A European study suggests that people with a large waist are almost twice more prone to premature death notwithstanding they were overweight or not, compared to their same-weight peers without a belly fat.

Researchers from Imperial College London, the German Institute of Human Nutrition, and other research institutions tracked 359,387 individuals ages 25 to 70 from 9 countries on the European continent.

At first, researchers calculated participants’ BMI (body-mass index), the standard formula for measuring weight. They found that people with a higher BMI had an increased risk of dying during the 10-year follow-up, compared to normal-weight people.

Afterward, participants’ waist circumference and waist-to-hip ratio alone were observed. Researchers noticed that between those two factors and a higher risk of mortality was a strong connection. A 2-inch boost in waist circumference increased mortality risk by 17 percent in men and 13 percent in women, irrespective of BMI. The bond was found strongest in people with a healthy weight, in contrast with the heavier participants.

"I was surprised that even people who would be considered normal weight in terms of their BMI have a higher risk of death if their waist circumference is increased," said slead author Tobias Pischon, a member of the department of epidemiology at the German Institute of Human Nutrition (DIfE).

The findings, which appeared on 13 November in the New England Journal of Medicine, also revealed that participants with a high BMI were more likely to die due to cardiovascular diseases and cancer, while those with a low BMI were more likely to die due to respiratory diseases.