Ethnicity, gender, and Type A differences in resting heart rate and blood pressure among young children.

We analyzed results of the Matthews Youth Test for Health for Anglo-American, black, and Mexican-American 5- and 6-year-old children to address three questions: (1) Do these children differ in the prevalence of type A behavior pattern or its component scales? (2) Are blood pressures or heart rates related to ethnicity, gender, or type A behavior pattern? (3) Can possible confounding factors account for observed differences? We identified several differences related to traditional risk factors: (1) Mexican Americans had the lowest systolic blood pressure, (2) girls had higher diastolic blood pressures than boys, and (3) black and Mexican-American boys had lower heart rates. Our analysis also revealed a significant gender-ethnicity interaction. Anglo- and Mexican-American girls had lower impatience-aggression scores than any other group. We detected no interaction effects for competitiveness scores, nor was there any significant relationship between competitiveness and blood pressure. We did find relationships between type A behavior pattern and blood pressure; these relationships were strengthened by use of the impatience-aggression subscale. Use of covariates strengthened observed associations. We conclude that the effects of type A behavior pattern on cardiovascular disease may be mediated by conventional risk factors.