The anti-bowel cancer benefits of aspirin reported by some previous studies may only affect people with a slight variation in their genetic make-up, according to US research.
The researchers studied 973 people over three years as part of the Aspirin/Folate Polyp Prevention Study.
Some participants were given aspirin and some were given placebos. Almost half of the participants carried one or two variant copies of a gene called ODC.
The study found that there was no link between carrying the genetic variation and the occurrence of bowel polyps - the precursor of bowel cancer.
But their genetic make-up did influence the effect of aspirin on polyp development. Participants with the ODC genetic variation who were given aspirin were 23 per cent less likely to develop new polyps and 49 per cent less likely to develop more advanced lesions, which lead to cancer.
"There is evidence that aspirin and related anti-inflammatory drugs can reduce the risk of colorectal adenomas [polyps] and cancer," said researcher Dr Elizabeth Barry.
"With this study, we looked closer at the impact of aspirin in people who have a higher risk of developing colorectal adenomas, which lead to cancer, by examining their ODC genotype.
"Aspirin appears to work better in people who have this slight genetic variation, and this finding could potentially be clinically useful in the future."
The study was conducted by the Dartmouth Medical School alongside others, and is published in the Journal of the National Cancer Institute
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