The prevalence and risk factors of allergic and respiratory symptoms in a regional cohort of extremely low birth weight children (<1000 g)

Abstract

BackgroundChildren who were <1000 g (ELBW extremely low birth weight) at birth more frequently present with wheezing which is the most common reason that pediatric consultation is sought. Therefore asthma is diagnosed very often. However is the asthma that is diagnosed in ELBW subjects atopic in origin, or is there a different etiology?AimTo determine if ELBW infants are at higher risk for the development of allergic and respiratory symptoms and to establish if there were any specific risk factors for these symptoms.Methods81 children born with a mean birthweight of 845 g (91% of available cohort) were evaluated at the mean age 6.7 years. The control group included 40 full-term children. The children were examined for clinical signs of allergy, and were subjected to the following tests: serum total IgE, skin prick tests (SPT), exhaled nitric oxide measurement (FeNO) and spirometry.ResultsELBW children had wheezing episodes more often (64% vs. 25%; OR (odds ratio): 5.38; 95% CI (confidence interval): 2.14-13.8) and were diagnosed more frequently with asthma (32% vs. 7.5%; OR: 5.83, 95% CI: 1.52-26) than their term born peers. The most important risk factors for wheezing persistence were hospitalization and wheezing episodes in first 24 months of life. Mean serum tIgE level (geometric mean: 32+/−4 vs. 56+/−4 kU/L; p=0.002) was higher and the number of children with positive results of tIgE level (12% vs. 32%; p=0.02) were more frequent in the control group. Children from the control group also more frequently had SPT, however this data was not statistically significant (11% vs. 24%; p=0.09). All of the ELBW had normal FeNO level (<=20 ppb), but 5 children from the control group had abnormal results (p=0.02). There was no difference between the groups in the occurrence of allergic symptoms.ConclusionELBW children have more frequent respiratory, but not allergic problems at the age of 6–7 years compared to children born at term. The need for rehospitalization in the first 2 years of life, was a more important risk factor of future respiratory problems at the age of 7 than perinatal factors, the diagnosis of bronchopulmonary dysplasia or allergy.

Associação entre variáveis clínicas relacionadas à asma em escolares nascidos com muito baixo peso com e sem displasia broncopulmonar

“…Many of them try to answer the question of whether the BPD and/or preterm birth are risk factors for asthma 411 , 21 , 26 As found in the present study, other authors have observed a higher prevalence of asthma in VLBW infants when compared with the prevalence of asthma in the world population,7 , 11 , 19 , 22 , 27 with values for extremely premature infants ranging between 26%5 , 19 , 27 and 40% 22…”

“…In contrast, the effects of BPD in the onset of atopy, asthma, and/or recurrent wheezing at older ages is controversial 34 , 9 , 13 , 15 , 16 The effect of BPD in lung function in the long term has been evaluated in numerous age groups, including newborns,17 infants,18 preschoolers,19 schoolchildren,7 - 11 adolescents,12 - 14 and adults 2022 Studies have shown reduced lung volumes in different age groups, but with low association to clinical symptoms.…”

A systematic review of early life factors which adversely affect subsequent lung function

“…They comprised 6 birth cohorts [17][18][19][20][21][22] and 19 population-based longitudinal studies. [12,13,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] Tables 1 and 2 give an overview of the included studies. The reasons for rejecting the remaining 30 papers [9,10, are summarised in Table 3.…”

“…Four studies were included in our review .Three of the five risk factor combinations investigated showed a significant association with subsequent low lung function. [18,29,30,37] The longest duration of follow-up in those studies was 12 years. A 21 year follow-up study of babies born extremely prematurely has reported that any differences in lung function compared with termborn controls during childhood disappears in adult life.…”

The impact of respiratory viruses on lung health after preterm birth

“…Thus, different pathophysiological mechanisms, other than allergic sensitization, are proposed to underlie the increased risk of asthma and wheezing disorders following preterm birth. This hypothesis has been supported by studies describing the lack of association between allergic sensitization, viral infection and the risk of asthma and diminished lung function later in life among preterm-born children [116–118]. …”