Submitted to: Obesity Research
Publication Type: Abstract Only
Publication Acceptance Date: 8/18/2004
Publication Date: 10/1/2004
Citation: Bastarrachea, R., Tejero, M., Cai, G., Cole, S., Mehta, N., Ellis, K.J., Butte, N.F., Comuzzie, A. 2004. Pleiotropy effects on endocrine traits and body composition in children. Obesity Research. S12(10):A194. Interpretive Summary: Not required for an abstract.
Technical Abstract: The prevalence of obesity and its related metabolic conditions has increased significantly among children and adolescents. Given the central role of thyroid hormones, insulin and leptin in the regulation of energy metabolism, we investigated the genetic factors influencing this group of traits in children. Hispanic families with at least one overweight child between the ages of 4 to 19 years were studied in the “Viva La Familia” project. A blood sample was collected under fasting conditions for analyses of circulating levels of thyroid hormones, insulin and leptin using reference methods. Anthropometric measurements and body composition data by DEXA were collected. Quantitative genetic analyses were conducted using SOLAR. Significant heritabilities were observed for body mass index z-score (BMIZ) (h2 = 0.34, p = 0.0001), free fat mass (FFM) h2 = 0.34, p<0.0001), levels of free T3 (h2 = 0.54, p <0.0001, total T3 (h2 = 0.42, (p <0.0001), free T4 (h2 = 0.75, p <0.0001), total T4 (h2 = 0.52, p < 0.0001), insulin (h2 = 0.17, p= 0.01) and leptin (h2= 0.35, p <0.0001). Significant genetic correlations were observed between insulin and total T3 (r=0.28, p=0.01), leptin and free T3 (r = -0.37, p=0.028), leptin and total T3 (r=0.28, p=0.008), and total T4 and FFM (r= -0.4, p= 0.002). Significant genetic correlations were observed among some measures of thyroid hormones such as levels of total T3 and T4 (r=0.36, p=0.02, free T3 and total T4 (r=0.29, p=0.04). These results suggest the presence of a significant genetic component controlling variation in these traits. The genetic correlations indicate that a common set of genes is influencing phenotypes associated with body composition, thyroid hormones, insulin and leptin levels.