Air pollution and homocysteine: more evidence that oxidative stress-related genes modify effects of particulate air pollution.
BACKGROUND
Ambient particles are associated with cardiovascular events and recently with total plasma homocysteine. High total plasma homocysteine is a risk for human health. However, the biologic mechanisms are not fully understood. One of the putative pathways is through oxidative stress. We aimed to examine whether associations of PM2.5 and black carbon with homocysteine were modified by genotypes including HFE H63D, C282Y, CAT (rs480575, rs1001179, rs2284367, and rs2300181), NQO1 (rs1800566), GSTP1 I105V, GSTM1, GSTT1 (deletion vs. nondeletion), and HMOX-1 (any short vs. both long). We attempted to replicate identified genes in an analysis of heart rate variability and in other outcomes reported in the literature.


METHODS
Study subjects were 1000 white non-Hispanic men in the Boston area, participating in a cohort study of aging. PM2.5, black carbon, total plasma homocysteine, and other covariates were measured at several points in time between 1995 and 2006. We fit mixed models to examine effect modification of genes on associations of pollution with total plasma homocysteine.


RESULTS
Interquartile range increases in PM2.5 and black carbon (7-day moving averages) were associated with 1.5% (95% confidence interval = 0.2% to 2.8%) and 2.2% (0.6% to 3.9%) increases in total plasma homocysteine, respectively. GSTT1 and HFE C282Y modified effects of black carbon on total plasma homocysteine, and HFE C282Y and CAT (rs2300181) modified effects of PM2.5 on homocysteine. Several genotypes marginally modified effects of PM2.5 and black carbon on various endpoints. All genes with significant interactions with particulate air pollution had modest main effects on total plasma homocysteine.


CONCLUSIONS
: Effects of PM2.5 and black carbon on various endpoints appeared to be mediated by genes related to oxidative stress pathways.
Ren
Cizao
C
Exposure, Epidemiology, and Risk Program, Harvard School of Public Health, Boston, MA 02215, USA. cren@hsph.harvard.edu
Park
Sung Kyun
SK
Vokonas
Pantel S
PS
Sparrow
David
D
Wilker
Elissa
E
Baccarelli
Andrea
A
Suh
Helen H
HH
Tucker
Katherine L
KL
Wright
Robert O
RO
Schwartz
Joel
J
D000368:Aged; D000369:Aged, 80 and over; D000397:Air Pollution / Q000009:adverse effects*; D015331:Cohort Studies; D004781:Environmental Exposure / Q000009:adverse effects; D005838:Genotype; D006339:Heart Rate / Q000187:drug effects / Q000235:genetics; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects* / Q000235:genetics; D052638:Particulate Matter / Q000009:adverse effects*; D020641:Polymorphism, Single Nucleotide / Q000187:drug effects / Q000235:genetics; D053260:Soot / Q000009:adverse effects; D014805:Vitamin B 12 / Q000097:blood; D025101:Vitamin B 6 / Q000097:blood
D052638:Particulate Matter; D053260:Soot; D006710:Homocysteine; D025101:Vitamin B 6; D014805:Vitamin B 12