Cadmium dietary intake and blood levels in early childhood

Abstract

Background: Low level cadmium (Cd) exposure during childhood is common and may contribute to poorer children’s health. Diet is the main source of Cd exposure in this population, however information on dietary Cd intake in children is limited. The aim of this study was to estimate the dietary Cd (DCd) intake from 1 to 6 years of age and its association with blood Cd levels (BCd).Methods: Diet was assessed longitudinally in children from the Programming Research in Obesity GRowth Environment and Social Stressors (PROGRESS) cohort in Mexico City, using a semi-quantitative food frequency past week questionnaire (FFQ) at 1 (n=558), 2 (n=452), 4 (n=593) and 6 (n=595) years of age. DCd was estimated using food composition tables from the US, European Food Safety Authority, Australia, Hong Kong, Canada and 5 food items from Mexico. Cd levels from the reports were averaged and standardized to mg/kg. We matched reported levels with the FFQ and estimated the individual DCd in grams at each time point. BCd was analyzed using ICP-QQQ. We modeled 4 year-old BCd and the arithmetic mean of 1, 2 and 4 year old DCd in tertiles, adjusted for child’s sex, age, BMI z-score and environmental tobacco exposure.Results: The mean weekly DCd intake was 0.0033±0.0027g, 0.0042±0.0024g, 0.0058±0.0029g and 0.0066±0.0029g at 1, 2, 4 and 6 years old respectively. The most Cd-containing consumed food items changed across age of assessment, however milk, sweets, potatoes, rice and bread were consistently identified Cd sources in all stages. Compared to the 1st tertile, DCd 2nd tertile was associated with increased BCd and DCd 3rd tertile with decreased BCd. Conclusion: Our results show that children’s Cd consumption increases with age and suggest a non-linear association between diet and blood Cd. Future studies will assess the relationship between DCd and children’s renal health.