Air quality and pediatric emergency room visits for asthma in Atlanta, Georgia, USA

Pediatric emergency room visits for asthma were studied in relation to air quality indices in a spatio-temporal investigation of approximately 130,000 visits (approximately 6,000 for asthma) to the major emergency care centers in Atlanta, Georgia, during the summers of 1993-1995. Generalized estimating equations, logistic regression, and Bayesian models were fitted to the data. In logistic regression models comparing estimated exposures of asthma cases with those of the nonasthma patients, controlling for temporal and demographic covariates and using residential zip code to link patients to spatially resolved ozone levels, the estimated relative risk per 20 parts per billion (ppb) increase in the maximum 8-hour ozone level was 1.04 (p < 0.05). The estimated relative risk for particulate matter less than or equal to 10 microm in aerodynamic diameter (PM10) was 1.04 per 15 microg/m3 (p < 0.05). Exposure-response trends (p < 0.01) were observed for ozone (>100 ppb vs. <50 ppb: odds ratio = 1.23, p = 0.003) and PM10 (>60 microg/m3 vs. <20 microg/m3: odds ratio = 1.26, p = 0.004). In models with ozone and PM10, both terms became nonsignificant because of collinearity of the variables (r= 0.75). The other analytical approaches yielded consistent findings. This study supports accumulating evidence regarding the relation of air pollution to childhood asthma exacerbation.

Minority workers and communities

Environmental and occupational hazards do not affect all communities equally. Members of ethnic and racial minorities, whether as working people or as community residents, sustain disproportionate risks from chemical, physical, and biological hazards. This paper reviews the nature of these disproportionate risks, focusing primarily on the workplace, but considering general environmental exposures as well. It discusses three principal mechanisms of increased risk: excessive hazardous exposures in both the workplace and the general environment, increased susceptibility, and inferior healthcare. It presents evidence that, as the result of these factors, members of minority groups display elevated rates of work-related illness, injury, fatality, and disability. Finally, it offers recommendations with regard to research, primary prevention, minority recruitment into the occupational health professions, and treatment and compensation for injured and ill minority workers.

Special populations in occupational health

This introductory chapter lays the groundwork for the in-depth examination of special populations that follows. Drs. Frumkin and Pransky discuss what makes a population special, health disparities over the generations, and the evolving recognition of special populations in occupational health.

Across the water and down the ladder: occupational health in the global economy

As the world economy becomes more integrated, and as industrial production expands in poor nations, workers in these nations face a range of occupational health and safety hazards. This article discusses the political economy of occupational health in developing nations by reference to multinational companies, free trade zones, free trade agreements, and the export of hazards. It reviews the special circumstances of occupational safety and health in developing nations and presents data on morbidity and mortality related to workplace exposures in these nations. Finally, it discusses approaches to improving workplace safety in developing nations, including policy initiatives, both mandated and voluntary, and public health initiatives, including training, technical assistance, collaborative research, and advocacy.

Multiple system atrophy following chronic carbon disulfide exposure

Carbon disulfide toxicity is well characterized. The principal target organ is the nervous system, although cardiovascular, reproductive, ophthalmologic, and other effects are also recognized. The neurotoxicity manifests in three ways: encephalopathy, peripheral and cranial nerve dysfunction, and movement abnormalities. This report describes a case of olivopontocerebellar atrophy, a form of multiple system atrophy, developing in an adult after over 30 years of occupational exposure to carbon disulfide. The patient presented with the insidious onset of balance problems, impotence, and irritability, without tremor, cogwheel rigidity, bradykinesia, or changes in facial expression. Over the next few years severe ataxia developed, and the clinical diagnosis was confirmed with computed tomography and magnetic resonance imaging scans. The patient experienced multiple medical complications and died approximately 9 years after diagnosis. This case is consistent with a large body of clinical and experimental literature, much of it 50 years old, showing that carbon disulfide can cause movement disorders. It also serves as a reminder that movement disorders, ranging from parkinsonism to dystonia, are associated with a variety of toxic exposures such as manganese, carbon monoxide, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, and medications.

Cigarette smoking and thyroid hormone levels in males

BACKGROUND

Cigarette smoking has been linked to thyroid disease, although studies of this problem have not shown consistent affects, with some studies linking smoking to increased thyroid hormone levels, and others to decreased thyroid hormone levels.

METHODS

We performed a secondary analysis of information collected from 4462 Vietnam-era male US Army veterans aged 31-49 years who participated in the Vietnam Experience Study in 1985-1986. The study group consisted of 1962 current smokers and 2406 current non-smokers who had no thyroid abnormalities on physical examination, no current use of thyroid medicine, and no history of thyroid disease.

RESULTS

We found that current smokers have higher thyroxine levels and lower thyroid stimulating hormone levels than never smokers and former smokers. The higher thyroxine levels that we detected in smokers, compared to non-smokers, diminished when we controlled for thyroxine-binding globulin and testosterone. We also found that heavy smokers had a smaller increase in thyroxine levels than did light smokers, when compared to non-smokers.

CONCLUSIONS

Our findings suggest at least two distinct mechanisms for the effect of tobacco smoke on thyroid function; one related to higher levels of thyroxine-binding globulin and testosterone among smokers compared to non-smokers and another related to higher levels of thyrotoxins in tobacco smoke in heavy smokers compared to light and moderate smokers.

Medical information on the Internet: a study of an electronic bulletin board

OBJECTIVE

To assess medical information provided in a medically oriented Internet discussion group, in terms of the professional status of the individuals providing information, the consistency of the information with standard medical practice, and the nature of the evidence cited in support of specific claims or recommendations.

DESIGN

Standardized review of 1,658 consecutive messages on a particular online discussion group during a 5-month period.

SETTING

An online discussion group for sufferers of painful hand and arm conditions.

SUBJECTS

All participants in this discussion group during the study period.

MEASUREMENTS AND MAIN RESULTS

Professional training of those offering medical information, consistency of the advice and recommendations offered with conventional medical practice, and nature of evidence cited in support of medical claims were determined. Of all messages, 55.9% (927) addressed a medical topic. Of these, 79% (732) provided medical information, of which 89.3% (654) were authored by persons without professional medical training, and 5.1% (37) were authored by trained health professionals. Approximately one third of the medical information provided was classified as unconventional. Personal experience was the basis of information provided in 61% of the nonprofessionals' messages and 13.5% of the professionals' messages, while no source was given as the basis of information provided in 29.8% of the nonprofessionals' messages and 67.6% of the professionals' messages. A published source was cited in 9.2% of the nonprofessionals' and 18.9% of the professionals' messages.

CONCLUSIONS

These findings suggest that medical information available on Internet discussion groups may come from nonprofessionals and may be unconventional, based on limited evidence, and/or inappropriate.

Cancer epidemiology and the workplace

Occupational exposure occurs most frequently through direct contact with carcinogenic agents, with any of their active metabolites during absorption (skin, respiratory tract); or during excretion (urinary tract). In the USA, from 2-8% of cancer are attributed to this circumstance. In developing countries emphasis should be made on prevention measures of possible carcinogenic exposure factors, with three basic premises: a) identify exposure markers (biological monitoring); b) identification of high risk subjects, presumable before exposure occurs, and c) early identification of signs of sickness (medical surveillance). This article proposes that, in theory, all occupational cancer can be prevented.

Systemic lupus erythematosus in relation to environmental pollution: an investigation in an African-American community in North Georgia

The etiology of systemic lupus erythematosus is not well understood, although gender, race, genetic predisposition, and certain drugs are risk factors. Several environmental exposures have been implicated. In this study, we examined the prevalence and incidence of lupus in an African-American community that experienced long-standing exposures to industrial emissions. We hypothesized that lupus was elevated among residents of a specific community in Gainesville, Georgia. We included both a retrospective cohort study and a cross-sectional study designed to assess the incidence and prevalence, respectively, of lupus. The prevalence of lupus was 3 cases/300 persons (1000/100,000). Compared with the highest reported prevalence, this represents a 6-fold increase. The incidence of lupus was 3 cases/4709 person-years (63.7 cases/100,000 person-years). Compared with the highest reported incidence, this represents a 9-fold increase. The hypothesis that environmental toxins may induce lupus is consistent with the known ability of certain medications to do the same. The results suggest that long-standing exposure to industrial emissions may be associated with an increased risk of lupus.

Manganese in the U.S. gasoline supply

Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic manganese compound recently approved for use in the United States as a gasoline additive. MMT use is expected to increase. This Commentary analyzes the impact of MMT use on population exposure to manganese, the health effects associated with manganese exposure, and the possibility that MMT use will lead to toxicity in the population. Although MMT use would result in only a small increment in most people's manganese exposure, certain populations will be disproportionately exposed. Although manganese is an essential nutrient at low levels, high-level manganese exposure leads to a characteristic severe nervous system toxicity. Pulmonary toxicity also occurs at high levels of exposure, and developmental toxicity to fetuses is an important concern based on more limited data. Selected subpopulations may be especially susceptible to the toxic effects of manganese. The critical question is whether the additional population exposure to manganese that would result from widespread MMT use would lead to toxic effects. Currently available evidence does not permit firm conclusions. Common sense and prudence therefore dictate that MMT not be used until further data are available and its safety is confirmed. Several measures are recommended to address the impending use of MMT in the U.S. gasoline supply.

Blood lead in pregnant women in the urban slums of Lucknow, India

OBJECTIVES

To determine the concentrations of blood lead (PbB) in pregnant women in the slums of Lucknow, north India.

METHODS

Of the 203 designated municipal slums in Lucknow, 70 were randomly selected for study and a cohort of 500 pregnant women was enrolled. Each participant was interviewed with questions on possible sources of exposure to lead, surrogates of nutritional status were measured, and PbB was measured.

RESULTS

The mean PbB was 14.3 micrograms/dl and 19.2% of women had PbB > or = 20 micrograms/dl. PbB was not associated with age, height, weight, gestation, or history of abortions, although higher PbB was associated with higher parity. Women living inner city neighbourhoods near heavy vehicular traffic had PbB 2.2 micrograms/dl higher (95% confidence interval (95% CI) 0.8 to 3.6) than those living in other neighbourhoods. The PbB was not associated with reported use of piped water or the presence of paint in homes, and increasing PbB was unexpectedly associated with decreasing use of eye cosmetic "surma" and the duration of gestation.

CONCLUSIONS

The high PbB found in this population raises concern about fetal development and points to the urgent need to reduce exposure to lead.

Occupational injuries in a poor inner-city population

This study aims to characterize occupational injuries in a defined poor inner-city population in terms of demographic features, types, and circumstances of injuries, and medical and financial consequences. It is a case series drawn from a larger population-based injury registry in emergency departments that serve 17 poor census tracts in Philadelphia. Of 335 patients from the study area who had been treated at the emergency departments under study for occupational injuries, 107 could be contacted by telephone 2 to 3 years after their injuries. Interviews sought information on the patients, their employment, their injuries, and the consequences. Respondents were almost all African-American, approximately 50% male, and had a median age of 32. Approximately one third were employed in the health care industry, one fourth in the service sector (including conventional service firms, restaurants, and hotels), and the remainder in construction, retail and wholesale trade, education, transportation, and manufacturing. Major causes of injuries included overexertion, contact with sharp objects, and falls. Major types on injuries included sprain/strains and lacerations. Approximately half the respondents had missed more than 3 days of work, with 15% missing more than 1 month. Almost 40% of respondents reported persistent health problems after their injuries. Only about one quarter had received workers' compensation. We conclude that poor and minority workers are at risk of a wide range of occupational injuries, which may result in considerable lost work time and have serious medical and economic consequences. More, attention to the workplace risks of these relatively marginalized workers and more vigorous preventive interventions are needed.

Upper-extremity Musculoskeletal Disorders in Keyboard Operators in Brazil: A Cross-sectional Study

This study sought to determine the prevalence of upper-extremity musculoskeletal disorders (UEMSDs) among keyboard operators in Sao Paulo, Brazil, and to compare this prevalence with that among other office workers. One hundred and thirty keyboard operators (mean age 33 years, 60 male/70 female) and 138 office workers (mean age 35 years, 82 male/56 female) from two computing centers were interviewed by a research assistant using a standardized questionnaire. Symptomatic subjects, defined as those who reported upper extremity pain or lost work time due to pain in the preceding 12 months, were examined by a rheumatologist. Mean (SD) lengths of employment were 9 (6) years for keyboard operators and 8 (6) years for office workers. Upper-extremity pain during the preceding seven days was reported by 66 keyboard operators (51%) and by 18 office workers (13%) (p < 0.0001); during the preceding 12 months, by 90 keyboard operators (69%) and by 26 office workers (19%) (p < 0.0001). UEMSDs were diagnosed following physical examination in 50 keyboard operators and in 12 office workers (9%) (p < 0.0001). Tenosynovitis was the most common disorder diagnosed among the keyboard operators (n = 23). Among the keyboard operators the prevalence of UEMSDs was significantly lower for males (p = 0.017, OR = 0.38, 95%CI = 0.17-0.86). The presence of a diagnosed UEMSD was significantly associated with duration of employment (p = 0.005) and lack of or insufficient rest breaks (p = 0.012). Keyboard operators had significantly more UEMSDs than did office workers. Strategies aimed at the reduction of repetitive strain injuries among keyboard operators, such as the provision of adequate work breaks, should be evaluated.

A case-control study of physical activity in relation to risk of cancer of the right colon and rectum in men

BACKGROUND

Epidemiological data suggest that physical activity is modestly or moderately protective against colorectal cancer. Additional data are needed to define better the slope of the dose-response curve and to clarify the types of activities that appear most protective.

METHODS

We examined the relation between occupational and vigorous leisure time physical activity and risk of cancer of the right colon and rectum in data from a case-control study conducted in New England from 1986 to 1988. We interviewed 163 cases with cancer of the right colon, 242 cases with cancer of the rectum, and 703 community controls.

RESULTS

Vigorous leisure time physical activity was associated with a decreased risk of cancer of the right colon; for men exercising > or = 2 hours per week the odds ratio was 0.60 (95% confidence interval [CI]: 0.35-1.00) compared with those who did not exercise. Adjustment for potentially confounding factors, including diet, had essentially no effect on the association. Self-reported occupational activity was less strongly related to risk of right colon cancer; the odds ratio for heavy work was 0.70 (95% CI: 0.32-1.51). Occupational activity coded according to job title was essentially unrelated to risk of right colon cancer. An association between physical activity and decreased risk of rectal cancer was not present in these data.

CONCLUSIONS

Our data add weight to the evidence that physical activity is related to decreased risk of colon cancer.

Occupational impairment and disability among applicants for Social Security disability benefits in Pennsylvania

OBJECTIVE

The study goal was to assess the extent of workplace-related disease and injury among Social Security Disability Insurance applicants.

METHODS

A convenience sample of 240 consecutive applicants to the Pennsylvania Bureau of Disability Determination was studied to assess the prevalence of work-related disorders. An applicant had a work-related condition if there was a clear statement of a workplace illness or injury associated with the impairment, or if the applicant had worked at an occupation with a high likelihood of exposures known or suspected to contribute to the condition of interest.

RESULTS

Of the 240 applicants, 166 (69%) were awarded disability insurance benefits; a total of 27 (11%) had work-related conditions, including 14 of the 166 (8%) who were found to be disabled. Forty percent of the 27 had a disorder that was musculoskeletal in origin. Of 59 applicants with cancer, 10.2% had some work-related etiological component. Of an estimated 71,680 adult disability insurance applicants in Pennsylvania in 1990, 5134 new insurance beneficiaries had a projected occupationally related disability.

CONCLUSIONS

A substantial number of applicants for disability insurance benefits suffer from an impairment caused or exacerbated by prior workplace exposures. These individuals may serve as sentinel events for initiating follow-up surveillance and prevention activities.