Influence of Race on the Effect of Premature Birth on Salivary Cortisol Response to Stress in Adolescents

OBJECTIVES: To compare pre- and post-stress salivary cortisol levels in adolescents born preterm to those born term, and to assess the influence of race and sex on this relationship. METHODS: We measured salivary cortisol before and 20 minutes after a maximal-exercise stress test and calculated the cortisol stress response. We used linear regression to compare cortisol stress responses between preterm-term groups, adjusting for birth weight z-score and maternal hypertension, and examined effect modification by race and sex. RESULTS: We evaluated 171 adolescents born preterm with very low birth weight and 50 born term. Adolescents born preterm had reduced cortisol stress response compared to term (0.03 vs. 0.08 μg/dL, p=0.04). This difference was race-dependent; non-Black adolescents born preterm had significantly reduced cortisol stress response compared to those born at term (adjusted β: −0.74; 95% CI −1.34,−0.15) while there was no difference in Black adolescents (0.53; −0.16,1.22). Sex did not modify the relationship. CONCLUSIONS: Adolescents born preterm exhibit a reduced salivary cortisol response to exercise stress, suggesting long term alterations in the hypothalamic-pituitary-adrenal axis. This relationship was evident in non-Black but not Black adolescents, suggesting that race may modify the influence of preterm birth on stress alterations of the hypothalamic-pituitary-adrenal axis.