Air Pollution Raises Risk of Heart Disease

A number of previous studies suggest an association between road traffic and heart disease.  Hagen Kalsch, from West-German Heart Center (Germany), and colleagues, analyzed data from the German Heinz Nixdorf Recall Study, involving 4,814 participants, mean age 60 years.  Their proximity to roads with high traffic volume was calculated with official street maps, their long-term exposure to particle pollutants assessed with a chemistry transport model, and road traffic noise recorded by validated tests. The participants' level of atherosclerosis was evaluated by measurement of vascular vessel calcification in the thoracic aorta, a common marker of subclinical atherosclerosis (known as TAC), by computed tomography imaging.  The team found that small particulate matter (PM2.5) and proximity to major roads were both associated with an increasing level of aortic calcification:  for every increase in particle volume up to 2.4 micrometers (PM2.5) the degree of calcification increased by 20.7% and for every 100 metre proximity to heavy traffic by 10%. The study also found a borderline increase in TAC for night time noise (of 3.2% per 5 decibels).  The study authors conclude that: “[thoracic aortic calcification]is associated with incident coronary events and all-cause mortality independent of traditional [cardiovascular] risk factors in the general population.”