The effect of early child care attendance on childhood asthma and wheezing: A meta-analysis

Environmental risk factors for respiratory infection and wheeze in young children: A multicentre birth cohort study

INTRODUCTION

Respiratory infections and wheeze have a considerable impact on the health of young children and consume significant healthcare resources. We aimed to evaluate the effect of environmental factors on respiratory infections and symptoms in early childhood.

METHODS

Environmental risk factors including: daycare attendance; breastfeeding; siblings; damp within the home; environmental tobacco smoke (ETS); child's bedroom flooring; animal exposure; road traffic density around child's home; and solid fuel pollution within home were assessed in children recruited to the GO-CHILD multicentre prospective birth cohort study. Follow-up information on respiratory infections (bronchiolitis, pneumonia, otitis media and cold or flu), wheeze and cough symptoms, healthcare utilisation and medication prescription was collected by postal questionnaires at 12 and 24 months. Log binomial and ordered logistic regression models were fitted to the data.

RESULTS

Follow-up was obtained on 1344 children. Daycare was associated with increased odds of pneumonia (odds ratio [OR] = 2.39, 95% confidence interval [CI]: 1.04-5.49), bronchiolitis (OR = 1.40, 1.02-1.90), otitis media (OR = 1.68, 1.32-2.14) and emergency department attendance for wheeze (RR = 1.81, 1.17-2.80). Breastfeeding beyond 6 months was associated with a reduced odds of bronchiolitis (OR = 0.55, 0.39-0.77) and otitis media (OR = 0.75, 0.59-0.99). Siblings at home was associated with an increased odds of bronchiolitis (OR = 1.65, 1.18-2.32) and risk of reliever inhaler prescription (RR = 1.37, 1.02-1.85). Visible damp was associated with an increased odds of wheeze (OR = 1.85, 1.11-3.19), and risk of reliever inhaler (RR = 1.73, 1.04-2.89) and inhaled corticosteroid prescription (RR = 2.61, 1.03-6.59). ETS exposure was associated with an increased odds of primary care attendance for cough or wheeze (OR = 1.52, 1.11-2.08). Dense traffic around the child's home was associated with an increased odds of bronchiolitis (OR = 1.32, 1.08-2.29).

CONCLUSION

Environmental factors likely influence the wide variation in infection frequency and symptoms observed in early childhood. Larger population studies are necessary to further inform and guide public health policy to decrease the burden of respiratory infections and wheeze in young children.

Early-Life Hygiene-Related Factors and Risk of Inflammatory Bowel Disease: A Scandinavian Birth Cohort Study

BACKGROUND

We aimed to investigate whether early-life hygiene-related factors influenced the risk of inflammatory bowel disease (IBD) in a Scandinavian population and test the association's consistency across cohorts.

METHODS

This study followed 117 493 participants in the All Babies in Southeast Sweden study and the Norwegian Mother, Father, and Child Cohort Study. IBD diagnoses were defined by national registers. Comprehensive data on hygiene-related exposures, such as having pets, rural living, daycare attendance, and siblings, were retrieved from questionnaires administered from pregnancy until child's age of 36 months. A multivariable Cox regression model yielded adjusted hazard ratios (aHRs) for IBD accounting for socioeconomic status and perinatal factors. Cohort-specific estimates were pooled using a random-effects model.

RESULTS

In over 2 024 299 person-years of follow-up 451 participants developed IBD. In pooled estimates children attending daycare up to 36 months of life vs not attending daycare were less likely to develop Crohn's disease (aHR, 0.60; 95% confidence interval [CI], 0.37- 0.98). Children having 1 or more siblings had a modestly increased risk of IBD (aHR, 1.17; 95% CI, 0.96-1.42; aHR for each sibling, 1.12; 95% CI, 1.01-1.24). The other hygiene factors were not significantly linked to later IBD. In the Norwegian Mother, Father, and Child Cohort Study cohort, bed sharing was associated with an increased risk of IBD, most notably for ulcerative colitis (aHR, 1.67; 95% CI, 1.01-2.78).

CONCLUSIONS

In this birth cohort study from 2 high-income Scandinavian countries, some early-life hygiene-related exposures were associated with IBD risk. The generalizability of these results to countries of other socioeconomic level is unknown.

Moraxella-dominated pediatric nasopharyngeal microbiota associate with upper respiratory infection and sinusitis

BACKGROUND

Distinct bacterial upper airway microbiota structures have been described in pediatric populations, and relate to risk of respiratory viral infection and, exacerbations of asthma. We hypothesized that distinct nasopharyngeal (NP) microbiota structures exist in pediatric populations, relate to environmental exposures and modify risk of acute sinusitis or upper respiratory infection (URI) in children.

METHODS

Bacterial 16S rRNA profiles from nasopharyngeal swabs (n = 354) collected longitudinally over a one-year period from 58 children, aged four to seven years, were analyzed and correlated with environmental variables, URI, and sinusitis outcomes.

RESULTS

Variance in nasopharyngeal microbiota composition significantly related to clinical outcomes, participant characteristics and environmental exposures including dominant bacterial genus, season, daycare attendance and tobacco exposure. Four distinct nasopharyngeal microbiota structures (Cluster I-IV) were evident and differed with respect to URI and sinusitis outcomes. These clusters were characteristically either dominated by Moraxella with sparse underlying taxa (Cluster I), comprised of a non-dominated, diverse microbiota (Cluster II), dominated by Alloiococcus/Corynebacterium (Cluster III), or by Haemophilus (Cluster IV). Cluster I was associated with increased risk of URI and sinusitis (RR = 1.18, p = 0.046; RR = 1.25, p = 0.009, respectively) in the population studied.

CONCLUSION

In a pediatric population, URI and sinusitis associate with the presence of Moraxella-dominated NP microbiota.

Duration of breastfeeding, age at introduction of complementary foods and allergy-related diseases: a prospective cohort study

Background

The influences of breastfeeding and infant diet in the prevention of allergy-related diseases are uncertain and many of the studies conducted on the topic are limited by methodological challenges. Our aim was to assess whether the duration of breastfeeding and age at complementary food introduction affected the prevalence of asthma, wheeze, allergic rhinoconjunctivitis (ARC) and eczema at two and six years of age.

Methods

We used information gathered between 2000 and 2014 through questionnaires in the Prevention of Allergy among Children in Trondheim (PACT) study, a prospective cohort study in Trondheim, Norway. The current study includes 6802 children who submitted questionnaires detailing breastfeeding duration and or age at introduction to complementary foods, as well as at least one of the child health questionnaires completed at two and six years of age. Adjusted odds ratios (aORs) were calculated for each combination of exposure and outcomes and sensitivity analyses were performed to assess the possible influence of recall bias and reverse causality.

Results

The mean duration of breastfeeding was 11 months (SD 5.6) in this study population and 5695 of 6796 (84%) infants had been breastfed for at least 6 months. We did not find any conclusive preventative effect of longer breastfeeding on parental reported doctor-diagnosed asthma, aOR 0.79 (95% CI 0.51, 1.21). However, at 6 years of age we observed a reduction in the less strictly defined outcome wheeze, aOR 0.71 (95% CI 0.53, 0.95). Longer breastfeeding was associated with a reduced risk of ARC at 2 years, aOR 0.65 (95% CI 0.49, 0.86), with a continued protective trend at 6 years, aOR 0.77 (95% CI 0.58, 1.04).

Conclusions

Longer breastfeeding resulted in a reduced risk of wheeze and a trend towards a protective effect on ARC up until school age. No conclusive associations were seen between the duration of breastfeeding or age at introduction to complementary foods and prevention of asthma, wheeze, ARC and eczema.

Trial registration

The trial is registered in Current Controlled Trials as ISRCTN28090297.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13006-020-00352-2.

Childhood wheeze trajectory-specific risk factors: A systematic review and meta-analysis

BACKGROUND

There is growing interest in the use of latent trajectory methodology to identify wheeze patterns in heterogeneous populations of children. This study systematically reviewed and meta-analyzed childhood wheeze trajectory studies to identify childhood wheeze trajectory group-specific risk factors among children from birth through to adolescence.

METHODS

We included studies that used latent trajectory methodology to identify wheeze trajectories and associated risk factors. We searched PubMed, EMBASE, and Google Scholar from 2000 through September 30, 2019, for relevant studies. The study was conducted according to the PRISMA recommendations.

RESULTS

Thirteen cohort studies conducted in eleven high-income countries were included in our meta-analysis with the length of follow-up ranging from 3 to 18 years. Five distinct latent wheeze trajectory groups were identified: Never/Infrequent, Early-Transient, Early-Persistent, Intermediate-Onset, and Late-Onset. We found moderate-to-strong evidence that family history of asthma predicted persistent childhood wheezing among male children but with lower risk among first-born children. There was weak-to-moderate evidence for childhood atopy, male sex, short duration of breastfeeding, tobacco exposure, daycare attendance, and having siblings as risk factors for Early-Transient wheezing; except for breastfeeding, these factors were also associated with intermediate and Late-Onset wheezing with varying effect sizes in high-risk vs general population cohorts.

CONCLUSIONS

Our findings confirm the consistency of wheeze trajectory groups defined by onset, peak prevalence, and duration; we also suggest a common nomenclature for future trajectory studies. With the exception of the relationship between a family history of asthma and persistent childhood wheezing, commonly suspected wheeze risk factors (childhood atopy, male sex, short duration of breastfeeding, tobacco exposure, daycare attendance, and having siblings) are not trajectory-specific and have varying effects in high-risk vs general population cohorts. Delineation of time-varying risk factor effects may be critical to the specificity of wheeze trajectory group prediction to better inform prognosis and targeted early preventive intervention among at-risk children.

The role of M2-2 PDZ-binding motifs in pulmonary innate immune responses to human metapneumovirus

Human metapneumovirus (HMPV) is a leading cause of lower respiratory tract infection (LRTI) in pediatric and geriatric populations. We recently found that two PDZ-binding motifs of the M2-2 protein, 29-DEMI-32 and 39-KEALSDGI-46, play a significant role in mediating HMPV immune evasion in airway epithelial cells (AECs). However, their role in the overall pulmonary responses to HMPV infection has not been investigated. In this study, we found that two recombinant HMPVs (rHMPV) lacking the individual M2-2 PDZ-binding motif are attenuated in mouse lungs. Mice infected with mutants produce more cytokines/chemokines in bronchoalveolar lavage (BAL) fluid compared to mice infected with wild-type rHMPV. In addition, both mutants are able to enhance the pulmonary recruitment of dendritic cells (DCs) and T cells and induce effective protections against the HMPV challenge. The DC maturation is also significantly improved by the motif mutation. Taken together, our data provide proof-of-principle for two live-attenuated M2-2 mutants to be promising HMPV vaccine candidates that are effective in inducing higher pulmonary innate immunity and generating protection against HMPV infection.

Prevalence and risk factors for asthma, rhinitis, eczema, and atopy among preschool children in an Andean city

Background

Limited data are available on prevalence and associated risk factors for atopy and allergic diseases from high-altitude urban settings in Latin America.

Objective

To estimate the prevalence of atopy, asthma, rhinitis, and eczema, and associations with relevant risk factors in preschool children in the Andean city of Cuenca.

Methods

A cross-sectional study was undertaken using a representative sample of 535 children aged 3–5 years attending 30 nursery schools in the city of Cuenca, Ecuador. Data on allergic diseases and risk factors were collected by parental questionnaire. Atopy was measured by skin prick test (SPT) reactivity to a panel of relevant aeroallergens. Associations between risk factors and the prevalence of atopy and allergic diseases were estimated using multivariable logistic regression.

Results

Asthma symptoms were reported for 18% of children, rhinitis for 48%, and eczema for 28%, while SPT reactivity was present in 33%. Population fractions of asthma, rhinitis, and eczema attributable to SPT were 3.4%, 7.9%, and 2.9%, respectively. In multivariable models, an increased risk of asthma was observed among children with a maternal history of rhinitis (OR 1.85); rhinitis was significantly increased in children of high compared to low socioeconomic level (OR 2.09), among children with a maternal history of rhinitis (OR 2.29) or paternal history of eczema (OR 2.07), but reduced among children attending daycare (OR 0.64); eczema was associated with a paternal history of eczema (OR 3.73), and SPT was associated with having a dog inside the house (OR 1.67).

Conclusions

A high prevalence of asthma, rhinitis, and eczema symptoms were observed among preschool children in a high-altitude Andean setting. Despite a high prevalence of atopy, only a small fraction of symptoms was associated with atopy. Parental history of allergic diseases was the most consistent risk factor for symptoms in preschool children.

Daycare attendance and asthma control, Asthma Call-back Survey 2012-2014

OBJECTIVE

To examine the association between daycare attendance and asthma control among children aged 0 to 4 years with asthma.

METHODS

We analyzed 2012-2014 data from the Behavioral Risk Factor Surveillance System Asthma Call-back Survey on 388 children with asthma aged 0 to 4 years with information on daycare attendance in the past 12 months. We calculated weighted prevalence ratios to assess the association between daycare attendance and asthma control (categorized based on day-time and nighttime asthma symptoms, activity limitation, and short-acting beta agonist use). Adjusted models controlled for parent or guardian education, household income, race, sex, cost barriers to asthma care, long-term control medication use, and the number of other children in the child's household.

RESULTS

In this sample of children with asthma, representative of 520,400 children in 26 U.S. states, 34% attended daycare in the past 12 months. Only 32% of children who attended daycare in the past 12 months reported having an asthma action plan on file at the daycare they most recently attended. Presence of the asthma triggers of pets, mold, and smoking in a child's daycare were reported to be uncommon. Prevalence of uncontrolled asthma was 44% in children who attended daycare in the past 12 months and 68% in children who did not. The adjusted prevalence ratio between daycare attendance and uncontrolled asthma was 0.96 (95% confidence interval 0.73, 1.25).

CONCLUSIONS

When adjusting for covariates, we observed no evidence of an association between daycare attendance in early life and uncontrolled asthma.