Documentation: Asbestos causes Cancer among Construction Workers

By Lars Vedsmand

It has through many years been documented again and again that asbestos causes serious and lethal diseases. First it was asbestosis. Later when the dust concentrations were reduced, the people exposed to asbestos lived for a longer time, enabling different types of cancer to get ”time” to develop. Asbestos can cause cancer in the larynx, the lungs, and in the mesotheliomas of the stomach and lungs. Mesothelioma was in the 1980’es in the UK called “The kiss of death”. There are no other known causes than asbestos for this dreary and almost 100% lethal type of cancer. It is very rare in Denmark – but when it occurs it will in most cases be possible to find that the patient has been exposed to asbestos, occupationally or by other means.

New report shows allocation of cancer

The Branch Sector Council for H&S in Construction has together with other Sector Councils have made a more thorough report about occurrence of different types of cancer. The report has been prepared by the Danish National Cancer Registry. In a later article we will get back to the main conclusions from the entire report on the professions in Construction, but here we will look a little further into the relations between asbestos and different types of cancer.

The report contains data about the following professions within building and construction:

The report contains a long description of method and treatment of data as well as the reservations one always has to make in relation to possible causes of cancer. Even if one profession has an excess of cancer it is not necessarily connected to occupational causes. You should also be aware that for most types of cancer many years pass from exposure to outbreak of the disease. For the possible asbestos-caused cancer types there may have passed up till 35-40 years. So the cancer diseases seen in the recent years may be caused by working conditions many years ago. It has been possible within the data to see, whether exposure has increased or decreased over the years, when inspecting some more precise data of relative risk. The report covers cancer cases reported to the National Cancer Registry in the period 1970 til 2003.

Many professions in Construction have an increased relative risk as a possible cause of exposure to asbestos

From results of the report this table shows which professions having a statistical significant increased relative risk and adjusted relative risk for the types of cancer, known to be caused by asbestos exposure:

The report makes some notes about the single professions:

Carpenters and joiners The relative risk seem to increase during the years 1970 to 2003 – a tendency apparently connected to the extraordinary long latency period from asbestos exposure to the diagnose of lung mesothelioma. For the partial group of men having their first employment in the branch before the age of 25 the risk of lung mesothelioma is almost 5-fold increased.

Plumbers and sanitary workers The relative risk for lung mesothelioma increases with duration of employment in the branch and duration of employment, which normally is a substantiate indication that the disease is occupational. There is a tendency that the adjusted RR for lung mesothelioma is greater the earlier you have had your first employment in the branch. This indicates that there has been an asbestos exposure before 1965, which has decreased later on. Still it is seen that the risk is high after 1985 but this result is based on only 3 cases and thus subject to uncertainty.

Insulation workers For lung mesothelioma there is fairly the same high relative risk (7-9 fold) for men being employed at least 2 years in the branch. The risk appears also to be fairly equal high no matter what periods of calendar-years and groups of birth year are watched. The vast majority of cases with lung mesothelioma (14 out of 24 %) are seen among men who had their first employment in the branch before 1965, which corresponds a 28-fold increased risk.

Electricians The risk of developing lung mesothelioma is greatest if the first year of employment is before 1965. This relative risk decreases if the first year of employment is in the period 1970-84, while there has not yet been registered cases with persons with first employment after 1985. This also indicates that earlier there has been a very big asbestos problem, while the exposure later on decreases.

General Contractors For lung mesothelioma it is seen that the risk dosen not increase remarkably by duration of employment – still the risk is a little increased by 2 to 5 years of employment tha by ½-2 years of employment. There is a trend that the relative risk increases the later the male employees are born. In this group employees born after 1944 seem to have more than 2-fold double the risk. Furthermore there is a trend that among those born later that the younger the men are at first employment at general contractors the higher the risk of developing lung mesothelioma later in life.

For the mentioned professions the prevalence of possibly asbestos related cancer types is statistically significant, which means that the resulting figures are within certain safety limits and thus are not coincident. More other professions have a tendency of increased risk for the asbestos related types of cancer, but where as it is not significant:

• Sewer contractors

• Brick-layers

• Glaziers

• Flooring- and terrazzo

• Scaffolding

It is now more than 20 years ago asbestos was banned in Denmark – and 35 years since it was banned for insulation purposes. There are still being reported an increasing numbers of cases to the National Compensation Board. So even if theoretically provided that nobody in any way would be exposed to asbestos any longer, the long latency period merely would mean that such diseases would still be reported in year 2040. Thus there is absolutely all reasons to make a survey and registration of asbestos and a political work for removing of the lethal asbestos – under completely controlled conditions.

This is a translation of an article in the magazine of the Danish Confederations of Construction workers’ Unions, the BAT-Cartel, by Lars Vedsmand