Showing papers in "American Journal of Industrial Medicine in 1998"

From cross-tabulations to multipurpose exposure information systems: a new job-exposure matrix.

Abstract: Previous job-exposure matrices (JEM) have usually cross-tabulated classified exposure information by chemical agent and occupational class. A new Finnish job-exposure matrix (FINJEM) was constructed for exposure assessment in large register-based studies. Unlike most other JEMs, FINJEM was designed to contain definitions, inferences, exposure data, and references. This documentation enables FINJEM to be applied also as a general exposure information system for hazard control, risk quantification and hazard surveillance. The system includes, e.g., workforce data, and it provides information on the numbers of exposed workers in Finland by agent, occupation, and level of exposure. The exposures of FINJEM cover major physical, chemical, microbiological, ergonomic, and psychosocial factors. The assessment period is 1945–1997, divided into several subperiods. Exposure is described by the prevalence of exposure and the level of exposure among the exposed, both estimated mainly on continuous scales. The user may also define the final criteria of exposure, and thereby influence the magnitude of misclassification. Am. J. Ind. Med. 33:409–417, 1998. © 1998 Wiley-Liss, Inc.

Job strain, psychological distress, and burnout in nurses

Abstract: The first phase of this longitudinal study consisted of a questionnaire completed by a cohort of 1,891 nurses (aged 23–65 years) from six acute care hospitals from the province of Quebec. This study was set up to investigate the association between the psychosocial environment of work and mental health. After adjusting for counfounding factors, a combination of high psychological demands and low decision latitude was associated with psychological distress and emotional exhaustion, one of the three dimensions of burnout. Social support at work, although associated with each of the mental health indicators, did not modify their association with job strain. The present study identified conditions of the work environment that are modifiable and provide the basis for interventions that focus beyond the modification of individual coping strategies. Am. J. Ind. Med. 34:20–28, 1998. © 1998 Wiley-Liss, Inc.

Diesel exhaust and lung cancer in the trucking industry: Exposure–response analyses and risk assessment

Abstract: Background Diesel exhaust is considered a probable human carcinogen by the International Agency for Research on Cancer (IARC). The epidemiologic evidence rests on studies of lung cancer among truck drivers, bus drivers, shipyard workers, and railroad workers. The general public is exposed to diesel exhaust in ambient air. Two regulatory agencies are now considering regulating levels of diesel exhaust: the California EPA (ambient levels) and the Mine Safety Health Administration (MSHA) (occupational levels). To date, there have been few quantitative exposure‐ response analyses of diesel exhaust and lung cancer based on human data. Methods We conducted exposure‐response analyses among workers in the trucking industry, adjusted for smoking. Diesel exhaust exposure was estimated based on a 1990 industrial hygiene survey. Past exposures were estimated assuming that they were a function of 1) the number of heavy duty trucks on the road, 2) the particulate emissions (grams/mile) of diesel engines over time, and 3) leaks from trucks’exhaust systems for long-haul drivers. Results Regardless of assumptions about past exposure, all analyses resulted in significant positive trends in lung cancer risk with increasing cumulative exposure. A male truck driver exposed to 5 µg/m 3 of elemental carbon (a typical exposure in 1990, approximately five times urban background levels) would have a lifetime excess risk of lung cancer of 1‐2%, above a background risk of 5%. Conclusions We found a lifetime excess risk ten times higher than the 1 per 1,000 excess risk allowed by OSHA in setting regulations. There are about 2.8 million truck drivers in the U.S. Our results depend on estimates about unknown past exposures, and should be viewed as exploratory. They conform reasonably well to recent estimates for diesel-exposed railroad workers done by the California EPA, although those results themselves have been disputed. Am. J. Ind. Med. 34:220‐228, 1998. r 1998 Wiley-Liss, Inc.

Work schedule characteristics and substance use in nurses

Abstract: Background In order to promote the health of nurses while maintaining performance and patient care safety standards, better research bases on the association of work organization with health are needed Methods Work schedule components (shift, shift length, weekends, and overtime) in a nationally representative sample of employed registered nurses participating in an anonymous mailed survey (n = 3,917) were examined in relation to past year alcohol, smoking and drug use Results Schedule components examined separately showed modest associations with substance use Combinations of shift and shift length interacted in association with substance use, so that nurses working night shifts >8 hr had the highest likelihood of alcohol use and smoking and those working rotating shifts >8 hr were more likely to report alcohol use Among women, the likelihood of substance use under adverse conditions varied by family/home demands Conclusions Administrative attention to the interplay of work schedules on workers along with consideration of competing family/home demands could lead to more healthful scheduling In addition to substance use, working longer night and rotating shifts might be related to other health behaviors and conditions that should be examined in the future Am J Ind Med 34:266–271, 1998 © 1998 Wiley-Liss, Inc

Agricultural injuries among older Kentucky farmers: The farm family health and hazard surveillance study

Abstract: This population-based study reports the cumulative incidence of agricultural injuries during a 1-year period in a sample of 998 farmers aged 55 years and older living in Kentucky. A total of 98 farm-related injuries were reported among 88 older farmers for a crude injury rate of 9.03 injured farmers per 100 farmers (95% confidence interval (CI) = 7.03–11.03) over a 1-year period. The leading external causes of farm injury were falls (24.9%), machinery (22.5%), wood-cutting (14.6%), and animal-related events (14.3%). Farmers working on farms with beef cattle (alone) (odds ratio = 1.90; 95% CI = 1.02–3.55) or farms with beef cattle and tobacco (odds ratio = 2.15; 95% CI = 1.00–4.59) had a statistically significant increased risk for a farm-related injury. Farmers reporting a prior injury that limited their ability to farm were at increased risk for a farm-related injury. Approaches to using farm injury surveillance data for injury control programs in the state are discussed. Am. J. Ind. Med. 33:341–353, 1998. © 1998 Wiley-Liss, Inc.

Empirical comparisons of proportional hazards, poisson, and logistic regression modeling of occupational cohort data.

Abstract: This research was conducted to examine the effect of model choice on the epidemiologic interpretation of occupational cohort data. Three multiplicative models commonly employed in the analysis of occupational cohort studies--proportional hazards. Poisson, and logistic regression--were used to analyze data from an historical cohort study of workers exposed to formaldehyde. Samples were taken from this dataset to create a number of predetermined scenarios for comparing the models, varying study size, outcome frequency, strength of risk factors, and follow-up length. The Poisson and proportional hazards models yielded nearly identical relative risk estimates and confidence intervals in all situations except when confounding by age could not be closely controlled in the Poisson analysis. Logistic regression findings were more variable, with risk estimates differing most from the proportional hazards results when there was a common outcome or strong relative risk. The logistic model also provided less precise estimates than the other two. Thus, although logistic was the easiest model to implement, it should be used only in occupational cohort studies when the outcome is rare (5% or less), and the relative risk is less than approximately 2. Even then, the proportional hazards and Poisson models are better choices. Selecting between these two can be based on convenience in most circumstances.

Association of occupational and non‐occupational risk factors with the prevalence of self‐reported carpal tunnel syndrome in a national survey of the working population

Abstract: To compare the association of occupational versus personal, nonoccupational risk factors with the prevalence of carpal tunnel syndrome (CTS), data from the 1988 National Health Interview Survey, Occupational Health Supplement, were analyzed. When both occupational factors (bending/twisting of the hands/wrists [B/T] and use of hand-held vibrating tools) and personal nonoccupational factors (gender, race, age, body mass index [BMI], smoking, education, and family income) were included in a multivariate logistic regression model, adjusted odds ratios (AORs) of these factors for reporting medically called CTS (MC-CTS) were: exposure to B/T, 5.5; exposure to vibration, 1.9; white race, 16.7; female gender, 2.3; BMI ≥25, 2.0; history of cigarette smoking, 1.6; age ≥40, 1.2; education >12 years, 1.2; and annual family income ≥$20,000, 1.5. Although both occupational and nonoccupational factors are associated with reporting of CTS, repetitive bending/twisting of the hands/wrists and use of vibrating tools remain important risk factors for work-related carpal tunnel syndrome. Am. J. Ind. Med. 32:550–556, 1997. © 1997 Wiley-Liss, Inc.

Risk and incidence of asthma attributable to occupational exposure among HMO members.

Abstract: Occupational asthma may account for a significant proportion of adult-onset asthma, but incidence estimates from surveillance of physician reports and workers’compensation data (0.9 to 15/100,000) are lower than expected from community-based cross-sectional studies of asthma patients. We conducted a prospective cohort study of 79,204 health maintenance organization members between the ages of 15 and 55 at risk for asthma. Computerized files, medical records, and telephone interviews were used to identify and characterize asthma cases. Evidence for asthma attributable to occupational exposure was determined from work-related symptoms and workplace exposure. The annual incidence of clinically significant, new-onset asthma was 1.3/1,000, and increased to 3.7/1,000 when cases with reactivation of previously quiescent asthma were included. Criteria for onset of clinically significant asthma attributable to occupational exposure were met by 21% (95% CI 12‐32%) of cases giving an incidence of 71/100,000 (95% CI 43‐111). Physicians documented asking about work-related symptoms in 15% of charts, and recorded suggestive symptoms in three cases, but did not obtain occupational medicine consultation, diagnose occupational asthma, report to the state surveillance program, or bill workers’compensation for any of them. These data suggest that the incidence of asthma attributable to occupational exposures is significantly higher than previously reported, and accounts for a sizable proportion of adult-onset asthma. Am. J. Ind. Med.

Mortality of a police cohort: 1950-1990.

Abstract: This study presents findings from an updated retrospective cohort mortality study of male police officers from January 1, 1950 to December 31, 1990 (n = 2,593; 58,474 person-years; 98% follow-up). Significantly higher than expected mortality rates were found for all cause mortality (Standardized mortality ratio [SMR] = 110; 95% confidence interval [95% CI] = 1.04-1.17), all malignant neoplasms (SMR = 125; 95% CI = 1.10-1.41), cancer of the esophagus (SMR = 213; 95% CI = 1.01-3.91), cancer of the colon (SMR = 187; 95% CI = 1.29-2.59), cancer of the kidney (SMR = 2.08, 95% CI = 100-3.82), Hodgkin's disease (SMR = 313; 95% CI = 1.01-7.29), cirrhosis of the liver (SMR = 150; 95% CI = 1.00-2.16), and suicide (SMR = 153; 95% CI = 1.00-2.24). All accidents were significantly lower (SMR = 53; 95% CI = 0.34-0.79). Mortality by years of police service showed higher than expected rates for (1) all malignant neoplasms in the 1- to 9-years-of-service group; (2) all causes, bladder cancer, leukemia, and arteriosclerotic heart disease in the 10 to 19-year group; and (3) colon cancer and cirrhosis of the liver in the over 30 years of service group. Hypotheses for findings are discussed.

Cancer risks among workers exposed to metalworking fluids: A systematic review

Abstract: Metalworking fluids (MWFs) are commonly used in a variety of industrial machining and grinding operations. The National Institute for Occupational Safety and Health (NIOSH) estimates that more than one million workers are exposed to MWFs. NIOSH conducted a comprehensive and systematic review of the epidemiologic studies that examined the association between MWF exposure and cancer. Substantial evidence was found for an increased risk of cancer at several sites (larynx, rectum, pancreas, skin, scrotum, and bladder) associated with at least some MWFs used prior to the mid-1970s. This paper provides the evidence pertaining to cancer at these sites. Cancer at those sites found to have more limited or less consistent evidence for an association with MWF (stomach, esophagus, lung, prostate, brain, colon, and hematopoietic system) will not be discussed in this paper but are discussed in the recent NIOSH Criteria for a Recommended Standard-Occupational Exposure to MWFs. Because the changes in MWF composition that have occurred over the last several decades may not be sufficient to eliminate the cancer risks associated with MWF exposure, reductions in airborne MWF exposures are recommended. Am. J. Ind. Med. 33:282–292, 1998. Published 1998 Wiley-Liss, Inc.1

Occupational exposure to pesticides and congenital malformations: A review of mechanisms, methods, and results

Abstract: Pesticides are chemicals that are widely used all over the world. Human beings can be exposed through environmental contamination and/or occupational use of pesticides. Although there is substantial information on the acute toxicity of many of these chemicals, available knowledge on delayed effects is much more limited. This paper reviews epidemiological studies on occupational exposure to pesticides, mainly in agricultural workers, and risk of congenital malformations. The discussion includes postulated mechanisms for birth defects from paternal or maternal exposure, a detailed review of method of the studies carried out so far on the relationship between occupational exposure to pesticides and congenital malformations, and a summary of main results obtained. From available information, it seems reasonable to conclude that, to date, there is inadequate evidence for either establishing a relationship between pesticides exposure in human beings and birth defects or for rejecting it. Avoiding the main limitations of previous studies, some of the key elements for future research are presented.

Occupational respiratory allergy in bakery workers: a review of the literature.

Abstract: Baker's asthma has long been recognized as a serious disease among workers in the bakery industry and the number of cases with baker's asthma is steadily increasing. This paper presents a review of the available literature on baker's allergy with a special focus on the allergens involved, the epidemiologic research and issues on exposure assessment, evidence of exposure-response-relationships, and possible prevention strategies. A large number of potential allergens have been identified and are described here. At present little is known about the incidence of baker's allergy. On the other hand, a large number of cross-sectional studies have been performed, showing that sensitization and work-related symptoms are common among bakery workers. Only atopy and exposure level have consistently been reported as determinants of this occupational disease. Age, gender, and smoking habits do not seem to be associated with sensitization or work-related respiratory symptoms. Recently, immunochemical methods have been developed to measure specific allergens in the bakery industry, which have been used to unravel the role of allergen exposure in the development of baker's asthma. Clear exposure-response-relationships have been found. The implications of these recent findings for prevention strategies and standard setting are discussed. Am. J. Ind. Med. 34:529–546, 1998. © 1998 Wiley-Liss, Inc.

Airways inflammation and glucan exposure among household waste collectors.

Abstract: A field study was made on 17 workers collecting unsorted household waste, eight workers collecting organic/nonorganic separated waste, and 24 controls. Measurements of airborne endotoxin and (1 3)-β-D-glucan were made in their working environments. Examinations consisted of a questionnaire for symptoms, spirometry, airway responsiveness, and blood and sputum sampling for determination of cell counts, eosinophilic cationic protein (ECP), and myeoloperoxidase (MPO). A higher proportion of waste collectors reported diarrhea, congested nose, and unusual tiredness as compared to controls. The number of blood lymphocytes was higher among waste collectors and were dose-related to the amount of airborne (1 3)-β-D-glucan at the workplaces. The amount of ECP and the number of macrophages were lower in sputum among waste collectors as compared with controls. The results suggest that certain dusts from household waste may cause airway inflammation as well as general symptoms, and the effects were associated with higher (1 3)-β-D-glucan levels. Am. J. Ind. Med. 33:463–470, 1998. © 1998 Wiley-Liss, Inc.

Pregnancy outcome following maternal organic solvent exposure: A meta‐analysis of epidemiologic studies

Abstract: Background Evidence of fetal damage or demise from occupational organic solvent levels that are not toxic to the pregnant woman is inconsistent in the medical literature. The risk for major malformations and spontaneous abortion from maternal inhalation of organic solvent exposure during pregnancy was summarized using meta-analysis. Methods Medline, Toxline, and Dissertation Abstracts databases were searched to locate all research papers published in any language from 1966 to 1994. Included were studies that were case-control or cohort in design and indicated first trimester (or up to 20 weeks gestation for spontaneous abortion) maternal solvent exposure. A summary odds ratio (ORs) with 95% confidence intervals (CI) was calculated from research results combined by the Mantel-Haenszel method. Results In total, 559 studies were obtained from the literature search. Five studies for each outcome of interest qualified for inclusion in the analysis. The ORs for major malformations from five studies (n = 7,036 patients) was 1.64 (CI 1.16–2.30) and for spontaneous abortion from five studies (n = 2,899 patients) was 1.25 (CI 0.99–1.58). Conclusions Maternal occupational exposure to organic solvents is associated with a tendency toward an increased risk for spontaneous abortion and additional studies may affect the trend. There is a statistically significant association with major malformations which warrants further investigation. Am. J. Ind. Med. 34:288–292, 1998. © 1998 Wiley-Liss, Inc.

Prevalence and predictors of long-term work disability due to carpal tunnel syndrome

Abstract: The objective of this study was to describe patterns and predictors of work absence in the prospective, community-based Maine Carpal Tunnel Study. Three hundred fifteen patients with carpal tunnel syndrome (CTS) were recruited from physicians' offices throughout Maine. The patients completed questionnaires at entry and after 6, 18, and 30 months. The questionnaires included scales measuring symptom severity, functional status, general and mental health status, exposure to physical stressors, work status, and other indicators. The analyses examined univariate and multivariate correlates of work absence. The mean age was 43, 72% of subjects were female, 71% underwent carpal tunnel release, and 45% were receiving Workers' Compensation. Fifty-two percent worked in managerial or technical occupations, 15% in service occupations, and 13% in heavy labor or machine operation. Forty-five percent of patients changed jobs or were absent from work (aside from postoperative recovery) during the 30-month follow-up. In multivariate logistic regression models, correlates of work absence at 18 months included worse functional status of the hand at study entry and at 6-month follow-up, involvement of an attorney at the time of enrollment (P < 0.002 for each), and work absence at 6 months (P = 0.03). Worse upper extremity functional status and having a contested Workers' Compensation claim are critical predictors of work absence and should be principal targets of interventions to reduce work disability in CTS.

Relation between occupational asthma case history, bronchial methacholine challenge, and specific challenge test in patients with suspected occupational asthma.

Abstract: Inhalative methacholine challenge (MC) was performed in 229 subjects presumed to suffer from occupational asthma due to exposure to airborne latex allergens (n = 62), flour (n = 28), isocyanates (n = 114), or irritants in hairdressers' salons (n = 25). They were also subjected to specific challenges with the occupational agents they were exposed to, completed a questionnaire using an abbreviated version of the ATS-DLD, and were interviewed by an experienced physician. Bronchial hyperresponsiveness in MC was defined by the results obtained in a previous study with 81 healthy volunteers. The threshold in these controls was set at a cumulative MC dose of 0.3 mg, corresponding to a sensitivity of 95%. The main purpose of the study was to investigate whether the MC and/or the occupational asthma case history are reliable predictors of the specific challenge test outcomes. In 40–72% of examined subjects, workplace-related asthma complaints occurred, with bronchial hyperreactivity in the MC ranging from 48% to 61%. However, only 12–25% demonstrated a significant bronchoconstructive reaction in the specific challenge test. MC results are only moderately associated with workplace-related asthma case histories. Positive outcomes of challenges with occupational agents are well correlated with positive MC results plus occupational asthma case histories. The combination of MC and occupational asthma case history shows a relatively high specifity (62%, 86%, 80%), but the sensitivity was moderately low (83%, 71%, 52%). MC sensitivities were 92%, 71%, and 62% (case histories of hairdressers were not available). We conclude that in most cases, occupational asthma (as defined by a specific challenge test response) is combined with bronchial hyperresponsiveness and workplace-related asthmatic symptoms. However, subjects of each exposure group demonstrated bronchial hyperresponsiveness and complained of workplace-related asthmatic symptoms, but occupational asthma could not be proved in the specific challenge test. In subjects with a positive occupational asthma case history, a negative MC test result can almost rule out a positive specific challenge test result. Hence, the MC test can reduce performance of the laborious specific challenge test. Am. J. Ind. Med. 33:114–122, 1998. © 1998 Wiley-Liss, Inc.

Meta-analyses of brain cancer and farming.

Abstract: Background A series of meta-analyses of peer-reviewed studies of brain cancer and farming were performed, using 33 studies published between 1981 and 1996. Methods Before the meta-analyses, all studies were reviewed and evaluated for heterogeneity and publication bias. A random-effect model was used to estimate the combined relative risk. Results A meta-analysis including all the studies yielded an estimator of relative risk equal to 1.30, with a 95% confidence interval (95%CI) of 1.09, 1.56. The estimator of relative risk obtained from a meta-analysis restricted to female farmers was 1.04 (95%CI = 0.84, 1.29). A third meta-analysis restricted to studies of farmers residing in the central United States resulted in an estimator of relative risk equal 1.25 (95%CI = 1.09, 1.44). These findings were not influenced by either a publication bias or a specific study design. Conclusion The consistent significant positive findings suggests that there is a weak association between brain cancer and farming. Exposures commonly experienced by farmers including infectious microorganisms and pesticides may contribute to the increased risk of brain cancer. Am. J. Ind. Med. 34:252–260, 1998. © 1998 Wiley-Liss, Inc.

Construction injury rates may exceed national estimates : Evidence from the construction of Denver International Airport

Abstract: Background Construction of Denver International Airport (DIA) provided a unique opportunity to describe the magnitude of injury on a major construction project for which complete data on injury and hours at risk were available for over 32,000 employees working 31 million hours. Methods Comprehensive payroll data for all workers, who were paid standard Davis-Bacon wages, allowed calculation of person-hours at risk by job classification. Complete reporting, facilitated by a single workers' compensation plan covering all contracts and by an on-site medical clinic and designated provider system, allowed us to determine both total and lost-work-time (LWT) injury rates per 200,000 hours at risk by industrial sector, company size, and year of construction. Workers' compensation payment rates were calculated and compared with expected loss rates, derived by the National Council on Compensation Insurance, by sector, company size, and year. Results DIA's overall total injury rates were over twice those published by the Bureau of Labor Statistics (BLS) for the construction industry for each year of DIA construction. Differences in LWT injury rates were more modest. Total injury rates were also at least twice BLS's rates for all contractor sizes. The injury rate pattern by company size at DIA differed from BLS's in that small firms had injury rates that were higher than or comparable to most other size categories; BLS's rates for small firms were lower than those for all but the very largest (250 or more employees) contractors. DIA's total workers' compensation (WC) payment rate of $7.06 per $100 payroll was only 11% higher than Colorado-specific expected loss rates reported by the National Council on Compensation Insurance. Discussion Complete reporting, facilitated by the existence of a single WC plan, an on-site medical clinic, and designated medical providers, yielded injury rates significantly higher than previously reported. The relatively small difference between DIA payment rates and expected loss rates suggests that the discrepancy between DIA's injury rates and national estimates is due to underreporting of non-LWT injuries to the BLS. The burden of on-site work-related construction injury may be higher and more costly than has been evident from national data. Am. J. Ind. Med. 34:105–112, 1998. © 1998 Wiley-Liss, Inc.

Associations between several sites of cancer and occupational exposure to benzene, toluene, xylene, and styrene: Results of a case‐control study in Montreal

Abstract: Background Except for the leukemogenic effects of benzene, there is inadequate or sparse evidence on the carcinogenicity of the most common monocyclic aromatic hydrocarbons. The purpose of this study was to generate hypotheses on associations between exposure to benzene, toluene, xylene, and styrene and various common types of cancer. Methods In the context of a population-based case-control study carried out in Montreal, 3,730 cancer patients (15 types of cancers, not including leukemia) and 533 population controls were interviewed, and their job histories were translated by a team of experts into occupational exposures, including benzene, toluene, xylene, and styrene. In the present analysis, exposure to these substances was compared between each case series and a control group pooling selected cancer patients and population controls, using logistic regression analysis. Results Exposure levels were low for most exposed subjects, and there was a high correlation between exposure to benzene, toluene and xylene. For most sites of cancer there was no evidence of excess risk due to these substances. However, limited evidence of increased risk was found for the following associations: esophagus-toluene, colon-xylene, rectum-toluene, rectum-xylene and rectum-styrene. Conclusions These latter observations warrant further investigation. Am. J. Ind. Med. 34: 144–156, 1998. © 1998 Wiley-Liss, Inc.

Health symptoms reported by Persian Gulf War veterans two years after return

Abstract: The role of actual or perceived events has considerable importance for individual well-being. Although the Persian Gulf War (PGW) has raised questions about the presence of hazardous environmental exposures, few, if any confirmed exposure data are available. Yet, a substantial number of PGW veterans report health problems since their return from that war. The present study was conducted to investigate possible associations between opportunities for exposure and increased rates of health symptom reporting. First, we examined descriptive data on types and rates of health symptoms reported by a cohort of Gulf War veterans. Then, using proxies for three wartime experiences, we examined associations between health symptoms reports and different Persian Gulf exposure scenarios (reported exposure to poison gas or germ warfare, being in a transportation unit, or high levels of combat exposure), adjusting for the effects of background characteristics (e.g., gender, psychological distress). Findings suggest that reported exposure to poison gas or germ warfare is related to higher symptom reporting by this cohort of New England area veterans. Limitations in the study design and the challenges involved in studying PGW veterans' illnesses are discussed. Am. J. Ind. Med. 33:104–113, 1998. © 1998 Wiley-Liss, Inc.

Reproductive outcome in offspring of parents occupationally exposed to lead in Norway.

Abstract: In Norway, great efforts have been made to protect both male and female employees against teratogenic exposures. Associations between occupational lead exposure and reproductive outcome in the offspring were studied. All births in Norway 1970-1993 with possible maternal or paternal occupational lead exposure were compared with a reference population of offspring of parents without occupational lead exposure. Offspring of lead exposed mothers had an increased risk of low birth weight (RR = 1.34; CI = 1.12-1.60) and neural tube defects (RR = 2.87; CI = 1.05-6.38). Effects on birth weight and gestational age showed significant dose-response associations. Offspring of lead exposed fathers had no increased risks of any of the analyzed reproductive outcomes. However, decreased risks were observed of low birth weight (RR = 0.91; CI = 0.86-0.96) and preterm birth (RR = 0.89; CI = 0.86-0.93). Further efforts seem to be needed to protect the offspring of lead-exposed mothers.

Work-related injuries among Iowa farm operators: an analysis of the Iowa Farm Family Health and Hazard Surveillance Project.

Abstract: In 1994, the Iowa Farm Family Health and Hazard Surveillance Project carried out a two-stage, stratified, cluster survey of Iowa farms using a mail survey. With data from this representative sample of Iowa farmers, we examined the associations between farm-work-related injuries and possible risk factors for 390 principal farm operators. Forty (10.3%) of these operators reported being injured while doing farm work. We developed a logistic regression to assess associations between potential risk factors and injury. We found three factors significantly associated with injury: younger age (odds ratio [OR] = 3.1, confidence interval [CI] = 1.1-9.3), having an impairment or health problem that limits work (OR = 2.4, CI = 1.5-3.8), and hand or arm exposure to acids or alkalis (OR = 2.6, CI = 1.1-5.9). In the univariate analysis, safety training did not seem to protect farmers from injuries.

Pathomechanisms and pathophysiology of isocyanate-induced diseases : Summary of present knowledge

Abstract: During recent years in Western countries, diisocyanates are one of the main causes of occupational asthma. The mechanism of diisocyanate-induced asthma is still unknown but recent evidence suggests immunological mechanisms, including cell-mediated immune responses. Immune responses to isocyanates may result in different illnesses, cell- and/or antibody-mediated entities. In addition, irritative, toxic, and mutagenic effects may occur. This review summarizes current knowledge of the pathomechanisms, including immunological and nonimmunological (mutagenic and genotoxic) aspects of isocyanate disorders.

Occupational injuries among adolescents in Washington State, 1988–1991

Abstract: Background To characterize work-related injuries and illnesses in minors Methods We analyzed Washington State workers' compensation claims from 1988 through 1991 Results There were 17,800 claims among adolescents from age 11 through 17 years accepted in the 4-year period, including three occupational fatalities, 22 amputations, and 464 fractures; 89% of all injuries occurred among the 16- and 17-year-olds Claims were most frequent in restaurants, food stores, service industry, other retail and wholesale trade, and agriculture Washington State census data were used for the denominator in calculating injury rates for adolescents and adults The crude injury rate for 16- and 17-year-olds employed at the time of the census was similar to that seen among adults (90 vs104 per 100 workers), despite that minors work fewer hours per year The rate among boys was almost twice that seen among girls (117 vs 64 per 100 workers) Highest rates, per 100 workers, were in public administration (270), construction (211), agriculture (114), and restaurants (110) Using census data for those working anytime over the course of the year and adjusted for the number of hours worked, the injury rate for 16- and 17-year-olds was 194/100 full-time equivalents compared with 106 of 100 full-time equivalents for adults Most injuries were lacerations, sprains and strains, contusions, and burns Conclusions Public health policy and injury prevention strategies for working adolescents should be developed and implemented Am J Ind Med 34:121–132, 1998 © 1998 Wiley-Liss, Inc

Occupational risk factors for breast cancer among women in Shanghai.

Abstract: Although female breast cancer rates are lower in China than in Western countries, rates have been rising rapidly in China. This increase may be due to changes in established breast cancer risk factors, but it is possible that exposure to occupational and environmental carcinogens in Shanghai also have contributed to the rise in incidence. We used data collected by the Shanghai Cancer Registry and the Chinese Third National Census to study the risk of breast cancer by occupation and by occupational exposures. Standardized incidence ratios (SIRs) were used to compare observed cases to expected numbers of cases, based on the incidence rates for Shanghai and the number of women in each occupation according to the 1982 census. Statistically elevated SIRs for breast cancer were seen for a number of professional occupational categories, with the greatest risk seen among scientific research workers (SIR = 3.3). Administrative clerks, political and security personnel, and makers of rubber and plastics products also had significant excesses. Significant deficits of risk were seen for the categories of production and related workers, construction workers, and transportation equipment operators. For specific occupations, the highest SIRs were observed among doctors of Chinese-Western medicine (SIR = 14.7, 95% CI = 5.9-30.3) and doctors of Chinese medicine (SIR = 7.2, 95% CI = 4.4-11.4). We also found excesses among teachers at each level of education, librarians, clerical workers, electrical and electronic engineers, nurses, lab technicians, accountants and bookkeepers, rubber manufacturing products makers, weavers, and knitters. SIRs were significantly elevated for high probability of exposure to organic solvents (SIR = 1.4). For benzene exposure, we found significant excesses for overall exposure (SIR = 1.1) and for medium level of exposure (SIR = 1.3). There was no evidence of an association between risk and electromagnetic fields (EMF) exposure. Based on a small number of exposed, SIRs were elevated for both medium probability and high level of exposure to pesticides. The elevations in occupations reported here support some previous reports. Our finding of an increased risk associated with benzene also has been reported previously; the finding for organic solvents is new. However, the literature on the risk of breast cancer related to occupational exposures is limited and there is no consistent body of literature for any of the exposures studied here. Further, many comparisons were made and the problem of multiple hypothesis testing cannot be ignored in a survey such as ours.

Cancer mortality and wood dust exposure among participants in the American Cancer Society Cancer Prevention Study-II (CPS-II)

Abstract: In 1994, the International Agency for Research on Cancer (IARC) classified wood duct as a human carcinogen, based on very strong evidence of a carcinogenic risk of sino-nasal cancer. Excesses of other cancers, including lung and stomach, have been reported among persons employed in wood industries or occupationally exposed to wood dust, but not as consistently. We investigated such possible associations using the mortality experience of 362,823 men enrolled in the American Cancer Society's Cancer Prevention Study-II in 1982 and followed up for 6 years. Within this group, 45,399 men (12.5%) reported either employment in a wood-related occupation or exposure to wood dust or both. Among woodworkers, a small but significant excess risk was found for all cases of death (RR 1.17 (95% CI 1.11-1.24)) and for total malignancies (RR 1.17 (1.05-1.30)). Among men who reported exposure to wood dust, there was an elevated risk of total mortality (Rr 1.07 (1.03-1.11)), total malignancies (RR 1.08 (1.01-1.15)), and lung cancer (RR 1.17 (1.04-1.31)). Among woodworkers, a significant trend (P = 0.02) of increasing risk of lung cancer with increasing duration of exposure was observed. An unexpected, significantly increased mortality from prostate cancer was observed in both wood-employed and wood-exposed, and a twofold increased risk of fatal brain cancer was seen among the former. Lung cancer mortality was especially high among woodworkers who also reported exposure to asbestos or formaldehyde, and it appears that exposure to these known carcinogens may partly explain the observed increased risks. Excess sino-nasal cancer was not observed, but the number of cases was small.

Prevalence of occupational lung disease in a random sample of former mineworkers, Libode District, Eastern Cape Province, South Africa.

Abstract: Background Gold mineworkers in South Africa are exposed to high levels of silica dust as a result of which they are at risk of developing silicosis, which is a compensable disease. The incidence of tuberculosis is also high. Methods To determine the prevalence of occupational lung disease and the previous compensation history in former migrant mineworkers, a study was undertaken in a random sample of men living in Libode, a rural district of Eastern Cape Province, South Africa. Two hundred thirty-eight ex-mineworkers were examined according to a protocol that included chest radiography and spirometry. Chest radiographs were read into the International Labour Organisation (ILO) classification for pneumoconioses by two readers. Results The mean age was 52.8 years, and the mean length of service was 12.15 years. The prevalence of pneumoconiosis (≥ILO 1/0) was 22% and 36% (variation by reader). For both readers, a significant association between length of service and pneumoconiosis and between pneumoconiosis and reduction in FVC and FEV was found. Twenty-four percent of study subjects were eligible for compensation. Conclusion There is a high prevalence of previously undiagnosed, uncompensated pneumoconiosis in the study group. As a result of the failure to diagnose and compensate occupational lung disease, the social and economic burden of such disease is being borne by individuals, households, and the migrant labor-sending communities as a whole. Am. J. Ind. Med. 34:305–313, 1998. © 1998 Wiley-Liss, Inc.

Surveillance of respirable crystalline silica dust using OSHA compliance data (1979–1995)

Abstract: Background The objective of this work was to estimate the percentage of workers by industry that are exposed to defined concentrations of respirable crystalline silica dust. Methods An algorithm was used to estimate the percentage of total workers exposed to crystalline silica in 1993 at concentrations of at least 1, 2, 5, and 10 times the National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL) of 0.05 mg/m3. Respirable crystalline silica air sampling data from regulatory compliance inspections performed by the Occupational Safety and Health Administration (OSHA), for the years 1979–1995, and recorded in the Integrated Management Information System (IMIS) were used to estimate exposures. Therefore, this work does not include industries such as mining and agriculture that are not covered by OSHA. The estimates are stratified by Standard Industrial Classification (SIC) codes. Results This work found that some of the highest respirable crystalline silica dust concentrations occurred in construction (masonry, heavy construction, and painting), iron and steel foundries (casting), and in metal services (sandblasting, grinding, or buffing of metal parts). It was found that 1.8% (13,800 workers) of the workers in SIC 174—Masonry, Stonework, Tile Setting, and Plastering—were exposed to at least 10 times the NIOSH REL. For SIC 162—Heavy Construction, Except Highway and Street Construction—this number is 1.3% (6,300 workers). SIC 172—Painting and Paper Hanging—which includes construction workers involved in sandblasting was found to have 1.9% (3,000 workers) exposed to at least 10 times the NIOSH REL. The industry that was found to have the highest percentage of workers (6%) exposed to at least the NIOSH REL was the cut stone and stone products industry. Conclusion Not enough is being done to control exposure to respirable crystalline silica. Engineering controls should be instituted in the industries indicated by this work. Am. J. Ind. Med. 34:547–558, 1998. © 1998 Wiley-Liss, Inc.

Occupational exposure to estrogenic chemicals and the occurrence of breast cancer: An exploratory analysis

Abstract: Background We conducted a population-based case-control study to describe the relationship between occupational exposure to estrogenic chemicals and the occurrence of breast cancer in Cape Cod, Massachusetts. Methods Incident cases of breast cancer (n=261) diagnosed from 1983 through 1986 and controls (n=753) were interviewed to gather information on breast cancer risk factors and all full-time jobs held since age 18. Blinded exposure assessments were employed using the data from the NIOSH National Occupational Exposure Survey, chemical production and usage information, and the expert judgment of a certified industrial hygienist. Results Overall, 29.5% of cases and 32.5% of controls had probable occupational exposure to one or more xenoestrogens. Probable exposure to nonylphenol (21.5% of cases, 21.4% of controls), butyl benzyl phthalate (10.0% of cases, 13.2% of controls), BHA (7.3% of cases, 9.6% of controls), bisphenol A (9.6% of cases, 11.6% of controls), and 4-tert-butylphenol (2.7% of cases and 5.3% of controls) were relatively common, while probable exposure to the other xenestrogens was rare. Only PCBs and 4-octylphenol were associated with moderate increases in the odds of breast cancer (PCBs: 5 exposed cases and 6 exposed controls, adjusted odds ratio: 3.2, 95%CI = 0.8–12.2, and 4-octylphenol: 6 exposed cases and 5 exposed controls, adjusted odds ratio: 2.9, 95%CI = 0.8–10.8). Conclusions Additional research is needed to corroborate these findings. Am. J. Ind. Med. 34:6–14, 1998. © 1998 Wiley-Liss, Inc.