Poster Topical Area: Community and Public Health Nutrition
Poster Board Number: 80
Objectives: Zinc supplementation has been shown to reduce the morbidity burden which in turn may reduce chronic stress. Hair cortisol has been promoted as an indicator of chronic stress by capturing systemic long-term cortisol exposure. We assessed the impact of different strategies for delivering supplementary zinc on hair cortisol concentrations (HCC) in young Laotian children.
Methods: In a randomized, double-blind, controlled trial, children aged 6-23 mo were randomized to one of four intervention groups and followed for ~36 weeks: daily preventive zinc (PZ) tablets (7 mg/d), daily multiple micronutrient powder (MNP) sachets (containing 10 mg zinc and 14 other micronutrients), therapeutic zinc (TZ) supplements for diarrhea treatment (20 mg/d for 10 days with each episode) or daily placebo powder (Control). In a randomly selected sub-group of 512 children, hair samples were collected at baseline and endline and HCC were assessed by high-sensitivity enzyme immunoassay. While blinded, we prepared a statistical analysis plan which established our approach to minimally adjusted models and covariate adjusted models. Linear regression models were used to assess group differences in HCC and un-blinded only after the analysis approach and adjustment covariates were finalized.
Results: At enrollment, mean age was 15.6 ± 5.0 mo and mean HCC was 28.8 ± 43.9 pg/mg [median (IQR) = 21.7 (13.8-35.1) pg/mg]. Endline mean HCC was 19.1 ± 15.2 pg/mg [median (IQR) = 15.9 (9.6-24.4) pg/mg]. In models adjusted for age at enrollment, health district, and baseline value of HCC there was no overall effect of the interventions on endline HCC and change in HCC. However, when controlling for additional predetermined covariates, there was a marginal effect on change in HCC (p=0.078) with a higher reduction of HCC in PZ group compared to TZ group (delta (CI) =-4.34 (-8.71, 0.03) pg/mg; p=0.053).
Conclusions: In this population of young Laotian children, MNP, PZ and TZ had no impact on HCC. The marginal difference between PZ and TZ groups after covariate adjustment was too small to be considered of health significance.
Funding Source: The Bill & Melinda Gates Foundation
The Micronutrient Initiative
The Mathile Institute for the Advancement of Human Nutrition
Postdoctoral Research Fellow
University of California Davis