Weight-loss surgery may help reduce urinary incontinence in extremely obese people, a study suggests.

Researchers followed nearly 2,500 obese men and women who had so-called bariatric surgery, which alters the stomach or intestines to induce weight loss.

Before the surgery, nearly half the women and about a fifth of the men had experienced urinary incontinence. A year later, the rate of incontinence was down to about 18 percent in women and 10 percent in men.

Non-surgical weight loss may also curb incontinence. But surgery might be recommended for people who are more than 100 pounds heavier than their ideal body weight or who have weight-related medical problems like diabetes, particularly if they haven’t been able to achieve a healthy weight by dieting.

Better urinary control can result from decreased pressure on the bladder and pelvic floor, improvements in other risk factors such as diabetes or inflammation, or from lifestyle changes, said lead study author Dr. Leslee Subak, a urogynecologist at the University of California, San Francisco.

“Obesity is a strong risk factor for incontinence,” Subak said by email. “Improvement in incontinence is one of many benefits of bariatric surgery.”

Subak and colleagues studied 2,458 obese patients getting bariatric surgery to see whether incontinence went into remission after the operation, meaning it occurred less than weekly.  More than three-fourths of the participants were women, and half were at least 47 years old.

About 80 percent of the patients, or 1,987 people, completed follow-up assessments.

Before the surgery, about 49 percent of women reported urinary incontinence.  After one year, the women on average lost about 30 percent of their body weight, and only about 18 percent of them reported being incontinent. At the three-year mark, the rate of incontinence had climbed back up slightly, to around 25 percent.

At the start, nearly 22 percent of the men reported problems with incontinence. The men had lost an average of 27 percent of their body weight after one year, when about 10 percent of them reported being incontinent. By three years, roughly 12 percent of them were incontinent.

Because the study only included people who got bariatric surgery, rather than comparing a surgical and non-surgical group, it can’t prove that the procedure causes a reduction in incontinence, the researchers acknowledge in JAMA Internal Medicine. Patients may have also under- or over-estimated the frequency of bladder difficulties when they reported this to researchers.

It’s possible that participants fared better after one year than after three years because they regained some of the weight they initially lost, Dr. Deborah Myers, a professor of obstetrics and gynecology at Brown University and author of an editorial accompanying the study, said by email.

Because frequent urinary incontinence can significantly worsen quality of life, addressing this problem might help motivate some obese patients who are good candidates for bariatric surgery to consider this option, said Dr. Holly Richter, a urogynecologist at the University of Alabama at Birmingham.

As with any major surgery, bariatric operations pose potential serious health risks, both short-term and long-term, and patients should discuss those with their doctors if they’re considering the procedures.

Overall, however, bariatric surgery “has significant effects on improving overall health and the conditions of diabetes, heart disease, osteoarthritis, hyperlipidemia and sleep apnea,” Richter, who wasn’t involved in the study, said by email. “Weight loss is a proven treatment for urinary incontinence.”