Moderators of ethnic differences in vasoconstrictive reactivity in youth

Three hundred and forty-one children (170 males and 171 females: 155 whites and 186 blacks) with a mean age of 11.2 years completed laboratory stressors of forehead cold and a video game. Impedance cardiography was used to assess total peripheral resistance indexed by body surface area (TPRI) at rest and during the stressors. Black youths exhibited greater TPRI and mean arterial pressure (MAP) reactivity to both stressors. It was hypothesized that anthropometric, demographic, lifestyle, and psychosocial variables might partially account for ethnicity differences in vasoconstrictive reactivity. Black youths' higher resting MAP and TPRI and greater MAP and TPRI reactivity to forehead cold were accounted for by anthropometric characteristics, physical activity, sedentary behavior (i.e., TV viewing) and family cohesion. The ethnic differences in TPRI and MAP video game reactivity were not accounted for by the various parameters.