Weight-loss surgery could prevent thousands of people in the UK suffering serious health conditions such as heart attacks and Type 2 diabetes, a study has shown.
Scientists compared rates of obesity-associated illnesses in 3,882 bariatric surgery patients and patients who had not undergone the procedures, which include by-passing the stomach or reducing its size.
They found that over a period of three and a half years, weight-loss surgery significantly improved existing Type 2 diabetes and lowered abnormally high blood pressure.
Applying the findings to the 1.4 million people believed to be morbidly obese in the UK, bariatric surgery could prevent 80,000 cases of high blood pressure, 40,000 cases of Type 2 diabetes and 5,000 heart attacks over four years, said the researchers.
A further 110,000 people with diabetes and 13,000 people with high blood pressure would also see significant benefits.
Bariatric surgery is reserved for people who are very obese and is available on the NHS when other options including lifestyle changes have not been successful.
Lead scientist Dr Ian Douglas, from the London School of Hygiene & Tropical Medicine, said: "Obesity is one of the biggest health problems of our generation. Rates of cardiovascular disease, although slowly declining, are still alarmingly high while Type 2 diabetes is on the rise, affecting 3.5 million people in Britain. Finding effective ways to tackle the obesity crisis is therefore a key public health strategy.
"Whilst effective prevention is clearly needed, our findings show that as well as helping patients substantially lose weight, bariatric surgery improves serious obesity-related illnesses as well as reducing the risk of developing them.
"People having weight-loss surgery were 70% less likely to have a heart attack, and those with Type 2 diabetes were nine times more likely to see major improvements in their diabetes. We also found positive effects on angina and the debilitating condition obstructive sleep apnoea."
The study, published in the journal Public Library of Science Medicine, found that gastric bypass was the most effective form of bariatric surgery, leading to an estimated average weight loss of 38 kilograms (six stone) over four years.
Co-author Professor Rachel Batterham, from University College London, said: "Bariatric surgery is safe and produces unrivalled health benefits that are life-changing for patients and cost-saving for the NHS. Unfortunately, less than 1% of the patients who could benefit from this surgery currently receive surgery. This represents a major missed opportunity in terms of improving health and economic savings. Action is now needed to remedy this situation."