Normal cortisol response to cold pressor test, but lower free thyroxine, after recovery from undernutrition

Abstract

Undernutrition is a stressor with long-term consequences, and the effect of nutritional recovery on cortisol and thyroid hormone status is unknown. To investigate basal thyroid hormones and the cortisol response to a cold pressor test in children recovered from undernutrition, a cross-sectional study was undertaken on children (6-16 years) separated into four groups: control (n 41), stunted (n 31), underweight (n 27) and recovered (n 31). Salivary cortisol was collected over the course of 10 h: upon awakening, before and after an unpleasant and a pleasant stimulus. Cortisol upon awakening was highest in the stunted and lowest in the underweight groups: control = 5.05 (95 % CI 3.71, 6.89) nmol/l, stunted = 6.62 (95 % CI 3.97, 11.02) nmol/l, underweight=2.51 (95 % CI 1.75, 3.63) nmol/l and recovered = 3.46 (95 % CI 2.46, 4.90) nmol/l (P = 0.005). Girls had higher cortisol concentrations upon awakening compared with boys (P=0.021). The undernourished groups showed an elevated cortisol response both to the unpleasant stimulus and at the last measurement (16.00 hours) compared with that of the recovered group: AUC, control= 2.07 (95 % CI 1.69, 2.45) nmol/l x 30 min, stunted = 2.48 (95 % CI 1.91, 3.06) nmol/l x 30 min, underweight=2.52 (95 % CI 2.07, 2.97) nmol/l x 30 min, recovered = 1.68 (95 % CI 1.26, 2.11) nmol/l x 30 min (P= 0.042)

and control= 2.03 (95 % CI 1.75, 2.39) nmol/l x 30 min, stunted = 2.51 (95 % CI 1.97, 3.19) nmol/l x 30 min, underweight=2.61 (95 % CI 2.16, 3.16) nmol/l x 30 min, recovered= 1.70 (95 % CI 1.42, 2.03) nmol/l x 30 min (P= 0.009). Lower free thyroxine (T4) was found in the recovered and stunted groups: control= 1.28 (95 % CI 1.18, 1.39) pmol/l, stunted = 0.98 (95 % CI 0.87, 1.10) pmol/l, underweight = 1.10 (95 % CI 1.01, 1.21) pmol/l and recovered= 0.90 (95 % CI 0.83, 0.99) pmol/l (P < 0.001). Multivariate analysis showed a lower cortisol concentration along 10 h (06.00-16.00 hours) in the recovered compared with the other groups (P = 0.017), and similar concentrations between the recovered and control group. In conclusion, the children with recovery in weight and height had a cortisol stress response similar to control but a lower basal free T4. Longitudinal studies are warranted to determine the extent of these endocrine changes after recovery of undernutrition and in adulthood.