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A new study has shown that teenagers who are obese and overweight may develop left ventricular hypertrophy and impaired performance of the left ventricle. Data from 4549 Native Americans were used, targeting 460 adolescents (245 girls and 215 boys), aged 14 to 20; 27 had hypertension and 10 had diabetes. Within this group, 24.9% had normal weight, 24.6% were overweight, and 48.5% were obese, based on body mass index. Left ventricular enlargement was prevalent in 3.5% of the normal-weight teens, 12.4% of the overweight teens, and 33.5% of the obese teens. The obese teens also were 4 times more likely than the normal-weight teens to have an enlarged left ventricular mass. This increased mass is associated with lower ejection fractions, myocardial contractility, and greater force needed from the left atrium to complete filling of the left ventricle. Also, although overweight and normal-weight teens had similar metabolic profiles, obese teens had many of the markers for metabolic syndrome, prompting researchers to suggest that the growth of the left ventricle may be the result of "neurohormonal effects of clustered metabolic factors." They noted that, because the results pertain to the Native American population, further studies on other populations are needed. The study results appear in the June 6, 2006, issue of the Journal of the American College of Cardiology.
Ms. Farley is a freelance medical writer based in Wakefield, RI.