Asthma rates may have leveled off in U.S. children after increasing in the 1980s and early 1990s, government research shows.
Earlier data suggested a similar trend among adults, but more evidence is needed to confirm it, according to the federal Centers for Disease Control and Prevention.
Rates in children increased by an average of 4.3 percent per year from 1980 through 1996, rising from 3.6 percent to 6.2 percent of all U.S. youngsters. The rate was 5.4 percent in 1997 and remained stable through 2000, according to CDC data published in August's Pediatrics.
The CDC researchers said their own numbers may be skewed because the survey used to collect asthma data changed slightly in 1997.
The American Academy of Allergy, Asthma & Immunology estimates that about 5 million U.S. children are currently affected by asthma, which is marked by wheezing, shortness of breath, coughing and tightness of the chest.
Black children were affected disproportionately, and the racial gap widened throughout the period, rising to 26 percent higher than whites in 1995-96, the CDC found.
The rate increased dramatically among Hispanics, though they generally had fewer asthma attacks than whites or blacks.
In 1985, there were 60 asthma cases per 1,000 children among blacks, 51 among whites and 31 among Hispanics. In 1999, rates were 74 per 1,000 among blacks, 50 among whites and 44 among Hispanics.
While asthma deaths are rare, the mortality rate increased by an average of 3.4 percent per year through 1998, though declining in 1997, the CDC data showed. In 1998, the overall death rate was 3.5 per 1 million children. Death rates were similar in whites and Hispanics but were more than four times higher among blacks by the late 1990s.