Aspirin has a protective effect that is apparent after just one year and is effective in the general population, researchers from Western General Hospital, Edinburgh, found.
The researchers assessed 2,279 people with bowel cancer, matched against 2,907 controls.
Participants completed dietary and lifestyle questionnaires, and gave information on use of NSAIDs. Intake was categorised as taking more than four tablets a month of low dose aspirin (75mg), other NSAIDs, or a mix.
Researchers then tracked participants for five years to assess impact of NSAID use on risk of developing bowel cancer and likelihood of survival.
They found low-dose aspirin use was associated with a 22 per cent reduced relative risk of lower colorectal cancer.
High doses of aspirin or other NSAIDs were not required for protection against bowel cancer, the authors concluded.
'This effect is apparent as early as one year but increases with time up to 10 years,' they said. 'Our results are applicable to the general population and not just high-risk groups.'