Air Quality Criteria for Lead Volume II of II - (NEPIS)(EPA) - US ...

AX4-25
Reference, Study
Location, and
Period Study Description
Mexico (cont’d)
Sanín et al. (2001)
Mexico City
1994-95
Gomaa et al. (2002)
Mexico City
Unknown
Table AX4-7 (cont’d). Bone Lead Studies in Pregnant and Lactating Subjects
Examined early postnatal growth
in a cohort of healthy breastfed
newborns in relation to maternal
bone Pb burden. 329 motherinfant
pairs sampled for umbilical
cord blood at birth and maternal
and infant venous blood at 1 mo
postpartum. Maternal evaluations
at 1 mo postpartum included Pb
measures in blood and bone.
Primary endpoints were attained
weight 1 mo of age, and weight
gain from birth to 1 mo of age.
Linear regression.
Aim to compare umbilical cord
PbB and maternal bone Pb as
independent predictors of infant
mental development (n = 197).
Prospective design. At 24 mo of
age, each infant was assessed
using the Bayley Scales of Infant
Development-II (Spanish
Version). Multiple linear
regression.
Lead Measurement (SD or range)
PbB in µg/dL, Bone Pb in µg/g Bone Mineral Findings, Interpretation
Included in analyses (n = 329):
Infant: cord PbB 6.8 (±3.9), PbB 1 mo 5.7 (±3.0)
Maternal: PbB 9.7 (±5.2), tibia Pb 10.1 (±10.3), patella Pb 15.2 (±15.2)
Excluded from analyses (n = 276):
Infant: cord PbB 6.3 (±3.0), PbB 1 mo 5.5 (±3.3)
Maternal: PbB 8.8 (±3.9), tibia Pb 9.75 (±10.3), patella Pb 14.2 (±17.3).
Infant PbB were inversely associated with weight gain, with an estimated
decline of 15.1 g/µg/dL of PbB. Children who were exclusively breastfed
had significantly higher weight gains; however, this gain decreased
significantly with increasing levels of patella Pb. Multivariate regression
analysis predicted a 3.6 g decrease in weight at 1 mo of age/µg Pb/g bone
mineral increase in maternal patella Pb levels.
Cord PbB 6.7 (±3.4), tibia 11.5 (±11.0), patella 17.9 (±15.2). After
adjustment for confounders, Pb levels in umbilical cord blood and patella
bone were significantly, independently, and inversely associated with the
Mental Development Index (MDI) scores of the Bailey Scale. In relation to
the lowest quartile of patella Pb, the 2nd, 3rd, and 4th quartiles were
associated with 5.4-, 7.2-, and 6.5-point decrements in adjusted MDI scores.
A 2-fold increase in cord PbB (e.g., from 5-10 µg/dL) was associated with a
3.1-point decrement in MDI score.
The authors concluded that
maternal Pb burden is negatively
associated with infant attained
weight at 1 mo of age and to
postnatal weight gain from birth
to 1 mo of age.
Suggest that higher maternal
patella bone Pb levels constitute
an independent risk factor for
impaired mental development in
infants at 24 mo of age. This
effect is probably attributable to
mobilization of maternal bone Pb
stores.