Causes, Victims of Asthma Epidemic Continue to Confound; Flawed Data Contribute to Confusion; Standardized Research Tools Needed

3/20/2002

From: Amy Gergely, 202-628-7772, for the Public Health Policy Advisory Board

WASHINGTON, March 20 -- Despite decades of data, researchers are no closer now to understanding the roots of the asthma epidemic than they were when it first began 20 years ago. Flawed and inconclusive data, as well as the absence of a standardized system for monitoring trends, have hampered efforts to understand and control the ongoing epidemic. This is the conclusion of a report released today by the Public Health Policy Advisory Board (PHPAB).

The report, "Asthma: Epidemic Increase, Cause Unknown," finds that, while the asthma epidemic is evident in both mortality and morbidity data, the reasons for the epidemic remain unknown.

The PHPAB calls on public health officials to focus on the epidemic specifically so as to identify its roots, as well as the reasons the condition seems to disparately affect those of certain ethnic groups, ages and genders. "The public health community has not yet adequately focused on gaining an understanding of the asthma epidemic. Without this, prevention is not possible," the report concludes.

"We have heard reports of asthma being linked to almost everything, from air pollution and exercise, to cockroaches and cooking smoke, but in fact, we have no conclusive evidence that the elimination of any one of these factors -- or all -- would stop the epidemic," said Dr. Louis W. Sullivan, M.D., PHPAB's chairman. "In the absence of reliable data and an understanding of the epidemic, these reports may do little more than to breed false hope, fear, confusion and skepticism."

Part of the problem is that federal asthma data have serious inconsistencies, the PHPAB argues. The implementation of a changed definition of asthma for the federal government's major health survey in 1997 without recalibration of previous statistics, makes it difficult to accurately compare trends in the prevalence of asthma before that date to those since. In fact, the report states, the use of the new definition produced an immediate and wholly artificial reduction by some 20 percent in the prevalence of asthma in children in the 1998 data. Additionally, federal definitions for important descriptors, such as children's age categories and racial and ethnic groupings, are inconsistent making apple-to-apple comparisons impossible.

Another thing that continues to confound researchers is the unexplained higher than average rate of asthma mortality among U.S. blacks and equally perplexing lower than average rate among Hispanics. According to 1998 federal data, blacks die from asthma at a rate twice that of whites (3.9/100,000 - 1.8/100,000) and three times that of Hispanics (1.2/100,000).

However, the report also notes, it is possible that the new federal definition of asthma is prejudicial against minorities, since inclusion requires an individual to have been diagnosed by a health professional to have asthma and to have experienced an asthma attack within the previous year. PHPAB Distinguished Fellow Ciro Sumaya, M.D. observed that, "Many cases of asthma among low-income minorities may be underreported simply because they are less likely to visit the doctor on a regular basis."

Asthma, one of the most prevalent chronic diseases in the U.S., remains a profound public health problem, more than doubling in magnitude between 1980 and 1999, from 6.8 to 17.3 reported cases, according to the Centers for Disease Control and Prevention. Deaths from asthma tripled from 1,674 in 1977 to 5,438 in 1998; and costs doubled from $6.2 billion in 1990 to $12.7 billion in 2000.

Other recent federal statistics on asthma include:

-- 34 Americans die every day from asthma-related causes. -- More than 12,000 asthma-related deaths occur annually. -- Asthma is the primary reason for about 14 million doctor's visits and two million hospital emergency room visits each year.

The Public Health Policy Board is an independent, not for profit public health advocacy group founded by Louis W. Sullivan, M.D., former Secretary of the U.S. Department of Health and Human Services. Its goal is effective public health policy through a process of sound, science-based policymaking.

EDITORS NOTE: "Asthma: Epidemic Increase, Cause Unknown," can be read online or downloaded in .pdf format at http://www.phpab.org. To order a copy of the report, e-mail reports@phpab.org.