To investigate relative frequency and features of diisocyanate (ISO) and non-diisocyanate (N-ISO) allowed occupational asthma (OA) claims in Ontario, Canada, during a 5-year period (1998 to 2002).
Records were abstracted from the Ontario Workplace Safety and Insurance Board using methodology similar to our previous investigation that had identified 30 ISO and 30 N-ISO claims/yr during 1980 to 1993.
There were 99 OA claims: 37 ISO (7.4 claims/yr) and 62 N-ISO (12.4 claims/yr). The ISO group had more males (86% vs 69%, p = 0.01), but there were no other significant differences. The commonest professions were spray painters (41%) and production workers (38%) in the ISO group and production workers (49%) and health care workers (8%) in the N-ISO group.
ISO and N-ISO claims declined from the previous period, especially for ISO, perhaps because of effective surveillance programs.