Slimming drugs reduce the risk of cardiovascular events by 20%.

Semaglutide reduces the risk of cardiovascular disease by 20% , and this protective effect is maintained in people without type 2 diabetes and with varying degrees of obesity. This is demonstrated by a study published this Wednesday in the scientific journal Lancet . This active ingredient, marketed as a drug under names such as Ozempic and Wegovy, was initially used to treat patients with type 2 diabetes, but was later shown to facilitate substantial weight loss.

The weight loss achieved thanks to semaglutide was accompanied by improvements in health. Most studies linked the two phenomena; obesity is the gateway to dozens of ailments, so it made sense that eliminating it would close that door. But some scientists speculated that perhaps there was something else going on, some side effect of the drug that had a protective effect. This is precisely what the current study, conducted on a massive database of more than 17,600 patients, aims to address.

“This new analysis seeks to determine whether the cardiovascular benefit is attributable solely to weight loss or if there is something else involved,” explains Juan José Gorgojo , head of the endocrinology and nutrition department at the Alcorcón Foundation University Hospital. “And when they stratify the population by different weight measurements, body mass index [BMI], or waist circumference, they see that everyone benefits.” But not to the same extent. Every five kilos lost, or five centimeters of waist circumference decreased, reduced the risk of cardiovascular events by 4%.

However, weight did not fully explain this protective effect. An estimated 33% of the observed benefit was mediated by waist circumference reduction, leading the authors to conclude that “the cardioprotective effects of semaglutide were independent of baseline adiposity and weight loss and had only a small association with waist circumference, suggesting some mechanisms of benefit beyond adiposity reduction.”

The trial was funded by Novo Nordisk, the manufacturer of Ozempic. Gorgojo, who is not involved in the trial, judges it positively. It's in line with previous scientific evidence, he points out. And it's based on a vast database. This is the SELECT trial, conducted in 2023 on 17,600 patients, the largest and most comprehensive ever conducted on semaglutide. Even then, a 20% reduction in heart attacks, strokes, and deaths was seen, as well as a 19% reduction in total deaths in just three and a half years. The current study is a more specific substudy than the original, taking into account the specific characteristics of each individual.

By using different variables to measure overweight, the study also delves into one of the controversies that has gripped endocrinologists and nutritionists in recent years: the need to review the BMI as a yardstick for measuring obesity. The BMI is calculated by dividing a person's weight in kilograms by the square of their height in meters. This gives us a number that indicates whether the person is overweight or obese. In recent years, many experts have questioned this measurement, which can provide clues but has proven to be ineffective. The BMI does not distinguish between visceral fat and subcutaneous fat, although the former is much worse. It does not even distinguish between fat and muscle. Some experts believe there are more effective ways to measure obesity, such as waist circumference, which can measure intravisceral fat, the more dangerous type.

The newly published analysis now appears to support this idea. There was no linear trend linking weight loss with subsequent risk of cardiovascular events, but there was a clear trend with waist circumference reduction.

“Humans are designed to accumulate fat under the skin,” explains Gorgojo. “But there comes a time when a subcutaneous fat compartment becomes saturated and can't accumulate any more. Then that fat accumulates where it shouldn't.” This is what's called ectopic fat, the accumulation of fat in organs like the liver, heart, pancreas, and muscles. Visceral fat, which accumulates around the waist, is a common cause of ectopic fat. And it can impair the normal function of these organs, increasing the risk of metabolic and cardiovascular diseases like fatty liver disease and insulin resistance.