Asthma, which can include wheezing and sometimes frightening shortness of breath, appears to be much more prevalent than previously thought even if many children suffer milder forms than cases seem in doctors' office.
Eleven percent of children surveyed in homeroom, science classes or physical education -- 13,619 -- reported being diagnosed with the illness and had current symptoms. Another 21,184, or 17 percent, said they suffered asthma-like symptoms within the previous year but had not been diagnosed.
Odds are that countless children in other states are going undiagnosed and untreated as well, researchers say. Earlier studies have shown that asthma has become increasingly prevalent over the past 20 years in this country and abroad for unknown reasons, possibly exposure to environmental allergens or irritants.
"The effect of asthma-like symptoms on the lives of children with no diagnosis is considerable," said Dr. Karin Yeatts, research assistant professor of epidemiology at the UNC School of Public Health.
"Twenty percent missed a half day or more of school per month because of wheezing, 25 percent had limited activities because of wheezing once or more per month, 32 percent had sleep disturbances in the last four weeks, 7 percent visited the emergency department and 5 percent were hospitalized for wheezing or breathing difficulties," she said
Even if many of the cases are mild, such figures on health effects are far in excess of what healthy children experience, the scientist said.
Yeatts is lead author of a report on the study in the June issue of the Archives of Pediatric and Adolescent Medicine, an American Medical Association Journal. Co-authors are Dr. Carl Shy, professor of epidemiology at UNC; Dr. Mark Sotir, a former UNC doctoral student now with the Centers for Disease Control and Prevention in Atlanta; Dr. Stan Music, now of Merck & Co. in West Point, Pa.; and Casey Herget, now with the National Respiratory Training Center.
"Sleep disturbances because of wheezing are one example of the major problems these children face," Yeatts said. "The long-term clinical implications include chronic sleep deprivation and the related reduced immune function, increased susceptibility to respiratory infections, reduced cognitive function and decreased learning ability," Yeatts said.
Of the 11 percent of children surveyed whose asthma already was diagnosed by a physician, almost half reported missing a half day or more of school in the past month, she said. Thirty percent said they visited emergency departments for their symptoms at least once in the previous year.
"People often believe asthma is an inner-city problem, yet we found it to be high all over North Carolina, half of which is classified as rural," the scientist said.
The N.C. Department of Health and Human Services' public health division supported the UNC research through a grant from its women's and children's health section.
Strengths of the study were its large size and high response rate, its population-based rather than clinic-based sample and an internationally standardized and validated survey, Yeatts said.
A possible limitation was that the information used was self-reported by adolescents, a small percentage of whom might have mistaken colds and related symptoms for asthma or exaggerated them, Yeatts said. Since researchers played for their subjects a videotape specially produced for the International Study of Asthma and Allergies in Childhood showing scenes of children wheezing, that possibility was reduced.
Note: Yeatts can be reached at (919) 843-1841 or 966-9899 or via email at karin_yeatts@unc.edu
School of Public Health Contact: Lisa Katz, (919) 966-7467
Broadcast Contact: Karen Moon, 962-8595
News Services Contact: David Williamson, (919) 962-8596
By DAVID WILLIAMSON
UNC News Services
Journal
Archives of Pediatrics and Adolescent Medicine