Risks and causes of Hodgkin lymphoma

Hodgkin lymphoma used to be called Hodgkin disease. It is not very common. About 1,800 cases are diagnosed in the UK each year.

About 1 in every 200 cancers diagnosed is a Hodgkin lymphoma. It is much less common than the other main type of lymphoma (non Hodgkin lymphoma), which is diagnosed in around 12,300 people each year.

We don't know exactly what causes Hodgkin lymphoma but there are some things that may make some people more likely to get it. Research is going on to try to find out exactly what does cause this cancer. What we do know is that, like all cancers, Hodgkin lymphoma is not infectious. You cannot catch it from someone who has it.

There is information below about factors that may increase or decrease risk of Hodgkin lymphoma.

A risk factor is anything that can increase your chance of developing cancer. Do bear in mind that having one or more of these risk factors does not necessarily mean that you will get Hodgkin lymphoma.

Hodgkin lymphoma can occur at any age, although it is rare. It becomes more common in the teens. There is a peak between 15 and 29 years of age. Hodgkin lymphoma is the 3rd most common cancer in this age group. It then becomes less common until older age, when the number of cases increases again. Hodgkin lymphoma is slightly more common in men than in women.

People treated for a previous non Hodgkin lymphoma (NHL) have an increased risk of Hodgkin lymphoma, which may be due to the treatment they had for the NHL.

Anyone whose immune system is not working properly is more likely to develop Hodgkin lymphoma. The immune system fights disease. You may have low immunity if you

• Are taking medicines to stop organ rejection after a transplant
• Have AIDS
• Were born with a rare medical syndrome that affects immunity
• Develop an 'autoimmune' condition, such as rheumatoid arthritis or systemic lupus erythematosus (SLE)

People with HIV or AIDS have a risk of Hodgkin’s lymphoma that is 11 times higher than the general population. People who have had an organ transplant are 4 times more likely to develop Hodgkin's lymphoma than other people in the population.

We don't know whether the increased risk in people with autoimmune disease comes from the drugs people have to take, from the autoimmune conditions themselves, or whether there are common factors that can cause both the autoimmune conditions and Hodgkin's lymphoma.

A few studies show that Hodgkin lymphoma risk is lower in groups of people who are exposed to infections early. If you live in crowded conditions, have brothers and sisters, or go to nursery, you are more likely to pick up common childhood infections early in life rather than later. Researchers think that getting infections early may help us to develop a healthy immune system and this could be what lowers the risk of Hodgkin lymphoma.

Epstein Barr virus is the virus that causes glandular fever (mononucleosis). Glandular fever is not a serious disease, although it can last a long time. People who have had glandular fever have an increased risk of Hodgkin lymphoma afterwards. But more than half of the people with Hodgkin lymphoma show no Epstein Barr virus infection. So the role that Epstein Barr virus plays is not clear. 

Results from a few studies show that people who have the Hepatitis C virus may have an increased risk of Hodgkin’s lymphoma.

First degree relatives of people with Hodgkin lymphoma have an increased risk of getting Hodgkin themselves. A first degree relative is a parent, child, sister or brother. A study published in 2005 also showed that first degree relatives of people with non Hodgkin lymphoma or chronic lymphocytic leukaemia have an increased risk of Hodgkin lymphoma. But we don't know whether this is due to an inherited gene change or whether it is due to shared lifestyle factors. 

An identical twin of a diagnosed Hodgkin lymphoma patient is nearly 100 times more likely to develop it than other people in the population. As the risk of Hodgkin lymphoma is very small, this big increase in risk is still quite a small risk. For non identical twins, there is no more risk than for any other close relative. Identical twins have the same genes and non identical twins do not. So this tells scientists that there is likely to be a faulty gene increasing the risk of developing Hodgkin lymphoma. This isn't likely to be a major factor because there is no family history in most people diagnosed. In America, research has shown that Hodgkin lymphoma is more common in white people than it is in black people. It is also more common in people of Jewish ethnicity. This is another piece of evidence that tells us a gene may be involved.

There is evidence of an increased risk of Hodgkin lymphoma in first degree relatives of people with ulcerative colitis and sarcoidosis. We need more research to find out why this is the case.

A study combining all the results of earlier research found a lower risk of Hodgkin lymphoma in children who had been breastfed, but we don't really know why this occurs or how important this is.

Several studies over the years have looked into hair dyes and risk of lymphomas. One paper combined all the results of earlier studies and found no link between hair dye use and risk of Hodgkin lymphoma. Since then, another study has looked into hair dye use in several European countries. These researchers said they could see an increased risk if they combined results for all countries they looked at except Germany. This may be just a blip, or there may be some other explanation we don't have yet. Realistically, it seems that there is only likely to be a very small link, if there is one at all.

A recent study reported that people exposed to pesticides in their work may have an increased risk of Hodgkin lymphoma. We need more research though before we know whether this is true. Another study has shown an increased risk of Hodgkin lymphoma in people who use some types of solvents in their workplace.

A few studies show a lower risk of Hodgkin lymphoma in alcohol drinkers. A study published in 2007 showed a lower risk in drinkers, but not in drinkers who smoked.

Several studies, including the large European study called EPIC (European Prospective Investigation into Cancer and Nutrition), have shown that the risk of Hodgkin lymphoma is doubled in people who currently smoke.

One research study has shown an increased risk of Hodgkin’s lymphoma for men who are very overweight (obese) but women did not have an increased risk.