Showing papers in "Journal of Occupational and Environmental Medicine in 1984"

The Lipid Research Clinics Coronary Primary Prevention Trial Results: I. Reduction in Incidence of Coronary Heart Disease, and II. The Relationship of Reduction in Incidence of Coronary Heart Disease to Cholesterol Lowering

Abstract: The Lipid Research Clinics Coronary Primary Prevention Trial (LRC-CPPT), a multicenter, randomized, double-blind study, tested the efficacy of cholesterol lowering in reducing risk of coronary heart disease (CHD) in 3,806 asymptomatic middle-aged men with primary hypercholesterolemia (type II hyperlipoproteinemia). The treatment group received the bile acid sequestrant cholestyramine resin and the control group received a placebo for an average of 7.4 years. Both groups followed a moderate cholesterol-lowering diet. The cholestyramine group experienced average plasma total and low-density lipoprotein cholesterol (LDL-C) reductions of 13.4% and 20.3%, respectively, which were 8.5% and 12.6% greater reductions than those obtained in the placebo group. The cholestyramine group experienced a 19% reduction in risk (p less than .05) of the primary end point--definite CHD death and/or definite nonfatal myocardial infarction--reflecting a 24% reduction in definite CHD death and a 19% reduction in nonfatal myocardial infarction. The cumulative seven-year incidence of the primary end point was 7% in the cholestyramine group v 8.6% in the placebo group. In addition, the incidence rates for new positive exercise tests, angina, and coronary bypass surgery were reduced by 25%, 20%, and 21%, respectively, in the cholestyramine group. The risk of death from all causes was only slightly and not significantly reduced in the cholestyramine group. The magnitude of this decrease (7%) was less than for CHD end points because of a greater number of violent and accidental deaths in the cholestyramine group. The LRC-CPPT findings show that reducing total cholesterol by lowering LDL-C levels can diminish the incidence of CHD morbidity and mortality in men at high risk for CHD because of raised LDL-C levels. This clinical trial provides strong evidence for a causal role for these lipids in the pathogenesis of CHD.

Assessment of workers' compensation claims for back strains/sprains.

Abstract: Workers' compensation claim data for 1979 obtained from the Bureau of Labor Statistics' Supplementary Data System (SDS) were utilized to examine the demographic and occupational incidence of back strains/sprains among U.S. industrial employees covered by state compensation systems. These data were combined with estimated employment figures to provide incidence ratios, which allowed better approximations of industry- and occupation-specific risk. Industries found to have the largest incidence ratios were construction (1.6 claims/100 workers) and mining (1.5 claims/100 workers). Occupations with the largest ratios were miscellaneous laborers (12.3 claims/100 workers) and garbage collectors (11.1 claims/100 workers). The 285,468 compensation claims due to back strains/sprains filed in the 26 SDS states in 1979 suggest that back injuries continue to be a large and costly problem for U.S. workers and their employers.

Some histological changes in carpal tunnel contents and their biomechanical implications

Abstract: The purpose of this study was to investigate the pathological influence of mechanical stresses that occur inside the carpal tunnel during exertions of the hand. Microscopic changes in fibrous tissue density, in synovial, subsynovial, and adjacent connective tissue density, and in median nerve epineurium density, arteriole wall muscle thickness, and arterial and venule endoproliferation were investigated at 5-mm increments along a 9-cm range of six postmortem wrist specimens. All of these changes increased from normal in the proximal portions of the wrist, -30 to -40 mm from the wrist crease, to maximal values 0- to 20-mm distal to the wrist crease. The changes then decreased toward normal in the distal sections, 20 to 40 mm. The location and character of these changes suggest that repeated exertions with a flexed or extended wrist are an important factor in their etiology. The consistency with which they are found in this and other studies suggests that extreme changes associated with highly repetitive work or additional stress factors are required to produce symptoms in most cases of carpal tunnel syndrome.

Reduced disability and health care costs in an industrial fitness program.

Abstract: A prospective longitudinal study of a group of participants in an industrial physical fitness program during a five-year period compares the disability and major medical costs incurred by the subjects before and after entry into the program. The members of the cohort were employees of an insurance company; most were well educated and held sedentary, white-collar jobs. Participation was voluntary and without financial incentives. The group experienced 45.7% reduction in major medical costs in the postentry year, rather than the expected inflationary increase. There was a reduction of 20.1% in the average number of disability days, and a 31.7% reduction in direct disability dollar costs in the one-year postentry period. The average combined savings per participant were $353.38; the average operational cost was $120.60. Results suggest that work-site wellness programs can make a substantial contribution to the reduction of health care and disability costs.

Work and pregnancy.

Abstract: Pregnancy outcomes of 7,155 women who worked between one and nine months of pregnancy were compared with outcomes of 4,018 women who were not employed. There were no differences in rates of prematurity, Apgar score, birthweight, perinatal death rate, or malformation prevalence. Working women were divided into those who left employment during the first eight months and those who worked all nine months. The latter had a lower rate of adverse outcome than the other working group and the nonworking group. This indicates that working to term in the absence of contraindications does not impose an added risk on mother or infant. After control of confounding by parity and other relevant factors, an increased risk of prolonged gestational age was seen among primiparous working women. There was an increased risk of fetal distress among those women leaving work prior to nine months who were having their third or subsequent child. A small decrease in birth weight was seen among women who left work prior to term but not among those who worked all nine months. Overall the results are reassuring that working during pregnancy is not in itself a risk factor for adverse outcome.

The mortality of Ontario undertakers and a review of formaldehyde-related mortality studies.

Abstract: In a study of the mortality of Ontario undertakers, a cohort of 1,477 men first licensed during 1928 through 1957 was followed up until the end of 1977. Numbers of observed and expected deaths were determined for the period 1950 through 1977, using mortality rates of Ontario men as the standard. In all, 319 persons had died, compared with 322 expected. Ontario undertakers were not at increased risk of death from cancers at sites of contact with formaldehyde. Cirrhosis of the liver (standardized mortality ratio, 238) and chronic rheumatic heart disease (standardized mortality ratio, 199) were the only causes of death found to be significantly in excess. The data are discussed in the context of current epidemiologic information on the mortality experience of persons exposed to formaldehyde.

Boilermakers' bronchitis. Respiratory tract irritation associated with vanadium pentoxide exposure during oil-to-coal conversion of a power plant.

Abstract: Severe respiratory tract irritation occurred in at least 74 of 100 boilermakers who were exposed to high levels of vanadium pentoxide fume during oil-to-coal conversion of a utility company power plant in a rural area of western Massachusetts. Many were welders working in confined areas with inadequate ventilation. Most frequent symptoms were productive cough, sore throat, dyspnea on exertion, and chest pain or discomfort. The illness was severe enough to cause 70 workers to consult physicians and most of them to lose time from work (median, five days). Wheezing (in 39%) was the most frequent finding on physical examination. Mild hypoxemia was noted in several workers; most (72%) had normal chest x-ray films. Expiratory flow rate over the middle 50% of the forced vital capacity was the pulmonary function test most remarkably affected (median, 57% of predicted for 24 workers tested). The Occupational Safety and Health Administration documented levels of vanadium pentoxide fume at or above the permissible exposure limit in all eight air samples taken from inside the boiler; it cited the company for inadequate mechanical ventilation and an inadequate respiratory protection program for workers. The report of this outbreak may help prevent future problems by drawing attention of physicians, workers, and managers to the potential pulmonary hazards in power plant conversion.

Shiftwork and the length and quality of sleep.

Abstract: Previous investigators have reported that amount and quality of sleep are reduced in the shiftworker. The finding that night and morning shifts lead to shortened sleeping hours is replicated in this study. Overall sleeping time, however, was not found to be different for workers on different shift schedules or for shiftworkers and nonshiftworkers. The correlation between length and quality of sleep was very low. Length of sleep was not predicted well by factors such as stress at work, noisiness of sleeping room, drinking coffee, and smoking cigarettes, although these and similar predictors were strongly related to quality of sleep. Shiftwork was found to have a consistent effect on quality of sleep, even when other variables were controlled. quality of sleep, even when other variables were controlled.

The relationship of job performance to exercise adherence in a corporate fitness program.

Abstract: An investigation of the relationship between exercise adherence and job performance was conducted over a six-month period among a group of white-collar workers (3,231) eligible to participate in a corporate fitness program. The study population was divided into four job categories - management (561), professional (1,265), clerical (1,078), and other (327) - and five exercise adherence groups - nonmember (1,090), nonexerciser (926), exercised less than one time per week (738), exercised one to two times per week (238), and exercised more than two times per week (239). Current job performance ratings were determined for all individuals. A strong association (p less than .01) was observed between above average performance and increasing adherence levels. An inverse relationship was demonstrated between poor performance and increasing adherences levels (p less than .0001). In each adherence group no differences in performance were noted when prior performance was compared with current performance. On the basis of these findings there appears to be a positive although probably noncausal relationship between exercise adherence in a corporate fitness program and above average job performance.

A mortality study of men exposed to elemental mercury

Abstract: A cohort of 2133 white males who were exposed to elemental mercury vapors between 1953 and 1963 was followed up through the end of 1978. Death certificates were obtained for 371 of the 378 workers who were reported by the Social Security Administration to be deceased. The mortality experience of this group was compared with the age-adjusted mortality experience of the US white male population. Mortality has not been studied previously in assessing the long-term health effects of mercury exposure. Standardized mortality ratios (SMRs) were calculated for a comparable unexposed worker population to determine the mortality patterns among workers at the same plant who were not involved in the mercury process. Statistically significant excesses of deaths from cancer of the lung and cancer of the brain and other CNS tissues were observed among the plant workers who were not involved in the mercury process. An excess of deaths from cancer of the lung was also observed among the mercury workers, although the elevation of this SMR was not statistically significant. Since excesses of lung cancer were evident in both groups of workers, it is unlikely that they are related to the mercury exposure and more probable that they are duemore » to some other factor present in the plant or to some life-style factor prevalent among the plant workers. Exposure to mercury vapors at this plant was not related to any excess of deaths from diseases or cancers of organs determined to be target organs for mercury (liver, lung, brain and CNS, and kidney). No excesses were found when level of exposure and length of exposure were considered.« less

The accuracy of occupation and industry data on death certificates.

Abstract: To assess the accuracy of occupation and industry data on death certificates, we compared the known occupation and industry of 3,789 individuals with information on their death certificates. All individuals were members of the National Institute for Occupational Safety and Health cohort studies and their occupation and industry were known from personnel or union records. We focused our analysis on 2,198 long-term workers who had 10 or more years of work experience (average, 18 years). Our principal finding was that for the long-term workers in our sample, the probability of the known occupation being listed on their death certificates was 64.7% (SE = 1.1) (for white workers this figure was 73.5% (SE = 1.2). Furthermore, for the long-term workers the probability of the plant or industry being named on their death certificates was 70.1% (SE = 1.2). Women and non-whites had lower matching rates. For women the probability of a matched listing was 45.1% for occupation and 60.4% for industry. For nonwhites, it was only 30.1% for occupation and 49.2% for industry. Our results for white long-term workers generally agree with the results of previous investigators who have used different methods.

The impact of health and safety committees. A study based on survey, interview, and Occupational Safety and Health Administration data.

Abstract: In a study conducted to determine if the existence of a joint labor-management health and safety committee (HSC) was correlated with either the number of Occupational Safety and Health Administration (OSHA) complaints or hazardousness, as measured by OSHA serious citations, virtually no effect could be detected in a sample of 127 Massachusetts manufacturing firms. At a sample of 13 firms, interviews of HSC members were conducted. Committee attributes and perceptions about committee effectiveness were compared with the number of OSHA complaints and serious citations. There were fewer complaints and fewer serious citations at firms with HSCs that were perceived as effective. Results of the study suggest that the objective attributes of the committee may be less important to its success than the commitment of management and labor to solving workplace safety problems.

Mortality among pulp and paper workers.

Abstract: Mortality among 2,113 U.S. and Canadian members of the Pulp, Sulfite, and Paper Workers' Union, 1935 through 1964, was studied using a proportionate mortality analysis. Mortality due to gastric cancer was found to be elevated in all jurisdictions, but only in mills using sulfate or sulfite pulping. An excess of mortality due to kidney cancer was limited to mills in Oregon and Washington. Excesses of deaths due to leukemia, Hodgkin's disease, and lymphosarcoma were observed only in mills in Oregon, Washington, and Wisconsin and the province of Quebec. Based on small numbers, excesses of deaths due to cancers of rectum, pancreas, kidney, and lymphosarcoma were seen primarily among sulfite process workers, while Hodgkin's disease deaths occurred primarily in sulfate (kraft) process workers. These findings suggest that cancer mortality in pulp and paper workers may be related both to pulping process and to tree species processed.

Occupational exposures among fathers of children with Wilms' tumor.

Abstract: An occupation-and-exposure linkage system was utilized to perform an epidemiologic case-control study of paternal occupation and Wilms' tumor in offspring. The first part of the study was designed to test the hypothesis that paternal lead (Pb) exposure is a risk factor for Wilms' tumor in offspring. The second part of the study was an exploratory analysis that sought to generate possible etiologic hypotheses about other paternal exposures in the workplace in relation to Wilms' tumor. Calculation of odds ratios indicated that there was no statistical difference in the frequency of occupational exposure to Pb, Pb alkyls, and Pb salts for fathers of children with Wilms' tumor and fathers of controls, a finding that contrasts sharply with the results of the one previously reported study in this area. In the exploratory phase of the study, case fathers were found more likely to have been exposed to boron, while control fathers were found more likely to have encountered insecticides, acetylene, o-chlorobenzylidene, oil orange ss, and diethylene glycol; the differences were statistically significant. Troublesome methodologic problems, including exposure misclassification, sample size, and multiple comparisons, are discussed.

Low-back pain in industry. An old problem revisited.

Abstract: Low-back pain is a major occupational health problem. Risk factors predisposing to the development of low-back pain are discussed. These include individual risk factors such as age, sex, anthropometry, musculoskeletal abnormalities, muscle strength and physical fitness, psychological factors, and previous attacks of low-back pain and workplace factors such as heavy work, lifting, bending, and slipping. Various programs for prevention are evaluated. These include selection of workers, education and training regarding lifting methods, design of lifting jobs, and fitness training. Limitations of the various studies of these programs are discussed. Preemployment strength testing and ergonomic job design together appear to offer the greatest promise.

Development and validation of a self-administered occupational health history questionnaire.

Abstract: Although the diagnosis of work-related illness relies heavily on the occupational history, there is no validated or widely used questionnaire available to obtain this information. We designed an occupational health history questionnaire (OHHQ) in order to assess (1) its usefulness in obtaining exposure and work histories and (2) its ability to discriminate among workers with different degrees of hazardous exposure. A self-administered OHHQ was completed by 100 consecutive patients known to have a high probability of work-related disease (group 1) and by 55 consecutive workers at low risk for occupational toxic exposures (group 2). Group 1 was found to have a significantly higher number of self-assessed overall exposures (SAESs) than group 2 (p less than .001). Within group 1, scores of SAESs were highly correlated with an assessment by an industrial hygienist of the degree of hazardous exposure (p less than .001). The OHHQ can be feasibly self-administered; it has discriminant validity (correctly identifying groups of workers with high and low hazardous exposures) and convergent validity (correlating with an independent assessment of hazardous exposures).

Infant leukemia and paternal exposure to motor vehicle exhaust fumes.

Abstract: The children of fathers who work in gas stations, automobile or truck repair, and aircraft maintenance appear to be at increased risk for acute leukemia during their first year of life. The odds ratio was found to be about 2.5 overall, but risk appears to be greater for female offspring. A decline in sex ratio was observed for the three decades of the study, with the lowest ratio observed from 1969 through 1978. These preliminary findings suggest that exposure to one or more of the components of exhaust fumes might be of etiologic importance for this malignancy. The limitations of this investigation are discussed.

Stress management in highway maintenance workers.

Abstract: The efficacy of a work-based stress management training program was assessed in highway maintenance workers. Volunteers received training in electromyogram (EMG) biofeedback (n = 17) or muscle relaxation (n = 12) or served as wait-list controls (n = 9). Daily one-hour training sessions were conducted at the workplace for two consecutive workweeks. The biofeedback group showed significant posttraining decreases in forehead EMG levels compared with controls, while decreases found in the muscle relaxation group were not significant. All groups reported significant increases in quality of sleep and in feeling refreshed at work and decreases in subjective tension levels. A three-month follow-up study revealed regression of EMG levels toward baseline in all groups although the percentages of EMG reductions at follow-up were larger for the trained groups than for controls. All groups showed significant improvement on measures of anxiety, somatic complaints, sleep behavior, job satisfaction, and alcohol use. The results support other recent studies indicating the usefulness of work-site stress management programs, although the specificity of training effects and the durability of physiological effects over time remain questionable.

The relationship between spinal canal diameter and back pain in coal miners. Ultrasonic measurement as a screening test

Abstract: Back pain is the commonest cause of absence among coal miners. However, the degree of morbidity is variable. To determine whether the susceptible individual can be identified, ultrasound was used to measure the spinal canal diameters of 204 miners. The results show that those men with the longest histories and the longest times off work and those who had to leave the coalface or who left the industry--i.e., those with the greatest morbidity--had significantly narrower canals. Ultrasonic measurement of the spinal canal diameter is safe and noninvasive. Its use should be further evaluated as part of a preemployment screening procedure for back pain.

Cost-effectiveness of work-site blood pressure control programs.

Abstract: The cost-effectiveness of work-site hypertension programs was examined at three manufacturing plants. A fourth plant was used as a control site to estimate expected levels of hypertension control from screening without further intervention. The annual cost per hypertensive employee of the three intervention programs was $26.26 for semiannual follow-up, $35 for full follow-up, and $96.19 for on-site treatment. Each intervention resulted in an additional 1% of hypertensive employees maintained under control, per dollar spent annually, with the highest cost per unit of effectiveness being incurred for free on-site treatment. Cost-effectiveness may vary considerably, however, depending on the additional costs a company may incur as a result of program adoption.

A cost-effective weight loss program at the worksite.

Abstract: A major focus of Lockheed Missiles and Space Company's wellness program (Sunnyvale, Calif.) was to motivate weight loss in a cost-effective manner. The educationally based "Take It Off '83" campaign was created using the concepts of competition and self-responsibility. Seventy percent of the initial 2,499 participants completed the program, and 90% of these lost weight. Program completion rates and weight lost were higher for men than for women and higher for those who participated as team members rather than as individuals. Encouraging the formation of supportive/competitive teams proved to be a very effective means of promoting weight loss. The cost-effective motivation of weight loss in an industrial setting was accomplished successfully through this program (the cost to the company per initial participant was +5.40). Because of these results, the program will be repeated annually.

Cancer risk among oil refinery workers. A review of epidemiologic studies

Abstract: The possibility that excess cancers result from occupational exposures in oil refineries has generated a great deal of interest. Ecological studies and case-control studies in the general population have suggested a positive association between oil industry activity and cancer rates, with more direct evidence provided by studies of refinery employees. The eight investigations of cancer risks among refinery employees are critically reviewed. The methodological strengths and weaknesses of these studies are evaluated with an emphasis on the likely impact on the results. While the results are markedly inconsistent across studies, there is some suggestion of excess risks for melanoma and for brain, stomach, kidney, and pancreatic cancers. Problems with exposure characterization, latency, and potential confounding factors limit all of the studies that were reviewed. 37 references, 9 tables.

Occupational mortality patterns among British Columbia farm workers.

Abstract: To examine mortality risks for farm laborers proportional mortality ratios (PMRs) were calculated for 2,328 British Columbia farm workers who died at age 20 years or over during the period 1950 through 1978. Significantly fewer deaths than expected from degenerative heart disease (PMR = 91, p less than .01) and from all cancers combined (PMR = 78, p less than .001) were observed. Deaths from bronchitis and emphysema (PMR = 70, p less than .05) were also fewer than anticipated. Elevated risks of death were found for accidents (PMR = 129, p less than .001), for homicide (PMR = 242, p less than .01), and for pneumonia (PMR = 146, p less than .001).

Acute airway obstruction followed by hypersensitivity pneumonitis in an isocyanate (MDI) worker.

Abstract: A rare combination of an acute asthmatic reaction followed by hypersensitivity pneumonitis after exposure to diphenylmethane diisocyanate (MDI) is described. The patient, who was nonatopic and did not show bronchial hyperreactivity to metacholine, was occasionally engaged at the workplace in spraying a mixture of MDI and polyol to produce a polyurethane foam for use as a packing material. Challenge testing by MDI resulted first in a significant immediate bronchial obstruction indicated by decreases in specific airway conductance and forced expiratory volume at 1 s, and then in a significant decrease in vital capacity and diffusing capacity, associated with systemic reactions such as anorexia, malaise, fever, and leukocytosis three to eight hours after challenge. Challenge testing by toluene diisocyanate produced a mild systemic reaction. This finding, as well as the detection of specific IgG antibodies to various isocyanate-human serum albumin conjugates, suggests immunologic cross-reactivity between different isocyanates. Neither skin testing nor the radioallergosorbent test indicated a type I sensitization. After contact with isocyanates was terminated, the disease did not recur.

Respiratory and eye irritation from boron oxide and boric acid dusts.

Abstract: Boron oxide has been shown in animals to irritate the respiratory mucosa and conjunctiva. The present study was undertaken to determine whether exposures to boron oxide and its hydration product, boric acid, cause respiratory and eye irritation in humans. One hundred thirteen workers exposed to these materials and 214 unexposed workers were interviewed regarding symptoms. Statistically significant associations were found between eye irritation, dryness of the mouth, nose, or throat, sore throat, and productive cough and mean exposures of 4.1 mg/m3 (which probably did not exceed 8.5 mg/m3).

Static ergonomic strength testing in evaluating occupational back pain

Abstract: Quantitatively describing work limitation due to occupational back pain is difficult. Static ergonomic strength testing (SEST) was employed as part of a multidisciplinary evaluation program for occupational back pain, providing a quantitative description of lift ability in several positions. Comparison of intrasubject with intersubject variation confirmed that SEST did truly measure a personal characteristic. The expected degree of intrasubject variability is independent of the degree of impairment and provides a guide for detecting inadequate subject efforts. The technique allows worker-specific work restriction limitations to be recommended.

Stress factors in the development of coronary artery disease.

Abstract: The epidemiologic evidence that stress contributes to cardiovascular disease is reviewed. No one characterization of stress has been associated with all manifestations of cardiovascular disease, yet specific characterizations have been associated with particular manifestations of disease. Type A behavior pattern is a risk factor for coronary artery disease (CAD) and is correlated with the severity and progression of atherosclerosis demonstrated angiographically. Work overload with job dissatisfaction also predisposes to CAD. Socioeconomic disadvantage in a society of urbanization and industrialization increases the risk of hypertension and CAD, while chronic states of anxiety, depression, and helplessness are associated with angina and sudden death. Traumatic life events, especially involving loss of or threat to self-esteem, may precipitate sudden death in patients with preexisting CAD. There is evidence that the mechanism linking the experience of stress and the development of acute coronary events is exposure to sympathetic hyperarousal and a deficit in soothing. Research is needed to determine if work environments can be designed to minimize hyperarousal and provide protective outlets for individuals experiencing such arousal.

Declining relative risks for lung cancer after cessation of asbestos exposure.

Abstract: All studies that provide follow-up information for workers more than 35 years after initial exposure to asbestos show a declining ratio of observed to expected lung cancer deaths at the end of follow-up. The most parsimonious explanation of this finding is that relative risk for lung cancer begins to decline sometime after cessation of asbestos exposure.