Insulin levels determine effect of weight loss on vascular function

Researchers have discovered that obese people who have lost considerable weight are more likely to have better blood vessel function if they show high levels of insulin following weight loss.

The study, published in the Journal of the American College of Cardiology, was conducted by researchers from Boston University School of Medicine (BUSM) and Boston Medical Center (BMC).

According to the American Heart Association, there are around 78 million obese adults in the US alone. Although obesity can cause numerous health concerns, cardiovascular-related issues, such as ischemic heart disease and stroke, are the leading cause of death from the weight condition.

Obese or overweight individuals who undergo various weight-loss strategies improve their cardiovascular functions, but previous studies have suggested that plasma insulin levels may determine the extent to which cardiovascular benefit can be achieved following weight loss.

To study this further, the researchers followed 208 overweight or obese patients undergoing medical, dietary or bariatric surgical weight-loss treatment over a period of 1 year.

At both the baseline of the study and following weight loss, the patients' plasma metabolic parameters and vascular endothelial functions (state of the inner lining of blood vessels) were measured using ultrasound. Median plasma insulin levels were also recorded.

Results of the study revealed that those who had higher plasma insulin levels who also achieved greater than 10% weight loss showed significant improvements in blood vessel functions.

However, those with lower insulin levels did not show the same level of improvement, even when they lost a similar amount of weight.

Additionally, when the researchers analyzed patients who had a weight loss of up to 5%, only microvascular responses improved in the group with higher insulin levels.

Noyan Gokce, associate professor of medicine at BUSM and director of echocardiography at BMC, says:

"Our study has shown that insulin status is an important determinant of the positive effect of weight reduction on vascular function with hyperinsulinemic patients deriving the greatest benefit.

Reversal of insulin resistance and endothelial dysfunction may represent key therapeutic targets for cardiovascular risk reduction in obesity."

The researchers say this study suggests that a minimum of 10% weight loss is required in order to achieve extensive cardiovascular benefit.

More evidence was presented that obesity may lead to heart disease in a recent study from the National Heart, Lung and Blood Institute, which suggested that those who are obese for 20 years or more have double the risk of hardened coronary arteries.

But researchers from the Department of Epidemiology and Public Health at University College London conducted a study last year suggesting that obese people are not always at higher risk of cardiovascular disease or death, as long as they are metabolically healthy.

Written by Honor Whiteman

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