Biomedical subjects

J W Pifer

Publications and source records attributed to J W Pifer.

10 recordsLinked to original sources

PubMed1995

Mortality study of employees engaged in the manufacture and use of hydroquinone.

Mortality in a 1942-1990 cohort of 858 men and 21 women employed in the manufacture and use of hydroquinone was evaluated through 1991. Average exposure concentrations, 1949-1990, ranged from 0.1 to 6.0 mg/m3 for hydroquinone dust and from less than 0.1 to 0.3 for quinone vapor (estimated 8-h time-weighted averages). Compared with general population and occupational referents, there were statistically significant deficits in total mortality and deaths due to cancer. No significant excesses were observed for such hypothesized causes as kidney cancer [2 observed vs 1.3 expected (both control groups), P approximately 0.39], liver cancer (0 vs 0.8, 1.3), and leukemia (0 vs 2.3, 2.7). Dose-response analyses of selected causes of death, including renal carcinoma, demonstrated no statistically significant heterogeneities or linear trends according to estimated career hydroquinone exposure (mg/m3-years) or time from first exposure.

Adult↗

PubMed1990

Absence of adverse mortality effects in workers exposed to methylene chloride: an update.

Mortality findings in a 1964 to 1970 cohort of 1013 hourly-wage men exposed to methylene chloride were substantially unchanged after 4 additional years of observation through 1988. Mean exposure was 26 ppm (8-hour time-weighted average) for 23 years; median follow-up from first exposure was 33 years. A comparison with death rates in both general population and industrial referents showed nonsignificant deficits in observed-expected ratios for such hypothesized causes as lung and liver cancer and ischemic heart disease. Overall mortality from 1964 to 1988 (n = 238) was significantly decreased v both referent groups. The study had 90% power to detect relative risks of 1.7 and 1.3 for lung cancer and ischemic heart disease, respectively; power was inadequate for hepatic cancer. No pancreatic cancer deaths occurred since the 1984 follow-up; eight have been observed v 4.2 expected (P = .13). An analysis of dose response for selected causes of death demonstrated no statistically significant trend according to either career methylene chloride exposure or latency. Similar results were observed when the data were analyzed using Poisson regression modeling.

Adult↗

PubMed1989

Absence of toxic effects in silver reclamation workers.

Recent reports have alleged that silver presents a toxic hazard to exposed workers. To define the potential risks of long-term exposure to silver better, a cross-sectional investigation was conducted of 27 Caucasian males occupationally exposed to primarily insoluble silver compounds and 27 matched referents. Physical examination and electron microscopy of skin biopsies revealed no cases of generalized argyria. Measurements of facial discoloration, judged from color photographs by panels of laymen and physicians, showed no significant difference between the two groups. Although 29% of the silver workers and none of the referents exhibited ocular silver deposition, optometric and contrast sensitivity test results revealed no significant deficits in visual performance. The kidney and respiratory findings were essentially normal in both populations. Despite the increased presence of silver in the blood, feces, and hair of the recovery workers versus the referents, there was no evidence that chronic silver exposure adversely affected the health of these employees.

Air Pollutants, Occupational↗

PubMed1987

Methylene chloride mortality study: dose-response characterization and animal model comparison.

To assess the potential chronic health effects of methylene chloride, the mortality experience of a maturing 1964 to 1970 cohort of 1,013 hourly men was evaluated through 1984. On average, employees were exposed at a rate of 26 ppm (eight-hour time-weighted average) for 22 years; median latency was 30 years. Compared with the general population, no statistically significant excesses were observed for such hypothesized causes as lung cancer (14 observed v 21.0 expected), liver cancer (0 v 0.8), and ischemic heart disease (69 v 98.1); dose-response relationships based on career methylene chloride exposure and latency were not demonstrated. Among nonhypothesized causes, a significant deficit was reported for total deaths (176 v 253.2). None of the industrial referent comparisons achieved statistical significance. Sufficient power was available to detect relative risks of 1.6 for lung malignancy and 1.3 for ischemic heart disease. In contrast, there was inadequate power to identify meaningful risk levels for hepatic cancer. With 14 combined lung and liver cancer deaths observed v 36.3 predicted (P less than .0001), the mortality estimate projected from a mathematical model derived from an animal bioassay substantially overestimated cancer mortality for these sites. This inconsistency emphasizes the need to incorporate epidemiologic evidence in assessing the human health risks associated with long-term exposure to this widely used solvent.

Air Pollutants, Occupational↗

PubMed1986

Mortality study of men employed at a large chemical plant, 1972 through 1982.

The mortality experience of a cohort of approximately 9,000 traced men employed at a Tennessee chemical plant was examined between 1972 and 1982. Statistically significant total mortality deficits of 41% to 46% and 14%, respectively, were observed compared with general population and occupational controls. Cancer deaths were 22% (significant) below expectation based on state and national vital statistics, whereas comparison with an employed group showed no difference. Significantly low mortality differentials were also reported for other major causes, including diseases of the circulatory, respiratory, and digestive systems. Analysis of the data by length of employment, payroll status, and chemical production division demonstrated no unusual patterns. The cohort's favorable mortality experience may be attributed to such factors as employee selectivity, health maintenance, accessibility to medical care, and less cigarette smoking.

Chemical Industry↗

PubMed1969