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

AX6-242
Table AX6-9.5 (cont’d). Effects of Lead on the Endocrine System in Children
Reference, Study
Location, and Period Study Description Pb Measurement Findings, Interpretation
United States (cont’d)
Siegel et al. (1989)
Connecticut
1987
Koo et al. (1991)
Ohio
NR
Design: cross-sectional
Subjects: children (n = 68, 32 female), ages
11 mo to 7 yr
Outcome measures: serum FT4, TT4
Analysis: linear regression
Design: longitudinal (subset of prospective)
Subjects: children (n = 105, 56 females), age
21, 27, 33 mo
Outcome measures: serum calcium
magnesium, phosphorus, PTH, CAL, 25-OH-
D, 1,25-OH-D, and bone mineral content
Analysis: structural equation modeling
Blood Pb (µg/dL) mean
(range):
25 (2–77)
Blood Pb (µg/dL)
geometric mean
(GSD, range):
Lifetime mean, based on
quarterly measurements:
9.74 (1.44, 4.8–23.6)
Concurrent:
15.01 (1.52, 6–44)
Maximum observed:
18.53 (1.53, 6–63)
No significant association between blood Pb concentration and
thyroid hormone outcomes. Linear regression parameters:
FT4: ∀ = 1.55 (SE 0.05), ∃ = 0.0024 (SE 0.0016), r 2 = 0.03,
p = 0.13
TT4: ∀ = 8.960 (SE 0.39), ∃ = 0.0210 (SE 0.0127), r 2 = 0.04,
p = 0.10
Significant association between increasing blood Pb (ln-transformed)
and covariate-adjusted decreasing serum phosphorus
(∀ = 1.83, ∃ = −0.091). No other covariate-adjusted outcomes were
significantly associated with blood Pb.
Covariates retained: age, sex, race, and sampling season.
Dietary calcium intake (mg/day)
#600: n = 4 (4%)
600–1200: n = 58 (55%)
>1200: n = 43 (41%)