Cumulative working level months were estimated for the time workers were in the water plants. Because airborne 222Rn concentrations in water plants can reach levels considered unsafe for underground miners, it would be prudent to monitor airborne 222Rn concentrations in water plants which aerate water as part of their treatment process.

Dissolution of 226Radium from pipe-scale deposits in a public water supply.

This study was undertaken to determine if dissolution of 226Radium from pipe-scale deposits contributes to enhanced waterborne 226Radium concentrations at the point of use. Water samples were collected from residential water customers of a small rural Iowa town. Sites were evenly divided between new and old water main connections. Daily samples were collected from the point-of-entry water. Point-of-use 226Radium concentrations ranged from 0.4 to 12.9 pCi L-1 (0.01 to 0.5 Bq L-1). The mean 226 Radium concentration for homes connected to old water mains was significantly higher than the mean 226Radium concentration of homes connected to new water mains, mean(standard deviation) equal 8.3(1.1) and 5.3(0.8) pCi L-1 [0.3(1.1) and 0.2(0.8) Bq L-1], respectively. 226Radium concentrations of the point-of-entry water ranged from 5.0 pCi L-1 to 10.3 pCi L-1 (0.2 Bq L-1 to 0.4 Bq L-1). This study indicates considerable variability of 226Radium exposure from drinking water among residents of the same water supply and has implications for regulatory compliance and exposure assessment in epidemiologic studies.

Temporal and spatial variation of waterborne point-of-use 222Rn in three water distribution systems.

Three water supply systems in Iowa were studied to examine temporal variation of 222Rn at the point of entry and the point of use. For the three towns, 71, 9, and 0% of the maximum point-of-use 222Rn concentrations were significantly higher than the point-of-entry 222Rn concentrations. Homes connected to older water mains in two of the towns had higher 222Rn concentrations than those connected to newer water mains. In one town, the waterborne 222Rn concentrations in the home were related to the home's location along an old water main. The increase in 222Rn concentrations, after the water leaves the water plant, were attributed to radium deposits in the water distribution system. In addition, the water plant's radium laden iron filters contributed 7 Bq L-1 and 60 Bq L-1 of 222Rn to the finished water in What Cheer, Iowa, and Wellman, Iowa, respectively. Backwashing schedules in the water treatment systems greatly affected point-of-entry 222Rn concentrations. The results of this study have important implications for 222Rn sampling, required for regulatory compliance.

An outbreak of naphthalene di-isocyanate-induced asthma in a plastics factory.

Seven cases of possible naphthalene di-isocyanate-related occupational asthma occurred in 1987 and 1988. These cases were reported to the National Institute for Occupational Safety and Health by personnel at a Midwest factory that manufactured plastic wheels for fork-lift trucks. The reporting of cases prompted (a) an evaluation of the workplace, including a medical screening of workers, to detect additional cases; and (b) an industrial-hygiene survey to determine the level of exposure to isocyanates.

Health hazards of working with ceramics. Recommendations for reducing risks.

Ceramics artists are at risk for pulmonary disease, heavy metal poisoning, and other toxic reactions caused by exposure to clays, glazes, and kiln emissions. Stringent personal hygiene, awareness of hazardous materials, and appropriate safety measures may reduce the health risks of repeated exposures.

A case of fatal methyl bromide poisoning.

A case of preventable fatality and a nearly greater disaster as a result of methyl bromide fumigation of a restaurant is presented. Methyl bromide is a nearly odorless, volatile hydrocarbon used as a fumigant in the food industry. As a result of this episode, recommendations are made for worker and community notification of the hazards involved whenever fumigation takes place. Addition of a mucosal irritant or olfactory stimulant is recommended to provide warning for methyl bromide exposure.

Early indicators of the effect of a breast cancer screening program for low-income women.

The National Breast and Cervical Cancer Early Detection Program (NBCCEDP) was developed to increase screening among low-income women who are uninsured or underinsured. This study reports early indicators of the effectiveness of this breast screening program in Iowa. Using data from the Census Bureau and the Iowa Behavioral Risk Factor Surveillance System, we found that racial and ethnic minorities aged 50 to 64 more likely were screened by the NBCCEDP than were their counterparts. Data collected by the Iowa BCCEDP showed a breast cancer detection rate (7.1 per 1,000 women screened) that was at least three times higher than its historical comparison, an indication of the lead time of the screened over the nonscreened population. Predictive values positive (referral and biopsy) and stage distribution were typically higher than for the national program but lower than in other countries. In conclusion, a breast cancer screening program among low-income women can be implemented successfully, judged by early indicators of program effectiveness.

Ambulatory care for traumatic brain injuries in the US, 1995-1997.

The burden of mild traumatic brain injury (TBI) is not well understood at the national level, but hospitalization rates show a decline over time. This paper describes ambulatory care for TBI patients at physician offices, hospital outpatient departments, and emergency departments (EDs) in comparison with non-TBI visits for the US during 1995-1997. An estimated 1.4 million visits for TBI were made each year for an average annual rate of 5.4/1,000 population. A decline in annual visit rate was noted during 1995-1997. Visit rates were higher for those aged 0 -14 and 75 and older. Falls (44%) and motor vehicles (28%) were the primary injury causes. Rural-urban differences were found, also in comparison with non-TBI. In 23% of visits to EDs, a CT scan was ordered or performed and in 33%, a mental status exam was conducted. Further investigations are warranted to describe ambulatory care for TBI in more detail, particularly in light of a decline in hospitalization rates.

Breast and cervical carcinoma: the correlation of activity limitations and rurality with screening, disease incidence, and mortality.

BACKGROUND: Although screening for breast and cervical carcinoma has been widely accepted as beneficial, specific segments of the population are not receiving these services as frequently as recommended. The objective of this study was to describe differences in breast and cervical screening prevalence among those with activity limitations and those residing in rural areas. Disparities in the incidence rates of in situ breast carcinoma and cervical carcinoma, as well as mortality among rural and urban women, are also described. METHODS: Data from the Iowa Behavioral Risk Factor Surveillance System (BRFSS) and Iowa's Surveillance, Epidemiology, and End Results (SEER) were used to determine the prevalence of screening and adverse outcomes among rural populations. To describe the rural nature of counties, the authors used the number of residents per square mile for each county and classified the results into five groups. Mulitple logistic regression was used to determine the prevalence of screening among those with activity limitations and rural residents. RESULTS: Using the BRFSS, those with activity limitations and those residing in rural Iowa were less likely screened for breast or cervical carcinoma. This translated into a lower in situ breast carcinoma incidence rate and a higher invasive cervical carcinoma incidence rate among rural women relative to their urban counterparts. No differences were found for mortality from these cancers. CONCLUSIONS: Lower screening prevalence among rural residents translated into adverse health outcomes. Interventions for increasing the frequency of screening are described.

An assessment of exposure to mercury and mercuric chloride from handling treated herbarium plants.

A curator at a university herbarium reported headache, nausea and mucosal irritation after initiating a project to remount plant specimens treated with mercuric chloride. Workplace exposure assessment indicated potential for mercury compound ingestion through hand-to-mouth contact. Blood, hair and urine assays were negative.

Methemoglobinemia: nitrate toxicity in rural America.

Nitrates are frequently found in vegetables and ground water. Nitrate levels in ground water have increased over the past two decades because of the heightened use of nitrogenous fertilizers. Following ingestion, nitrates are converted to nitrites by fecal organisms. Nitrites are absorbed and form methemoglobin, which interferes with the oxygen-carrying capacity of hemoglobin. Infants are particularly susceptible to nitrate poisoning because fetal hemoglobin is more readily oxidized to methemoglobin. In infants, the most common source of nitrate exposure is well water, which is mixed with infant formula. Affected infants may present with asymptomatic cyanosis, which can progress to dyspnea and lethargy or coma. Blood methemoglobin concentrations are elevated. Treatment consists of the administration of oxygen and intravenous and oral methylene blue.

Prospective evaluation of associations between hearing sensitivity and selected cardiovascular risk factors.

The prospective decline of hearing sensitivity was evaluated in an occupational cohort of university blue collar workers in relation to age, gender, occupational and nonoccupational noise exposure, smoking, blood pressure, and cholesterol. Each of these were associated with loss of hearing sensitivity univariately. When controlling for age and historical noise exposure in a multiple regression model, systolic blood pressure and cholesterol level were independently associated with decline in auditory sensitivity.

Cholinesterase-inhibiting insecticide toxicity.

Organophosphate toxicity can be fatal. It accounts for almost 40 percent of all insecticide- and pesticide-related illnesses reported by the American Association of Poison Control Centers. Skin contamination is the most important route of occupational exposure. Carbamate insecticides exhibit a similar mechanism of acute toxicity. Organophosphate pesticides act as irreversible acetylcholinesterase inhibitors, while carbamate pesticides produce reversible effects. The inhibition of acetylcholinesterase causes accumulation of acetylcholine at nerve endings, resulting in a cholinergic or hypersecretory syndrome. Persons who are exposed to organophosphates must be admitted to the hospital for careful observation. Symptoms should be treated with atropine, and most patients should also receive pralidoxime, a cholinesterase-regenerating drug.

Safety behavior among Iowa junior high and high school students.

The goal of this study was to determine demographic factors associated with reported safety behavior by studying 2250 Iowa junior high and high school students via a self-administered questionnaire. Students attending rural schools used front seat belts and helmets less frequently than urban students. Seat belt and helmet use and swim safety decreased dramatically with age. Occurrences of driving or riding while drunk or high increased with age. Boys were less likely than girls to wear back seat belts and moped helmets and to check water depth before diving. Possession of a driver's license was not independently associated with any of the safety behaviors.

Epidemiology of back injury in university hospital nurses from review of workers' compensation records and a case-control survey.

Reviewing Workers' Compensation records for back injury from a large university hospital for a 2-year period, we found a yearly incidence of lost work time back injury among nurses of 2.0% per year, exceeded only by physical plant staff, who had a rate of 3.5%. Nurses' aides had an injury rate 3.3-fold higher than registered nurses and licensed practical nurses and higher than any other occupational group. We compared 100 cases of nurses with back injury in the previous 2 years with 197 noninjured control subjects using a mailed 40-item questionnaire. Multivariate logistic modelling showed that prior nonback injury and performing combined lifting activities were statistically significant risk factors for back injury, and being overweight approached significance, after adjusting for the effects of age, gender, and each of the evaluated risk factors.

Lead exposure among workers renovating a previously deleaded bridge: comparison of trades, work tasks.

Airborne and surface lead exposures were evaluated for construction trade groups at a previously deleaded bridge renovation site in the midwestern United States. Although all lead-based paint should have been removed, old layers of leaded paint were still present on some sections of the bridge. Ironworkers performing metal torch cutting had the highest exposures (188 microg/m3), followed by workers engaged in clean-up operations and paint removal (p < 0.001). Respirators were most frequently worn by workers with the greatest lead exposures; however, laborers performing clean-up operations had exposures to lead dust of 43 microg/m3 and often wore no respiratory protection. Wipe samples revealed that almost all contractor vehicles were contaminated with lead. Heavy equipment operators with low airborne lead exposure had the highest levels of surface contamination in personal vehicles (3,600 microg/m2). Laborers cleaning structural steel with compressed air and ironworkers exposed to lead fumes from cutting had the highest concentrations of lead dust on clothing (mean 4,766 microg/m2). Handwashing facilities were provided, but were infrequently used. No separate clothes changing facility was available at the site. The potential for "take-home" contamination was high, even though this site was thought to be relatively free of lead. Construction contractors and their workers need to be aware that previous deleading of a site may not preclude exposure to significant amounts of lead.

Lead poisoning among construction workers renovating a previously deleaded bridge.

This study evaluated lead poisoning among construction workers renovating a previously deleaded bridge. Twelve of 44 tested workers had blood leads exceeding 20 micrograms/dL. One was 50 micrograms/dL and two exceeded 40 micrograms/dL. Following medical intervention, blood leads dropped significantly, while ZPPs did not. Renovation released lead that had been inaccessible during deleading. Workers did not use engineering controls or respirators, change clothes, wash hands, or shower. Intervention included a lead-compliance program with provisions for exposure evaluation, training, hygiene, and engineering controls. Construction contractors and workers need to be aware that deleading of bridges and other structures may not remove lead from inaccessible locations. In particular, owners of these structures should specify provisions for anticipating and controlling this hazard in contracts.

1983 occupational injury hospital admissions in Iowa: a comparison of the agricultural and non-agricultural sectors.

An occupational injury surveillance project was conducted in 15 of Iowa's 99 counties. Trained abstractors reviewed the medical records of persons admitted for trauma to hospitals during 1983. Based on these chart reviews, subsequent mail-out questionnaires and phone contacts were made, and rate estimates for occupational injury hospitalization for farmers and non-farmers were generated. The 1980 U.S. census data for occupation and market area data for the sample hospitals were used for the rate calculations. Approximately 14.7% of hospitalizations for trauma in the sample area were for work-related injuries. Farmers were hospitalized for occupational injuries at a rate of 1,521/100,000 compared to non-farmers at a rate of 497/100,000. There were no significant differences in the mean number of days per hospitalization for farmers versus non-farmers, (7.4 days for farmers and 6.7 days for non-farmers). Based on the questionnaire data, farmers were much less likely to receive any form of remuneration for injury, (odds ratio = 0.26, p less than 5 x 10(-6]. Farmers also reported less time off from work, with a mean of 79 days compared to non-farmers with a mean of 289 days.

Proportionate mortality study of golf course superintendents.

A proportionate mortality study of a cohort of golf course superintendents was conducted using death certificates for 686 deceased members of the Golf Course Superintendents Association of America who died from 1970 to 1992. White males were included in the study population from all 50 states. The study objective was to compare mortality from this cohort to the general U.S. white male population. The proportionate mortality ratio (PMR) for all types of cancer was 136 (CI: 121, 152). Significant excess mortality from smoking-related diseases was observed. The PMR for arteriosclerotic heart disease was 140, which was significantly elevated (CI: 127, 155). In addition, the PMR for all respiratory diseases was 176 (CI: 135,230), while the PMR for emphysema was 186 (CI: 101,342). The PMR for lung cancer was 117 (CI: 93, 148). Mortality for four cancer types--brain, lymphoma (non-Hodgkin's lymphoma, NHL), prostate, and large intestine--occurred at elevated levels within this cohort: brain cancer PMR = 234 (CI: 121,454), non-Hodgkin's lymphoma (NHL) PMR = 237 (CI: 137,410), prostate cancer PMR = 293 (CI: 187,460), and large intestine cancer PMR = 175 (CI: 125,245). The PMR for diseases of the nervous system was 202 (CI: 123,333). A similar pattern of elevated NHL, brain, and prostate cancer mortality along with excess deaths from diseases of the nervous system has been noted among other occupational cohorts exposed to pesticides.