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

AX4-34
Reference, Study
Location, and
Period Study Description
United States (cont’d)
Kosnett et al.
(1994)
Dickson City, PA
Popovic et al.
(2005)
Bunker Hill, ID
1994
Canada
Webber et al.
(1995)
Canada
Unknown
Table AX4-8 (cont’d). Bone Lead Studies of Menopausal and Middle-aged to Elderly Subjects
Aim to determine the influence of
demographic, exposure and medical
factors on the bone Pb concentration of
subjects with environmental Pb exposure.
101 subjects (49 males, 52 females; aged
11 to 78 yrs) recruited from 49 of 123
households geographically located in a
suburban residential neighborhood.
108 former female smelter employees
and 99 referents to assess the PbB versus
bone Pb relationship.
Tested hypothesis that women on
hormone replacement therapy should
have higher bone Pb content and lower
plasma Pb as hormone replacement
therapy would suppress the transfer of
endogenous Pb to the circulation.
56 women, some using hormone
replacement therapy over ~4 yrs.
Lead Measurement (SD or range)
PbB in µg/dL, Bone Pb in µg/g Bone Mineral Findings, Interpretation
Log-transformed bone Pb highly correlated with age
(r = 0.71; p # 0.0001).
Exposed: PbB 2.73 (±2.39), tibia 14.4 (±0.5)
Referents: PbB 1.25 (±2.10), tibia 3.22 (±0.50)
Pb concentrations in tibia and blood significantly
higher in the exposed group. Endogenous release rate
(µg Pb per dL blood/ µg Pb/g bone) in
postmenopausal women was double the rate found
in premenopausal women (0.132 ± 0.019 versus
0.067 ± 0.014).
Low dose hormone replacement therapy (n = 15):
PbB 4.08 (±1.60), tibia 19.37 (±8.62), calcaneus 24.02
(±10.88)
Moderate dose hormone replacement therapy (n = 11):
PbB 5.22 (±3.36), tibia 16.80 (±11.68), calcaneus
23.83 (±14.18)
Calcium only (n = 22): PbB 4.6 (±1.59), tibia 11.13
(±6.22), calcaneus 21.12 (±13.55)
Bone Pb showed no significant change up to age
20 yr, increased with the same slope in men and
women between ages 20 and 55 yr, and then
increased at a faster rate in men older than 55 yr.
Higher tibia bone Pb (and PbB) was associated
with use of estrogen (present or former) in both the
whole referent group and postmenopausal women
in the referent group.
Women not taking hormones had significantly
lower Pb values in cortical bone compared to
all women on hormone replacement therapy
(p = 0.007). Showed higher tibia Pb levels but no
increase in calcaneus Pb level or decrease in PbB.