Around 2,500 annual deaths from mesothelioma cancer are expected in the UK until 2020 before numbers may begin to decline, according to latest Health and Safety Executive figures, July 2016. (Mesothelioma Mortality in Great Britain, HSE 1968-2014).

However, separate research – ‘Projection of Mesothelioma Mortality in Great Britain’, (Tan and Warren, 2009) – suggests that the projections may be under-estimated. While a total of 44,131 male fatalities were recorded, rising every year from 114 in 1968 to 2,123 in 2013, the number of deaths between 1968 and 2025 could actually reach more than 2,800 every year.

Biggest cause of occupational deaths

Despite of overwhelming medical evidence and growing asbestos awareness of exposure by the middle of the 21st century, mesothelioma – the incurable cancer of the lung linings – looks set to eventually claim the lives of 61,500 males or a total of 91,000 (1968-2050). While mesothelioma accounts for just one per cent of all cancers diagnosed, the figures point to asbestos as the biggest cause of occupational deaths in UK history.

The shocking conclusion drawn from the revised forecast is that, in the 21st century, Britain’s legacy of industrial asbestos use in the 20th century – especially through the 1950s, 60s and 70s – is far from over. Yet, the two most toxic asbestos fibres – blue ‘crocidolite’ asbestos – was actually last imported into the UK in 1970 and brown ‘amosite’ asbestos, in 1983, just prior to the first UK ban in 1985. White ‘chrysotile’ asbestos continued to be imported until at least 1998 before finally being banned at the end of 1999.

The reasons for the continuing loss of life to asbestos-related disease decades after the decline in use and the halt in imports are often cited as being due to the length of time taken for the disease to potentially develop. There can be between 15 and 50 years or more before asbestosis symptoms emerge and a diagnosis confirmed. However, more recent analysis of patient data reveal further factors, which appear to be playing an increasing part in maintaining the high numbers of mesothelioma victims.

Further factors maintaining the high numbers of mesothelioma victims

Studies indicate that there has been a gradual shift in the age group of those who lose their life to the fatal cancer. Between 1968 and 1972, nearly all of the deaths (90%) occurred to patients below the age of 74. However, between 2009 and 2013, the proportion of those who died who were above that age had risen to 50 per cent.

Researchers offer several reasons. Firstly, the previously high incidence of asbestos-induced diseases early in life has reduced, i.e. males in their teens starting apprenticeships in asbestos using industries. Secondly,  a larger proportion of exposure victims have survived long enough to go on to develop mesothelioma, with its exceptionally long period where it appears to lay dormant. As the widespread, industrial use of asbestos declined, it is assumed that the severity of exposure also reduced while the use of antibiotics increased.

In addition, clinical analysis show that the severity of exposure to asbestos is related to the length of time the disease remains dormant. It appears that those who experienced only low levels of exposure to asbestos would have longer periods of dormancy and would therefore, develop mesothelioma only if they survive into their 70s or older.

It is also possible that ‘environmental’ levels of exposure could have started earlier in life than ‘occupational’ exposures, such as in the home and/or in school, where a proportion of an increased period of dormancy could be offset by earlier exposures.

Doubling of mesothelioma risk

As a rough guide, for each 10 year reduction in age for a first exposure below the age of 30 there is a doubling of the mesothelioma risk. Each 10 year increase in life expectancy beyond the age of 80 also doubles the mesothelioma risk. Those children first exposed at age 10 and surviving to age 90 would have an eight times greater risk of developing mesothelioma than 30-year-old adults who were equally exposed with a 50 year life expectancy.

Figures released by the Office of National Statistic (ONS, 2015) indicate that between 1968 and 2013, the number of males aged between 50 and 70 increased by about 25 per cent and will increase by about a further 20-35 per cent by 2050.

Mesothelioma deaths will continue to rise sharply

Between 2012 and 2050 the numbers of males in the higher age bands are predicted to increase progressively from a factor of about 2 for those aged 70-74 to a factor of about 30 for those aged 90 and above. Analysts suggest that given that men aged over 70 accounted for 72 per cent of male mesothelioma deaths in 2013, the predicted increase in the number of men above that age over the next four decades indicates that the number of mesothelioma deaths will continue to rise sharply throughout the same period.

It is calculated that male mesothelioma deaths will jump from about 11,000 between 2014 and 2019 to around 30,000 between 2045 and 2049. It is also estimated that total male mesothelioma deaths will reach 130,000 between 2014 and 2049, and will total about 180,000 between 1969 and 2049,or twice previous projections.