Occupational Asthma in Chemical, Pharmaceutical and Plastics Processors and Manufacturers in the United Kingdom, 1989–1990

Of 1118 cases of occupational asthma reported to the SWORD project, 1989–1990, 121 were attributed to work exposure in chemical, pharmaceutical and plastics industries; 47% of cases were ascribed to isocyanates. More detailed information was obtained in 105 (87%) of the cases; 94 were confirmed, almost all by a work-related history, supplemented in half by spirometry and/or immunological tests. Using data from the 1989 Labour Force Survey and 1988 General Household Survey, risks of disease by time since first exposure and by smoking habit were estimated. Compared with persons employed 5 or more years, the relative risk of asthma was 5.7 in the first and 1.6 in the second 3 months of employment. After standardization for age, sex, country of residence and socioeconomic group there was no evidence that asthma occurred more frequently in smokers than nonsmokers (RR = 0.88; 95% CI = 0.63–1.22).