Duration of NICU Exposure Associated With Decreased Risk of Atopic Dermatitis

Abstract

To study the infant and environmental factors that may contribute to lowered incidence of atopic dermatitis (AD) in preterm infants.The study included infants born from June 1, 2011, to April 20, 2017, at the University of Florida.In this single-center retrospective study, researchers used electronic health records (EHRs). The study population was subdivided to those receiving primary care within the UF health system. Inclusion criteria were children who had at least 2 well-child visits, with 1 of the visits being at or after 300 days of life. The diagnosis of AD was determined if certain International Classification of Diseases, Ninth Revision, or International Classification of Diseases, 10th Revision, codes were used in the EHR record. Demographic, birth, maternal, and clinical information were extracted during EHR review. Independent samples t tests or χ2 tests were used to compare those with or without AD on continuous variables and categorical variables separately. The association of the predictor variables including sex, delivery mode, gestational age, birth weight, and length of stay in the NICU, with AD were examined by using logistic regression.Inclusion criteria was met by 4016 pairs of mother and infants. Nearly one-half (49%) of the infants were female. The distribution of race and ethnicity was as follows: 39.2% were Black, 38.5% were non-Hispanic White, 7.1% were Hispanic, and 15.2% were other race and ethnicities. The majority (65%) of deliveries were vaginal. A diagnosis of AD was made in 26.6% of the included study population. The incidence of AD was significantly associated with delivery mode (P = .13), NICU stay (P < .001), gestational age (P = .001), and birth weight (P = .002) in bivariate analysis. Longer gestation, vaginal delivery, no NICU stay, or higher birth weight were associated with an increased risk of developing AD. The lowest rates of AD were observed in extreme preterm infants (<28 weeks), and very preterm infants (28 to <32 weeks' gestation). When AD was modeled with the predictor variables, NICU length of stay was the only one to remain significantly (P = .004) associated with a lower risk of AD.A longer stay in the NICU correlated with a decreased risk of an infant developing AD.With this study, the authors provide a connection between NICU stay and incidence of AD development. This begs the question as to what factors associated with a NICU stay may contribute to this decreased incidence. In recent years, the human microbiome and its role in disease development have been at the forefront of novel research. Further exploration into the influence of NICU environmental exposures on cutaneous immunity as well as skin and intestinal microbiomes is warranted.