Occupational Medicine

OCCUPATIONAL AND ENVIRONMENTAL AIRBORNE EXPOSURES

Brief Description

This program focuses on studies of cardiopulmonary responses to occupational and environmental airborne exposures, and is carried out by a multidisciplinary team of biomedical researchers, epidemiologists, toxicologists, occupational hygienists, chemists and atmospheric scientists. The environmental research arm features a unique (to Canada) human exposure facility that concentrates urban ambient particulate matter and adds gaseous outdoor pollutants.  Studies have tested for cardiovascular and upper and lower airway responses, including nasal washing, sputum and blood cytology and inflammatory markers, airway responsiveness, pulmonary function, heart rate variability and vascular function. Studies have included both healthy adults and susceptible populations (adult asthmatics, healthy and asthmatic children, COPD patients), and are aimed at understanding biological processes that may explain the epidemiological associations between pollutant levels and cardiopulmonary morbidity/mortality.

The occupational research is focussed on epidemiologic studies of groups of workers exposed to respiratory sensitizers or irritants, with subsequent characterization of responses in representative subgroups to assess mechanisms of response (including markers in induced sputum and physiologic responses during workplace exposures and controlled challenges).  Risk factors are identified and intervention studies developed. Studies have included diisocyanate-exposed workers, health care workers with natural rubber latex exposure, medical radiation technologists, physiotherapists and sawmill workers. Barriers to diagnosis of occupational respiratory disease (asthma, lung cancer) are being explored.

Principal Investigators

Recent Original Research Publications

Brook RD, Brook JR, Urch B, Vincent R, Rajagopalan S, Silverman F. Inhalation of fine particulate air pollution and ozone causes acute arterial vasoconstriction in health adults. Circulation 105:1534-1536, 2002.

Liss GM, Tarlo SM, McCaskell L, Greene J, Doherty J. Physician diagnosed asthma, respiratory symptoms and associations with workplace tasks among radiographers in Ontario, Canada.  Occup Env Med 60:254-261, 2003.

Petrovic S, Urch B, Brook J, Datema J, Purdham J, Liu L, Lukic Z, Zimmerman B, Tofler G, Downer E, Corey P, Tarlo S, Broder I, Dales R, Silverman F. Cardiorespiratory effects of concentrated ambient PM2.5: a pilot study using controlled human exposures. Inhal Toxicol 12(Supplement 1):173-188, 2000.

Tarlo SM, Liss G, Yeung KS. Changes in rates and severity of occupational claims for asthma due to diisocyanates: a possible effect of medical surveillance measures. Occup Env Med 59:58-62, 2002.

Tarlo SM, Broder I, Corey P, Chan-Yeung M, Ferguson A, Becker A, Rogers C, Okada M, Manfreda J. The role of symptomatic colds in asthma exacerbations: influence of outdoor allergens and air pollutants. J Allergy Clin Immunol 108:52-58, 2001.

Future Directions

The program will develop a focus on research at the cellular and molecular level. The occupational studies will be expanded to: 1) identify groups of workers at increased risk of developing asthma; 2) further collaborations with University of Cincinnati and other centers to explore genetic markers of occupational asthma; and 3) study effective health service delivery for occupational respiratory diseases.

The air pollution studies will be expanded to: 1) patient groups at increased risk of manifesting effects; and 2) further collaborations with, University of British Columbia, McMaster, University of Alberta, Harvard, Health Canada, and Environment Canada, to incorporate techniques to better assess systemic bone marrow responses, cardiac electrophysiology, and air pollutants as adjuvants to systemic and pulmonary allergic responses.