Cesarean delivery and the risk of allergic rhinitis in children

Maternal asthma during pregnancy and risks of allergy and asthma in progeny: A systematic review and meta-analysis

BACKGROUND

Clinical and preclinical evidence indicate that in utero maternal asthma exposure increases progeny asthma risk. Whether maternal asthma also increases the risks of progeny allergy is unclear.

OBJECTIVES

To synthesise the available evidence on the relationship between in utero exposure to maternal asthma and postnatal asthma, wheezing and allergic diseases (Prospero: CRD42020201538).

SEARCH STRATEGY

We systematically searched MEDLINE [PubMed], Embase [Ovid], Web of Science, Informit Health, the Cochrane Library, CINAHL [EBSCOhost], MedNar [Deep Web Technologies], ProQuest Theses and Dissertations, Scopus [Elsevier] and Trove, to the end of 2023.

SELECTION CRITERIA

Studies reporting asthma, wheeze and/or allergic disease in progeny of women with and without asthma or with asthma classified by control, exacerbation or severity.

DATA COLLECTION AND ANALYSIS

Double screening, selection, data extraction and quality assessment were performed, using Joanna Briggs Institute (JBI) scoring.

MAIN RESULTS

Of 134 non-overlapping studies, 127 were included in ≥1 meta-analysis. Maternal asthma ever was associated with greater risks of asthma (65 studies, risk ratio [95% confidence interval] 1.76 [1.57-1.96]), wheeze (35 studies, 1.59 [1.52-1.66]), food allergy (5 studies, 1.32 [1.23-1.40]), allergic rhinitis (7 studies, 1.18 [1.06-1.31]) and allergic dermatitis (14 studies, 1.17 [1.11-1.23]) ever in progeny. Asthma during the pregnancy, more severe, and uncontrolled maternal asthma were each associated with greater risks of progeny asthma.

CONCLUSIONS

Children of mothers with asthma are at increased risk for the development of allergic diseases. Whether improved maternal asthma control reduces risks of child allergy as well as asthma requires further investigation.

Cesarean section and the risk of allergic rhinitis in children: a systematic review and meta-analysis

Multiple evidence indicates that perinatal factors make impact on immune development and affect offspring allergic rhinitis (AR) risk. In this systematic review and meta-analysis, we examined available published studies to clarify the relationship between cesarean section (C-section) and offspring AR in children. To explore the relationship between C-section, especially the special attention was paid to different cesarean delivery mode, and the risk of AR in children. Articles were searched using PubMed, Web of Science, EMBASE, Cochrane Library, China knowledge Network, Wanfang, and China Science and Technology Journal databases. A meta-analysis of 22 studies published before August 1, 2022, which included 1,464,868 participants, was conducted for statistical analysis with RevMan5.4. The correlation strength between C-section and offspring AR was determined by combining odds ratio (OR) and 95% confidence interval (95% CI). Meta-regression and subgroup analyses were used to explore potential sources of heterogeneity. Publication bias was detected using the funnel chart and Egger tests. Meta-analysis revealed that there was a significant correlation between C-section and children AR (OR = 1.19, 95% CI: 1.12-1.27, P < 0.001), especially C-section with a family history of allergy (OR = 1.82, 95% CI: 1.36-2.43, P < 0.001). Moreover, elective C-section (without genital tract microbe exposure) had the higher risk of offspring AR (OR = 1.24, 95% CI: 1.05-1.46, P = 0.010) compared with the whole study. Meta-regression demonstrated that sample size explained 38.0% of the variability between studies, and year of publication explained 18.8%. Delivery by C-section, particularly elective C-section and C-section with a family history of allergy can increase the risk of AR in children.

The global/local (limited to some regions) effect of cesarean delivery on the risk of pediatric allergic rhinitis: a systematic review and meta-analysis

Background

Allergic rhinitis is a chronic and refractory disease that can be affected by a variety of factors. Studies have shown an association between cesarean section and the risk of pediatric allergic rhinitis.

Methods

The PubMed, Springer, Embase, Cochrane Library, and Web of Science databases were searched to retrieve all studies published from January 2000 to November 2022, focusing on the relationship between cesarean section and the risk of pediatric allergic rhinitis. A meta-analysis was conducted to find a correlation between cesarean section and the risk of pediatric allergic rhinitis. A subgroup analysis was performed, considering the region and family history of allergy, after adjusting for confounding factors. Pooled odds ratios (ORs) were calculated, publication bias was assessed using a funnel plot, and heterogeneity between study-specific relative risks was taken into account.

Results

The results showed that cesarean section was significantly associated with an increased risk of pediatric allergic rhinitis (OR: 1.27, 95% CI: 1.20-1.35). Subgroup analysis stratified by region indicated that cesarean section increased the risk of pediatric allergic rhinitis, with the highest increase in South America (OR: 1.67, 95% CI: 1.10-2.52) and the lowest in Europe (OR: 1.13, 95% CI: 1.02-1.25). The results of the subgroup analysis stratified by family history of allergy indicate that family history of allergy was not associated with the risk of pediatric allergic rhinitis.

Conclusion

An association exists between cesarean section as the mode of delivery and the increased risk of pediatric allergic rhinitis, and cesarean section is a risk factor for allergic rhinitis.

Factors associated with allergic rhinitis and combined allergic rhinitis and asthma syndrome (CARAS) in adults undergoing immunotherapy in a tropical country: Is ISAAC-III questionnaire useful in adult populations?

BACKGROUND

Allergic diseases affect about 10-30% of the population in low- or middle-income tropical countries. Few studies describe the factors associated with allergic diseases in adult patients undergoing immunotherapy in Latin American countries.

OBJECTIVE

This study aimed to determine the factors associated with allergic rhinitis (AR) and AR in comorbidity with asthma (CARAS) in adults treated with immunotherapy in two allergy referral centers in Bogotá (Colombia).

MATERIAL AND METHODS

Observational, cross-sectional study conducted between January 2018 and January 2019. ISAAC-III and sociodemographic questionnaires were applied to determine the factors associated with AR and CARAS in adults treated with immunotherapy who attended the allergy consult at the Fundación Santa Fe de Bogotá and Unimeq-Orl.

RESULTS

Among 416 adults aged 18-68 years, 71.4% (n = 297) were women. Regarding the sensitization results obtained by skin prick test, the most frequent allergens were house dust mites (64.18%): 49.03% were positive for both Dermatophagoides pteronyssinus and Dermatophagoides farinae, while 28.61% were positive for Blomia tropicalis. Excluding house dust mites, the most frequent allergens were dog hair (31.01%), cat hair (15.1%), grasses (15.9%), and food (15.9%). The main factor associated with exclusive AR was regular acetaminophen use more than four times a year: Prevalence ratio (PR) = 1.77 (95% CI: 1.12-2.25). The main factor associated with CARAS was cesarean delivery PR: 1.44 (95% CI: 1.09-1.78).

CONCLUSION

The main factor associated with AR was regular acetaminophen use, while that associated with CARAS was cesarean delivery. The ISAAC-III questionnaire can be a useful low-cost tool to assess the factors associated with allergic diseases in adults in tropical countries.

Neonatal Immune System Ontogeny: The Role of Maternal Microbiota and Associated Factors. How Might the Non-Human Primate Model Enlighten the Path?

Interactions between the immune system and the microbiome play a crucial role on the human health. These interactions start in the prenatal period and are critical for the maturation of the immune system in newborns and infants. Several factors influence the composition of the infant's microbiota and subsequently the development of the immune system. They include maternal infection, antibiotic treatment, environmental exposure, mode of delivery, breastfeeding, and food introduction. In this review, we focus on the ontogeny of the immune system and its association to microbial colonization from conception to food diversification. In this context, we give an overview of the mother-fetus interactions during pregnancy, the impact of the time of birth and the mode of delivery, the neonate gastrointestinal colonization and the role of breastfeeding, weaning, and food diversification. We further review the impact of the vaccination on the infant's microbiota and the reciprocal case. Finally, we discuss several potential therapeutic interventions that might help to improve the newborn and infant's health and their responses to vaccination. Throughout the review, we underline the main scientific questions that are left to be answered and how the non-human primate model could help enlighten the path.

Cesarean section and risk of allergies in Ecuadorian children: A cross-sectional study

BACKGROUND

Studies have shown an association between cesarean section (CS) and increased prevalence of childhood allergic diseases. While these observations have been consistent in industrialized countries, evidence from developing countries is limited.

OBJECTIVE

To assess the association between the mode of delivery and allergic diseases in children aged 3-12 years in Quito, Ecuador.

METHODS

In this cross-sectional study, parents were surveyed using an anonymous, standardized questionnaire from the International Study of Asthma and Allergies in Childhood project to assess the presence of asthma, allergic rhinitis, atopic dermatitis, and food allergies in their children. The children's age, sex, birthplace, delivery mode (CS/vaginal), socioeconomic status, and ethnicity were recorded. Other parameters included gestational age, breastfeeding, smoking status during pregnancy, and parental allergic diseases.

RESULTS

After adjusting for confounding factors, children delivered via CS were found to have a higher risk of wheezing (odds ratio [OR] = 4.12, 95% confidence interval [CI]: 1.43-11.89), physician-diagnosed asthma (OR = 24.06; 95% CI: 1.98-292.3), and pimples, or eczema with the itching for 6 months (OR = 2.65; 95% CI: 1.06-6.61) than children delivered vaginally. No association was found between the delivery mode and rhinitis or food allergies. After stratifying by socioeconomic status, CS was only associated with allergic disorders in children of medium/high socioeconomic backgrounds.

CONCLUSIONS

As seen in industrialized settings, children born by CS in nonindustrialized countries have an increased risk of developing allergic disorders including asthma and dermatitis, compared to those delivered vaginally.