Asbestosis

Summary

• Based on Death certificates where asbestosis is described as being the underlying cause there were 96 deaths due to the disease in 2007.
• There were 380 deaths in total in 2007 where the death certificate mentioned the term "asbestosis", and 66 of these are also included on the mesothelioma register because the death certificate also mentioned the term "mesothelioma".
• Disablement benefit cases for asbestosis have risen erratically since the early 1980s, with the trend increasing strongly from the late 1990s through to the middle of the new millennium. The number of cases for 2008 is 795.

Introduction

Asbestosis is defined as lung fibrosis caused by the inhalation of asbestos fibres. Diagnosis is made on the basis of clinical features, X-ray appearances and a history of heavy asbestos exposure. It is generally recognised that heavy asbestos exposures are required in order to produce clinically significant asbestosis within the lifetime of an individual. Current trends therefore still largely reflect the results of heavy exposures in the past.

Overall scale of disease including trends

The Health and Safety Executive maintains a register of all deaths where death certificates mention asbestosis. These deaths include those where the underlying cause is specifically identified as asbestosis, but also those with other underlying causes but where asbestosis was nevertheless mentioned in the textual description of the cause of death. (The underlying cause of death is defined as the disease or injury that initiated the train of morbid events leading directly to death.) Thus the total number of deaths on the asbestosis register gives an indication of the number of individuals who were suffering from asbestosis when they died. In 2007 there were 380 deaths where the death certificate mentioned asbestosis and of these 96 had asbestos recorded as the underlying cause of death (Table ASIS01).

Interpretation of these figures is complicated by two issues:

1. Cases of asbestosis may sometimes not be recorded as such because they may be mistaken for other types of lung fibrosis or may go undiagnosed.
2. The word "asbestosis" is often mentioned on death certificates along with other asbestos-related diseases - i.e. mesothelioma and/or lung cancer. On some death certificates the wording of the cause of death description suggests that the term has been used incorrectly to indicate the role of asbestos in causing mesothelioma and/or lung cancer, rather than the presence of asbestos-induced lung fibrosis per se. This is particularly the case for mesothelioma, where the phrase "industrial disease of asbestosis" is often used when mesothelioma is given as a cause of death.

Figure 1 (below) illustrates four different categories of asbestosis deaths in 4 bands across the chart. The bottom band shows deaths where the underlying cause of death was specified as asbestosis. The second band shows deaths where asbestosis was not given as the underlying cause but was mentioned in the absence of other asbestos related diseases. Bands 3 and 4 show deaths certificates where asbestos was mentioned with lung cancer and mesothelioma respectively. (NB: a few death certificates mentioning all three diseases are included within band 4).

Table IIDB06 and Figure 1 above show the number of new cases of asbestosis (and other forms of pneumoconiosis) assessed under the Industrial Injuries and Disablement Benefit (IIDB) scheme. The number of cases have increased from 132 in 1978 to 795 in 2008.

Table ASIS02 shows the total number of death certificates mentioning the term asbestosis among males, and equivalent death rates, by age group for the ten three-year time periods during 1978-2007. Death rates for males are also shown in Figure 2. There are large differences in the magnitude of the rates between the different age groups. Death rates at ages below 65 have been reducing since the early 1990s with strongly increasing rates confined to deaths at age 75 and above.

Less than 4% of the total number of deaths in which the death certificate mentioned the term asbestosis were among women. Because of these small numbers, age-specific death rates for women have not been shown.