Young children are particularly vulnerable to otitis media (OM) which globally affects over 80% of children below the age of 3 years. Although there is convincing evidence for an association between environmental tobacco smoke exposure and OM in children, the relationship with ambient air pollution is not clear. We aimed to systematically review the literature on the relationship between ambient air pollution exposure and OM in children. A systematic search was performed in PubMed and EMBASE databases. Of 934 references identified, 24 articles were included. There is an increasing body of evidence supporting an association between higher ambient air pollution exposure and a higher risk of OM in children. While NO₂ showed the most consistent association with OM, other specific pollutants showed inconsistent associations. Studies were mainly conducted in high/middle income countries with limited evidence from low-income countries. Although there was a general consensus that higher air pollution exposure is associated with a greater prevalence of OM, the evidence for associations with specific pollutants is inconsistent. More well-designed studies on associations between specific air pollutants as risk factors for OM are warranted, especially in low income countries with high air pollution levels.

Despite the growing body of evidence on lung function trajectories over the life course and their risk factors, the literature has not been systematically synthesized. Publications related to lung function trajectories were identified from PubMed, EMBASE and CINAHL databases. Two authors independently identified publications for inclusion according to predefined selection criteria. Studies that modelled lung function trajectories and reported associated exposures were included. Meta‐analyses could not be conducted due to heterogeneity in the exposures and methods used to model lung function trajectories. Nine publications were eligible for inclusion of which four used group‐based trajectory modelling to model lung function trajectories, while five used latent profile analysis. Studies with repeated lung function measurements over the life course identified more trajectories than others. Only one study spanning from childhood to middle age reported catch‐up trajectory. The following childhood risk factors for subnormal lung function trajectories were observed in at least across two studies: low birth weight, early wheezing, asthma, allergic sensitization, eczema, allergic rhinitis, lower respiratory tract infections, family history of asthma and second‐hand smoke exposure. Adult active asthma and personal cigarette smoking were observed to be associated with accelerated decline lung trajectories. Our review identified 10 risk factors associated with the growth, catch‐up, reduced plateau and decline trajectories of lung function. Intervention directed at childhood asthma and infections, and tobacco smoke exposure at all ages would help promote lung health and prevent subnormal lung function trajectories.

With the global trend of increasing asthma and allergic disorders there is strong interest regarding early life nutrition as a potentially modifiable risk factor for lung disease. This systematic review includes 10 studies that assessed the effect of breastfeeding on lung growth and function. The review found breastfeeding to be beneficial for lung function, with the most consistent effect on increased forced vital capacity. There was no clear evidence that the relationship between breastfeeding and lung function was mediated through other factors. Furthermore, the findings from the few studies that investigated if maternal asthma modified the effect of breastfeeding on lung function were inconsistent. Further research is needed to determine the specific details such as duration and type (exclusive vs partial) of breastfeeding that leads to improved lung function.

Background: Traumatic dental injuries (TDIs) are highly prevalent during childhood and adolescence and have a significant effect on their oral health related quality of life (OHRQoL). Uncomplicated TDIs, dental trauma involving enamel, enamel and dentin and tooth discolorations, account for approximately two-thirds of all diagnosed TDIs in children and adolescents. Hence, it may be important to understand the impact of uncomplicated TDIs on OHRQoL, by synthesizing the available literature.Methods: Medline, Embase, Web of Science and Scopus databases were systematically searched from January 1966 to April 2018. Studies that evaluated the effect of TDIs on the OHRQoL of children and adolescents using validated methods were selected for analysis. A narrative synthesis and a meta-analysis were performed. The studies were pooled according to age groups and OHRQoL questionnaire used. A random-effect model was applied to calculate the pooled odds ratios (OR) and their respective 95% confidence intervals.Results: There were 712 identified studies. Of these, 26 articles were selected for the review and included in the narrative synthesis, 20 of these articles concluded that uncomplicated TDIs were not associated with a negative impact in OHRQoL. Seventeen were included in the meta-analysis. The estimates were pooled by age groups: children (OR: 1.01; 95%CI; 0.85–1.19; I² = 51.9%) and adolescents (OR: 1.07; 95%CI; 0.91, 1.26; I² = 50.2%).When pooling all estimates the OR was 0.96 (95% CI: 0.85–1.10; I² = 61.4%).Conclusions: Uncomplicated TDIs do not have a negative impact on the OHRQoL of children and adolescents. Further prospective studies are needed to confirm the results of this review. The majority of the studies included were of cross-sectional design, which may have limited the ability to reach conclusions on the nature of this association. The PROSPERO systematic review registry is CRD42018110471.

Summary: Background: Eczema is a chronic inflammatory skin disease. Domestic water with high mineral content (hard water) is a risk factor for eczema in children, but this association has not been assessed in adults. Objectives: To examine the association between domestic hard water supply and eczema prevalence and incidence in adults aged 40–69 years and the contextual effect in eczema outcomes by postcode in adults in the UK. Methods: We used data from the UK Biobank study collected in 2006–10 (baseline) and 2013–14 (follow-up). Eczema prevalence at baseline (2006–10) and at follow-up (2013–14) and incidence (new onset between baseline and follow-up) were determined from the touchscreen questionnaires and nurse-led interviews. Domestic hard water information was obtained in 2005 and 2013 from the local water supply companies in England, Wales and Scotland as CaCO3 concentrations. We fitted multilevel logistic regression models with random intercepts for postcode areas to examine the effect of domestic hard water on eczema outcomes, and we measured components of variance. Results: In total, 306 531 participants with a mean age of 57 years nested across 7642 postcodes were included in the baseline analysis, and 31 036 participants nested across 3695 postcodes were included in the follow-up analysis. We observed an increase in the odds of eczema at baseline [odds ratio (OR) 1·02, 95% confidence interval (CI) 1·01–1·04] per 50 mg L−1 of CaCO3 increase. Furthermore, exposure to domestic hard water (> 200 mg L−1 of CaCO3) was associated with increased odds of prevalent eczema at baseline (OR 1·12, 95% CI 1·04–1·22). Moreover, there was a significant linear trend (P < 0·001) in which increasing levels of hard water increased eczema prevalence risk. No association was observed with incident eczema or eczema at follow-up. The intraclass correlation coefficient for postcode was 1·6% (95% CI 0·7–3·4), which remained unexplained by area-level socioeconomic measures. Conclusions: Increasing levels of domestic hard water, as measured by CaCO3 concentrations, were associated with an increased prevalence of eczema in adults but not increased incidence. Ongoing efforts to reduce hard water exposure may have a beneficial effect in reducing the burden of eczema in adults. Further research is needed to explore area-level factors that may lead to eczema. What is already known about this topic? Hard water is formed when minerals are dissolved in water from filtration through sedimentary rocks.Several studies have reported a higher prevalence of eczema in areas with hard water.However, all studies on this topic have assessed this in infants and school-aged children, while this association has not been explored in adults. What does this study add? Our findings suggest that exposure to higher concentrations of domestic hard water is associated with an increase in eczema prevalence in adults aged 40–69 years.Ongoing efforts to reduce hard water exposure may have a beneficial effect in reducing eczema prevalence in adults.