Obesity and Left Ventricular Function in American Indian Adolescents: Strong Heart Family Study

Obesity is a known risk factor for developing cardiovascular disease (CVD). American Indian (AI) children have the highest obesity rates of all racial/ethnic groups in the United States (US). However, cardiometabolic health among AI adolescents is understudied. The purpose of this study was to describe the cardiometabolic characteristics of AI adolescents enrolled in the Strong Heart Family Study (SHFS), a longitudinal study of CVD from 12 AI communities, and associations with the development of abnormal left ventricular mass index (LVMI) and ejection fraction (EF).

This study included AI youth ages 14-22 years. Primary outcome variables were depressed EF (< 55%) and abnormal LVMI at 6-year follow-up. The primary predictor variable was BMI. Covariates included sex, cholesterol levels, blood pressure, and hemoglobin A1c. Wilcoxon signed-rank test for matched pairs evaluated cardiometabolic trends over time. Stratified univariate logistic regression by obese/nonobese categories evaluated associations with depressed EF and abnormal LVMI.

There were 384 subjects, 58% of whom were overweight (n = 87) or obese (n = 122) at baseline. Among overweight/obese subjects, cholesterol and triglyceride levels were elevated. At 6-year follow-up, BMI increased while EF decreased among overweight/obese males, with 3.6 times the odds of having depressed EF (95% CI 1.22-10.98, p = 0.021) compared to normal-weight males. There were no significant cardiometabolic associations with LVMI.

This is one of the largest longitudinal evaluations of CVD in AI adolescents. Concerning trends in BMI and depressed EF among AI males suggest the importance of culturally competent interventions to promote healthy weight and reduce cardiometabolic risk.