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BMI in male teens predicts cardiomyopathy risk



Male teens who were even slightly overweight were at significantly greater risk than their lean peers of developing cardiomyopathy in adulthood, and their risk increased as body mass index increased, according to the results of a nationwide, prospective, registry-based cohort study from Sweden.

The association was strongest for dilated cardiomyopathy, wrote Josefina Robertson, MD, and associates at the University of Gothenburg (Sweden). Over a median of 27 years of follow-up, the risk for dilated cardiomyopathy in adulthood was approximately 38% greater when adolescent body mass index was 22.5-25.0 kg/m2, using a lean but not underweight BMI (18.5-20.0 kg/m2) as the reference group. The increase in risk for dilated cardiomyopathy continued to rise with adolescent BMI and exceeded 700% at a BMI over 35.

The rate of hospitalizations for heart failure caused by cardiomyopathy more than doubled in Sweden from 1987 to 2006, the researchers noted. Adolescent obesity is strongly linked to early heart failure, but few studies have assessed whether adiposity as measured by BMI is associated with cardiomyopathy, and none have confirmed diagnostic validity or looked at subtypes of cardiomyopathy.

“The already marked importance of weight control in youth is further strengthened by [our] findings,” the researchers wrote, “as well as greater evidence for obesity as a potential important cause of adverse cardiac remodeling independent of clinically evident ischemic heart disease.”

The study included 1,668,893 male adolescents who had enlisted for military service in Sweden between 1969 and 2005, when compulsory enlistment ended. It excluded women and the small proportion of men lacking weight or height data. A total of 4,477 cases of cardiomyopathy were diagnosed during follow-up, 59% were dilated cardiomyopathy, 15% were hypertrophic cardiomyopathy, and 11% were alcohol or drug-related cardiomyopathy.

The link between even slightly elevated BMI and dilated cardiomyopathy did not depend on age, year, location, or baseline comorbidities. For each unit increase in BMI, the adjusted risk of dilated cardiomyopathy rose by approximately 15%, the risk of hypertrophic cardiomyopathy rose by 9%, and the risk for drug- or alcohol-related cardiomyopathy rose by 10%. Estimated risks were generally similar after controlling for blood pressure, cardiorespiratory fitness, muscle strength, parents’ level of education, and alcohol or substance use disorders.

Funders included the Swedish government; Swedish Research Council; Swedish Heart and Lung Foundation; and Swedish Council for Health, Working Life, and Welfare. The researchers reported having no conflicts of interest.

SOURCE: Robertson J et al. Circulation. 2019 May 20.

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