Growth retardation is associated with changes in the stress response system and behavior in school-aged Jamaican children

Abstract

In the developing world, 39% of children <5 y old are short for their age (stunted, defined as height-for-age less than -2 SD of National Center for Health Statistics references), and many have poor levels of mental development along with behavioral problems. We showed previously that 8- to 10-y-old children from a longitudinal cohort who experienced early childhood stunting had altered hypothalamic-pituitary-adrenocortical (HPA) and sympathetic-adrenomedullary (SAM) system activity. We repeated the study with 31 newly recruited, stunted Jamaican school children (less than -2.0 SD height-for-age) and nonstunted controls (n = 31, more than -1.0 SD height-for-age) matched for sex, age and school. All children were tested in a 1.5-h session, including psychological and physiologic stressors, in which their behaviors, salivary cortisol concentrations and heart rates were measured. In addition, we measured urinary catecholamine (epinephrine, norepinephrine, dopamine) concentrations, which were not reported for the children in the longitudinal cohort. After controlling for covariates that differed between groups (child intelligence quotient, body mass index and birth weight), stunted children had faster resting heart rates while lying and sitting (P < 0.05) and also during psychological testing (P < 0.05), as well as higher concentrations of urinary epinephrine (P < 0.05) and norepinephrine (P < 0.05), compared with nonstunted children. In addition, the stunted children were less happy (P < 0.01), more inhibited (P < 0.01) and more frustrated (P < 0.05) during the psychological tests than nonstunted children. These results suggest that growth retardation is associated with alterations in stress-sensitive systems, particularly the SAM system, and that this connection may contribute to the poor levels of development observed in stunted children.