6-n-Propylthiouracil sensitivity and obesity status among ethnically diverse children.

OBJECTIVE To examine the relationship of 6-n-propylthiouracil (PROP) sensitivity to BMI while statistically controlling for demographic characteristics in two age groups of children: 9-10 years and 17-18 years (n 1551). DESIGN Cross-sectional design with a multi-ethnic (White, African-American, Hispanic, Other) sample of 813 children aged 9-10 years and 738 children aged 17-18 years. Children were recruited from local elementary and high schools with at least 30 % minority ethnic enrolment. Children's height, weight and waist circumference were measured along with their PROP taster status. PROP was measured using two paper discs, one impregnated with NaCl (1.0 mol/l) and the other with PROP solution (0.50 mmol/l). RESULTS A significant PROP sensitivity by socio-economic status (SES) interaction term (P = 0.010) was detected wherein supertasters had the largest BMI percentile and Z-score, but only among the group with highest SES. CONCLUSIONS The results suggest that other factors overwhelmed the influence of PROP sensitivity on adiposity in lower-SES groups. The percentage of variance accounted for by the interaction term was about 1 %. Thus, PROP supertasters had the largest BMI percentile and Z-score, but only among the highest-SES group.