Prenatal exposure to lead in relation to risk of preterm low birth weight: a matched case-control study in China

We investigated the association between prenatal exposure to lead (Pb) and the risk of preterm low birth weight (PLBW). Pb concentrations in maternal urine collected at birth from 408 subjects (102 cases and 306 matched controls) were analyzed and adjusted by creatinine. The median Pb concentration in the PLBW cases (10.60 μg Pb/g creatinine) was higher than that of the controls (7.28 μg Pb/g creatinine). An adjusted odds ratio (OR) of 2.96 (95% CI = 1.49-5.87) for PLBW was observed when the highest tertile was compared to the lowest tertile of Pb levels. The association was more pronounced among female infants (adjusted OR = 3.67 for the highest tertile; 95% CI = 1.35-9.93) than male infants (adjusted OR = 1.91 for the highest tertile; 95% CI = 0.74-4.95). Our study suggests that prenatal exposure to levels of Pb encountered today in China is associated with an elevated risk of PLBW.