There was also a significant association of wheezing with dermatitis and high number (six or more) of cold and pneumonia episodes in the first year of life. Maternal breastfeeding lasting less than

four months was also a risk factor, as shown in Fig. 1. The main risk factors associated with recurrent wheezing were familial asthma, early onset of wheezing, nocturnal symptoms, over six episodes of colds, asthma diagnosis, and severe symptoms (Fig. 2). Many studies worldwide have observed a high prevalence of wheezing during the first years of life. The first international comparison of EISL14 studied over 30,000 children from 17 centers in Europe and Latin America, including eight in Brazil. The recently published data demonstrated that there is a great variability in the prevalence and Venetoclax in vivo severity of wheezing in the different centers, but with a tendency to higher prevalence and severity in children from Latin America. The prevalence MLN8237 of wheezing in that study, considering the total study population, was 45.2%, 20.3% of which corresponded to recurrent wheezing. When the data was stratified for Latin America, the prevalence was 47.3% and 21.4% for wheezing and recurrent wheezing, respectively, and for Europe, 34.4%, and 15.0%, respectively.14 In Brazil, the prevalence of wheezing in the first year of life

ranged between 43% and 63.6%, and 21.9% and 36.6% for occasional and recurrent wheezing, respectively. The values observed here show great variability; this difference is possibly associated with differences in climatological, environmental, and socioeconomic characteristics of different regions.14 This study observed a prevalence of 37.7% for occasional wheezing and 16.2% for recurrent wheezing; this

prevalence of recurrent wheezing is below that found in other studies using the EISL protocol,10 especially in Brazil. The identification of the determinants of wheezing in infants has been the subject of several studies. In fact, several factors appear to play a decisive role in the triggering and maintenance of wheezing in infants, such as genetic, immunological, and environmental variables, as well as infection and maternal breastfeeding, among others. This study showed a significant association of wheezing with respiratory infection Baf-A1 order for all types of wheezing. Respiratory infections are common in childhood and have an important role in infant morbimortality. They require several outpatient clinic visits, hospital admissions, and consequently increase public health care costs in many countries.15 There appears to be an important association between respiratory infections, particularly those caused by viruses, and the pathogenesis of wheezing in childhood.16 and 17 The EISL showed a significant association between the occurrence of colds in the first three months of life and wheezing in infants in countries from Europe and Latin America, especially those with recurrent wheezing.18 Other factors also contribute to the risk of wheezing.