Chemical constituents of ambient particulate air pollution and biomarkers of inflammation, coagulation and homocysteine in healthy adults: A prospective panel study

Abstract

BackgroundAmbient air pollution has been associated with activation of systemic inflammation and hypercoagulability and increased plasma homocysteine, but the chemical constituents behind the association are not well understood. We examined the relations of various chemical constituents of fine particles (PM2.5) and biomarkers of inflammation, coagulation and homocysteine in the context of traffic-related air pollution.MethodsA panel of 40 healthy college students underwent biweekly blood collection for 12 times before and after their relocation from a suburban campus to an urban campus with changing air pollution contents in Beijing. Blood samples were measured for circulatory biomarkers of high-sensitivity C reactive protein (hs-CRP), tumor necrosis factor alpha (TNF-α), fibrinogen, plasminogen activator inhibitor type 1 (PAI-1), tissue-type plasminogen activator (t-PA), von Willebrand factor (vWF), soluble platelet selectin (sP-selectin), and total homocysteine (tHcy). Various air pollutants were measured in a central air-monitoring station in each campus and 32 PM2.5 chemical constituents were determined in the laboratory. We used three different mixed-effects models (single-constituent model, constituent-PM2.5 joint model and constituent residual model) controlling for potential confounders to estimate the effects of PM2.5 chemical constituents on circulatory biomarkers.ResultsWe found consistent positive associations between the following biomarkers and PM2.5 chemical constituents across different models: TNF-α with secondary organic carbon, chloride, zinc, molybdenum and stannum; fibrinogen with magnesium, iron, titanium, cobalt and cadmium; PAI-1 with titanium, cobalt and manganese; t-PA with cadmium and selenium; vWF with aluminum. We also found consistent inverse associations of vWF with nitrate, chloride and sodium, and sP-selectin with manganese. Two positive associations of zinc with TNF-α and of cobalt with fibrinogen, and two inverse associations of nitrate with vWF, and of manganese with sP-selectin, were independent of the other constituents in two-constituent models using constituent residual data. We only found weak air pollution effects on hs-CRP and tHcy.ConclusionsOur results provide clues for the potential roles that PM2.5 chemical constituents may play in the biological mechanisms through which air pollution may influence the cardiovascular system.

Cardiovascular and lung function in relation to outdoor and indoor exposure to fine and ultrafine particulate matter in middle-aged subjects

“…A 7-day intervention study with air filtration in the homes of a wood smoke impacted area found an association between the indoor concentration of PM 2.5 and CRP (Allen et al, 2011), whereas three other studies with air filtration in Copenhagen, Denmark, showed no effect on CRP (Brauner et al, 2008a,b;Karottki et al, 2013). There seem to be mixed results with regard to associations between ambient or individual-level PM 2.5 exposure and CRP; some studies have shown positive associations (Huttunen et al, 2012;Zhao et al, 2013), whereas other studies have reported no effect on CRP levels in the circulation (Liu et al, 2009;Ruckerl et al, 2007a;Strak et al, 2013;Wu et al, 2012). A review concluded that there was an association between air pollution exposure and elevated levels of CRP in children, whereas there were inconsistent results on healthy adults (Li et al, 2012).…”

Long-term effects of elemental composition of particulate matter on inflammatory blood markers in European cohorts

“…Wu et al (2012) observed a 3.9% [0.3, 7.6%] increase in fibrinogen in association with elevated 24 h-averages in PM 2.5 Fe. This association strengthened (5.9% [0.2;12.0%]) when including PM 2.5 in the model.…”

“…To date, the effects of chemical components of PM on inflammatory blood markers were only assessed in a panel study (Wu et al, 2012) and in a semi-experimental investigation (Strak et al, 2013). Wu et al (2012) observed a 3.9% [0.3, 7.6%] increase in fibrinogen in association with elevated 24 h-averages in PM 2.5 Fe.…”

“…However, there is a limited number of studies exploring the association between PM components and health. Furthermore, previous epidemiological studies have mainly investigated short-term effects (Ostro et al, 2007;Bell et al, 2009;Zanobetti et al, 2009;Wichers Stanek et al, 2011;Wu et al, 2011Wu et al, , 2012Wu et al, , 2013 rather than long-term effects of PM components on cardiovascular health. Two studies from the US consistently observed an increased risk of ischemic heart disease (IHD) mortality for PM 2.5 iron and sulfur/sulfate, but evidence was inconsistent for potassium, silicon, zinc, nickel and vanadium (Ostro et al, 2010;Lippmann et al, 2013).…”

Association of chemical constituents and pollution sources of ambient fine particulate air pollution and biomarkers of oxidative stress associated with atherosclerosis: A panel study among young adults in Beijing, China

“…The panel study used a repeated-measure study protocol to quantify short-term air pollution exposures and health observations over time in order to facilitate assessment of the health effects of changes in exposure over time (Janes et al, 2008). Detailed information on the study design and participant recruitment could be found elsewhere (Wu et al, 2012(Wu et al, , 2013. The BIT has 2 campuses about 30 km apart, one (BIT Liangxiang campus) is located in the southwest suburban area and the other one (BIT main campus) is located in the northern urban area of Beijing.…”