Diet quality and blood lead levels in Uruguayan first graders

Foods are a potential source of lead but also contain nutrients that counteract the intestinal absorption of lead. Translatable evidence is needed to better understand the relationship between whole diets and blood lead levels (BLLs) in children. In this cross-sectional study we investigated the association between dietary variety, adequacy, moderation, and overall diet quality with children's BLLs.

First graders (~ 7 years) from Montevideo, Uruguay were evaluated in years 2009-13 (Phase I, n = 303) and 2015-19 (Phase II, n = 443). Lead was measured in fasting blood via atomic absorption spectrometry and primary caregivers completed two non-consecutive 24-h recalls. Indices of dietary variety (maximum score of 20), adequacy (maximum 40), moderation (maximum 30), and overall diet quality were calculated from food and nutrient intakes averaged over two recall days. The indices were adapted from the Diet Quality Index-International based on dietary recommendations for children. Missing covariate data were imputed. The associations between diet quality measures and BLLs were modeled separately in Phase I and II with multivariable linear models, testing for sex differences via interaction terms and stratified models.

The median[IQR] BLLs were 3.8[2.6, 4.9] and 1.3[0.7, 3.6] μg/dL in study Phases I and II, respectively. All diet quality scores were <60 % of the maximum values and daily intakes of key food groups fell below recommended levels. There was little evidence of an association between measures of diet quality and children's BLLs overall. On the other hand, higher diet variety, adequacy, and overall diet quality were associated with slightly higher BLLs among girls in Phase I only.

In the context of low lead exposure and food consumption patterns that fall short of recommended levels, the relation of diet quality to children's BLLs may depend on lead exposure levels.