Nursing and Weight Gain Markedly Influence the Levels of PCB 153 in Blood of 4, 8 and 12 Year Old Children

摘要

Background and Aims: WHO recommends full nursing of infants for 6 months. Infants are exposed to lipid-soluble PCB in breast milk. To what degree does nursing affect blood levels of PCB in children? Methods: PCB 153, marker of total PCB, was measured in blood serum from 37 first-born children (4, 8 and 12 years old), in maternal serum during pregnancy week 32-34 and 4-12 years after delivery, and in breast milk 3 weeks after delivery. A detailed questionnaire about breast-feeding was answered. Associations between blood PCB 153 levels and breast-feeding were analyzed by multiple linear regression. Results: The women had nursed (both full and partial) their children in total for 20 months (mean, range 0-51). Maternal mean PCB 153 serum level decreased from 63 ng/g lipid to 33 ng/g lipid during follow-up (paired t-test, p＜0.001). The largest decrease was seen for women sampled 12 years after their first delivery (mean: 55%, range: 26-82; N=15). After adjustment for follow-up time and BMI change, serum PCB 153 levels decreased 1.0% per month (SE: 0.23) of any nursing (p＜0.001). Mothers had breast-fed their firstborn child full-time for 4 months (mean, range 0-12). Partial nursing was reported to 4 months (mean, range 0-11). 4 year old children had the highest mean serum PCB 153 level (N=6; 47 ng/g lipid), followed by 8 year old (32 ng/g lipid; N=15, t-test: p=0.18), and 12 year old children (21 ng/g lipid; N=16, p=0.037). Child serum PCB 153 level increased with 2.7 ng/g lipid (SE: 0.64) per month of full breast-feeding (N= 36; p＜0.001), and with 2.3 ng/g lipid (SE: 0.68) per month of partial breast-feeding (p＜0.002). The CB 153 level decreased 1.2 ng/g lipid (SE: 0.34) per kg increase in child body weight (p=0.002), and increased 0.15 ng/g lipid (SE: 0.15) per ng PCB 153/g lipid increase in breast milk (p=0.078). The regression model explained 73% of the variation of child PCB 153 levels. Conclusions: Nursing strongly influenced child PCB 153 body burden. Weight increase during childhood diluted the PCB 153 accumulated during the nursing period.