The Risk of Asthma in Late Preterm Infants

Abstract

RationalePreterm infants have been reported to have a higher risk of asthma compared to term infants. However, little is known about the risk of asthma among late preterm (LPT) infants (34 0/7 to 36 6/7 weeks of gestation).MethodsThis study used a retrospective birth cohort born in Olmsted County, Minnesota from 2002 through 2006 that was identified using the Rochester Epidemiology Project. Appropriate for gestational age (AGA) weight LPT infants and AGA term infants (37 0/7 to 40 6/7 weeks of gestation) were randomly sampled with regard to gender, birth year, and institution using frequency matching. Asthma status was ascertained by applying predetermined criteria for asthma. Study subjects were followed until 12/31/2010 by censoring event, last follow up date, and end of study period. Cumulative incidence of asthma during the first 8 years of life was compared using log-rank test and Kaplan-Meier curves.ResultsThere were 654 LPT infants and 7447 term infants born during the study period. We enrolled 200 eligible AGA LPT infants and 200 frequency matched term infants. In this preliminary report, 119 LPT infants (50% male, 67% Caucasian) and 116 term infants (54% male, 72% Caucasian) were available. The cumulative incidence of asthma among LPT infants during the study period was 24.5% while in term infants it was 14.5% (p=0.041).ConclusionsBased on this preliminary data, the risk of asthma is higher in former LPT infants. The results warrant completion of this ongoing study given the significant finding. The nature of this association needs to be further examined. RationalePreterm infants have been reported to have a higher risk of asthma compared to term infants. However, little is known about the risk of asthma among late preterm (LPT) infants (34 0/7 to 36 6/7 weeks of gestation). Preterm infants have been reported to have a higher risk of asthma compared to term infants. However, little is known about the risk of asthma among late preterm (LPT) infants (34 0/7 to 36 6/7 weeks of gestation). MethodsThis study used a retrospective birth cohort born in Olmsted County, Minnesota from 2002 through 2006 that was identified using the Rochester Epidemiology Project. Appropriate for gestational age (AGA) weight LPT infants and AGA term infants (37 0/7 to 40 6/7 weeks of gestation) were randomly sampled with regard to gender, birth year, and institution using frequency matching. Asthma status was ascertained by applying predetermined criteria for asthma. Study subjects were followed until 12/31/2010 by censoring event, last follow up date, and end of study period. Cumulative incidence of asthma during the first 8 years of life was compared using log-rank test and Kaplan-Meier curves. This study used a retrospective birth cohort born in Olmsted County, Minnesota from 2002 through 2006 that was identified using the Rochester Epidemiology Project. Appropriate for gestational age (AGA) weight LPT infants and AGA term infants (37 0/7 to 40 6/7 weeks of gestation) were randomly sampled with regard to gender, birth year, and institution using frequency matching. Asthma status was ascertained by applying predetermined criteria for asthma. Study subjects were followed until 12/31/2010 by censoring event, last follow up date, and end of study period. Cumulative incidence of asthma during the first 8 years of life was compared using log-rank test and Kaplan-Meier curves. ResultsThere were 654 LPT infants and 7447 term infants born during the study period. We enrolled 200 eligible AGA LPT infants and 200 frequency matched term infants. In this preliminary report, 119 LPT infants (50% male, 67% Caucasian) and 116 term infants (54% male, 72% Caucasian) were available. The cumulative incidence of asthma among LPT infants during the study period was 24.5% while in term infants it was 14.5% (p=0.041). There were 654 LPT infants and 7447 term infants born during the study period. We enrolled 200 eligible AGA LPT infants and 200 frequency matched term infants. In this preliminary report, 119 LPT infants (50% male, 67% Caucasian) and 116 term infants (54% male, 72% Caucasian) were available. The cumulative incidence of asthma among LPT infants during the study period was 24.5% while in term infants it was 14.5% (p=0.041). ConclusionsBased on this preliminary data, the risk of asthma is higher in former LPT infants. The results warrant completion of this ongoing study given the significant finding. The nature of this association needs to be further examined. Based on this preliminary data, the risk of asthma is higher in former LPT infants. The results warrant completion of this ongoing study given the significant finding. The nature of this association needs to be further examined.