Elaine Dorken

A Follow-up Study of the Grain Elevator Workers in the Port of Vancouver

Abstract A second respiratory survey was conducted on 587 grain elevator workers in the Port of Vancouver and on 111 civic workers, 25 years after the first health survey. The prevalence of respiratory symptoms and lung function findings among grain elevator workers in the second survey were almost identical with those in the first health survey, even though the dust concentration was lower in the elevators during the second survey. The longitudinal study in 396 grain workers showed that the prevalence of respiratory symptoms increased slightly during the second health survey among workers who had the same smoking habits during both surveys. Of the smokers who had respiratory symptoms or lung function impair-ment in the first survey, 23.5% followed our advice and gave up smoking; the prevalence of cough and sputum pro-duction decreased among these workers. The annual decline in function was greater for grain workers than civic workers particularly among workes over the age of 50 years when the differences...

Plicatic acid-specific IgE and nonspecific bronchial hyperresponsiveness in western red-cedar workers☆

In a cross-sectional survey of 652 workers in a western red-cedar sawmill, we obtained data on symptoms, pulmonary function, immediate skin reactivity to common allergens, nonspecific bronchial responsiveness, total IgE level, and sensitization to plicatic acid conjugated with human serum albumin as measured by RAST. Dust exposure was estimated by personal and area sampling for total dust during a work shift and cumulative exposure by duration of employment. Seven percent of the workers had an elevated RAST, and 20% had nonspecific bronchial hyperresponsiveness. Elevation in RAST was associated with bronchial hyperresponsiveness. Almost half (46%) of the workers with RAST elevation had bronchial hyperresponsiveness compared to 18% in workers with no RAST elevation. The association was unaffected by total IgE level or by limiting the analysis to workers without respiratory symptoms and was most apparent in younger workers. Bronchial hyperresponsiveness was associated with increased prevalence of respiratory symptoms as well as with lower levels of pulmonary function. The likelihood of bronchial hyperresponsiveness increased with increasing age but was unrelated to the dust-exposure concentration. RAST elevation was unrelated to employment duration or dust exposure and was not associated with an increased prevalence of symptoms or lower levels of pulmonary function independent of bronchial hyperresponsiveness. We conclude that plicatic acid-specific IgE and nonspecific bronchial hyperresponsiveness are associated in western red-cedar workers and that this association may reflect a causal connection.

Tuberculosis in Canadian Eskimos

The tuberculosis rates among Canadian Eskimos are among the highest in the world, in the period 1967 to 1969, the average annual incidence was 131 cases per 10,000 while the corresponding rate for all Canadians was just over 2 per 10,000. The rates are highest in eastern Arctic where the peak incidence occurs in young women and reaches almost 4% per annum. The risk of developing tuberculosis is very high in all epidemiological groups such as inactive cases, positive tuberculin reactors with normal chest x-ray film, and even BCG-vaccinated individuals.

Ten year evaluation of a trial of cremoprophylaxis against tuberculosis in Frobisher Bay, Canada

A trial of chemoprophylaxis to prevent tuberculosis in Canadian Inuit (Eskimos) was carried out in Frobisher Bay, Canada during 1971-1974. A completely supervised regimen of isoniazid and ethambutol thrice weekly for 18 months was administered. A 10-year evaluation of 370 treated persons and 217 control subjects demonstrates the sustained value of adequate chemoprophylaxis in reducing the risk of developing active tuberculosis in the 3 groups under study--1, those with a previous episode of active tuberculosis, 2, positive tuberculin reactors with normal chest X-ray and 3, BCG vaccinated individuals with large tuberculin reactions. There were 3 cases of active disease in the treated group, a risk of 0.1% per annum, and 13 cases among the controls, a risk of 1.0% per annum.