Older adults who take aspirin regularly may be reducing their chance of developing colorectal cancer by 20 percent, according to research published in the journal JAMA Oncology.

But there’s a catch, of sorts: The risk reduction appeared to apply only to those who started taking a daily aspirin dose at a younger age, generally in their 50s or 60s, and thus had taken aspirin regularly for five or more years before turning 70.

The researchers reported that people who waited until their 70s to start taking aspirin reaped no reduction in risk for colorectal cancer.

The findings came from pooled analysis of two large studies, involving 94,540 participants who were tracked for about three decades. For the study, regular use was defined as taking aspirin, either low-dose (81 milligrams) or standard-dose (325 mg), two or more times a week.

Although daily aspirin is often taken for possible cardiovascular benefits, research over the years also has linked the medication to benefits related to various cancers – including those affecting the prostate, breast, lung and stomach – as well as colorectal cancer. Some health experts believe the potential benefits stem from aspirin’s ability to fight inflammation.

Aspirin also helps keep blood clots from forming, but it comes with risks, too. Regular use can irritate the gastrointestinal lining, cause stomach ulcers and lead to internal bleeding. Don’t start taking aspirin regularly without first conferring with your doctor.