Smoking and Leukaemia

A relationship between myeloid leukaemia and cigarette smoking in men

Ray Foan takes a look at the risk factors and implications

Recently in our stop smoking clinics concerns between the relationship of smoking and leukaemia have been raised.

Leukaemia, sometimes referred to as blood cancer, is a cancer of unidentified cause. It developes when the bone marrow produces large numbers of abnormal cells. The abnormal cells reduces the space for the normal bone marrow cellsand they are pushed into smaller and smaller areas, which results in fewer normal cells surviving or reproducing.

The particular type of leukaemia that effects smokers and non smokers, subjected to sidestream smoke, is chronic myeloid leukaemia (CML).
CML is rare and effects 500 people each year in the UK. The condition produces an over abundence of of imature white blood cells, known as a blast. Normally white blood cells reproduce themselves in a controlled manner, however with CML the process gets out of control and the cells continue to divide and mature abnormally.

The Ash (Action on Smoking and Health) fact sheet no 4 identifies from a study among 248,000 US veterans that 723 died of leaukaemia during a 16 year follow up. The follow up showed a significant increase in the risk of leukaemia associated with cigarette smoking, together with a dose response relationship between risk and the amount you smoke. High levels of smoking increases the risk.

What is the link and who is at risk?

The link seems to be the amount of benzene and benzo(a)pyrene, which are petrochemical additives added to cigarettes by the manufactures.
Tobacco smoke contains over 4000 chemicals either in the form of particles or gases. Particles include tar, nicotine, benzene and benzo(a)pyrene. Some of these chemicals have marked irritant properties and 60 of them are known or suspected carcinogens (cancer causing substances). The gases include carbon monoxide, ammonia, dimethylnitrosamine, formaldeyhde, hydrogen cyanide and acrolein. Many of the chemicals and gases are more concentrated in sidestream than in mainstream smoke. The Enviromental Protection Agency in the USA classified tobacco smoke as a Class A (known human) carcinogen along with asbestos, arsenic, benzene and radon gas. This indicates that smokers and non smokers, subjected to sidestream smoke, are at risk.

The CANCERBACUP support organisation note that ‘Allthough the cause of chronic myeloid leukaemia is unknown, reasearch is going on all the time to try and find the cause’ They have identified that people who have been exposed to the chemical benzene for a long time have a higher risk of developing chronic myeloid leukaemia.

There are many types of leukaemia and each of them is classified according to the exact cell type affected by the disease. Children are at risk of contracting many forms of leukaemia but rarely effected by chronic myeloid leukaemia. This could also support the causal link between smoking and myeloid leukaemia.

Is your continued use of cigarettes worth the risk?

No.