Gregory G. Bond

An update of mortality among chemical workers exposed to benzene.

Mortality was updated to the end of 1982 for 594 employees exposed to benzene who had been studied previously and for an additional 362 exposed workers not studied previously. Cause specific mortality comparisons were made using United States white male, age, and calendar year adjusted rates. Total mortality was observed to have been significantly below expectation, and this was particularly evident for deaths from accidental causes. Mortality from skin cancer was significantly raised, although there were no unusual or common characteristics among the affected individuals which would suggest a link with exposure to benzene. A non-significant excess of total deaths from leukaemia was noted based on four observed cases; however, all four were myelogenous leukaemias and this represented a significant excess in that subcategory. These and other deaths of possible interest are reviewed in detail. Analyses by work area, duration of exposure, and cumulative dose index did not show patterns suggestive of a causal association between exposure to benzene and any particular cause of death.

Cause specific mortality among employees engaged in the manufacture, formulation, or packaging of 2,4-dichlorophenoxyacetic acid and related salts.

Mortality is reported to the end of 1982 for 878 chemical workers potentially exposed to 2,4-dichlorophenoxyacetic acid (2,4-D) at any time between 1945 and 1983. Observed mortality was compared with expected levels based on adjusted rates for United States white men and for other male employees from this manufacturing location who were not exposed to 2,4-D. Because of a recently reported increased incidence of astrocytomas in male rats fed the highest dose level of 2,4-D, special attention was given to deaths from brain neoplasms in the cohort. None was observed. The absence of an increased risk of brain cancer in people exposed to 2,4-D is supported by studies of other exposed populations and those studies are briefly reviewed. Moreover, in the present study, analyses by production area, duration of exposure, and cumulative dose showed no patterns suggestive of a causal association between 2,4-D exposure and any other particular cause of death.

Acrylamide cohort mortality study.

The mortality experience of 371 employees assigned to acrylamide monomer and polymerisation operations was examined with particular emphasis on cancers at sites identified from animal studies such as the central nervous system, thyroid gland, other endocrine glands, and mesotheliomas. A total of 29 deaths was observed up until 1982 (38.0 expected). No statistically significant excesses were noted in the total cohort and no deaths were found for the hypothesised sites of cancer. The observed deaths in the total cohort for the all cancers category were somewhat in excess (11 v 7.9); however, this was due entirely to excess cancers of the digestive tract and respiratory system in the subgroup with previous exposure to organic dyes. Among those employees not exposed to organic dyes, four deaths were due to malignancies versus 6.5 expected. This study does not support a cause effect relation between exposure to acrylamide at this work site and overall mortality, total malignant neoplasms, or any specific cancers.

Incidence of chloracne among chemical workers potentially exposed to chlorinated dioxins.

Company medical charts were reviewed for 2192 chemical workers who were potentially exposed to chlorinated dioxins during 1940 to 1982 to determine whether they were ever diagnosed as having chloracne. Nearly 16% of the 2072 workers with medical records were found to have been so affected. The incidence of chloracne was noted to have been highest among the youngest workers, and among those who worked in the production of chlorinated phenols rather than with products derived from those materials. Chloracne incidence was found to increase with several measures of intensity and cumulative dose of tetra- and hexa- to octachlorinated dioxins, but these analyses were hampered somewhat by the limitations of both the exposure and medical outcome data.

Medical and morbidity surveillance findings among employees potentially exposed to TCDD.

Available medical and morbidity surveillance findings from 1976 to 1978 for two employee cohorts potentially exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were compared with those of matched unexposed employees. The medical surveillance findings were derived from a screening programme offered to all active employees and included an analysis of various medical history questions and blood chemistry results. Group medical insurance claims served as the source of morbidity surveillance data and the period prevalence of selected diseases was analysed. Few significant differences between the exposed and unexposed were detected. Among the cohort of employees potentially exposed during the manufacture of 2,4,5-trichlorophenoxyacetic acid (2,4,5,-T), a significantly greater frequency of x-ray proved ulcer was reported and significantly more members of this group had diseases of the digestive system diagnosed. Such findings were absent in the more highly TCDD-exposed cohort engaged in 2,4,5-trichlorophenol production, making it unlikely that dioxin was a cause.

Evaluation of the mortality experience of workers exposed to the chlorinated dioxins

Abstract Mortality patterns were analyzed for the time period 1940 through 1979 of 2,189 men with potential occupational exposure to chlorinated dibenzo-p-dioxins. Special attention was directed toward 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and deaths due to soft-tissue sarcoma, non-Hodgkins lymphoma, Hodgkins disease, liver cancer, stomach cancer, and nasal or nasopharyngeal cancer. With United States white males as the comparison population for this employee cohort, the stadardized mortality ratio for all causes of death was 91 and for total malignant neoplasms, 96. Among the malignancy categories of particular interest, none demonstrated a significant deviation from expected. Nor were any significant trends noted for any specific cause of death category when analyzed by estimated cumulative exposure.

Morbidity among employees engaged in the manufacture or formulation of chlorpyrifos.

The prevalence of selected illnesses and symptoms during 1977-85 was compared between 175 employees potentially exposed to the organophosphate insecticide chlorpyrifos and 335 matched controls with no history of exposure to organophosphates. Subjects were subdivided into three exposure intensity groups on the basis of job title and air monitoring data for dose response testing. This classification scheme was shown roughly to correlate with plasma cholinesterase inhibition in the workers. No statistically significant differences in illness or prevalence of symptoms were observed between the exposed and unexposed groups or among the three exposure subgroups. Potentially exposed employees did report symptoms of dizziness and of malaise and fatigue relatively more often than subjects from the comparison group; however, further analyses by exposure level, process area, or time did not support a relation with exposure. No cases of peripheral neuropathy were seen among the exposed workers. Although the sample size was small and the statistical power limited, the cumulative exposures likely to have been experienced by this workforce exceed those to be expected for individuals using the product as recommended. The absence of exposure related adverse effects, including neurological impairment, is reassuring.

Prevalence of back pain and joint problems in a manufacturing company.

To estimate prevalence of back pain and joint problems in employees of a chemical manufacturing company, a questionnaire was administered during medical surveillance examinations between 1987 and 1989. Among 5903 employees completing the questionnaire 35.4% reported back or joint pain during the past year. Back pain lasting 30 days or more occurred in 5.3% of employees, while joint pain and/or swelling occurred in 19.3% of employees. A physician visit was involved for 10.5% and 11.1% of employees reporting back pain and joint problems respectively. A trend of increasing prevalence with increasing age was significant (P less than .001) for all musculoskeletal outcomes. Unadjusted prevalence of back pain and joint problems was significantly higher among men and among whites. After adjusting for age, race, and occupation using logistic regression, the difference in prevalence for the two sexes was diminished or reversed. Similarly, differences in race were diminished when other variables were controlled. Differences in prevalence by occupation were attenuated after adjustment for age, gender, and race. Back pain tended to be reported more frequently for managers, back pain and joint problems for technicians, and back pain requiring physician visit for craftsmen. Self-reported back pain and joint problems during the previous year vary more by age and occupation and less by gender and race in this employed population.

A 5-year evaluation of a smoking cessation incentive program for chemical employees

BACKGROUND This 5-year study of the Dow Chemical Texas Operations 1984-1985 Smoking Cessation Incentive Program (SCIP) evaluated the smoking habits of 1,097 participants and 1,174 nonparticipants. RESULTS We observed, via questionnaire and saliva cotinine data, that participants were 2.3 times more likely to be long-term (greater than or equal to 5 years) nonusers of tobacco than nonparticipants (10.2% vs 4.4%, P less than or equal to 0.01). However, smoking cessation rates for 3-4 years, 1-2 years, and less than 1 year were similar for participants who remained smokers at the conclusion of SCIP and nonparticipants. Age and the interaction between the management job category and having quit smoking for at least 30 days sometime prior to the worksite program were important predictors of smoking cessation among participants. Thirty-six percent of the participants who were considered exsmokers of 6 months duration at the conclusion of the program in 1985 remained long-term quitters 5 years later. Stress and enjoyment of smoking were the two most important reasons provided by participants for recidivism. CONCLUSIONS The results of this 5-year evaluation demonstrate the heterogeneity of employee participation and success with a worksite smoking cessation program.

A comparison of cause-specific mortality among participants and nonparticipants in a work-site medical surveillance program.

Nonparticipants in general population health surveys have been found to be less healthy than participants, but data on nonparticipants in work-site health surveys have been more scarce. We compared cause-specific mortality among 11,156 male employees of The Dow Chemical Company who participated in at least one work-site health examination between 1967 and 1978 with 6915 employees who did not participate. The nonparticipants experienced higher mortality rates for nearly every cause of death examined but particularly from smoking and alcohol-abuse related diseases. This was especially true during the first 5 years of follow-up, suggesting that some employees do not participate because they are already ill. These findings have important implications for the use of examination data for both primary and secondary disease prevention purposes, and these are discussed.