Inflammation and micronutrient status of children and adolescents in 12 countries are only weakly associated: the BRINDA Project.

BACKGROUND: Inflammation may bias estimation of burden of certain micronutrient deficiencies; however, few studies have examined the magnitude and direction of this bias in school-age children and adolescents. OBJECTIVES: Associations between biomarkers of inflammation [C-reactive protein (CRP) and α-1-acid-glycoprotein (AGP)] and multiple micronutrient biomarkers [serum folate (SFO), red blood cell folate (RBC folate), serum vitamin B12, serum 25(OH)D, and serum zinc] were examined in children 5-19y. METHODS: This analysis included 13 cross-sectional surveys of children (n=46,363) from 12 countries with ≥1 micronutrient biomarker of interest, CRP or AGP, and n > 100 per survey. Spearman rank correlations between each micronutrient and inflammation biomarker were calculated by survey. To examine the dose-response relationship between inflammation and micronutrient levels, geometric means of each micronutrient biomarker were plotted across deciles of AGP and CRP, stratified by age groups (5-9, 10-14, and 15-19y), and overall (5-19y). RESULTS: Prevalence of inflammation (CRP >5 mg/L or AGP >1 g/L) ranged from 2.7-29.6% by survey with medians ranging from 0.5-0.8 g/L for AGP and 0.2-1.9 mg/L for CRP. The prevalence of micronutrient deficiencies ranged from 0.1-87.7% for SFO, 0.1-24.4% for RBC folate, 0.5-54.8% for vitamin B12, 4.6-25.6% for serum 25(OH)D, and 0.6-57.3% for zinc, with median values from 4.2-45.5 nmol/L for SFO, 452.1-1000.0 nmol/L for RBC folate, 131-442 pmol/L for vitamin B12, 43.2-60.0 nmol/L for serum 25(OH)D, and 59.4-92.9 μg/dL for zinc. Associations between micronutrient biomarkers and AGP or CRP were weak (most absolute r < 0.2) with no clear pattern across positive, negative, and null associations. Geometric means of micronutrient biomarkers did not show clear patterns of association with CRP or AGP deciles, overall or stratified by sex or age group. CONCLUSIONS: With weak and inconsistent correlations between inflammation and select micronutrient biomarkers, these findings do not support the routine adjustment for inflammation when estimating folate, vitamin B12, vitamin D, or zinc deficiencies in children 5-19y.