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Microbial metabolism of specific dietary components, such as fiber, contributes to the sophisticated inter-kingdom dialogue in the gut that maintains a stable environment with important beneficial physiological, metabolic, and immunological effects on the host. Historical changes in fiber intake may be contributing to the increase of allergic and hypersensitivity disorders as fiber-derived metabolites are evolutionarily hardwired into the molecular circuitry governing immune cell decision-making processes. In this review, we highlight the importance of fiber as a dietary ingredient, its effects on the microbiome, its effects on immune regulation, the importance of appropriate timing of intervention to target any potential window of opportunity, and potential mechanisms for dietary fibers in the prevention and management of allergic diseases. In addition, we review the human studies examining fiber or prebiotic interventions on asthma and respiratory outcomes, allergic rhinitis, atopic dermatitis, and overall risk of atopic disorders. While exposures, interventions, and outcomes were too heterogeneous for meta-analysis, there is significant potential for using fiber in targeted manipulations of the gut microbiome and its metabolic functions in promoting immune health.

Histamine intolerance (HIT) is a common adverse reaction to food where elimination and reintroduction of histamine-rich food is part of the investigation. Analysis of the enzyme diamine oxidase (DAO) is sometimes used as an additional tool for diagnosis. This study aimed to describe the distribution of DAO in a large representative cohort of adults and to determine the association between DAO activity and possible associated factors. The study is based on the population-based West Sweden Asthma Study and includes 1051 subjects. Subjects underwent structured interviews including questions on demography, asthma, allergy symptoms, and lifestyle factors. Subjects were assessed for specific-IgE-antibodies and measurement of DAO activity in serum. Previously suggested cut-off levels for low values (10 U/mL), and median levels of DAO were used. In the group of 1051 subjects, only a few presented reactions upon histamine intake, whereas 44% presented DAO levels below the suggested normal cut-off levels. BMI and age were shown to have an impact on DAO activity among women with increasing activity of DAO with increasing BMI and age. Among men, only increasing age was seen to have an impact on DAO levels. There was no difference in DAO levels with different sensitization status to common foods or airborne allergens. No association between DAO levels and reported symptoms to histamine-rich foods could be found. In conclusion, the determination of the DAO enzyme needs to be re-evaluated and may not be used as a valuable tool for histamine intolerance using current cut-off values. Further studies are needed to improve the use of DAO as a biomarker for histamine intolerance.

Background Evidence on the role of exogenous female sex steroid hormones in asthma development in women remains conflicting. We sought to quantify the potential causal role of hormonal contraceptives and menopausal hormone therapy (MHT) in the development of asthma in women. Methods We conducted a matched case-control study based on the West Sweden Asthma Study, nested in a representative cohort of 15,003 women aged 16–75 years, with 8-year follow-up (2008–2016). Data were analyzed using Frequentist and Bayesian conditional logistic regression models. Results We included 114 cases and 717 controls. In Frequentist analysis, the odds ratio (OR) for new-onset asthma with ever use of hormonal contraceptives was 2.13 (95% confidence interval [CI] 1.03–4.38). Subgroup analyses showed that the OR increased consistently with older baseline age. The OR for new-onset asthma with ever MHT use among menopausal women was 1.17 (95% CI 0.49–2.82). In Bayesian analysis, the ORs for ever use of hormonal contraceptives and MHT were, respectively, 1.11 (95% posterior interval [PI] 0.79–1.55) and 1.18 (95% PI 0.92–1.52). The respective probability of each OR being larger than 1 was 72.3% and 90.6%. Conclusions Although use of hormonal contraceptives was associated with an increased risk of asthma, this may be explained by selection of women by baseline asthma status, given the upward trend in the effect estimate with older age. This indicates that use of hormonal contraceptives may in fact decrease asthma risk in women. Use of MHT may increase asthma risk in menopausal women.

Following the “hygiene hypothesis”, a plethora of studies have investigated the role of sibship composition in atopic diseases, but findings are largely conflicting. We undertook the first systematic review to synthesize the global literature linking birth order and sibship size to the risk of allergic rhinitis. Fifteen databases were searched from inception until 20 October 2021. Screening and data extraction were performed in pairs. Comparable numerical data were analyzed using meta-analysis with robust variance estimation (RVE). We included 76 reports based on 66 studies that met our inclusion criteria, encompassing >2 million subjects. Being second- or later-born child was associated with protection against both current (pooled risk ratio [RR] 0.79, 95%CI 0.73-0.86) and ever (RR 0.77, 95%CI 0.68-0.88) allergic rhinitis. Having siblings, regardless of birth order, was associated with a decreased risk of current allergic rhinitis (RR 0.89, 95% CI 0.83-0.95) and allergic rhinoconjunctivitis (RR 0.92, 95%CI 0.86-0.98). These effects were unchanged across age, time period, and geographical regions. Our findings indicate that primarily, a higher birth order, and to a lesser extent the number of siblings, is associated with a lower risk of developing allergic rhinitis.

Background Maternal smoking during pregnancy is associated with a host of detrimental effects on the exposed child. However, emerging evidence suggests that the adverse effects of smoking during pregnancy may be transmitted across generations. We conducted a systematic review to comprehensively summarize evidence on the association between grandmaternal smoking during pregnancy and health outcomes in the grandchild. Methods We searched MEDLINE, EMBASE, and 10 other databases from inception to March 02, 2021, updated on October 18, 2021, to identify analytic epidemiologic studies (prospective or retrospective cohort and case-control design) investigating the association between grandmaternal smoking during pregnancy and multiple health outcomes in the grandchild in all countries and settings. Three investigators independently screened records, extracted data, and assessed study quality using the Effective Public Health Practice Project (EPHPP) tool. Random-effects robust variance estimation was used to combine effect estimates whenever possible, separately for maternal and paternal line. Results Twenty-four reports from 15 unique studies with 23 health outcomes and 231,478 grandchildren were included. The overall study quality was moderate. In maternal line, grandmaternal smoking during pregnancy was associated with an increased risk of asthma (seven studies, 148,527 grandchildren, risk ratio (RR) 1.10, 95% CI 1.02 to 1.18) and higher birth weight (four studies, 19,478 grandchildren, mean difference (g) 40.04, 95% CI 22.60 to 57.49) in the grandchild. There was suggestive evidence that maternal grandmaternal smoking was associated with increased risks of acute lymphoblastic leukaemia, any cancer, autism, and attention deficit hyperactivity disorder, decreased risks of early-onset myopia and small birth weight for gestational age, and higher birth length and body mass index at birth. In paternal line, grandmaternal smoking during pregnancy was not associated with asthma (four studies, 41,069 grandchildren, RR 1.01, 95% CI 0.85 to 1.19), but there was suggestive evidence for lower intelligence quotient scores and decreased risks of early-onset myopia and intolerance to loud sound. Conclusions The effects of maternal smoking during pregnancy may not be limited to the exposed child, but be transmitted to the grandchild, possibly through germline epigenetic inheritance. Further public health efforts are warranted to strengthen smoking cessation programs for pregnant women.

Recent reports indiciate that the prevelance of food allergy is increasing, but accurate estimates remain a challenge due to cross-reactivity and limited use of precise diagnostic methods. Component-resolved diagnostics (CRD), in which sensitization to individual molecular components of whole food allergen extracts is measured, is emerging as a promising tool for evaluation of sensitization profiles. In this systematic review, we summarized estimates of prevalence of sensitization to food allergen components in the general population in Europe. We searched seven databases with no restrictions on publication date or language. Two reviewers independently screened the literature and appraised the risk of bias in the included studies. From 4,776 de-duplicated records, five studies, with low to moderate overall risk of bias, were included and narratively synthesized. Forty-six components from 18 foods were investigated. Overall, the prevalence of sensitization was low, particularly for major allergens, and non-existent for 10 components (0% [95% CI 0-0.8]). The highest prevalence was seen for PR-10 proteins, such as Cor a 1.04 (13.6% [95% CI 10.9-16.9]). There were not enough studies to discern regional differences or perfom meta-analysis, highlighting the need for more population-representative studies in order to elucidate patterns of sensitization to food allergen components in Europe.

Microbial metabolism of specific dietary components, such as fiber, contribute to the sophisticated inter-kingdom dialogue in the gut that maintains a stable environment with important beneficial physiological, metabolic, and immunological effects on the host. Historical changes in fiber intake may be contributing to the increase of allergic and hypersensitivity disorders as fiber-derived metabolites are evolutionarily hardwired into the molecular circuitry governing immune cell decision making processes. In this review, we highlight the importance of fiber as a dietary ingredient, its effects on the microbiome, its effects on immune regulation, and potential mechanisms for dietary fibers in the prevention and management of allergic diseases. In addition, we review the human studies examining fiber or prebiotic interventions on asthma and respiratory outcomes, allergic rhinitis, atopic dermatitis, and overall risk of atopic disorders. While exposures, interventions and outcomes were too heterogeneous for meta-analysis, there is significant potential for using fiber in targeted manipulations of the gut microbiome and its metabolic functions in promoting immune health.

Supplemental material, Supplementary_Material for Using Household Socioeconomic Indicators to Predict the Utilization of Maternal and Child Health Services Among Reproductive-Aged Women in Rural Yemen by Abdullah Nagi Alosaimi, Bright Nwaru, Riitta Luoto, Abdul Wahed Al Serouri and Halima Mouniri in Global Pediatric Health

Information collected when enrolling into the platform. This contains the questionnaire used for enrolment into the database. (DOCX 22 kb)

Case studies of success. This is a summary of the key features of existing analogous platforms. (DOCX 24 kb)

Appendix 1. Read codes for asthma, version 2. Appendix 2. List of asthma medications by BNF codes. Appendix 3. Read codes for asthma, version 3. Appendix 4. Price weights and costings methodology. Appendix 5. Data sources and mapping used in economic modelling of the cost of asthma in theUK by member countries. Appendix 6. Cost modelling technical supplement. Appendix 7. Comparison of mapped inpatient episodes to known values for their respective countries. (DOCX 88 kb)

Appendix 1. Read codes for asthma, version 2. Appendix 2. List of asthma medications by BNF codes. Appendix 3. Read codes for asthma, version 3. Appendix 4. Price weights and costings methodology. Appendix 5. Data sources and mapping used in economic modelling of the cost of asthma in theUK by member countries. Appendix 6. Cost modelling technical supplement. Appendix 7. Comparison of mapped inpatient episodes to known values for their respective countries. (DOCX 88 kb)