Correlation of Blood Lead Level in Mothers and Exclusively Breastfed Infants: A Study on Infants Aged Less Than Six Months

Background: It has been shown that there is a partial correlation between blood lead level (BLL) of infants and their mothers. This study was designed to evaluate the BLL of exclusively breast-fed infants less than 6 months of age and their mothers. Methods: This was a cross-sectional study on infants below 6 months of age and their mothers who were referred to Mashhad Imam Reza Hospital, Iran. BLL was determined by atomic absorption spectroscopy method. Demographic features and economic status of the subjects were also collected. Results: Sixty infants and their mothers in total were studied and 76.7% of the infants were boy. Mean (SD) age of children was 24.6 (31.8) days. Economic status of 16.7% of subjects was evaluated to be "poor", 38.3% "middle" and 45% "good". All of the mothers were housewives. Most subjects (88.3%) were living in the urban areas, and the remainder (11.7%) in rural areas. Mean (SD) of mothers’ BLL was 75.9 (31.1) mg/L. Mean (SD) of BLL in infants was 63.6 (26.8) mg/L. In 8 mothers (13.3%) and 4 infants (6.7%) BLL was higher than 100 mg/L. There was a significant relationship between BLL of infants and mothers (P < 0.001, r = 0.64). No significant correlation between maternal BLL and infants’ age, infant birth weight and current infant weight was established. Mean BLL in male infants was 73.4 (25.4) mg/L and in female infants was 84.8 (45.3) mg/L which was not significantly different from each other. The relationship between economic status and infants’ BLL was close to the level of significance (P = 0.08). Mean BLL in infants living in urban areas was 65.2 (27.1) mg/L, while in infants living in rural areas was 51.9 (23.3) mg/L; nonetheless, it was not significantly different between them (P = 0.22). Conclusion: There was a direct relationship between BLL in exclusively breastfed infants and their mothers. This may ascertain that lead can be excreted to the breast milk. Also, it may also suggest that both mothers and children were exposed to same level of air lead pollution.