Bariatric surgery could reduce the risk of cancer in obese women by 42% but not in obese men, according to a new research published in The Lancet.

Researchers from Sweden’s University of Gothenburg used data from the ongoing Swedish Obese Subjects (SOS) study and compared 2,010 obese patients who had undergone bariatric surgery with 2,037 receiving regular treatment.

About 70% included in the study were women and the trial was conducted for the period between 1987 and 2001.

The study found the overall cancer risk was 33% lesser in the surgery group but had no effect on cancer occurring in men.

The positive effects of bariatric surgery on cancer might be due to factors other than weight loss or reduced energy intake and will need further evaluation, according to researchers.