Attenuated growth of breast-fed children exposed to increased concentrations of methylmercury and polychlorinated biphenyls.
Breast-feeding has been linked to slowed postnatal growth. Although the basis for this "weanling's dilemma" is unclear, environmental contaminants in human milk may be of relevance. We studied a Faroese birth cohort of 182 singleton children, born at term in 1994-95. Concentrations of mercury in cord blood and of polychlorinated biphenyls in maternal milk were measured, and duration of breast-feeding was recorded. At 18 months, children who had been exclusively breast-fed for at least 6 months weighed 0.59 kg less [95% confidence interval (CI) = 0.03, 1.16 kg] and were 1.50 cm [95% CI = 0.52, 2.47 cm] shorter than those not breast-fed. However, calculated transfer of contaminants from human milk fully explained the attenuated growth. Irrespective of duration of breast-feeding, a doubling of the mercury concentration in cord blood was associated with a decrease in weight at 18 months by 0.19 kg (95% CI = 0.03, 0.35 kg) and in height by 0.26 cm (95% CI = -0.02, 0.55 cm). Weight and height at 42 months showed the same tendencies, but the main effect occurred before 18 months of age. Thus, in communities with increased contaminant exposures, risks associated with lactational transfer of toxicants to the infant must be considered when judging the benefits of prolonged breast-feeding.
Grandjean
Philippe
P
Department of Environmental Health, Boston University Schools of Medicine and Public Health, Boston, Massachusetts, USA. pgrand@health.sdu.dk
Budtz-Jørgensen
Esben
E
Steuerwald
Ulrike
U
Heinzow
Birger
B
Needham
Larry L
LL
Jørgensen
Poul J
PJ
Weihe
Pál
P
D001827:Body Height / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D001942:Breast Feeding; D002675:Child, Preschool; D015331:Cohort Studies; D004781:Environmental Exposure / Q000009:adverse effects; D004785:Environmental Pollutants / Q000009:adverse effects; D005260:Female; D006128:Growth / Q000187:drug effects*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008767:Methylmercury Compounds / Q000009:adverse effects*; D011078:Polychlorinated Biphenyls / Q000009:adverse effects* / Q000097:blood; D011237:Predictive Value of Tests; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011446:Prospective Studies
D004785:Environmental Pollutants; D008767:Methylmercury Compounds; D011078:Polychlorinated Biphenyls