Risk factors for airway remodeling in asthma manifested by a low
postbronchohator FEV1/vital capacity ratio - A longitudinal population
study from childhood to adulthood
AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE, 165 (11):
1480-1488 (June 2002)Abstract
Airway remodeling may lead to irreversible loss of lung function in
asthma. The Impact of childhood asthma, airway responsiveness, atopy,
and smoking on airway remodeling was Investigated In a birth cohort
studied longitudinally to age 26. A low postbronchodilator ratio of
forced exhaled volume In 1 second (FEV1) to vital capacity (VC) at age
18 or 26 was used as a marker of airway remodeling. ``Normal'' study
members with no history of asthma ever, no wheezing in the last year,
and no smoking ever were used to determine sex- and age-specific
reference values for this ratio. The lower limit of normal was defined
as the mean ratio minus 1.96 standard deviation, delimiting the 2.5\% of
the normal population with the lowest FEV1/VC ratio. A low
postbronchodilator FEV1/VC ratio was found in 7.4\% and 6.4\% of study
members at ages 18 and age 26 and 4.6\% at both assessments. Lung
function was low throughout childhood In those with a consistently low
postbronchodilator FEV1/VC ratio at both ages. Those with consistently
low postbronchodilator ratios also showed a greater decline in the
prebronchodilator FEV1/VC ratio from ages 9 to 26 compared with those
with normal postbronchodilator ratios at both ages (males, -12\% versus
-6\%, p < 0.0001; females, -10.5\% versus -5.5\%, p < 0.01). Asthma,
male sex, airway hyperresponsiveness, and low lung function In childhood
were each independently associated with a low postbronchodilator FEV1/VC
ratio, which In turn was associated with an accelerated decline In lung
function and decreased reversibility. These data suggest that airway
remodeling In asthma, as manifested by Impaired lung function, begins In
childhood and continues into adult life.