Health and Safety
Executive / Commission
Statistics
The term "pneumoconiosis" refers to a group of lung diseases caused by the inhalation - and retention in the lungs - of dusts. The most commonly occurring types of pneumoconiosis (apart from asbestosis) are coal workers' pneumoconiosis, arising from the inhalation of coal dust, and silicosis, arising from the inhalation of respirable crystalline silica (RCS). There is a long delay - almost invariably 10 years or more - between exposure and onset of disease and hence most new cases or deaths from pneumoconiosis reflect the working conditions of the past and a majority of cases occur in individuals who have retired.
Two main data sources provide information about annual incident (meaning newly diagnosed) cases of pneumoconiosis in Great Britain: the Department for Work and Pensions (DWP) Industrial Injuries and Disablement Benefit (IIDB) scheme and The Health and Occupation Reporting (THOR) network. The IIDB figures may underestimate incidence of pneumoconiosis since some individuals may not be aware of their entitlement to claim compensation or may not wish to do so. The figures are also subject to large fluctuations from time to time in response to changes to the administration of the compensation system. Incidence may be more substantially underestimated by THOR since the scheme will only include those cases that are serious enough to be seen by a chest consultant, or that occur in individuals with access to occupational physicians.
IIDB pneumoconiosis cases can be readily classified into 3 groups: 1) coal worker’s pneumoconiosis, 2) asbestosis, and 3) silicosis or other unspecified pneumoconiosis (see Table IIDB01). Causal agents other than coal or asbestos are not recorded, but details of the industrial setting in which cases occurred suggest that the majority of the cases in the third group are in fact silicosis. For the THOR statistics, the category “pneumoconiosis” includes all kinds of pneumoconiosis.
In 2007, the number of cases of coal worker’s pneumoconiosis (280) continued to fall compared with previous years, whereas the number of cases of silicosis or other pneumoconiosis (95) increased slightly (see Table IIDB01 and Figure 1). For silicosis and other pneumoconiosis cases, the industries affected are quarrying, foundries and potteries, suggestion that silica is the predominant cause (see Table IIDB06).
Over the last 10 years the annual average estimated number of new cases of pneumoconiosis within the THOR scheme was around 200 per year, with 168 cases reported in 2007 (See Table THORR01 and Figure 1).
Both the IIDB and THOR schemes indicate that most cases of pneumoconiosis occur in men over retirement age (see Table IIDB07 and THORR03). For example, over 70% of non-asbestos pneumoconiosis IIDB cases assessed in 2007 were aged 65 years or more.
Both the IIDB and THOR data sources are likely to substantially underestimate the incidence of silicosis. Silicosis may be necessary cause for silica-related lung cancer and the current burden of lung cancer in GB due to past exposures to silica in construction has recently been estimated to be in excess of 500 deaths per year1 (see RR595, page 63, Figure 9). This figure suggests that the extent of the underestimation of silicosis could be very considerable. The risk estimate for silicosis for those with 15 years exposure to silica at the current WEL reported in the Regulatory Risk Assessment2 (see CD203, page 12, Table 1) also implies a much higher figure than recorded in the available statistics.
Trends in the number of IIDB pneumoconiosis cases are difficult to interpret. Awards are known to have been affected by the introduction of benefit for coal miners with chronic bronchitis and emphysema in September 1993, and the changes to the eligibility criteria for these diseases in 1997. Claimants who fail to meet the criteria for these diseases often receive awards in respect of pneumoconiosis: in both 1994 and 1998 there was a sharp rise in pneumoconiosis claims which tailed off in subsequent years, which can be seen in Figure 1. The substantially higher numbers of cases from 2002 is likely to be due to a publicity campaign by the Department for Work and Pensions inviting people whose claims had been wrongly disallowed between 1994 and 1999 to re-claim, and also a more accurate method of data collection introduced in April 2002. Year on year changes in the estimated annual cases based on the THOR scheme are also difficult to interpret because the figures are affected by changes in the numbers and reporting habits of participating physicians.
Table DC01 and Figure 1 show deaths due to silicosis and other work-related pneumoconiosis (excluding asbestosis). The number of pneumoconiosis deaths is largely determined by changes in the size and employment conditions of the mining industry many years ago. A downward trend in the number of pneumoconiosis deaths other than silicosis or asbestosis is event over the last few years (with 153 such deaths recorded in 2006). There have typically been between 10 and 30 deaths each year recorded as silicosis in the underlying cause in recent years (14 in 2006).
