Association of cardiac and vascular changes with ambient PM_2.5in diabetic individuals

<p>Abstract</p> <p>Background and Objective</p> <p>Exposure to fine airborne particles (PM_2.5) has been shown to be responsible for cardiovascular and hematological effects, especially in older people with cardiovascular disease. Some epidemiological studies suggest that individuals with diabetes may be a particularly susceptible population. This study examined effects of short-term exposures to ambient PM_2.5on markers of systemic inflammation, coagulation, autonomic control of heart rate, and repolarization in 22 adults (mean age: 61 years) with type 2 diabetes.</p> <p>Methods</p> <p>Each individual was studied for four consecutive days with daily assessments of plasma levels of blood markers. Cardiac rhythm and electrocardiographic parameters were examined at rest and with 24-hour ambulatory ECG monitors. PM_2.5and meteorological data were measured daily on the rooftop of the patient exam site. Data were analyzed with models adjusting for season, weekday, meteorology, and a random intercept. To identify susceptible subgroups, effect modification was analyzed by clinical characteristics associated with insulin resistance as well as with oxidative stress and by medication intake.</p> <p>Results</p> <p>Interleukin (IL)-6 and tumor necrosis factor alpha showed a significant increase with a lag of two days (percent change of mean level: 20.2% with 95%-confidence interval [6.4; 34.1] and 13.1% [1.9; 24.4], respectively) in association with an increase of 10 μg/m³in PM_2.5. Obese participants as well as individuals with elevated glycosylated hemoglobin, lower adiponectin, higher ferritin or with glutathione S-transferase M1 null genotype showed higher IL-6 effects. Changes in repolarization were found immediately as well as up to four days after exposure in individuals without treatment with a beta-adrenergic receptor blocker.</p> <p>Conclusions</p> <p>Exposure to elevated levels of PM_2.5alters ventricular repolarization and thus may increase myocardial vulnerability to arrhythmias. Exposure to PM_2.5also increases systemic inflammation. Characteristics associated with insulin resistance or with oxidative stress were shown to enhance the association.</p>