BMI is calculated by a person’s height and weight, and has been found to be a good predictor of risk for heart disease, high blood pressure, gallstones and certain cancers, according to the National Institutes for Health.
The new study compares health outcomes of identical twins in order to rule out other genetic causes for disease, providing a relatively even view of the effects of high BMI, the researchers said in a press release.
For the study, published in the journal JAMA Internal Medicine, researchers analyzed data on 4,046 monozygotic twin pairs with different BMIs collected between 1998 and 2003 for the national twin registry in Sweden.
Among heavier twins, with an average BMI of 25.9, 5 percent had a heart attack and 13.6 percent died. The numbers were similar among leaner twins, with an average BMI of 23.9; 5.2 percent had heart attacks and 15.6 percent died during the follow-up period. Even among twins with BMI above 30, researchers report the prevalence of heart attack and death stayed the same.
Risk for onset of diabetes was nearly twice as likely for heavier twins, however, and the likelihood that a heavier twin would develop the condition grew depending on the difference in BMI between siblings.
“Higher BMI was not associated with an increased risk of MI [myocardial infarction] or death but was associated with the onset of diabetes,” researchers write in the study. “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.”