The Relationship of Low Birth Weight to Blood Pressure, Cortisol Levels, and Reactivity in African American Adolescents: A Pilot Study

Abstract

Epidemiological studies show a relationship between low birth weight (LBW) and adult cardiovascular disease. Blood pressure and cortisol hyper-responsiveness during physiologic stress may function as biological markers for hypertension. The purpose of this study was to explore the relationship of blood pressure and cortisol levels with induced physiologic stress to LBW. Forty-eight adolescents, 14 to 16 years old, were tested for blood pressure and cortisol levels at rest and in response to a physiological stressor. A history of LBW was obtained. Multivariate repeated measures analysis and chi-square analyses were used to determine the changes in blood pressure and cortisol.Forty-eight African American adolescents, mean age 14.98 years (SD = 0.33), completed the study. Thirteen adolescents (27%) reported LBW. Although not statistically significant, systolic and diastolic pressures were 6 mmHg and 2 mmHg, respectively, higher in the LBW group when compared with the normal birth weight (NBW) group (p = 0.33 and p = 0.21, and 6 (46%) had elevated blood pressures (p = 0.005)). Blood pressure changes, cardiovascular reactivity, elevated blood, or all of these were significantly higher in LBW African American adolescents (p = 0.006). Cardiovascular reactivity was not significant (p = 0.208)). The mean average cortisol levels were (18.8 nmol/dL (SD = 11.0) but comparable (p = 0.72)). The number of LBW adolescents with cortisol reactivity was significantly higher that in the NBW group (p = 0.041). This study adds support to the association of LBW to biological markers of hypertension in childhood.

Vasomotor sympathetic outflow in the muscle metaboreflex in low birth weight young adults

“…Exaggerated neuroendocrine and vasoconstrictive responses have been shown to predict the development of hypertension in adults. 4 Therefore, the exaggerated EPR response, in our study, may function as a marker for the pathophysiologic phases of hypertension.…”

“… 3 Previous studies have also shown that exaggerated vasoconstrictive and neuroendocrine responses are associated with development of hypertension in adults and may function as markers for preclinical or pathophysiologic phases of hypertension. 4 , 5 LBW is associated with an increased sympathetic nerve activity and therefore predisposing LBW individuals to development of hypertension in adulthood. 6 – 8 …”

Blood pressure and the capacity‐load model in 8‐year‐old children fromNepal: Testing the contributions of kidney size and intergenerational effects

“…Another factor contributing to our findings could have been “white coat” effect during the measurement of blood pressure, as the children would not have been familiar with these measurements. Other studies have reported higher vascular reactivity to stressors in adulthood in those born small or after intrauterine growth retardation (Feldt et al, ; McCormick Covelli, ; Painter et al, ). As the physiological toleration of stress may also be considered a component of homeostasis, this could still be considered under the umbrella of a broad capacity‐load model, in which greater nutritional investment in early life promotes multiple components of metabolic capacity.…”