(P19-011-23) Inflammation Does Not Mediate Relationship Between BMI/BMI-for-Age Z-Score and Retinol or Retinol-Binding Protein in Adult Women or Young Children: An Analysis of 24 Surveys

Objectives: The extent to which inflammation associated with overweight or obesity may influence interpretation of retinol or retinol binding protein (RBP) is uncertain. We examined relationships between weight status, inflammation, and retinol or RBP among non-pregnant women of reproductive age (15-49 years, WRA) and preschool-age children (6-59 months, PSC) with normal weight to overweight or obesity in differing geographic settings.

Methods: Cross-sectional data were separately analyzed from n=13 surveys (WRA) and n=22 surveys (PSC) (24 total surveys) from the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project, excluding observations with underweight, wasting, pregnancy, or malaria. Relationships were assessed between BMI (WRA) or BMI-for-age z-score (BAZ, PSC), inflammatory biomarkers C-reactive protein (CRP) and/or α-1-acid glycoprotein (AGP), and retinol or RBP by linear regression; we also examined potential mediation by CRP and/or AGP in relationships between BMI or BAZ and retinol or RBP with structural equation modeling. Regression and mediation models accounted for complex survey designs and were adjusted for potential confounders.

Results: Among WRA, greater BMI was positively associated with retinol or RBP in 5 of 13 surveys, BMI was positively associated with CRP and/or AGP in 10 of 13 surveys, but associations between biomarkers of inflammation and retinol or RBP were inconsistent. Among PSC, BAZ was not associated with retinol, RBP, CRP, or AGP, but biomarkers of inflammation were consistently negatively associated with retinol or RBP. In 3 of 13 surveys among WRA and 1 of 22 surveys among PSC, inflammation partially mediated the relationship between BMI or BAZ and retinol or RBP; however, the direction of association varied and the percent change in retinol or RBP concentration for every 1-unit increase in BMI/BAZ ranged from -0.2% to 0.8%.

Conclusions: In these surveys, inflammation associated with overweight and obesity does not appear to impact vitamin A assessment when measured with retinol or RBP; however, inflammation should continue to be measured to interpret vitamin A status.

Funding Sources: Supported by the Bill & Melinda Gates Foundation, CDC, Eunice Kennedy Shriver National Institute of Child Health and Human Development, HarvestPlus, and USAID