An evaluation of the incidence of work-related asthma in the United States

The objective of the study was to estimate the incidences of physician-diagnosed cases of work-related asthma (WRA) in Michigan and the entire United States. The statewide surveillance system for WRA in Michigan receives reports primarily from three sources: physicians, hospital discharge data, and worker's compensation claims. Knowledge of the overlap in reports from these sources was used in conjunction with capture-recapture methods to estimate the total number of diagnosed cases of WRA, and incidence rates were calculated using the estimated number of civilian employees in Michigan as the population at risk. For the entire United States, the product of a national incidence rate for asthma among adults and estimates of the proportion that is work-related was used. A total of 933 cases of WRA were reported to the Michigan surveillance program during 1988-1995, of which 904 were reported by at least one of the three main sources and equaled an average incidence of 27 cases/10(6)/year. This estimate was less than the range of estimates 58 to 204 cases/10(6)/year in Michigan arrived at using the capture-recapture methods. The national estimates of WRA ranged from 63 to 441 cases/10(6)/year. The authors' indirect estimates are closer to estimates from Canada, Sweden, and Finland than most existing direct estimates in the United States, but probably still underestimates the magnitude of WRA incidence because of the limitations of physician recognition of the work-relatedness of asthma among adults.     

Victoria M. Trasko: champion of state-based surveillance of occupational diseases in the United States, 1937 to 1971.

Victoria M. Trasko (1907-1979), a relatively unknown figure to many currently practicing occupational health specialists, was a pioneer in state-based surveillance of occupational diseases in the United States. To highlight her accomplishments during her career with the United States Public Health Service from 1937 to 1971, this report briefly reviews her publications on occupational disease surveillance. Her span of work includes guidelines for state industrial hygiene programs, numbers of workers in state occupational health programs, compilation of state and local laws related to industrial hygiene, proposals for standardized reporting of occupational disease, and analysis of trends in workers' compensation and mortality statistics for occupational diseases. She pilot tested the first state-based model system for occupational disease reporting in the United States. She documented the great difficulty experienced by states in getting physicians to report cases of occupational diseases, and pointed out that surveillance of other existing data sources was worthwhile, at least for some occupational diseases. She was the first to report on the distribution of silicosis cases in the United States by state, industry, and job title. She was the first to comment on mortality trends for the pneumoconioses and to document problems in comparability between different International Classification of Disease (ICD) periods.     

How much work-related injury and illness is missed by the current national surveillance system?

OBJECTIVE: We sought to estimate the undercount in the existing national surveillance system of occupational injuries and illnesses. METHODS: Adhering to the strict confidentiality rules of the U.S. Bureau of Labor Statistics, we matched the companies and individuals who reported work-related injuries and illnesses to the Bureau in 1999, 2000, and 2001 in Michigan with companies and individuals reported in four other Michigan data bases, workers' compensation, OSHA Annual Survey, OSHA Integrated Management Information System, and the Occupational Disease Report. We performed capture-recapture analysis to estimate the number of cases missed by the combined systems. RESULTS: We calculated that the current national surveillance system did not include 61% and with capture-recapture analysis up to 68% of the work-related injuries and illnesses that occurred annually in Michigan. This was true for injuries alone, 60% and 67%, and illnesses alone 66% and 69%, respectively. CONCLUSIONS: The current national system for work-related injuries and illnesses markedly underestimates the magnitude of these conditions. A more comprehensive system, such as the one developed for traumatic workplace fatalities, that is not solely dependent on employer based data sources is needed to better guide decision-making and evaluation of public health programs to reduce work-related conditions.     

What is the most cost‐effective way to identify silica problem worksites?

BACKGROUND: State based surveillance systems to identify cases of silicosis have been developed over the past 18 years to target worksite interventions to reduce the incidence of silicosis. Using data from the Michigan silicosis surveillance system, we conducted an analysis to determine the most cost-effective way to identify problem worksites. METHODS: The initial reporting source of all 470 confirmed cases of silicosis reported to the Michigan surveillance system from 1989 to 1995 was identified. The cost of identifying confirmed cases, worksites, problem worksites, silica problem worksites, and the number of current silica-exposed workers was determined for four reporting sources: hospitals; physicians; workers' compensations; and death certificates. RESULTS: Hospital reports were the first to identify 67% of the confirmed cases, 74% of the worksites, and 58% of the problem worksites. Physician reports initially identified 17% of confirmed cases, 15% of worksites, and 26% of problem worksites. Workers' compensation records initially identified 11% of confirmed cases, 4% of worksites, and 8% of problem worksites. Death certificates initially identified 5% of confirmed cases, 7% of worksites, and 8% of problem worksites. Hospital reports were the most cost-effective way to identify cases (US$ 143), worksites (US$ 313), and problem worksites (US$ 454). CONCLUSIONS: Hospital discharge records identified the greatest number of confirmed cases and problem worksites and was the most cost-effective approach to identify both individuals with silicosis and worksites with problems.     

National surveillance of occupational fatalities in agriculture

Agriculture is one of the most hazardous industries in the United States. Although estimates vary, all reporting agencies show agriculture having an occupational fatality rate three to five times higher than that of the general private sector. The National Institute for Occupational Safety and Health (NIOSH), Division of Safety Research's National Traumatic Occupational Fatalities (NTOF) data base monitors occupational fatal injuries in all industries in the United States through death certificates. Uniform case-selection criteria are applied nationwide. NTOF shows that for the years 1980 through 1985, agriculture had a work-related fatality rate of 20.7 deaths per 100,000 workers compared with 7.9 deaths per 100,000 workers for the private sector U.S. work force. Age-specific rates indicate that the risk of fatal occupational injury increases with age for agricultural workers. Workers over 64 years old have an average annual rate of 55.7 deaths per 100,000 workers. Other uses of the surveillance system, as well as its limitations, are discussed.     

Deaths due to unknown foodborne agents

This study reviews the available evidence on unknown pathogenic agents transmitted in food and examines the methods that have been used to estimate that such agents cause 3,400 deaths per year in the United States. The estimate of deaths was derived from hospital discharge and death certificate data on deaths attributed to gastroenteritis of unknown cause. Fatal illnesses due to unknown foodborne agents do not always involve gastroenteritis, and gastroenteritis may not be accurately diagnosed or reported on hospital charts or death certificates. The death estimate consequently omitted deaths from unknown foodborne agents that do not cause gastroenteritis and likely overstated the number of deaths from agents that cause gastroenteritis. Although the number of deaths from unknown foodborne agents is uncertain, the possible economic cost of these deaths is so large that increased efforts to identify the causal agents are warranted.     

Asbestos-related x-ray changes in foundry workers

Michigan has a statewide mandatory occupational disease reporting system. As part of that system, reports are received from hospitals, physicians, death certificates, the workers' compensation bureau, and company medical departments. Based on this reporting, the State of Michigan has a special emphasis program for the surveillance of silicosis, a known disease outcome among foundry workers. From 1985–1996, 115 cases reported to the State Surveillance System as silicosis, pneumoconiosis not specified, or pulmonary fibrosis were reclassified as having asbestos related x-ray changes after a B-reader interpretation of each case's chest x-ray. During this same period there were an additional 697 reports confirmed as silicosis and 6,724 cases reported to the surveillance system as asbestosis. Among the 115 reports reclassified as having asbestos-related x-ray changes without evidence of silicosis-related x-ray changes, 54 had worked in foundries. Only 7 (14.8%) of these individuals had their primary work in maintenance in the foundry; 40 (85.1%) had their primary foundry work in a production job; and for 10 individuals the occupation was not known. Asbestos has been used in foundries on pipe laggings, boiler coverings, as insulation in fan housings, in gloves, aprons and curtains, as insulation in cupolas, and in ladles and insulation in sand molds. Clinicians caring for foundry workers need to be aware that asbestos-related x-ray changes are not uncommon in this population and asbestos exposure should be considered as one of the carcinogens contributing to the known increased risk of lung cancer among foundry workers. Am J. Ind. Med. 34:197–201, 1998. © 1998 Wiley-Liss, Inc.     

Investigating asthma deaths among children and young adults: Michigan Asthma Mortality Review

OBJECTIVE: We developed a surveillance system to investigate asthma deaths in children and young adults. METHODS: A rapid asthma death notification and investigation system for Michigan was developed to identify interventions to prevent future deaths among people aged 2-34 years. Multidisciplinary panels to determine causal factors and recommend preventative actions reviewed information from death certificates, autopsies, next-of-kin interviews, and medical records. An annual report was disseminated to public health workers, health-care providers, insurers, and others. RESULTS: Eighty-six asthma deaths in Michigan residents, aged 2-34, occurred from 2002-2004. Sixty-one next of kin were interviewed and medical records were obtained for 84 of the deceased. Summaries were prepared on each of the deceased and were reviewed by expert panels, which reached consensus on causal factors and potential preventive action for each death. Each year an annual report, which summarized the causal factors and potential preventive activity, was prepared. CONCLUSION: This review has informed and catalyzed interventions to improve asthma care and management in Michigan. Factors leading to the review's success and future activities are discussed.     

Cost-effectiveness of hospital discharge records for reaching selected endpoints in the surveillance of silicosis

Background The Sentinel Event Notification System for Occupational Risks (SENSOR) is a state/federal system for the surveillance and intervention of occupational conditions. The Ohio SENSOR program identifies silicosis cases from a number of data sources, although hospital discharge records have largely been considered the most successful means of carrying out SENSOR objectives. However, the cost-effectiveness of hospital discharge records has not been evaluated. Thus, a cost analysis was conducted to compare the effectiveness of hospital discharge records with other data sources for achieving prevention-related endpoints of silicosis surveillance. Methods Total costs of reaching three endpoints (obtaining case names, identifying work sites, and identifying silica problems in work sites) were estimated retrospectively and measured in 1996 dollars for four data sources: hospital discharge records, physician reports, workers' compensation claims, and death certificates. Total costs were then divided by output for each source/endpoint combination to produce estimates of average costs. Results The average cost per case was $30 for hospital records, $212 for physician reports, $19 for workers' compensation claims, and $7 for death certificates. However, for identifying problem work sites, hospital records were most expensive at $2,883 per work site, compared with $2,558 for physician reports, $1,318 for workers' compensation claims, and $1,310 for death certificates. Conclusions Hospital discharge records were least cost-effective for accomplishing prevention-related goals of surveillance. A change in the mix of resources applied to silicosis surveillance and intervention under SENSOR, i.e., a shift away from follow-up of hospital records toward more cost-effective methods for identifying work sites with silica problems may result in more efficient use of public health resources devoted to the prevention of silicosis. Am. J. Ind. Med. 34:484–492, 1998. © 1998 Wiley-Liss, Inc.     

Estimating the undetected burden of influenza hospitalizations in children

During the 2004-2005 influenza season two independent influenza surveillance systems operated simultaneously in three United States counties. The New Vaccine Surveillance Network (NVSN) prospectively enrolled children hospitalized for respiratory symptoms/fever and tested them using culture and RT-PCR. The Emerging Infections Program (EIP) and a similar clinical-laboratory surveillance system identified hospitalized children who had positive influenza tests obtained as part of their usual medical care. Using data from these systems, we applied capture-recapture analyses to estimate the burden of influenza related-hospitalizations in children aged<5 years. During the 2004-2005 influenza season the influenza-related hospitalization rate estimated by capture-recapture analysis was 8.6/10,000 children aged<5 years. When compared to this estimate, the sensitivity of the prospective surveillance system was 69% and the sensitivity of the clinical-laboratory based system was 39%. In the face of limited resources and an increasing need for influenza surveillance, capture-recapture analysis provides better estimates than either system alone.     

Work-related death: a continuing epidemic

Worldwide, work-related illnesses and injuries kill approximately 1.1 million people per year. In 1992, an estimated 65,000 people in the United States died of occupational injuries or illness. Most estimates indicate that occupational diseases account for far more fatalities than occupational injuries. However, an accurate enumeration of occupational disease fatalities is hampered by a paucity of data, owing to underdiagnosis of occupational diseases and inadequacy of current surveillance systems. In this commentary, the authors review the epidemiology of death due to occupational disease and injury in the United States and discuss vulnerable populations, emerging trends, and prevention strategies for this ongoing public health problem.     

Surveillance of sentinel occupational mortality in the District of Columbia: 1980 to 1987.

Epidemiological surveillance of sentinel occupationally related deaths commonly relies on computerized analyses of mortality data obtained from vital statistics records. A computer search of death records in the District of Columbia for the period 1980 to 1987 identified 15 cases that noted asbestosis, silicosis, coal worker's pneumoconiosis, or primary cancer of the pleura/mesothelioma as the underlying cause of death. A manual review of the death certificates for the same period identified three times as many cases (n = 48) with any mention of these conditions. Problems with performing surveillance of these events using death certificates include the lack of sufficient information to identify mesotheliomas and the failure to code and computerize all contributing causes of death.     

Surveillance of traumatic occupational fatalities in Alaska--implications for prevention.

Data on occupational injury fatalities in Alaska for the period 1980-85 were complied from workers' compensation claims and death certificates. These data yielded 422 unique cases for the 6-year period, for an average annual fatality rate of 36.3 per 100,000 workers. This rate is 5 times higher than the Bureau of Labor Statistics estimate of 7.6 per 100,000 for the United States during the same period. The four industries with the highest fatality rates were the same for Alaska as for the nation (agriculture-forestry-fishing, construction, mining, and transportation-communication-public utilities). The leading causes of occupational fatalities in Alaska, however, were considerably different than for the United States as a whole. Nationally, motor vehicles and industrial equipment accidents are the leading causes of death. In Alaska, the leading causes of occupational injury mortality are aircraft crashes and drowning. These findings highlight the benefit of local surveillance in planning prevention strategies.     

Representativeness of deaths identified through the injury-at-work item on the death certificate: implications for surveillance.

BACKGROUND. This research investigated the accuracy of the injury-at-work item on the death certificate for surveillance of occupational injury deaths in Oklahoma during 1985 and 1986. METHODS. Representativeness of occupational injury deaths identified by death certificates was assessed by comparing these deaths with all occupational injury deaths identified through death certificates, workers' compensation reports, medical examiner reports, and OSHA records for categories of occupation, industry, and external causes of death. RESULTS. Certain external causes of death (e.g., motor vehicle traffic deaths) and certain occupations (e.g., farming) and industries (agriculture and services) are more often underidentified through death certificates. CONCLUSIONS. The findings of this study support Baker's observation that no single data source contains all deaths or all the data elements necessary to describe occupational injury deaths. Data sources may be combined to improve representativeness through more complete case ascertainment.     

Underreporting of minority AIDS deaths in San Francisco Bay area, 1985-86

A disproportionately high number of AIDS cases in the United States involve members of racial minorities. Even so, AIDS deaths of minority members may be undercounted. The completeness of reporting of AIDS deaths to the California AIDS Registry (ARS) among Hispanics, blacks, and whites in 1985 and 1986 from the San Francisco Bay Area was investigated. Death certificates listing AIDS as a cause of death or associated condition were identified and cross-checked with cases reported to ARS, current to December 1988. Death certificates were checked by hand for racial or ethnic classification using a definition of Hispanic based on information available on certificates. Three causes of undercounting in ARS were identified: a death was not reported as an AIDS case at all, an AIDS case was reported to ARS but the person was listed as still living, or an AIDS death was reported to ARS with a different racial or ethnic classification. The proportion of cases not reported at all was similar for all three racial-ethnic groups (5-8 percent). The proportion of deaths reported for persons listed in the registry as still living was 12 percent for Hispanics and 9 percent for blacks, compared with 5 percent for whites. For Hispanics, under-counting was largely due to ethnic misclassification. Twenty percent of Hispanics had been counted as white in the AIDS registry. In comparison, 4 percent of blacks and 1 percent of whites were misclassified by race. AIDS deaths among blacks and Hispanics may be undercounted, even in an area with good AIDS surveillance systems. This suggests that overrepresentation of minorities among AIDS cases in the United States may be even greater than indicated by current reporting data.     

Food-related illness and death in the United States.

To better quantify the impact of foodborne diseases on health in the United States, we compiled and analyzed information from multiple surveillance systems and other sources. We estimate that foodborne diseases cause approximately 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths in the United States each year. Known pathogens account for an estimated 14 million illnesses, 60, 000 hospitalizations, and 1,800 deaths. Three pathogens, Salmonella, Listeria, and Toxoplasma, are responsible for 1,500 deaths each year, more than 75% of those caused by known pathogens, while unknown agents account for the remaining 62 million illnesses, 265,000 hospitalizations, and 3,200 deaths. Overall, foodborne diseases appear to cause more illnesses but fewer deaths than previously estimated.     

Pattern and model makers,proportionate mortality 1972–1978

A proportionate mortality study of deceased white male workers in the pattern and model making trades was conducted. Death certificates were obtained for 1257 death benefit-eligible members of the Pattern Makers' League of North America who had died in the years 1972-1978, and age-adjusted proportionate mortality was calculated using 1975 United States white male death rates. For the entire nationwide union, statistically significant excess proportions of deaths were observed due to colon cancer (proportionate mortality ratio, PMR = 167) and to brain tumors (PMR = 211). A statistically significant excess proportion of deaths due to colon cancer (PMR = 163) and to leukemia (PMR = 200) were observed among the members of the predominantly wood shop locals. Nonsignificant excess proportions of cancer deaths occurred at a number of other anatomical sites. Predominant occupational exposures included wood and plastic dusts and epoxy resins in wood shops and cutting oil mists and solvent vapors in the metal shops. These results suggest the need for better work practices in this industry while more definitive studies are completed.     

Review of occupational lung carcinogens

Lung cancer is the most common malignancy in the United States and is ranked second only to bladder cancer in the proportion of cases thought to be due to occupational exposures. We review the epidemiology of occupational lung cancer, focusing on agents identified as pulmonary carcinogens by the International Agency for Research on Cancer. We derive estimates of overall relative risks from the major studies of these lung carcinogens, and we also provide estimates of the number of exposed workers. Using our data as well as estimates from other authors, we estimate that approximately 9,000–10,000 men and 900–1,900 women develop lung cancer annually in the United States due to past exposure to occupational carcinogens. More than half of these lung cancers are due to asbestos. This estimate is likely conservative, in that we have restricted our analysis to confirmed lung carcinogens and have ignored occupations with documented excess risk but for which the specific agents are unknown. Also, our estimate of the proportion of workers exposed in the past is probably too low. Our estimate should be viewed only as a broad approximation. Nevertheless, it is in line with other estimates by authors using different methods. The current number of cases estimated to be due to occupational exposures reflects past high exposures and is likely to drop in the future, unless other occupational lung carcinogens are confirmed or new carcinogens are introduced into the workplace. (This article is a US Government work and, as such, is in the public domain in the United States of America.) © 1996 Wiley-Liss, Inc.     

Deaths attributable to Alzheimer's disease in the United States.

OBJECTIVES: This study provided 2 estimates of the number of deaths attributable to Alzheimer's disease in the United States. METHODS: One estimate was based on data from the East Boston, Mass, study. The second was based on a simulation using population-based estimates of prevalence and separate estimates of excess death by duration of disease. RESULTS: Despite different methods and very different estimates of prevalence, these 2 methods led to very similar estimates of 173,000 and 163,000 excess deaths. CONCLUSIONS: These estimates suggest that 7.1% of all deaths in the United States in 1995 are attributable to Alzheimer's disease, placing it on a par with cerebrovascular diseases as the third leading cause of death.     

Capture-recapture method to estimate lower extremity amputation rates in Rio de Janeiro, Brazil.

OBJECTIVE: To estimate rates of lower extremity amputations (LEAs) in persons with peripheral vascular disease, diabetes mellitus, trauma, neoplasm, osteomyelitis, or emphysematous gangrene. METHODS: Regional amputee registries were used to estimate the rate of lower extremity amputations with the capture-recapture (CR) technique. Data were extracted from three amputee registries in Rio de Janeiro: source 1, with 1,191 cases from 23 hospitals; source 2, with 157 cases from a limb-fitting center; and source 3, with 34 cases from a rehabilitation center. Amputee death certificates from source 1 identified 257 deaths from 1992 to 1994. Three CR models were evaluated using sources 2 and 3. In order to avoid an overestimation of the rate of LEAs, two models were applied for the data analysis: in one case, deceased patients listed in source 1 were excluded from the model, and in the other case, deceased patients were included as well. RESULTS: Excluding the 257 deaths, the estimated number of amputations in the municipality of Rio de Janeiro from 1992 to 1994 was 3,954, for a mean annual incidence rate of 13.9 per 100,000 inhabitants. Among persons with diabetes, the annual incidence rate of lower extremity amputations was substantially higher (180.6 per 100,000 persons per year), representing 13 times the risk of individuals without diabetes. The yearly rate of LEAs according to the routine surveillance system was estimated at 5.4 and 96.9 per 100,000 in the general population and in diabetics, respectively. If data from the three registries are added, 1,382 patients with LEAs were identified, with the reasons for the amputations distributed as follows: peripheral vascular disease = 804 (58.1%); diabetes mellitus = 379 (27.4%); trauma = 103 (7.4%); osteomyelitis = 44 (3.1%); gangrene = 36 (2.6%), and neoplasm = 16 (1.1%). CONCLUSIONS: These findings show a high incidence of LEAs in Brazil, when compared to countries such as Spain, that is attributable mainly to peripheral vascular disease and diabetes mellitus.