Parental hyperdynamic circulation predicts insulin resistance in offspring- The Tecumseh Offspring Study

Controversy surrounds the pathogenetic mechanisms of the relationship betwe en hyperdynamic circulation and insulin resistance. Two hundred eight child ren and young adults (mean age, 17.2+/-3.0 years; range, 11 to 26 years) fr om the Tecumseh Offspring Study whose parents had been assessed with Dopple r echocardiography at the age of 34 years during the previous Tecumseh Bloo d Pressure Study were considered for this analysis. Offspring data were str atified according to tertiles of parental cardiac index. Parents in the top cardiac index tertile had increased heart rate (P=0.001), stroke volume (P = 0.0001), left ventricular fractional shortening (P = 0.02), and plasma e pinephrine (P=0.02) compared with parents in the other tertiles. Body mass index (BMI) and blood pressure were similar in all groups. Offspring of par ents with a high cardiac index had greater BMI (P=0.001), skinfold thicknes s (P=0.008), and waist/hip ratio (P=0.02), higher diastolic blood pressure (P=0.02) and plasma insulin level (P=0.001), and higher heart rate during S troop's color test (P=0.02) than offspring of parents with a lower cardiac index. In a multivariate regression analysis, offspring BMI was predicted b y parental BMI and cardiac index (P = 0.0001 and 0.003, respectively). The mother-child relationship explained most of the cardiac index-BMI associati on. In summary, parental hyperdynamic circulation was an important predicto r of overweight, abnormal fat distribution, increased blood pressure, and h yperinsulinemia in offspring. Our results illustrate the complexity of inte raction between a genetic tendency and its phenotypic expression. We specul ate that the degree of beta-adrenergic responsiveness may be a major determ inant of the phenotypic differences between the parents and offspring found in this study.