Relationship between age and serum vitamin A in children aged 4-11 y.

The association between age and serum vitamin A concentrations in children was examined by using total serum vitamin A values from the second National Health and Nutrition Examination Survey (NHANES II) and serum retinol values for Mexican Americans from the Hispanic HANES. Analyses included multivariate strategies to identify confounders of serum vitamin A. After the effect of the use of vitamin-mineral supplements on total serum vitamin A values was controlled for, the data indicated that younger children (aged 4-5 y) have lower serum vitamin A concentrations than do older children (aged 9-11 y) regardless of whether the measure was total serum vitamin A or serum retinol. This relationship was systematic across the distribution of values and suggested that the difference may be due to normal physiological events. A different interpretive criterion may be needed for younger and older children when serum vitamin A is used to indicate vitamin A status.