A health study was conducted in three communities in the greater Montreal region; the first two were characterized by relatively high particulate and sulfur dioxide levels, respectively, and a third community without major industrial pollution. In each community, 300 men and women 45 to 64 yr of age were studied. Residents of the two more polluted communities exhibited a higher prevalence of respiratory symptoms and mean lung function evaluated by various tests was lower than in residents of the less polluted community. When intercity differences in age and smoking were accounted for, no statistically significant intercity differences in health status could be shown. Given the limitations of this study, the results provide no evidence to suggest that current Canadian standards for sulfur dioxide adequately protect human health as measured by the indices used in the study, for adults in the age range of 45 to 64 yr.
There is a relationship between dust exposure, on the one hand, and serious disease and death, on the other, in chrysotile asbestos mine and mill workers of Quebec. Studies in current working populations indicate that prevalence of abnormality increases with increasing exposure. However, the relationship is weak and offers only a partial explanation of between-subject variability. In addition, there is no certain way to detect or predict change. Because of the relative nonspecificity of the health measurements examined and their poor relationship to exposure, control should be based on environmental monitoring, with biologic monitoring considered in a complementary role. This leaves the clinician with the dilemma of how best to advise the worker in whom questionable changes have been detected. At present, there appears little doubt that the decision must remain essentially clinical, based, on one hand, on all available information about the man, his job, and the plant or mine in which he works, from which an estimate of likely outcome must be made, and, on the other hand, on the social and human factors concerned, including the fact that removal from exposure does not necessarily prevent the appearance of abnormality.
The evidence of an association between passive smoking and occurrence of respiratory symptoms is relatively strong in children, whereas studies conducted in adult populations have provided inconsistent results. The objective of the present study was to examine the relations between exposure to environmental tobacco smoke (ETS) and development of respiratory symptoms in young adults during a study period of 8 years, with emphasis on the evaluation of potential dose-response pattern of the relations. The study population consisted of 117 "never smokers," who were 15 to 40 years of age at the time of initial examination, when they answered a standardized questionnaire on respiratory health, and who were reexamined 8 years later. ETS exposure at home and at work during the study period was recorded at the 8-year examination with a structured questionnaire. The symptoms studied as outcomes included wheezing, dyspnea, cough, and phlegm production. The relations between ETS exposure and development of respiratory symptoms were studied in multivariate logistic regression models controlling for age, gender, atopy, and the presence of other respiratory symptoms. Cumulative incidences of the respiratory symptoms, except of phlegm production, were consistently greater among subjects exposed to ETS compared with the reference group. A significant dose-related increase in the risk of developing dyspnea was observed in relation to ETS exposure, with an OR of 2.37 for an average exposure of 10 cigarettes/day (95% confidence interval, 1.25-4.51). The risk of developing other respiratory symptoms, apart from phlegm, was also related to ETS exposure, but these relations did not achieve statistical significance. The results provide evidence of adverse respiratory effects of ETS exposure in the home and office work environments in young adults. These findings emphasize the need for effective measures in the prevention of involuntary smoking during young adulthood.
As an approach to evaluating the public health burden from current air pollution levels, we examined the relationship of daily emergency room (ER) visits for respiratory illnesses (25 hospitals, average 98 visits/d) to air pollution in Montreal, Canada, from June through September, 1992 and 1993. Air pollutants measured included ozone (O3), particulate matter diameter PM10 > SO4. Ozone and PM10 levels never exceeded 67 ppb and 51 microg/m3, respectively (well below the U.S. National Ambient Air Quality Standards of 120 ppb and 150 microg/m3, respectively). The present findings have public health implications with regard to the adverse health effects of urban photochemical air pollution on older individuals.
Population-based studies of hospital usage have been used to identify the ongoing adverse impacts of photochemical air pollutants on respiratory health. In this study we examined the relationship between the number of daily emergency room (ER) visits for respiratory illnesses (25 hospitals) and outdoor air pollution in Montreal, Quebec (June-August, 1989-1990). Air pollutants measured included 1- and 8-h maximum ozone (O3) and estimated particulate matter
The standard approach to government-mandated aerometric monitoring of airborne particulates across North America is to sample every sixth day year round. However, such data are inadequate for epidemiological studies which aim to examine daily time series relationships of particulate air pollution to respiratory health responses. The aim of the present study was to estimate missing daily particulate matter
In 1974 changes in dyspnea, lung function, and pneumoconiotic radiographic abnormalities were recorded among the 1,015 Quebec chrysotile miners and millers surveyed in 1967-1968. The aim was to relate these changes to dust exposure--age, smoking, and earlier health status being taken into account. Dyspnea and lung function were assessed in 722 men, and for 277 recent radiographs were read separately by three experts for changes in the parenchyma and pleura. Each measure was analyzed independently for men without any abnormality when first seen (eligible for "attack") and for others (eligible for progression/regression). Age significantly influenced the rate of attack of pleural abnormality and the rates of attack and progression of dyspnea and lung function decline. Smoking had comparatively minor effects. The only associations with exposure were for progression of parenchymal change (one reader), and for progression of dyspnea. These essentially negative findings are similar to those obtained in a previous longitudinal survey of radiographs from the same workforce.