Response of biomarkers of inflammation and coagulation to short-term changes in central site, local, and predicted particle number concentrations

Abstract

Purpose-Previous studies have reported acute (hours-28 days) associations between ambient ultrafine particles (UFP; diameter <0.1) and biomarkers of cardiovascular health using central site data. We evaluated particle number concentration (a proxy measure for UFP) measured at a central site, a local near-highway site and predicted residential concentrations with response of biomarkers of inflammation and coagulation in a near-highway population.Methods-Participants provided two blood samples for analysis of interleukin-6 (IL-6), highsensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α receptor II, and fibrinogen. Mixed effect models were used to evaluate the association between PNC levels on the same day, prior 2 days, and moving averages of 3 to 28 days.Results-Estimated effects on biomarkers of a 5000 unit increase in central site PNC generally increased with longer averaging times for IL-6, hs-CRP, and fibrinogen. Effect estimates were highest for a 28-day moving average, with 91% (95% confidence interval [CI]: 9, 230) higher IL-6 levels, 74% (95% CI: −7, 220) higher hs-CRP levels, and 59% (95% CI: −13, 130) higher fibrinogen levels. We observed no clear trend between near-highway or predicted residential PNC and any of the biomarkers. HHS Public Access Author Manuscript Author ManuscriptAuthor Manuscript Author ManuscriptConclusions-Only central site PNC increased blood markers of inflammation while nearhighway and predicted residential values did not. We cannot fully explain this result, although differing PNC composition is a possibility. Future studies would assist in understanding these findings.

Lessons from in-home air filtration intervention trials to reduce urban ultrafine particle number concentrations

“…In the absence of a sufficient washout period, effects could carry over into the subsequent sham period diluting the apparent impact on biomarkers. Observational panel studies suggest that hsCRP and IL-6 could have maximal changes in response to UFP at three to four weeks [34, 35]. We accounted for carryover effects in our statistical analysis, but it would have been preferable to eliminate them from affecting biomarker data.…”

“…In our review of the literature, we found that only one [36] out of five [16, 17, 29, 37] recent HEPA intervention studies for CV outcomes had a washout period. Further, all but two of these studies had intervention periods that were shorter than we suspect is necessary (three weeks or more) based on observational studies [34, 35, 38, 39]. Given the logistical challenge of adding long washout periods to randomized crossover trials, it is worth considering standard randomized controlled trials, as have been used in some HEPA intervention studies for asthma [40].…”

“…While our study had several limitations, it also had some strengths: 1) We succeeded in blinding participants to the filtration type; 2) indoor-outdoor monitoring allowed us to assess efficacy of filtration and to see evidence of PNC reductions during sham filtration; 3) based on observational research outcomes [34, 35] the length of our intervention and sham periods, three weeks, should have been long enough to see the influence of PNC exposure on the blood biomarkers; 4) the randomized crossover design, while problematic in other ways, effectively eliminated confounding as a concern; 5) having continuous monitoring in all homes for the entire (six-week) study period is rare in HEPA intervention trials and gave us greater confidence that we knew the PNC levels in each home; and 6) our ability to separate indoor-generated spikes in PNC from the rest of PNC exposure is innovative for intervention studies and needs to be replicated by others.…”

Occupational exposures and determinants of ultrafine particle concentrations during laser hair removal procedures

“…The literature on the health effects of UFP is growing rapidly [17]. Acute exposure to ambient UFP has been associated with decreased lung function, decreased heart rate variability, increased inflammation and coagulation in the lungs and peripheral blood, and risk of myocardial infarctions [18–24].…”

“…Acute exposure to ambient UFP has been associated with decreased lung function, decreased heart rate variability, increased inflammation and coagulation in the lungs and peripheral blood, and risk of myocardial infarctions [18–24]. Chronic ambient exposure to UFP has been associated with increased risks of overall and cardiovascular mortality and increased systemic inflammation and oxidative stress [17, 25, 26]. …”