Lieberman Op-Ed in National Review Online
by Ben Lieberman
April 5, 2002
Asthma is on the rise, and the experts are not sure why. Outdoor air pollution is the most politically popular culprit but is unlikely to be the cause. More plausible explanations have received scant attention in comparison. The latest study from the Public Health Policy Advisory Board (PHPAB), a not-for-profit public-health advocacy group, underscores the many uncertainties regarding this increasingly common disease. Nonetheless, "Asthma: Epidemic Increase Cause Unknown," is important reading in that it spells out what needs to be learned before this epidemic can be effectively addressed.
This much is known asthma incidence and mortality have sharply increased in the past two decades, particularly among children. The study cites statistics showing a doubling of asthma cases from 6.8 million in 1980 to 14.6 million in 1996, and a further increase to 17.3 million in 1999. There is some question about changing definitions of asthma and the possibility of higher diagnosis rates, but there is little doubt that the increase is real. Tragically, asthma deaths have tripled from 1,674 in 1977 to 5,438 in 1998, making it the leading cause of death in young children.
One might think that such a sharp rise could easily be traced to some clear cause, but none has yet emerged. Although doctors know many of the factors that contribute to the development of asthma and cause asthma attacks, there is no consensus regarding the reasons behind the increase.
Without question, genetics plays a role. Asthma runs in families, and medical statistics show racial and ethnic differences not attributable to income levels. For example, the study notes that asthma is considerably more common in African-American children as compared to whites, but is less common among Hispanics. However, genetics cannot explain the increase, unless there is some genetic predisposition to asthma that needs an environmental trigger to manifest itself.
That leads to the next question what has changed about the environment in which children live that has made asthma so much more prevalent? Again, there are no easy answers, although indoor air contaminants may play a role in both the development of asthma and the exacerbation of asthma attacks. The study references a report by the National Academy of Science's Institute of Medicine that identified a number of indoor air pollutants, including insect remains, for which there is evidence of a contributing role. This hypothesis may also help explain the timing of the asthma increase, as the energy crisis of the 1970s gave rise to regulations and incentives to cut down on "excessive" ventilation and create tighter, more energy-efficient buildings. These energy-conservation measures may well have had the unintended consequence of concentrating the indoor air contaminant levels in millions of newer homes and schools. Nonetheless, more needs to be learned before indoor air can be clearly implicated as the cause of the asthma increase.
One interesting hypothesis surrounds day care, and the relatively new phenomenon of large groups of infants spending many hours per day within close proximity of each other. Many parents have learned that kids in day care give each other colds and other contagious diseases with alarming frequency, thus the possibility of a role in asthma cannot be ignored. But, as the study concedes, the current body of evidence regarding day care and asthma is far from definitive.
Unfortunately, the potential cause taken most seriously in Washington is the one most easily dismissed outdoor air pollution. Environmental activists and their political allies have been quick to exploit the emotional issue of childhood asthma. Some cite research showing weak statistical associations between current air pollution levels and asthma as a justification for a host of regulations aimed at motor vehicle and industrial emissions. However, the study notes that "the long running increase in asthma prevalence has occurred during an era when, paradoxically, outdoor air has become cleaner." Unfortunately, as has occurred with the decades-long attempt to blame cancer on pollution, the misuse of the asthma issue by those with an environmental agenda may lead to a counterproductive misallocation of resources.
The study concludes that "the state of available data on asthma is a major barrier to understanding the epidemic," and calls for increased research into the reasons for the increase. Only when we better understand the cause of the asthma epidemic can an effective public-health response be created.
SOURCE: Public Health Policy Advisory Board (PHPAB)