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A lung cancer case-control study was conducted in a Slovenian asbestos-cement factory for which unusually good records of asbestos exposures were available. The cohort consisted of all 6714 workers employed at the Salonit Anhovo factory after 31 December 1946 who worked there for at least one day between 1964 and 1994. Fifty-eight histologically confirmed cases of primary lung cancer and 290 controls were selected from the cohort. Working life exposure histories to amphibole and chrysotile forms of asbestos were estimated separately. Airborne asbestos concentrations were low. For example, the arithmetic mean exposure to all forms of asbestos in the highest exposure period (1947-1971) was 1.2 f/cm(3). Chrysotile asbestos made up about 90% of this exposure (mean 1.1 f/cm(3)), whereas amphibole accounted for 10% (0.1 f/cm(3)). Comparing those above and below the 90 percentile of cumulative exposure, the odds ratios for all asbestos, chrysotile and amphibole were 1.5, 1.6 and 2.0, respectively, but confidence intervals were wide. There are only a few asbestos-lung cancer studies with high-quality exposure data and exposures in this low range. Though imprecise, the findings are important to the ongoing debate about asbestos risks.

A total of 675,626 active duty Army soldiers who were known to be at risk for deployment to the Persian Gulf were followed from 1980 through the Persian Gulf War. Hospitalization histories for the entire cohort and Health Risk Appraisal surveys for a subset of 374 soldiers were used to evaluate prewar distress, health, and behaviors. Deployers were less likely to have had any prewar hospitalizations or hospitalization for a condition commonly reported among Gulf War veterans or to report experiences of depression/suicidal ideation. Deployers reported greater satisfaction with life and relationships but displayed greater tendencies toward risk-taking, such as drunk driving, speeding, and failure to wear safety belts. Deployed veterans were more likely to receive hazardous duty pay and to be hospitalized for an injury than nondeployed Gulf War-era veterans. If distress is a predictor of postwar morbidity, it is likely attributable to experiences occurring during or after the war and not related to prewar exposures or health status. Postwar excess injury risk may be explained in part by a propensity for greater risk-taking, which was evident before and persisted throughout the war.

Background: Low level effects of granite dust on one-second forced expiratory volume (FEV1) are estimated in 618 Vermont granite workers followed for 5 years with annual pulmonary function tests. Reduced pulmonary function has already been reported for the subset of subjects lost to follow-up (dropouts) suggesting possible bias in analyses based only on survivors., Method: Healthy worker selection bias is directly assessed by comparing the dose-response associations between survivors who remained in the study for the full 5-year observation period and the dropouts., Results: The 353 survivors had an FEV1 of 96% of predicted at baseline and were losing FEV1 at an average rate of 44 ml/yr. No association was found in this group between the rate of FEV1 decline and lifetime dust exposure. However, the 265 workers with incomplete follow-up, 'dropouts', had a lower FEV1 at baseline (94%) and were losing FEV1 at an average rate of 69 ml/yr. The dose-response parameter in this group was estimated to be 4 ml/yr loss per mg/m3-year and was statistically significant., Conclusions: These results provide an illustration of bias due to the healthy worker effect and an example of the failure to detect a true work-related health effect in a study based only on a 'survivor' population.

An interactive computer program which computes the standardized mortality odds ratio and the standardized proportional mortality ratio has been developed for use in the analysis of occupational mortality studies. The program provides flexibility in the selection of the comparison (unexposed) population, permitting both internal and external comparison, including comparison with the United States general population. Considerable control for potential confounding factors and for differences in information collection procedures can be exercised through careful choice of the comparison population. The user must select the reference cause(s) of death among 55 categories (59 for women). The condition for equivalence of the standardized mortality odds ratio and the standardized mortality ratio will be met when the selected reference cause(s) is unrelated to the exposure. The program reduces the loss of information due to sparse data during stratification by allowing the user to define the length of the age and time intervals. The program is written in Fortran IV and is designed to produce rapid, cost-efficient interactive results on any mainframe computer system.

The potential for introducing bias in studies of pulmonary function by the exclusion of subjects with nonrepeatable measurements was examined in a cohort of Vermont granite workers followed for five years. At each annual survey, a "test failure" was defined as a test in which the two largest forced expiratory volumes in one second (FEV1) differed by more than 200 ml. "Persistent test failure" was defined in terms of 1) the number of test failures for each worker over the six surveys and 2) the difference between the two best efforts at each survey, averaged over all surveys for each worker. The rate of FEV1 loss was estimated for each subject based only on repeatable measurements. It is widespread practice to exclude subjects from analysis who do not perform repeatable lung function tests. The authors found that subjects with persistent test failure were losing FEV1 at a faster rate than subjects without. The results suggest that the application of rigid repeatability criteria may bias epidemiologic findings by the exclusion of many subjects with accelerated loss of lung function.

For effort dependent tests, the estimation of measurement precision (reproducibility) is complicated by learning effects and submaximal efforts which inflate the variance of repeated trials. To illustrate an approach to the estimation problem, precision was evaluated for three neurobehavioural tests based on the responses of 76 boatbuilders tested on four separate test occasions within a one-week period. The average Coefficient of Variation (CV) for repeated trials within a test session was 6%, 16% and 13% for the Continuous Performance Test (CPT), Symbol-Digit substitution test (SDS) and the Hand-Eye motor-coordination test (HEM), respectively. In order to adjust for the effects of learning, the first trial(s) of a session were excluded from the calculation of performance level and its precision. This adjustment for learning significantly improved the precision for SDS and HEM to a CV of 8%. Inspection of the distributions of best efforts by trial number indicated that dropping the early trial(s) eliminated the best efforts of 34%, 22% and 7% of the subjects on the three tests respectively. When the worst two trials were excluded regardless of order, precision improved significantly to less than 5% for all three tests. On the basis of these results, a 5% precision rule for CPT and a 10% precision rule for SDS and HEM are provisionally recommended. The test results of subjects unable to meet this criterion should be identified, but in order to avoid selection bias, they should be analysed separately rather than excluded.

The relationships between occupation, smoking, and the three most common histologic types of lung cancer (squamous cell carcinoma, small-cell carcinoma, and adenocarcinoma) were explored in a case-control study with the use of data collected during the Third National Cancer Survey. The largest histologic group was squamous cell carcinoma (152 cases), followed by adenocarcinoma (50 cases), and small-cell carcinoma (45 cases). The control series was comprised of cancers at all anatomic sites except those believed to be associated with either smoking or occupational exposures. Cigarette smoking was significantly associated with all three histologic types of lung cancer. Overall, the relationship with small-cell carcinoma was strongest (odds ratio = 5.1), whereas those with squamous and adenocarcinoma were approximately equivalent (odds ratio = 3.1). Dose-response relationships were evident for all three histologic types; however, the linear relationship was found to be statistically significant (P less than 0.05) only for squamous and small-cell carcinomas. Squamous cell carcinoma was the type most frequently associated with occupational categories. It was significantly associated (P less than 0.05) with "blue collar" professions (odds ratio = 2.1). No occupational categories were significantly associated with adenocarcinoma. In addition, no occupational categories were associated with all histologic types of lung cancer combined. This last observation suggested that the sensitivity of epidemiologic studies might not only be increased by use of improved occupational histories but more specifically by consideration of histology in examination of associations between occupation and respiratory cancer.

Several population data bases were used to generate hypotheses about associations between colorectal cancer and workplace exposures. The Third National Cancer Survey interview sample was used to select 343 male and 208 female cases and 626 male and 1,235 female cancer controls. Potential work exposures were assigned with the use of data from the National Institute for Occupational Safety and Health National Occupational Hazard Survey. Dietary factors were modeled from the National Health and Nutrition Examination Survey data. Work-related stress was considered with the use of a model based on the U.S. Department of Labor's Quality of Employment Survey. Other risk factors included age, race, ponderosity, and menopausal status. Logistic analysis yielded hypotheses for colon cancer risk in males with potentially high exposure to solvents, abrasives, and fuel oil and in those in jobs with high demand and low control (high "stress"). Hypotheses emerged for females with potentially high exposure to dyes, solvents, and grinding wheel dust.

The objectives of this paper were 1) to identify occupations with potentially high cancer risk by combining the results of 12 major occupational disease surveillance studies, 2) to develop a quantitative methodology for accomplishing the first objective, and 3) to make recommendations concerning priorities for occupational cancer research and control on the basis of the results of this analysis in conjunction with other available epidemiologic, industrial hygiene, toxicologic, and employment data. It was suggested that the first priority be the investigation and control of occupational exposure to asbestos, particularly in the automobile repair and construction industries. Of the 34 occupational groups found to be at high risk for lung cancer in this analysis, 18 have potential asbestos exposure. The second priority was suggested to be research into the consistent lung-cancer excess found among motor vehicle drivers. This excess may be due to occupational exposure to diesel and gasoline engine exhaust, to cigarette smoking, or to both of these factors.