Exposure to mercury among Spanish adolescents: Eleven years of follow-up.
Level 3 - non-randomized controlled study
Prospective non-randomized birth cohort follow-up study.
PubMed 37211180 · doi:10.1016/j.envres.2023.116204
What was done
Researchers evaluated mercury exposure from birth through age 11 in 338 adolescents from the INMA birth cohort in Valencia, Spain. Total mercury (THg) was measured in cord blood at birth (converted to hair equivalent) and in hair samples at 4, 9, and 11 years of age. Fish consumption and sociodemographic variables at age 11 were collected via questionnaires. Multivariate linear regression models assessed the association between THg concentrations, fish intake, and covariates.
What was found
The geometric mean hair THg concentration at 11 years of age was 0.86 µg/g (95% CI: 0.78–0.94), representing an estimated 69% reduction from birth. Despite this decline, 45.2% of participants had hair THg concentrations exceeding the US EPA reference dose equivalent (1 µg/g). A 100 g/week increase in swordfish consumption was associated with a 125% increase in hair mercury (95% CI: 61.2–214.9%), while canned tuna was the largest overall contributor to Hg exposure due to its higher consumption frequency.
Why it matters
Even with sustained reductions in mercury exposure through childhood, nearly half of adolescents in this high-seafood-consuming population remain above international reference thresholds, highlighting the specific dietary contribution of canned tuna and predatory fish.
Limits
The study was confined to a single geographic sub-cohort in eastern Spain. Dietary intake was self-reported via questionnaires. Hair mercury concentrations at birth were estimated from cord blood rather than directly measured, and direct clinical or cognitive health endpoints were not assessed.
Cited by
- supports Limiting tuna consumption helps reduce elevated blood mercury levels.