Asthma and occupation in the 1958 birth cohort.

OBJECTIVE: To examine the association of adult onset asthma with lifetime exposure to occupations and occupational exposures. METHODS: We generated lifetime occupational histories for 9488 members of the British 1958 birth cohort up to age 42 years. Blind to asthma status, jobs were coded to the International Standard Classification of Occupations 1988 and an Asthma Specific Job Exposure Matrix (ASJEM) with an expert re-evaluation step. Associations of jobs and ASJEM exposures with adult onset asthma were assessed in logistic regression models adjusting for sex, smoking, social class at birth and childhood hay fever. RESULTS: Of the 7406 cohort members with no asthma or wheezy bronchitis in childhood, 639 (9%) reported asthma by age 42 years. Adult onset asthma was associated with 18 occupations, many previously identified as risks for asthma (eg, farmers: OR 4.26, 95% CI 2.06 to 8.80; hairdressers: OR 1.88, 95% CI 1.24 to 2.85; printing workers: OR 3.04, 95% CI 1.49 to 6.18). Four were cleaning occupations and a further three occupations were likely to use cleaning agents. Adult onset asthma was associated with five of the 18 high-risk specific ASJEM exposures (flour exposure: OR 2.12, 95% CI 1.17 to 3.85; enzyme exposure: OR 2.32, 95% CI 1.22 to 4.42; cleaning/disinfecting products: OR 1.67, 95% CI 1.26 to 2.22; metal and metal fumes: OR 1.45, 95% CI 1.02 to 2.07; textile production: OR 1.71, 95% CI 1.12 to 2.61). Approximately 16% (95% CI 3.8% to 27.1%) of adult onset asthma was associated with known asthmagenic occupational exposures. CONCLUSIONS: This study suggests that about 16% of adult onset asthma in British adults born in the late 1950s could be due to occupational exposures, mainly recognised high-risk exposures.

Are we failing workers with symptoms suggestive of occupational asthma?

AIMS: To assess the route to secondary care for patients with possible occupational asthma, and to document the duration of workrelated symptoms and referral times. METHODS: Consecutive patients with suspected occupational asthma were recruited to a case series from six secondary care clinics with an interest in occupational asthma. Semi-structured interviews were performed and hospital case notes were reviewed to summarise relevant investigations and diagnosis. RESULTS: 97 patients were recruited, with a mean age of 44.2 years (range 24-64), 51 of whom (53%) had occupational asthma confirmed as a diagnosis. Most (96%) had consulted their general practitioner (GP) at least once with work-related respiratory symptoms, although these had been present for a mean of 44.6 months (range 0-320 months) on presentation to secondary care. Patients experienced a mean delay for assessment in secondary care of 4 years (range 1-27 years) following presentation in primary care. CONCLUSIONS: Significant diagnostic delay currently occurs for patients with occupational asthma in the UK.