Bowel cancer is influenced by a variety of genetic and lifestyle factors and frequent consumers of processed meat were already known to be at a greater risk of developing the disease.
In order to find out how common genetic variants might influence bowel cancer risk, scientists pooled data from ten diet studies involving around 9,000 colorectal cancer patients and a similar number of controls.
They scanned the data, looking for any effects of 2.7 million common variants on bowel cancer risk and detected a significant interaction between the variant 'rs4143094' and processed meat consumption.
Compared with people whose diet included little or no processed meat, the heaviest consumers were more than twice as likely to develop bowel cancer if they carried the 'worst' version of the variant.
Bowel cancer is the fourth most common form of cancer in the UK. Figures from Cancer Research UK show that in 2010 there were 65 new cases of bowel cancer for every 100,000 people.
'Diet is a modifiable risk factor for colorectal cancer', said the study's first author Dr Jane Figueiredo of the University of Southern California. 'Our study is the first to understand whether some individuals are at higher or lower risk based on their genomic profile. This information can help us better understand the biology and maybe in the future lead to targeted prevention strategies'.
The researchers think that the variant's proximity to GATA3 might explain its influence on bowel cancer risk. In the paper they say that 'a plausible though speculative biological basis for our findings is that processed meat triggers a [cancer-inducing] inflammatory or immunological response'.
The study was published in the journal PLOS Genetics.