In making New Year's resolutions, many healthy adults might consider quitting one small daily habit: aspirin.

A review of recent studies suggests aspirin might do more harm than good as a preventive health measure for adults with no symptoms of heart disease. Investigators in the UK looked at 27 studies published between 2008 and 2012, including nine randomized clinical trials. For years, doctors have recommended aspirin for its ability to disrupt arterial clotting following the buildup of fatty deposits.

"There is a plethora of evidence in this area, but nobody has drawn together the advantages and disadvantages of aspirin in a systematic way," investigator Paul Sutcliffe, of the University of Warwick, told Reuters. "We need to be extremely careful about promoting the daily use without fully understanding all the evidence.”

But Sutcliffe also stopped short of discouraging the practice. “All I would say is to not stop taking aspirin without talking to your doctor," he said.

In the review, Sutcliffe and his colleagues linked the aspirin regimen to 33 to 46 fewer deaths from any cause per 10,000 people during a 10-year period. However, aspirin also causes unwanted side effects in some. During that same period, the drug was linked to 46 to 49 major bleeds and 68 to 117 gastrointestinal bleeds. Thus, the study population using aspirin experienced a 37 percent increased risk of stomach bleeding and a 38 percent increased risk of hemorrhagic stroke.

The investigators concluded that “the absolute harms exceed the benefits” when aspirin is used as a primary prevention of cardiovascular disease. Moreover, they found that evidence supporting a preventive cancer benefit relied on possibly faulty methods: selective retrospective re-analysis of randomized controlled trials.

However, some medical scientists advised caution in response to the review. Peter Rothwell, a clinical neurologist at the University of Oxford, told Reuters the study failed to impress him. "The study is just another meta-analysis of published overall trial results and contains no new data," he said. "The question of the balance of risk and benefit of aspirin is important, but superficial meta-analyses of very limited published data are not, unfortunately, able to cast any useful light."

Still other doctors took the new review as a chance to criticize the aspirin regimen, including Peter Sandercock, of the University of Edinburgh. "Too many healthy people think that aspirin will prevent heart attacks and cancer," he said. "This shows that if you are healthy, with no symptoms of cardiovascular disease, then it's not sensible to take regular aspirin. It won't improve your health.”

Source: Sutcliffe P, Connock M, Gurung T, et al. Aspirin In Primary Prevention Of Cardiovascular Disease And Cancer: A Systematic Review Of The Balance Of Evidence From Reviews Of Randomized Trials. PLoS One. 2013.