The air is cleaner than it was a generation ago, as the Clean Air Act has significantly reduced airborne toxic emissions and smog, and the prevalence of cigarette smoking has decreased. And yet rates of asthma are sharply on the increase, according to the Centers for Disease Control and Prevention, which reports that U.S. asthma rates rose more than 12% from 2001 to 2009. Now 1 in 12 residents has asthma, or about 8%.
While all demographic group showed "significant" increases in asthma rates, the disease still affects children, especially poor children, and particularly poor black children, more than any other group. Among children, boys are more likely to have asthma than girls, but as adults, women are more likely to have asthma than men.
The CDC study only measured rates of disease, and did not attempt to determine the underlying causes for the increased prevalence. In commentary accompanying the study, however, researchers noted the baffling incongruity of the statistics, given the broad advances in air quality. "Although probable causes for the increase in asthma are unclear, CDC's top priority is getting people to manage their asthma better," researchers wrote.
Among the factors that researchers identified as possibly interacting to cause increased and uneven asthma rates: genetic predisposition, allergies, health risk factors including smoking and obesity, exposure to environmental allergens and pollutants. "In particular, obesity and exposure to tobacco smoke each have been associated with increased asthma severity," researchers noted.
Other government health research agencies associated with the National Institutes of Health are actively looking for the causes underlying the increases in asthma.
The National Institute of Environmental Health Sciences is "working to understand how exposures to environmental agents trigger diseases such as asthma, and how we can prevent, diagnose and treat these diseases." Among the programs is the use of a robot, nicknamed by its acronym PIPER (Pre-toddler Inhalable Particulate Environmental Robotic sampler), which roams floors to reproduce the conditions that toddlers experience in their day-to-day lives of crawling, "while collecting better estimates of young childrens exposure to indoor air pollutants, such as particulate matter, pesticides, allergens, endotoxins and airborne fungi." Another project, in collaboration with the Environmental Protection Agency, has found that children living near highways are more likely to have asthma.
The National Institute of Allergy and Infectious Diseases is conducting a study to determine whether Vitamin D supplements given to pregnant women could prevent their children from developing asthma. Its research program is looking into understanding how allergens, pollutants, infections and genetics interact with the immune system to cause and aggravate asthma.
The EPA recommends taking these five steps to prevent asthma attacks:
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