DNA hyperploidy as a marker for biological response to bladder carcinogen exposure.

A marker for biological response to bladder carcinogen exposure was evaluated in a cross-sectional study of 504 workers at high risk due to a range of exposures to various carcinogenic aromatic amines, primarily 2-naphthylamine. A quantitative fluorescence cytology method using the DNA-binding dye, acridine orange, was employed to measure DNA in exfoliated urothelial cells. DNA hyperploidy (greater than 5 C) was observed in 16 (21.6%) of 74 workers who had been exposed compared with 15 (3.5%) of 430 workers who had not (p less than 0.001). The prevalence of DNA hyperploidy increased in a dose-response manner from 3.5% to 60% with increasing duration of exposure. The association between DNA hyperploidy and exposure persisted when adjustment was made for age and cigarette smoking (p = 0.0001). The prevalence of the marker was greatest for exposed workers who smoked (23%), and lowest for those who had no exposure and who had not smoked (2%). This study indicates that DNA hyperploidy can serve as a marker for identifying workers who are at increased risk in occupational groups exposed to bladder carcinogens.

Risk factors for bladder cancer in a cohort exposed to aromatic amines.

Occupational and nonoccupational risk factors for bladder cancer were analyzed in a cohort of 1385 workers with known exposure to a potent bladder carcinogen, beta-naphthylamine. Bladder cancer was approximately seven times (95% confidence interval [CI] = 3.9, 12.4) more likely in exposed rather than nonexposed individuals, yet, otherwise, the groups were generally similar in other exogenous or hereditary risk factors. A total of 13 cases of bladder cancer were identified. After the first year of a screening program involving 380 members of the cohort, 9 of the 13 cases of bladder cancer and 36 persons with atypical bladder cytology, histology, or pathology were compared with 335 noncases for distributions of different variables. Occupational variables were significant in a multivariate model that controlled for age, cigarette smoking history, and source of drinking water. The estimated odds ratio for the association for bladder cancer and the duration of employment, when controlling of these other variables, is 4.3 (95% CI = 1.8, 10.3). In addition to the occupational factors, age was significant in the multivariate analysis. Other potential risk factors, such as consumption of coffee or artificial sweeteners, use of phenacetin, or decreased use of vitamin A were not found to be significantly different in cases and noncases.

Risk for bladder cancer. Psychological impact of notification.

Informing persons that they have been exposed to a carcinogenic chemical (beta-naphthylamine) may adversely affect these persons and their families. The purpose of this study was to identify and assess the psychological impact of a bladder cancer notification and screening program on persons at risk and their families. Approximately 140 subjects were randomly selected from 850 workers exposed to beta-naphthylamine. The Family APGAR, Impact of Event Scale, and Improved Readability Form of the Minnesota Multiphasic Personality Inventory were administered within four weeks of the initial medical screening and readministered six months later. Results show no evidence of disruption to families or substantive psychopathology among these persons. While the actual acquisition of cancer is undoubtedly a psychological trauma, mere notification of risk may not be traumatic in every situation.

KIE: It has been suggested that informing people that they have been exposed to a carcinogenic chemical may have an adverse psychological impact on them and their families. This study assessed the impact on 140 randomly selected subjects from a population of 850 persons enrolled in a bladder cancer screening and notification program. Administration of psychological tests within four weeks and again six months after the medical screening showed no evidence of substantial psychopathology or family disruption. The investigators caution that additional studies in similar populations and work environments must be performed before any firm conclusions can be drawn.

Risk assessment of a cohort exposed to aromatic amines. Initial results.

A cohort of 1,385 workers potentially exposed to carcinogenic amines was evaluated to determine the extent of its risk for bladder cancer. The cumulative incidence of bladder cancer was determined from death certificates, from interviews with community urologists, and from a screening program. A total of 13 confirmed cases of bladder cancer were identified at the conclusion of the first year of study. The entire cohort has approximately a fourfold excess risk of bladder cancer; however, black workers with more than 10 years of employment had a risk ratio of 111 (based on three cases). The onset of disease occurred, on the average, 15 years earlier in these black workers than in the general U.S. population. The cumulative incidence of bladder cancer increased with the duration of employment, ranging from 0.4% for workers with five or fewer years of employment to 36% for those with greater than 20 years. No significant differences were found between cases and noncases for cigarette smoking, coffee drinking, use of artificial sweeteners, or prior employment in high-risk occupations. More cases of bladder cancer are expected in this cohort because many members have not yet achieved the average latency found for the confirmed cases.

Notification of a cohort of workers at risk of bladder cancer.

Surviving members of occupational cohorts studied in retrospective analyses of mortality usually are not notified individually of positive study results. However, concern has arisen that such results may contain risk information pertinent to study subjects. To evaluate the effects and implications of individually notifying survivors of such cohorts, we conducted a pilot notification study. Members of a cohort of 1,385 chemical workers who had handled carcinogenic amines were notified by mail that they were likely to be at increased risk of bladder cancer. Also a bladder cancer screening and follow-up program was established. The study demonstrated that notification is a complex action and that much care needs to be taken when communicating information on risk. Notification requires development of (1) criteria as to what constitutes a notifiable risk and (2) programs to meet the medical and social needs of the various parties involved in notification.

Kaolin dust concentrations and pneumoconiosis at a kaolin mine.

Kaolin is removed from underground seams in the mining area to a processing area, where it is sliced, dried, and pulverised to make the finished product. A study was undertaken to determine the dust concentrations in various work areas and to assess the prevalence of radiographic and pulmonary function abnormalities in 65 workers at a Georgia kaolin mine. Respirable dust concentrations were higher in the processing area than in the mine or maintenance areas for all determinations from 1977 to 1981. The mean respirable dust level in the processing area in 1981 was 1.74 mg/m3 and 0.14 mg/m3 in the mine area. Five workers, all of whom had worked at the processing area, had radiographic evidence of kaolin pneumoconiosis. The mean values of forced vital capacity (FVC) and FEV1 of the entire group were within the normal range. When the spirometric values were expressed as a percentage of the predicted values, the FVC and FEV1 were significantly lower in the workers with kaolinosis than in other workers in the processing area. The FVC and FEV1 also declined significantly with increasing years of work in the processing area. The FEV1/FVC%, however, was not significantly altered either by the presence of kaolinosis or by an increasing number of years of work, indicating that the impairment was restrictive and hence likely to be a consequence of dust inhalation rather than smoking. In this study the highest dust concentrations occurred in the processing area, and kaolin pneumoconiosis was limited to those who had worked there. Kaolin exposure appeared to have a small but significant effect on ventilatory capacity in those with kaolin pneumoconiosis and in workers with a longer exposure. There was no association between the radiographic appearances of kaolinosis and cigarette smoking or between the presence of radiographic abnormalities and reduced arterial blood gas tensions.