There have been few attempts to assess the validity of occupational histories obtained from interviews. A nested case-control study of lung cancer conducted in 1985 among a cohort of 19,608 male workers at a Texas chemical production facility provided such an opportunity. Telephone interviews were attempted with 308 lung cancer patients and 588 matched controls or their next of kin in order to gather information on tobacco use, diet, places of residence, and occupations. Interview data from 734 respondents (143 subjects and 591 next of kin) were then compared with the records of work area assignments maintained by the company and with exposure profiles developed by an industrial hygienist. Respondents recalled 48.4 per cent of all documented work area assignments, but only 2.6 per cent of the chemical agents judged as likely exposures. Recall of usual work area assignment was 70.8 per cent. Among the factors found to have most influenced recall were the number and durations of assignments, a subjective assessment of the quality of the interview, and the relationship of the interview respondent to the subject. The elapsed time from job assignment to interview was also found to affect recall of the longest assignment of the subject.

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.Acrylamide is a white crystalline solid which is important as a chemical intermediate and as a monomer used in the production of polyacrylamides. The effects of exposure to acrylamide have been reported to include peeling and redness of the skin of the hands, localised numbness of the legs, excessive sweating of the feet and hands, and both central and peripheral nervous system damage.' Epidemiological studies of employees exposed to acrylamide have not been published to date.The chronic effects of acrylamide in rats have been investigated in a two year toxicity-oncogenicity study.2 Fischer 344 rats were divided into groups of 90 rats by sex and dose level and given water formulated to provide 0. 0-01, 0 1, 0 5, and 2-0 mg/kg/day of acrylamide. Histopathological examination indicated that in the female rats at the highest dose level there was a statistically significant increase in the number of neoplasms of the mammary gland, nervous system, clitoral gland, uterus, oral cavity, and thyroid gland. Data from male rats indicated an increased incidence of mesothelioma in the scrotal cavity at dosages of 0-5 and 2-0 mg/kg/day. The incidence of benign tumours of the thyroid gland was also statistically increased at doses of 2-0 mg/kg/day. Although not statistically significant, there appeared to be an increased incidence of tumours in the brain and spinal cord at the highest level in the male rats.2

Cause specific mortality was surveyed among 37,682 male employees with three or more days of service between 1940 and 1982 at the Midland or Bay City, Michigan, locations of Dow Chemical USA. Vital status was ascertained through 1982 for 97.5% of the cohort members, and death certificates were obtained for 97.1% of the 7,751 decedents. Comparisons of observed mortality with expected levels based on any of three general population groups (US, Michigan, or seven local counties) consistently demonstrated lower mortality in the cohort from each of the major causes of death, including total malignant neoplasms. Unique among hourly employees was significant excess mortality in the categories of cancer of other lymphatic tissue, and motor vehicle accidents, and both hourly and salaried nonexempt employees experienced significantly higher mortality from other and ill-defined cancers. The influence of duration of employment and age at and period of hire were explored with the Mantel-Haenszel method as adapted for a cohort study. Results were evaluated both including and excluding the mortality experience of subsets of employees with past exposure to known human carcinogens (arsenic, asbestos, bis-chloromethyl ether, benzene, organic dyes, and vinyl chloride). The use of the general mortality survey in monitoring whether or not there are major health problems among the employees and in setting research priorities is emphasized.

Mortality was updated through 1982 for 611 arsenic-exposed employees originally studied through 1973. In the earlier report, total mortality was observed to have been below the comparable U.S. population; however, mortality was significantly elevated for respiratory cancer. The focus of the update was on respiratory cancer and of special interest was whether the risk of respiratory cancer remained in excess for individuals alive as of the end of the last study. In the update, 9 additional respiratory cancers were observed subsequent to 1973, the end of the follow-up in the original study, versus 7.8 expected. The risk ratio for the time-interval 1974-1982 (standardized mortality ratio SMR = 116) was diminished compared to that reported in the original study (SMR = 330). When the entire study period was analyzed, the risk of respiratory cancer did not appear to decline with interval since exposure cessation. Analyses by duration of arsenic exposure and interval since first exposure did not reveal any obvious dose-response relationships.

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