THURSDAY, April 6, 2023 (HealthDay News) -- It’s well known that being overweight or obese can increase health risks.

But a new study finds that the reasons why a person is obese may have some impact on heart disease risk.

Specifically, being obese because of lifestyle carried higher risks than it did if the extra weight was due to genetic predisposition, researchers found.

“The link between obesity and cardiovascular disease was twice as strong in those with a genetic predisposition to a low BMI as it was in those with obesity driven by genetic factors,” said study author Ida Karlsson, an assistant professor at the Department of Medical Epidemiology and Biostatistics at the Karolinska Institute in Solna, Sweden.

To study this, her team used data from more than 15,000 twins from the Swedish Twin Registry. Information included their BMI and their genetic predisposition for high BMI. The researchers also used data from medical registries to establish the incidence of heart disease in this group.

Karlsson stressed that a healthy lifestyle is always important for everyone. The risk of heart disease was still higher in all people who were overweight or obese compared to people with a healthy weight.

“Obesity is a complex common disease that can have many different causes,” Karlsson said in an institute news release. “Since it’s so stigmatized, the results can help us understand that its effects on health differ from one individual to the next.

“Even though we all know that it takes more than exercise and diet to combat obesity, there’s still a large stigma attached to it," she added. "I think much could be gained by focusing on what has caused the obesity and what we can do to reduce the risk of comorbidities in each individual instead of mainly focusing on BMI."

Researchers noted that nearly one-third of the world’s population is now overweight or obese.

“The figure is alarming since it is well established that a high BMI in middle age increases the risk of developing cardiovascular [heart] disease and other conditions,” Karlsson said.

She and her colleagues plan to research how people who are overweight or obese because of genetic factors or lifestyle factors differ in regards to blood sugar levels, cholesterol and inflammation markers.

The findings were published April 6 in the journal eClinicalMedicine.

More information

The U.S. Centers for Disease Control and Prevention has more on the health impacts of obesity.

SOURCE: Karolinska Institute, news release, April 6, 2023