Eva Chan

RISING MORTALITY FROM MOTONEURON DISEASE IN THE USA, 1962-84

From 1962 to 1984, age-specific mortality for motoneuron disease (MND) in the United States rose in all demographic groups over the age of 40. The increase was seen in both men and women, and both whites and non-whites, and was most pronounced in the elderly (eg, 378% in white women aged 80-84 years). Men were at 50% higher risk than women, and whites had twice the risk of non-whites. These increases may reflect an improvement in case ascertainment, but they also seem to show a true rise in the incidence of MND, particularly among the elderly. Such an increase suggests an environmental aetiology.

Long term radiological effects of short term exposure to amosite asbestos among factory workers.

Chest radiographs were read from a sub-cohort of 386 factory workers with short term exposure to amosite asbestos (median exposure six months) and long follow up (median 25 years). Prevalence of abnormality was determined independently by two readers from the first film available after 20 years from first employment. Serial films were obtainable for 238 men (median interval from first to last film: nine years). Progression was classified with a direct progression scoring scale. Individual dust exposure estimates were derived from dust counts from two similar plants. With as little as one month or less of employment, about 20% of the films showed parenchymal abnormality and about a third showed pleural abnormality. Those in the lowest cumulative exposure stratum (less than 5 fibre-years/ml) were similarly found to have high rates of abnormality. Dose-response relations were present in the data of both readers. Smokers had higher rates of parenchymal abnormality. On multivariate analysis, cumulative exposure was the exposure variable most closely related to parenchymal abnormality, and time from first employment was the variable most closely related to pleural abnormality. Progression (including first attacks) 20 or more years after ceasing employment occurred and was more common for pleural than for parenchymal abnormality. It is concluded that with exposure to high concentrations to amosite such as existed in this factory and with follow up for at least 20 years, (1) exposure for as little as a month was sufficient to produce radiological signs of parenchymal and pleural fibrosis, (2) no cumulative exposure threshold for parenchymal and pleural fibrosis was detectable, and (3) parenchymal and pleural progression were still detectable >/= 20 years after the end of exposure.

Parkinsonism Death Rates by Race, Sex and Geography: A 1980s Update

To evaluate temporal changes in the geographic distribution of Parkinsons disease (PD) mortality in the United States, we reviewed death rates for PD in the nine regions of the United States for 1980-1984. Age-adjusted mortality for all ages and for the elderly (65 years of age and older) was analyzed. Variation in PD mortality was observed among the regions for all demographic groups. The patterns were different from those reported during 1959-1961. Changing geographic patterns in mortality provide evidence for an environmental etiology for PD.

Life events, chronic strain, and psychological distress: Longitudinal causal models

This prospective study examines the causal relations among life events, chronic strain, and psychological distress. The influence of total number of life events; recent events; and undesirable, disruptive, and unanticipated events on marital strain and work/economic strain is assessed using latent variable structural equation modeling. It is hypothesized that chronic strain mediates the effects of life events on psychological distress. The data analyzed are from the first two waves of a prospective study on psychosocial factors and cancer mortality in a sample of skilled blue collar workers exposed to asbestos. A subsample of married and employed men within a relatively narrow age range was selected for this study to facilitate the investigation of the relations among life events, strain, and distress among individuals similarly situated in the life course. The results show that total number of events and recent, undesirable, disruptive, and unanticipated events increase work/economic strain and that, through this increase in strain, life events influence both contemporaneous levels of psychological distress and changes in distress. Life events do not have a direct effect on psychological distress when prior levels of events, work/economic strain, and distress are controlled. In contrast, life events do not have an impact on marital strain; rather, marital strain exerts a direct effect on distress. Undesirable, unanticipated, and disruptive events exert modest but significant direct effects on psychological distress in models including marital strain. These findings are discussed in terms of the place of the sample of workers in the life course, and implications for the design of preventive intervention programs are presented.

Epidemiologic investigation of a cancer cluster in professional football players

In 1976, the New York Giants professional football team relocated to the newly constructed Meadowlands Sports Complex (MSC) in East Rutherford, NJ. Between 1980 and 1987 four team members developed cancer: one case each of non-Hodgkins lymphoma, glioblastoma, angiosarcoma, and Hodgkins disease. Because the surrounding area contains three superfund sites, concern was widespread that the cancers were related to environmental contamination. To assess for a possible environmental etiology, we conducted clinical, environmental, and epidemiologic studies at the MSC. Measurements of volatile organic compounds were all below occupational exposure limits and were similar to ambient levels in nearby Lyndhurst, NJ. Outdoor AM radio broadcast field strengths were in the uppermost 0.1% of field strengths measured in urban areas of the United States. Proportionate mortality ratio and proportional cancer incidence ratio studies of the MSC workforce found no excesses of cancer deaths or of incident cancer cases either for all sites combined or for any specific site. No significant differences in cancer incidence or mortality were found between indoor and nonindoor workers. Based on examination of all available data, the four cancer cases were judged most likely to have been clustered by chance and not to have been caused by environmental conditions at the MSC.