Trends in pneumoconiosis and other lung diseases, as reported to a UK-based surveillance scheme for work-related ill-health

Abstract

The changing nature of industries associated with exposure to hazardous dusts in manufacture or in use, as well as better control methods, might be expected to be associated with a reduction in incidence of pneumoconiosis and other lung diseases. Data collected by the University of Manchester's ODIN/THOR network on work-related ill-health in the UK (as diagnosed by specialist physicians) can be used to estimate time trends in the lung diseases reported to the surveillance schemes. Reporters of work-related lung diseases in THOR (previously ODIN) mainly comprise two groups, namely clinical specialists in respiratory medicine and occupational physicians. These reporters return information on work-related cases of ill-health using postal reporting cards or an on-line web form. 'Report cards' are returned even if no new cases are seen, with responses recorded each month i.e. whether a card is returned and number of cases returned. Probabilities of a non response and, for returned cards, of a 'zero' return were modelled as a function of calendar time and/or membership time using 2-level logistic models. Annual change in disease incidence (all work-related respiratory disease and specific diagnoses) was estimated using 2-level Poisson models controlling for reporter characteristics, season, and whether or not a first report. The impact of membership time on reporting was also investigated. Case reports include information on patient demographics, diagnoses, industry, occupation, and suspected agents/exposures. These case details are coded and analysed using SPSS. Annual change in incidence of all work-related respiratory disease reported by specialist chest physicians (1999-2006) was -1.7% (95% CI: -3.1%, -0.2%). Specific diagnoses reported by chest physicians showed that the annual change in incidence for asthma was -3.1% (95% CI: -5.8%, -0.4%), for mesothelioma was -4.1% (95% CI: -6.7%, -1.5%), for benign pleural plaques was +1.1 (95% CI; -1.0%, +3.2%), and for pneumoconiosis was -2.6 (95% CI: -6.6, +1.5) over the same time period. Occupational physicians' reporting showed a change in incidence of -6.1% (95% CI: -11.6%, -0.4%) for all respiratory disease, and -8.4% (95% CI: -15.3%, -0.9%) for asthma. Given variation between reporter groups, and according to model assumptions, time trends from surveillance data need to be interpreted with caution, but may have some place in planning interventions aimed at improving the health of a workforce. Further work to investigate case details (such as suspected agent/exposures) should also add to this knowledge base.