Traffic-related particles are associated with elevated homocysteine: the VA normative aging study.
BACKGROUND
Recent epidemiologic studies have shown that homocysteine, a sulfur-containing amino acid formed during the metabolism of methionine, is a risk factor for atherosclerosis, myocardial infarction, stroke, and thrombosis. Particulate air pollution has been related to cardiovascular death and hospital admission, but the underlying mechanisms are not fully elucidated.


OBJECTIVE
We examined the associations between ambient particulate air pollution and plasma concentrations of homocysteine among 960 community-residing older men (mean age, 73.6 +/- 6.9 yr).


METHODS
Total homocysteine in plasma, measured using high-performance liquid chromatography with fluorescence detection, was regressed on each ambient particulate pollutant (black carbon, organic carbon, sulfate or PM(2.5)), and effect modification by plasma and dietary B vitamins (folate, B6, and B12) was examined.


RESULTS
The median concentration of total homocysteine was 10.6 micromol/L. Statistically significant positive associations of total homocysteine were observed with traffic-related particles (black carbon and organic carbon). No association was observed with sulfate, an indicator of coal combustion particles, or PM(2.5) (particulate matter < or = 2.5 microm in aerodynamic diameter). The effects of black carbon and organic carbon were more pronounced in persons with low concentrations of plasma folate and vitamin B12.


CONCLUSIONS
Exposures to ambient particles, particularly from traffic, are associated with elevated plasma total homocysteine. Homocysteine may be a component or biological marker of the oxidation pathways underlying the effect of ambient particles on the cardiovascular system.
Park
Sung Kyun
SK
Department of Environmental Health Sciences, University of Michigan School of Public Health, 109 S. Observatory Street, SPH II-M6240, Ann Arbor, MI 48109, USA. sungkyun@umich.edu
O'Neill
Marie S
MS
Vokonas
Pantel S
PS
Sparrow
David
D
Spiro
Avron
A
Tucker
Katherine L
KL
Suh
Helen
H
Hu
Howard
H
Schwartz
Joel
J
D000368:Aged; D000369:Aged, 80 and over; D000393:Air Pollutants / Q000009:adverse effects / Q000032:analysis*; D000397:Air Pollution / Q000009:adverse effects / Q000032:analysis*; D015415:Biomarkers / Q000097:blood; D002244:Carbon / Q000009:adverse effects / Q000032:analysis*; D005492:Folic Acid; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D052638:Particulate Matter / Q000009:adverse effects / Q000032:analysis*; D013455:Sulfur / Q000032:analysis; D001335:Vehicle Emissions / Q000032:analysis; D014805:Vitamin B 12 / Q000097:blood
D000393:Air Pollutants; D015415:Biomarkers; D052638:Particulate Matter; D001335:Vehicle Emissions; D006710:Homocysteine; D013455:Sulfur; D002244:Carbon; D005492:Folic Acid; D014805:Vitamin B 12