Among children who exhibit asthma-like symptoms during preschool years, researchers have found that patterns of wheezing prevalence and levels of lung function are established by age 6 and do not significantly change for at least 10 years.
Their findings were reported in the second issue of the November 2005 American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society.
Fernando D. Martinez, M.D., of the Arizona Respiratory Center, University of Arizona Health Sciences Center, Tucson, along with eight associates, studied 826 children based on the occurrence of "wheezing lower respiratory illnesses" before age 3 and active wheeze at age 6. Among this group, there were 425 "never wheezers," 164 "transient early wheezers," 113 "persistent wheezers," and 124 "late-onset wheezers."
The four types of pre-school wheeze that were used to classify the children were defined as based on either the presence or absence of at "least one physician-diagnosed wheezing 'lower respiratory illness' in the first 3 years of life," and at least "one episode of 'parent-reported wheeze' during the past year for the child at age 6."
During the followup on each child at ages 8, 11, 13, and 16 years, parents completed a questionnaire on the youngster's prevalence of wheeze (with or without a cold). Researchers characterized current wheeze at each age as either "no wheeze," "infrequent wheeze" (one to three episodes in the past year), and "frequent wheeze" (four or more episodes in the past year). In addition, the investigators performed a pulmonary function test on each participant at age 11.
"There was no significant change in lung function among subjects within either of the different wheezing groups or the non-wheezing group studied, relative to their peers, from age 6 to 16 years," said Dr. Martinez.