Effect of Maternal Smoking on Breast Milk Interleukin-1α, β-Endorphin, and Leptin Concentrations

Abstract

Tobacco smoke is immunotoxic, but the effect of smoking on the immunologic function of the mammary gland of mothers who smoke cigarettes (“smoker mothers”) has not been studied. Our objective was to test, in smoker mothers, the colostral and transitional milk concentrations of interleukin-(IL)1α. The immunomodulators β-endorphin and leptin were also tested. Pregnant women who self-identified as smokers (≥ 5 cigarettes per day through pregnancy) or nonsmokers were recruited for study participation. The study population included 42 smoker and 40 non-smoker nursing mothers, with otherwise uncomplicated gestation, delivery, and puerperium, who were breast-feeding ad libitum their healthy neonates. Colostrum was obtained on the third postpartum day at 0900 hr and transitional milk on the 10th postpartum day at 0900 hr. IL-1α concentrations were significantly reduced in the colostrum of smoker mothers compared with nonsmoker mothers ( p < 0.01). Colostral β-endorphin and leptin concentrations were comparable. No significant differences were found between smoker and nonsmoker lactating mothers in transitional milk concentrations of IL-1α, β-endorphin, and leptin. Moreover, β-endorphin and leptin concentrations were significantly reduced in transitional milk samples compared with colostrum of both smoker and nonsmoker mothers ( p < 0.05); also, IL-1α transitional milk concentrations were reduced compared with colostrum, but without any significance. This analysis shows that maternal smoking alters the colostral milk levels of the proinflammatory cytokine IL-1α. The altered postnatal provision of alternative source of the proinflammatory cytokine IL-1α adds understanding to how breast-feeding could be nonprotective against infections among the neonates nursed by smoker mothers.