Risk factors for incidence and persistence of asthma-like symptoms

Abstract

Asthma represents the most common chronic disease in childhood. Children with asthma are at increased risk for developing long-term irreversible airway obstruction in adult life, the fourth leading cause of death in USA. Our aims were to: (1) Determine whether reduced IFNgamma production and plasma soluble CD14 (sCD14) levels in early life are significant risk factors for the development of wheezing in the first year of life; (2) Estimate rates of persistence and remission of childhood wheezing after puberty; (3) Study risk factors affecting persistence of childhood wheezing after puberty. We used data from the two large ongoing birth cohorts of the Tucson Infant Immune Study (IIS) and the Tucson Children's Respiratory Study (CRS). Among 238 children from IIS, we found the odds of developing recurrent wheezing in the first year of life to be 4.5 times higher for children in the lowest quartile of IFNgamma production at 3 months (p = .0005) and 3.2 times higher for children in the lowest quartile of sCD14 levels at birth (p = .004) as compared with children in the other 3 combined quartiles of IFNgamma and sCD14, respectively. We studied persistence and remission of wheezing after puberty among 732 children from the CRS cohort. We found that 29% of children with infrequent wheezing during childhood experienced persistent wheezing after contrast, the proportion of persistent wheezing was much higher (60%) among children meeting the for asthma during childhood. Frequency of wheezing during childhood, obesity, an early onset of puberty, bronchial hyperresponsiveness, and skin test sensitization were significant predictors of persistent asthma after puberty. By looking at genetic factors, we also found that the homozygous status for Gly in codon 16 of the beta2 Adrenoceptor doubled the risk for persistent wheezing after puberty among boys (RR 2.01, p = .0008) but not girls. Our findings from two population-based longitudinal cohorts provide the first evidence that altered immunological markers precede the onset of wheezing early in life, challenge the commonly held view that most asthma cases remit during adolescence, and provide a profile of risk.