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A response to media reports on the link between teenage obesity and the chances of developing lymphoma

The Bloodwise logo. Bloodwise appears in black text against a white background
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22 Feb 2016

Some media outlets have reported on a study that claims being tall or overweight during adolescence can increase chances of developing non-Hodgkin lymphoma later in life. It is important to put these findings in context.

Some media outlets have reported on a study that claims being tall or overweight during adolescence can increase chances of developing non-Hodgkin lymphoma later in life. It is important to put these findings in context.

The stories originate from a paper published in the journal Cancer. Researchers from the Sheba Medical Center in Israel examined medical records from nearly 2.4 million teenagers over a 40 year time period. 

Key findings from the study were that overweight teenagers had a 25% increase in risk of developing non-Hodgkin lymphoma. Statistically, shorter than average teenagers had a 25% reduced risk of developing lymphoma, while the tallest teenagers were 28% more likely than those of average height to get the blood cancer sometime in their lifetime.  

Taller people or those who were obese as teenagers should not be unduly worried by these findings. The increase in risk of developing non-Hodgkin lymphoma may be ‘significant’ in a statistical sense but in real terms, the increased risk for individuals is very small. 

A person’s overall risk of developing non-Hodgkin lymphoma in their lifetime is thankfully low, at around 1 in 50 (around 4 in 200). Comparatively, according to the researchers’ findings, obese teenagers and the tallest teenagers have a 1.25 in 50 and 1.28 in 50 risk respectively (around 5 in 200) of developing the disease.

One of the study’s authors is quoted as saying that the research shows that, “it is important to be aware that overweight and obesity are not risk factors only for diabetes and cardiovascular disease but also for lymphomas.” Putting the tiny increased overall risk in developing lymphoma in the same class as diabetes and heart disease, which have proven links to obesity, is overstating the significance of the findings. 

As the researchers themselves admit, the reason why overweight or taller teenagers may have a slight increased risk of developing non-Hodgkin lymphoma is unknown. They have only established that there are correlations between height and weight and the chances of developing lymphoma, not necessarily direct causations. There may well be other factors involved.