PURPOSE OF THE STUDY.
To test the hypothesis that reduced lung function in early life is associated with increased risk of persistent wheeze at age 18 years.
A total of 253 subjects were originally recruited at age 1 month.
Maximal flow at functional residual capacity (VmaxFRC) was measured in 1-month-old infants who were then followed up at ages 6, 12, and 18 years. On the basis of symptoms reported, the subjects were categorized as having remittent wheeze (wheezing at earlier assessments but not at age 18 years), later-onset wheeze (wheezing at age 18 years but not earlier), persistent wheeze (wheezing at age 18 years and at least 1 earlier assessment), or no wheeze. Smoking status was also noted at age 18 years.
Of the subjects originally recruited, 150 were followed up at age 18 years. Thirty-seven of them had recent wheeze. Compared with the no-wheeze group (n = 96), persistent wheeze (n = 13) was independently associated with a reduced percentage of predicted VmaxFRC (mean reduction: 43%; 95% confidence interval [CI]: 13%–74%). Compared with the no-wheeze group, persistent wheeze was also associated with atopy in infancy (odds ratio [OR]: 7.1; 95% CI: 1.5–34.5), maternal asthma (OR: 6.8; 95% CI: 1.4–32.3), and active smoking (OR: 4.8; 95% CI: 1.0–21.3). When only wheeze at age 18 years was considered, a reduced percentage of predicted VmaxFRC was associated with wheeze at age 18 years only among current smokers (P = .04).
Persistent wheezing is associated with multiple factors, including reduced lung function at age 1 month, infant-onset atopy, maternal asthma, and active smoking. Wheeze at age 18 years, regardless of previous wheeze status, is associated with active smoking but only among those with reduced lung function in infancy.
This study included a small cohort and further investigation is needed, but it provides new insight into the link between reduced lung function in infancy and wheezing beyond childhood. This study also may have important implications for public health in identifying young adults who are at the highest risk of wheezing if they smoke.
- Copyright © 2013 by the American Academy of Pediatrics