Interaction of the delta-aminolevulinic acid dehydratase polymorphism and lead burden on cognitive function: the VA normative aging study.
OBJECTIVE
We evaluated the modifying influence of a delta-aminolevulinic acid dehydratase (ALAD) polymorphism on the relation between lead burden and cognition among older men.


METHODS
Information on ALAD genotype, lead measurements, potential confounders, and cognitive testing was collected from 982 participants. For each cognitive test and lead biomarker, we fit separate multiple linear regression models, which included an interaction term for ALAD genotype and the lead biomarker and adjusted for potential confounders.


RESULTS
With higher levels of tibia lead, ALAD 1-2/2-2 carriers exhibited worse performance on a spatial copying test in comparison with ALAD 1-1 carriers (P interaction = 0.03). However, there was no consistent pattern of an ALAD genotype-lead interaction for the other tests.


CONCLUSIONS
The results provide some evidence that ALAD genotype may modify the relation between lead and cognition among older men with low lead burden. However, future work in this area is needed to confirm these suggestive findings.
Rajan
Pradeep
P
Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA. prajan@hsph.harvard.edu
Kelsey
Karl T
KT
Schwartz
Joel D
JD
Bellinger
David C
DC
Weuve
Jennifer
J
Spiro
Avron
A
Sparrow
David
D
Smith
Thomas J
TJ
Nie
Huiling
H
Weisskopf
Marc G
MG
Hu
Howard
H
Wright
Robert O
RO
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001822:Body Burden; D001842:Bone and Bones; D003072:Cognition Disorders / Q000150:complications / Q000201:enzymology* / Q000235:genetics; D004798:Enzymes / Q000235:genetics*; D006801:Humans; D007854:Lead / Q000009:adverse effects* / Q000032:analysis / Q000493:pharmacokinetics; D007855:Lead Poisoning / Q000523:psychology*; D008297:Male; D008404:Massachusetts; D008875:Middle Aged; D011110:Polymorphism, Genetic; D000623:Porphobilinogen Synthase / Q000235:genetics*; D014481:United States; D014493:United States Department of Veterans Affairs; D055815:Young Adult
D004798:Enzymes; D007854:Lead; D000623:Porphobilinogen Synthase
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