Lead-related dietary pattern is inversely associated with cognitive functioning in school children

Abstract

Background: The role of diet has been documented to be linked with blood lead levels (BLL). While it is well known that blood lead levels are inversely related to children’s cognitive functioning, few studies have assessed lead-related dietary patterns (LDP) in association with children’s cognitive functioning.Methods: This cross-sectional study is part of the China Jintan cohort study. Participants included 617 children (53.5% boys) with mean age of 13.0 ± 0.9 years old. Dietary pattern was assessed with a self-administrated food frequency questionnaire that asked children to recall what they had eaten during past three months. Blood lead level was measured using a graphite furnace atomic absorption spectrophotometer. Reduced rank regression was used to construct LDP with blood lead level as a response variable. Cognition was assessed with the Chinese version of the WISC, with full scale IQ (FIQ) composed of verbal (VIQ) and performance (PIQ) IQ. LDP score was recoded into tertiles. Multivariable linear regression was used in the analyses.Results: The LDP explained 5.2% of the blood lead variation and was characterized by high intake of soft drinks, both caffeinated and non-caffeinated, and juice but low intake of fruit, yoghurt and fish. LDP was inversely associated with verbal IQ. Comparing extreme tertiles of the dietary pattern, the regression coefficient for verbal IQ was -4.73 (-7.07--2.38) after adjusting for age and gender. Further adjusting for father’s education slightly attenuated the association. A trend of inverse association between LDP and FIQ was found. However, no association between LDP and PIQ was found. Conclusion: Lead-related dietary pattern is associated with children’s poor cognitive functioning, partly due to high consumption of soft drinks and juice, while consumption of fruit, yogurt, and fish is associated with improved cognition scores.