Does Higher BMI Increase Risk of Heart Attack, Death?

Higher body mass index (BMI) may not increase the risk of myocardial infarction (MI) or death but may be associated with diabetes onset, according to a study of identical twins from Sweden.

Although previous studies have found that obesity is a major risk factor for cardiovascular disease and death, it is still unclear how genetic confounding affects the risk.
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To further investigate the genetic factor, the researchers recruited 4046 monozygotic (MZ) twin pairs who differed in BMI and were listed in the nationwide Swedish twin registry from March 17, 1998, to January 16, 2003.

The researchers tracked deaths, MI events, and incident diabetes and compared the results of the heavier twin with his or her lighter twin sibling.

After a mean 12.4-year follow-up, the researchers found that MI or death risk was not higher among the heavier twins—even those with a BMI of 30 kg/m² or more. However, heavier twins were at a higher risk of type 2 diabetes than their lighter twin counterparts.

Among the heavier twins (having a mean BMI of 25.9 kg/m²), 203 had had an MI and 550 had died, and 209 MI events and 633 deaths were recorded among the lighter twins (having a mean BMI of 23.9 kg/m²).

“In [monozygotic] twin pairs, higher BMI was not associated with an increased risk of MI or death but was associated with the onset of diabetes,” the researchers concluded. “These results may suggest that lifestyle interventions to reduce obesity are more effective in decreasing the risk of diabetes than the risk of cardiovascular disease or death.”

—Amanda Balbi

Reference:

Nordström P, Pedersen NL, Gustafson Y, Michaëlsson K, Nordström A. Risks of myocardial infarction, death, and diabetes in identical twin pairs with different body mass indexes [published online August 1, 2016]. doi:10.1001/jamainternmed.2016.4104.