Background: Exposure to natural rubber latex (NRL) has been recognized as a cause of occupational asthma (OA), especially among health care workers (HCWs) associated with use of gloves. Little or no population-based data are available which chart the changes over time in the number of cases of OA as this problem was increasingly recognized and then interventions instituted.
Methods: We obtained the numbers of allowed asthma claims with exposure to latex by year in the province of Ontario, Canada from the Ontario Workplace Safety and Insurance Board; details of the cases from the largest teaching hospital were reviewed. Interventions included: (1) in 1996, the Board recommended in its focus for accommodation of sensitized workers, the reduction of aerosols of latex proteins and that hospital facilities use powder-free, low-protein or nonlatex gloves; and (2) hospitals instituted latex policies and glove changes at various dates. For example, at the largest teaching hospital, interventions included education and voluntary medical surveillance in 1994; substitution of low protein, "powder-free" NRL gloves for non-sterile powdered gloves in 1995; and replacement of powdered sterile NRL gloves by lower protein, "powder-free" NRL gloves in 1997.
Results: Through 1999, there were 60 allowed claims for asthma in Ontario with exposure to latex; of these 49 (82%) were among HCWs. The number of claims among HCWs changed from 0 to 2 per year up to 1990; increased to 7 to 11 per year between 1991-1994; and declined to 3 per year in 1995-1996 and 1 to 2 per year in 1997-1999. Of the ten institutions having two or more OA latex claims, all claims occurred in 1996 or earlier at 8 (80%). At the largest hospital, there were five accepted claims with year of diagnosis in 1993 (1 case), 1994 (3 cases), and 1995 (1 case).
Conclusions: These findings suggest that, despite the effect of increasing recognition, the introduction of gloves with reduced powder and/or protein, as well as other interventions have been associated temporally with declines in the number of cases of latex OA.
Copyright 2001 Wiley-Liss, Inc.