Association between infant swimming and rhinovirus-induced wheezing.

AIM Infant swimming has been considered as a risk factor for wheezing, but the role that respiratory viruses play is unclear. We explored the effects of infant swimming on the risk of all wheezing illnesses and wheezing associated with rhinoviruses. METHODS We followed up a birth cohort of 1827 children until 17 months of age, collecting data on infant swimming, other risk factors and physician-diagnosed bronchiolitis or recurrent wheezing. Viral diagnostics were performed in a subset of children with all respiratory tract infections. RESULTS Data on infant swimming were obtained for 1038 children, with viral follow-up for 635 children. At least one wheezing illness was documented in 45/469 (9.6%) swimming children versus 39/569 (6.9%) nonswimming children (p = 0.11), and rhinoviruses were associated with wheezing in 11/296 (3.7%) swimming children versus 4/339 (1.2%) nonswimming children (p = 0.04). In adjusted logistic regression analyses, swimming had an odds ratio of 1.71 (p = 0.05) for bronchiolitis and 3.57 (p = 0.06) for rhinovirus-associated wheezing. An association between infant swimming and rhinovirus-associated wheezing was detected for children with atopic eczema (p = 0.006). CONCLUSION There may be a link between infant swimming and rhinovirus-induced wheezing illnesses in atopic infants.</p

Daycare attendance and respiratory tract infections: A prospective birth cohort study

Objective: We explored the burden of respiratory tract infections (RTIs) in young children with regard to day-care initiation.Design: Longitudinal prospective birth cohort study.Setting and methods: We recruited 1827 children for follow-up until the age of 24 months collecting diary data on RTIs and daycare. Children with continuous daycare type and complete data were divided into groups of centre-based daycare (n=299), family day care (FDC) (n=245) and home care (n=350). Using repeated measures variance analyses, we analysed days per month with symptoms of respiratory tract infection, antibiotic treatments and parental absence from work for a period of 6 months prior to and 9 months after the start of daycare.Results: We documented a significant effect of time and type of daycare, as well as a significant interaction between them for all outcome measures. There was a rise in mean days with symptoms from 3.79 (95% CI 3.04 to 4.53) during the month preceding centre-based daycare to 10.57 (95% CI 9.35 to 11.79) at 2 months after the start of centre-based daycare, with a subsequent decrease within the following 9 months. Similar patterns with a rise and decline were observed in the use of antibiotics and parental absences. The start of FDC had weaker effects. Our findings were not changed when taking into account confounding factors.Conclusions: Our study shows the rapid increase in respiratory infections after start of daycare and a relatively fast decline in the course of time with continued daycare. It is important to support families around the beginning of daycare.</p

Respiratory syncytial virus infections in children 0–24 months of age in the community

Objectives: Respiratory syncytial virus (RSV) is a major cause of hospitalization in young children, but there are little data on RSV infections in early childhood in the community. We conducted a prospective population-based birth-cohort study to determine the rates and characteristics of RSV infections in young children.Methods: We followed 923 children for acute respiratory infections (ARIs) from birth to age 24 months with daily diaries and study clinic visits. Nasal swab samples were obtained at the onset of ARIs and analyzed for RSV by RT-PCR and antigen tests. The rates of RSV infections and associated outcomes were estimated.Results: RSV was detected in 289 (6%) of 4728 ARIs with a nasal sample. The mean estimated annual rate of RSV infections was 37 (95% confidence interval [CI], 35–38) per 100 children at age 0–24 months. For RSV-associated outcomes, the estimated annual rates per 100 children were 34 (95% CI, 32–37) physician visits, 16 (95% CI, 15–17) antibiotic treatments, 12 (95% CI, 11–13) acute otitis media, and 6 (95% CI, 4–7) wheezing illnesses. The prevalence of RSV was 0.6% in asymptomatic children.Conclusions: RSV infections impose a high burden of disease in healthy young children in the community.</p

Antibiotic treatments during infancy, changes in nasal microbiota, and asthma development: Population-based cohort study

Early-life exposures to antibiotics may increase the risk of developing childhood asthma. However, little is known about the mechanisms linking antibiotic exposures to asthma. We hypothesized that changes in the nasal airway microbiota serve as causal mediator in the antibiotics-asthma link.In a population-based birth-cohort study in Finland, we identified longitudinal nasal microbiota profiles during age 2-24 months using 16S rRNA gene sequencing and unsupervised machine learning approach. We performed a causal mediation analysis to estimate the natural direct effect of systemic antibiotic treatments during age 0-11 months on risks of developing physician-diagnosed asthma by age 7 years and the natural indirect (causal mediation) effect through longitudinal changes in the nasal microbiota.In our birth cohort of 697 children, 8.0% later developed asthma. Exposure to ≥2 antibiotic treatments during age 0-11 months was associated with a 4.0% increase in the absolute risk of developing asthma (absolute increase, 95%CI, 0.9%-7.2%, P=0.006). Unsupervised clustering approach identified six longitudinal nasal microbiota profiles. Infants with a larger number of antibiotic treatments had a higher risk of having a profile with early Moraxella sparsity (per each antibiotic treatment, adjusted relative rate ratio, 1.38; 95%CI, 1.15-1.66; PEarly exposures to antibiotics were associated with an increased risk of asthma, and the effect was mediated, in part, by longitudinal changes in the nasal airway microbiota.</div

Longitudinal changes in early nasal microbiota and the risk of childhood asthma

International audienceOBJECTIVES: Although the airway microbiota is a highly dynamic ecology, the role of longitudinal changes in airway microbiota during early childhood in asthma development is unclear. We aimed to investigate the association of longitudinal changes in early nasal microbiota with the risk of developing asthma. METHODS: In this prospective, population-based birth cohort study, we followed children from birth to age 7 years. The nasal microbiota was tested by using 16S ribosomal RNA gene sequencing at ages 2, 13, and 24 months. We applied an unsupervised machine learning approach to identify longitudinal nasal microbiota profiles during age 2 to 13 months (the primary exposure) and during age 2 to 24 months (the secondary exposure) and examined the association of these profiles with the risk of physician-diagnosed asthma at age 7 years. RESULTS: Of the analytic cohort of 704 children, 57 (8%) later developed asthma. We identified 4 distinct longitudinal nasal microbiota profiles during age 2 to 13 months. In the multivariable analysis, compared with the persistent Moraxella dominance profile during age 2 to 13 months, the persistent Moraxella sparsity profile was associated with a significantly higher risk of asthma (adjusted odds ratio, 2.74; 95% confidence interval, 1.20–6.27). Similar associations were observed between the longitudinal changes in nasal microbiota during age 2 to 24 months and risk of asthma. CONCLUSIONS: Children with an altered longitudinal pattern in the nasal microbiota during early childhood had a high risk of developing asthma. Our data guide the development of primary prevention strategies (eg, early identification of children at high risk and modification of microbiota) for childhood asthma. These observations present a new avenue for risk modification for asthma (eg, microbiota modification). Copyrigh