Risk factors and characteristics of respiratory and allergic phenotypes in early childhood.

BACKGROUND: Unsupervised approaches can be used to analyze complex respiratory and allergic disorders. OBJECTIVE: We investigated the respiratory and allergic phenotypes of children followed in the Pollution and Asthma Risk: An Infant Study (PARIS) birth cohort. METHODS: Information on respiratory and allergic disorders, medical visits, and medications was collected during medical examinations of children at 18 months of age; biomarker data were also collected (total and allergen-specific IgE levels and eosinophilia). Phenotypes were determined by using latent class analysis. Associated risk factors were determined based on answers to questionnaires about environmental exposures. RESULTS: Apart from a reference group, which had a low prevalence of respiratory symptoms or allergies (n=1271 [69.4%]), 3 phenotypes were identified. On the basis of clinical signs of severity and use of health care resources, we identified a mild phenotype (n=306 [16.7%]) characterized by occasional mild wheeze and 2 severe phenotypes separated by atopic status. The atopic severe phenotype (n=59 [3.2%]) included 49 (83%) children with wheezing and was characterized by a high prevalence of atopy (61% with allergenic sensitization) and atopic dermatitis (78%). In contrast, atopy was rare among children with the nonatopic severe phenotype (n=195 [11%]); this group included 88% of the children with recurrent wheezing. Risk factors for respiratory disease included parental history of asthma, male sex, siblings, day care attendance, exposure to tobacco smoke or molds, indoor renovations, and being overweight, although these factors did not have similar affects on risk for all phenotypes. CONCLUSION: Atopy should be taken into account when assessing the risk of severe exacerbations (that require hospital-based care) in wheezing infants; precautions should be taken against respiratory irritants and molds and to prevent children from becoming overweight.

Can early household exposure influence the development of rhinitis symptoms in infancy? Findings from the PARIS birth cohort.

BACKGROUND: Allergic rhinitis (AR) has become the most prevalent chronic allergic disorder in childhood, and the role of environment has been questioned, particularly in early life. OBJECTIVE: To investigate the risk factors for rhinitis symptoms in infants included in the PARIS (Pollution and Asthma Risk: an Infant Study) birth cohort. METHODS: Infants were invited to participate at age 18 months in a health examination conducted by a pediatrician. Allergic rhinitis was defined as the presence of rhinitis symptoms (runny nose, blocked nose, sneezing in the absence of a cold) combined with biological atopy (elevated total immunoglobulin E [IgE], specific IgE, or eosinophilia) and nonallergic rhinitis (NAR) as symptoms without biological atopy. Information about indoor exposures and lifestyle was collected during a telephone interview when the child was 1 month of age. Risk factors for AR and NAR were studied by using a polytomous regression model. RESULTS: The prevalence of AR and NAR was 70/1,850 (3.8%) and 99/1,850 (5.4%), respectively. Allergic rhinitis and NAR did not share similar risk factors. Male sex (odds ratio [OR] = 1.99 [1.19-3.32]), parental history of AR (OR = 1.89 [1.16-3.08]), low socioeconomic class (OR = 2.23 [1.05-4.72] for low vs high level), and the presence of cockroaches in the home (OR = 3.15 [1.67-5.96]) were risk factors for AR. Conversely, the presence of particle-board furniture less than 12 months old in the child's bedroom was associated with an increased risk of NAR (OR = 1.87 [1.21-2.90]). CONCLUSIONS: This study should raise awareness about the impact of indoor exposures, particularly with regard to cockroaches and particle-board furniture, because they could influence the occurrence of noninfectious rhinitis.