Artikel
Endothelial dysfunction, vascular inflammation and cardiac rhythm: associations with exposure to fine particles in diabetic patients
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Autoren
Veröffentlicht: | 6. September 2007 |
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Gliederung
Text
Exposure to fine airborne particulate matter (PM2.5) has been shown to be responsible for cardiovascular and hematological effects, especially in older people with cardiovascular disease. Some epidemiological studies suggest that subjects with diabetes may be a particularly susceptible population. The purpose of this study was to analyze the short-term effects of ambient PM2.5 on inflammatory blood markers, on cardiac function and on a marker of endothelial function in diabetic patients.
A prospective panel study was conducted on 22 people with diabetes in Chapel Hill, NC, USA, from November 2004 to December 2005. Each subject was studied for four consecutive days. Daily measurements of PM2.5 and meteorological data were acquired on the rooftop of the patient exam site. Plasma levels of inflammatory blood markers and brachial artery flow mediated dilatation (FMD) were also assessed on each day. Cardiac function was examined with 24-hour Holter monitors. Data were analyzed using mixed models with random patient effects.
Results are presented for an increase of 10µg/m³ PM2.5 as percent changes of mean with a 95% confidence interval. FMD decreased in association with PM2.5 during the first 24 hours (-20.7% [-36.5%; -5.0%]). Interleukin-6 (IL-6) showed a significant increase with a lag of 2 days (20.2% [6.4%; 34.1%]). Subjects with a BMI over 30 kg/m2 and subjects with glycosylated hemoglobin (HbA1c) over 7% showed higher IL-6 effects (23.7% [8.7%; 38.8%] and 24.8% [9.4%; 40.2%], respectively). T-wave amplitude increased in association with PM2.5 after a lag of four days (7.3% [3.3%; 11.3%]). This effect was even higher for the nine subjects not on beta blockers (11.7% [5.7%; 17.8%]). These data demonstrate that PM exposure may cause immediate endothelial dysfunction while vascular inflammation and cardiac dysfunction may take some days to be apparent. Heavier diabetics as well as those with higher HbA1c levels may be especially responsive.
This abstract does not necessarily represent EPA policy.