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

AX6-147
Table AX6-5.1 (cont’d). Effects of Lead on Blood Pressure and Hypertension
Reference, Study
Location, and
Period Study Description Pb Measurement Findings, Interpretation
Europe (cont’d)
Fewtrell et al.
(2004)
Global
1988-2002
Using available global figures on
categorized blood Pb ranges by age group,
authors calculated relative risk ratios
relating increased blood pressure to
ischemic heart disease, cerebrovascular
disease, hypertensive disease, and other
cardiac diseases. They used a calculation of
“impact fraction,” based on the proportion
of the population within the particular Pb
exposure category and the relative risk at
that exposure category compared to the risk
at the reference level. They used the metaanalysis
of Schwartz (1995) to derive an
accumulating 1.25 mm Hg increase in
blood pressure in men for 5-10, 10-15, and
15-20 µg/dL, and an increase of
3.75 mm Hg for blood Pb levels above
20 µg/dL. Comparable blood pressure
increases in women for each Pb category
was 0.8 mm Hg for each of the first three
categories and 2.4 mm Hg for blood Pb
>20 µg/dL.
See left for blood Pb
categories used.
The largest risk ratios were for hypertensive disease populations at ages 15-44,
calculated at 1.12, 1.41, 1.78, and 2.00 for each of the four Pb categories for
men, and 1.08, 1.25, 1.45, and 1.56 for women. Risk ratios for all disease
categories increased with increasing Pb category and decreased for populations
older than 44 yrs.
The authors assumed a linear relationship between blood pressure and blood
Pb, whereas available evidence suggests it may be non-linear. If blood Pbblood
pressure concentration-response function is log-linear, as implicitly
accepted by over half the reviewed studies, the calculated global risk ratios for
all cardiovascular disease will be overestimated at higher blood Pb levels and
underestimated at lower blood Pb levels.