Ethnicity and children's cardiovascular responses to stress: Examining the roles of psychosocial and behavioral factors

Cardiovascular reactivity (CVR) has been identified as a potential mediator of the relationship between ethnicity and cardiovascular disease. Studies examining the relationship between ethnicity and children's CVR have not included Latino children and have not systematically examined the roles of psychosocial and behavioral factors. The major objectives of the present study were to examine ethnic differences in children's CVR and recovery from laboratory stressors and to examine the potential mediating and moderating roles of 2 psychosocial (stress and depression) and 2 behavioral factors (dietary fat intake and physical activity) on the relationship between ethnicity and CVR. One hundred seventy-three children (mean age 10.2 +/- .9 years; 61 African Americans, 56 Latinos, 56 non-Latino Whites) completed self-report questionnaires and participated in a laboratory protocol consisting of a video game, an interview, and a handgrip task. Heart rate (HR) and blood pressure [systolic (SBP) and diastolic (DBP)] were assessed at rest and during and following the stressors. African American children exhibited greater HR, SBP, and DBP reactivity to the video game and greater SBP and DBP reactivity to the handgrip task than non-Latino White children. Latino children's CVR scores (HR, SBP, and DBP) were between those of the African American and non-Latino White children on each task. For recovery, African American children exhibited slower SBP recovery from the video game and the handgrip task than non-Latino White children. Latino children exhibited slower SBP recovery to the video game and slower HR recovery to the interview compared to non-Latino White children and slower HR recovery to the handgrip task compared to African American children. Mediator analyses indicated that frequency of stressful life events partially mediated the relationship between ethnicity and overall SBP reactivity (mean of SBP reactivity to 3 tasks). Moderator analyses indicated that ethnic differences in overall SBP and DBP reactivity were more pronounced at higher levels of physical activity than at lower levels. The results extend previous research by providing preliminary evidence that ethnic differences in CVR parallel ethnic differences in the prevalence of hypertension. The findings also suggest that psychosocial and behavioral factors play a role in ethnic differences in CVR.