Type A behavior and physiological cardiovascular risk factors in school-age twin children.

The relationship of Type A behavior pattern (TABP) and its components to physiological cardiovascular disease (CVD) risk factors of blood pressure, obesity, and lipids and lipoproteins was examined in 112 pairs of twin children. Blood pressure, triceps skinfold thickness, and fasting venous specimens for lipid profiles were collected during a home visit. Teachers rated children's Type A-B behaviors using the Matthews Youth Test for Health (MYTH) (Matthews & Angulo, 1980). For statistical analyses, one member of each twin pair was assigned to Group I and the co-twin to Group II. In Groups I and II, significant, p less than or equal to .01, negative correlations between the impatience-aggression component of TABP and atherogenic lipids were observed before and after covariate adjustments. Children were classified as MYTH Type A or B on the basis of a median-split. Marginally significant differences (B greater than A) were found between the mean lipid levels of Type A and Type B children. No significant A-B differences in blood pressure or measures of obesity were observed in either group. Multivariate analysis of variance results suggested that lipid profiles in Group I differed significantly, p less than or equal to .02, by Type A-B classification. The results of this study suggest that TABP and its components are not positively associated with physiological risk factors for CVD; and the impatience-aggression component of TABP is associated with lower levels of atherogenic lipids.