Many people who are severely obese and have difficulty achieving permanent weight loss through diet and exercise, eventually turn to bariatric surgery.

Few large-scale, long-term studies have investigated the longevity of weight loss after surgery, and whether the incidence of obesity-linked diseases such as type II diabetes, hypertension, heart attack, and sleep apnea is reduced.

Researchers at the London School of Hygiene and Tropical Medicine set out to answer these questions. They identified 3,882 patients, who underwent one of three types of bariatric surgery, from a large UK database that hosts anonymous clinical information submitted by primary care physicians. They then compared the data from these patients with that of comparably obese patients who had not had the surgery.

They found that people who had bariatric surgery lost weight rapidly, at a rate of almost five kilograms per month during the first four months post-surgery, and then lost weight more slowly over the following four years. Those who did not have surgery did not lose weight during that period.

There was greater initial weight loss in patients who underwent gastric bypass and sleeve gastrectomy compared to those who underwent gastric banding, all procedures designed to reduce the size of the section of the stomach that receives food.

Also, patients who had surgery had a lower risk of developing type II diabetes, hypertension, angina, heart attack, and obstructive sleep apnea. In many patients who had type II diabetes and hypertension at the time of surgery, the conditions resolved.

“While avoiding obesity in the first place remains a key aim in public health, bariatric surgery is an intervention that works, and is not used as often here in the UK as elsewhere,” says epidemiologist, Ian Douglas, from London School of Hygiene and Tropical Medicine.

Widening the availability of bariatric surgery could lead to substantial health benefits for many people who are morbidly obese, the researchers conclude.

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