World / Science & Health

Obesity raises heart attack risk


Obesity raises the chance of a heart attack regardless of whether a person has the cluster of cardiovascular risk factors known as metabolic syndrome, according to a study that challenges previous beliefs.

Metabolic syndrome, a condition that includes high blood pressure, high cholesterol and high blood sugar, accounts for about 12 percent to 26 percent of the risk of heart attack and heart disease due to being overweight and obese, researchers found. The rest of the increased risk is mostly due to a person’s body mass index, said Borge Nordestgaard, senior author of the study in JAMA Internal Medicine.

The findings counter previous assumptions that as long as a person didn’t have the risk factors of metabolic syndrome then being overweight was generally inconsequential to cardiovascular health. The latest study suggests that a person’s weight may provide a clearer picture of their heart health than other cardiovascular risk factors, the authors said.

“It is being overweight and obesity that are the real causes of heart attack and disease,” Nordestgaard, chief physician at Copenhagen University Hospital and the University of Copenhagen in Denmark, said in an email. “Thus, you don’t need to examine for metabolic syndrome to tell whether a person is at increased risk of heart attack. Just looking at them or measuring their body mass index is sufficient.”

About 78 million U.S. adults are considered obese. The majority — more than 50 million — are non-Hispanic white, according to an October report from the National Center for Health Statistics, part of the U.S. Centers of Disease Control and Prevention. Obesity raises the risk of heart disease, diabetes, some cancers, osteoarthritis, sleep apnea and stroke, the CDC has said.

Obesity is measured using body mass index, or BMI, a calculation of weight and height. For example, a 163-cm woman weighing 79 kg has a BMI of 30. A BMI of 30 or more is considered obese while a BMI of 25 to 29.9 is considered overweight, according to the National Institutes of Health.

Researchers examined data from 71,527 people in a general population study. They found that metabolic syndrome was present in 10 percent of normal-weight people, 40 percent of overweight people and 62 percent of those who were obese, according to the paper. Those who were overweight had a 38 percent higher risk of having a heart attack and a 25 percent increased risk of having heart disease than someone who was normal weight. Those who were obese had more than double the risk of heart attack and a 64 percent increased risk of heart disease than someone who was normal weight, Nordestgaard said.

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