Mode of delivery and childhood hospitalizations for asthma and other wheezing disorders

Risk of Asthma and Allergies in Children Delivered by Cesarean Section: A Comprehensive Systematic Review

BACKGROUND

It is unclear whether cesarean delivery increases the risk of allergic diseases in offspring.

OBJECTIVE

To investigate the association between cesarean delivery and the risk of allergic diseases in offspring.

METHODS

We searched PubMed, Embase, and the Cochrane Library for relevant studies up to October 12, 2023. Observational studies comparing the risk of allergic diseases in offspring delivered by cesarean section versus those delivered vaginally were included. Most-adjusted estimates from individual studies were synthesized by meta-analysis.

RESULTS

A total of 113 studies were included, 70 of which had a low risk of bias. Compared with offspring delivered vaginally, offspring delivered by cesarean section had significantly greater risks of asthma (odds ratio [OR] = 1.20; 95% CI, 1.16-1.25), allergic rhinitis or conjunctivitis (OR = 1.15' CI 1.09-1.22), atopic dermatitis or eczema (OR = 1.08; CI, 1.04-1.13), food allergies (OR = 1.35; CI, 1.18-1.54), and allergic sensitization (OR = 1.19; CI, 1.10-1.28). Cesarean delivery did not significantly increase urticaria risk. Sensitivity analyses including only studies with a low risk of bias, adjusted estimates, prospective data collection, large sample sizes, or outcomes from medical records generally supported these findings. Offspring age, study region latitude, economy type, and cesarean delivery rate accounted for some of the clinical heterogeneity. We found no data on allergic purpura.

CONCLUSIONS

Most-adjusted estimates suggest that cesarean delivery is associated with increased risks of asthma, allergic rhinitis or conjunctivitis, atopic dermatitis or eczema, food allergies, and allergic sensitization in offspring. The impact of cesarean delivery on urticaria and purpura remains uncertain.

Diverging patterns in innate immunity against respiratory viruses during a lifetime: lessons from the young and the old

Respiratory viral infections frequently lead to severe respiratory disease, particularly in vulnerable populations such as young children, individuals with chronic lung conditions and older adults, resulting in hospitalisation and, in some cases, fatalities. The innate immune system plays a crucial role in monitoring for, and initiating responses to, viruses, maintaining a state of preparedness through the constant expression of antimicrobial defence molecules. Throughout the course of infection, innate immunity remains actively involved, contributing to viral clearance and damage control, with pivotal contributions from airway epithelial cells and resident and newly recruited immune cells. In instances where viral infections persist or are not effectively eliminated, innate immune components prominently contribute to the resulting pathophysiological consequences. Even though both young children and older adults are susceptible to severe respiratory disease caused by various respiratory viruses, the underlying mechanisms may differ significantly. Children face the challenge of developing and maturing their immunity, while older adults contend with issues such as immune senescence and inflammaging. This review aims to compare the innate immune responses in respiratory viral infections across both age groups, identifying common central hubs that could serve as promising targets for innovative therapeutic and preventive strategies, despite the apparent differences in underlying mechanisms.

Age-period-cohort analysis and projection of cancer mortality in Hong Kong, 1998-2030

OBJECTIVES

To explore the relationship between immigration groups and cancer mortality, this study aimed to explore age, period, birth cohort effects and effects across genders and immigration groups on mortality rates of lung, pancreatic, colon, liver, prostate and stomach cancers and their projections.

DESIGN, SETTING, AND PARTICIPANTS

Death registry data in Hong Kong between 1998 and 2021, which were stratified by age, sex and immigration status. Immigration status was classified into three groups: locals born in Hong Kong, long-stay immigrants and short-stay immigrants.

METHODS

Age-period-cohort (APC) analysis was used to examine age, period, and birth cohort effects for genders and immigration groups from 1998 to 2021. Bayesian APC models were applied to predict the mortality rates from 2022 to 2030.

RESULTS

Short-stay immigrants revealed pronounced fluctuations of mortality rates by age and of relative risks by cohort and period effects for six types of cancers than those of long-stay immigrants and locals. Immigrants for each type of cancer and gender will be at a higher mortality risk than locals. After 2021, decreasing trends (p<0.05) or plateau (p>0.05) of forecasting mortality rates of cancers occur for all immigration groups, except for increasing trends for short-stay male immigrants with colon cancer (p<0.05, Avg+0.30 deaths/100 000 per annum from 15.47 to 18.50 deaths/100 000) and long-stay male immigrants with pancreatic cancer (p<0.05, Avg+0.72 deaths/100 000 per annum from 16.30 to 23.49 deaths/100 000).

CONCLUSIONS

Findings underscore the effect of gender and immigration status in Hong Kong on mortality risks of cancers that immigrants for each type of cancer and gender will be at a higher mortality risk than locals.

Evaluation of the factors affecting lung function in pediatric patients with asthma

PURPOSE

This study aimed to analyze the risk factors affecting lung function in children with asthma based on clinical data to advice on clinical treatment and prognosis.

METHODS

This study included newly diagnosed patients with asthma admitted to the Respiratory Department of Chengdu Women's and Children's Central Hospital in Sichuan from July 2020 to June 2021. The factors associated with lung function were analyzed using univariate and multivariate linear regression with the forward method, while factors affecting lung ventilation function were analyzed using multivariate logistic regression.

RESULTS

Sixty percent of the patients had normal lung function. Age was significantly negatively correlated with forced vital capacity (FVC)/FVC_predicted (B = -1.385, p = 0.001), FEV₁/FEV_1predicted (B = -2.092, p < 0.001), and FEV₁%/FEV₁%_predicted (B = -0.834, p = 0.001). Body mass index (BMI) for age Z score (B = 1.661, p = 0.045) and cesarean delivery (B = 4.471, p = 0.013) were significantly positively correlated with FVC/FVC_predicted. Birth weight was significantly positively correlated with FEV₁/FEV_1predicted (B = 4.593, p = 0.027). Multivariate logistic regression analysis revealed that age ≥6 years and cough variant asthma (CVA) were risk factors for abnormal lung function.

CONCLUSIONS

Age, BMI for age Z score, mode of delivery, and birth weight were significantly correlated with lung function in children with asthma. Furthermore, children with asthma and normal lung function were more likely to be overlooked. More attention should be given to children with asthma and normal lung function, and CVA.

Parto por cesárea y su asociación con el síndrome obstructivo bronquial agudo en pacientes de 12 a 36 meses de edad

Objetivo. Identificar la asociación entre partos por cesárea y el Síndrome obstructivo bronquial agudo (SOBA) en pacientes de 12 a 36 meses de edad hospitalizados en el Hospital de Vitarte-MINSA durante el año 2017-2019. Material y métodos. Se realizó un estudio analítico, retrospectivo, de casos y controles. La población estudiada fueron los pacientes de 12-36 meses de edad hospitalizados durante el año 2017-2019, conformada por 306 niños siendo 102 casos y 204 controles (1:2). Los datos a estudiar se obtuvieron de la historia clínica donde se registró las siguientes variables: edad, sexo, cesárea, APGAR, edad gestacional, lactancia materna, vacunación, hacinamiento y número de hermanos. Resultados. La población de estudio estuvo conformada principalmente por niños de 1 año de edad (53,27%) de sexo femenino (52,29%). El parto por cesárea representó el 41,18% de los nacimientos y se asoció a la presencia de SOBA (OR=2,50; IC95%=1,51-4,15; p<0,001) en comparación con el parto vaginal. De mismo modo se encontró asociación entre lactancia materna exclusiva (OR=0,42; IC 95%=0,23-0,78; p=0,006), vacunación (OR=0,56; IC 95%=0,33-0,94; p=0,027) y hacinamiento (OR=1,77; IC 95%=1,04-3,01; p=0,034); sin embargo, no hubo diferencia estadística entre la edad (p=0,343; IC95%=0,62-1,18%), sexo (p=0,871; IC95%=0,42-1,29), edad gestacional (p=0,164; IC95%=0,71-1,06), APGAR (p=0,685; IC95%=0,73-1,23) y número de hermanos (p=0,357; IC95%=0,89-1,39). Conclusión. El parto por cesárea se encuentra asociado al desarrollo del SOBA. Presentando 2 veces mayor riesgo de padecerlo si se nace por cesárea, esto debido a que causa un deterioro del sistema inmune.

The effects of different parity and delivery mode on wheezing disorders in the children-a retrospective cohort study in Fujian, China

BACKGROUND

The relationship between childbirth delivery methods and the risk of wheezing in children remains controversial. Few studies have explored it under different maternal conditions.

OBJECTIVE

To explore the influence of childbirth delivery method on the onset of wheezing in children of different parity.

METHODS

A total of 21716 patients were included in this retrospective observational study. Multivariable logistic regression was used to analyze the relationship between childbirth delivery method and wheezing in children under 18 years of age in Fujian Province.

RESULTS

Wheezing differed statistically based on the child's sex, age, season of onset, parity, jaundice history, and feeding patterns (P < 0.05). After adjusting for confounding factors, in cases of parity greater than two, the risk of wheezing in cesarean section deliveries was higher than that in vaginal deliveries (OR: 1.107; 95% CI 1.010-1.214). In girls with parity greater than two (OR: 1.179; 95% CI 1.003-1.387) and normal-weight infants with parity greater than two (OR: 1.106; 95% CI 1.003-1.220), the risk of wheezing in cesarean section deliveries was higher. The interaction term between the mode of childbirth and parity was significant in girls (P = 0.014).

CONCLUSION

The method of childbirth delivery and parity are related to the risk of wheezing and may be relevant to gender and birth weight. Parity and gender have synergistic effects on wheezing.

The role of Caesarean section in childhood asthma

OBJECTIVE

As indicated by previous studies, children born via Caesarean section may have an increased risk of developing asthma compared with those born via vaginal delivery. The aim of this study is to assess the association between a Caesarean section and the risk of childhood asthma. Methods: This was a case-control study carried out in Basrah, Iraq including 952 children aged 3-12 years. Four hundred and seven asthmatic cases and a control group of 545 age-matched non-asthmatic children were enrolled. Binary logistic regression was used to assess the relationship between asthma and birth via Caesarean section.

RESULTS

The mean age of the children was 6.7±2.5 years. Two-hundred eighty-three children (29.7%) were delivered via Caesarean section. The binary logistic regression analysis showed that delivery via Caesarean section was found to be an independent significant risk factor for asthma (OR=3.37; 95% CI=1.76-6.46; p<0.001). In addition, many other risk factors were found to be significant predictors of asthma, including bottlefeeding (OR=27.29; 95% CI=13.54-54.99; p<0.001) and low birth weight (OR=16.7; 95% CI=6.97-37.49; p<0.001).

CONCLUSION

Caesarean section is significantly associated with an increased risk of childhood asthma.

Prenatal and neonatal factors involved in the development of childhood allergic diseases in Guangzhou primary and middle school students

BACKGROUND

Allergic diseases, such as asthma, dermatitis, rhinitis, and eczema, are highly prevalent in Chinese school children. Environmental factors, including air pollution and automobile exhaust, play an important role in the etiology of these diseases. However, prenatal and neonatal factors, such as gender, maternal diseases during pregnancy, and premature birth, may also be associated with allergic disease occurrence. The objective of this study was to explore prenatal and neonatal factors that are involved in the development of allergic diseases among primary and middle school students in Guangzhou, China.

METHODS

A cross-sectional survey was launched by the Health Promotion Centre for Primary and Secondary Schools of the Guangzhou Municipality in October 2017. All primary and middle school students in Guangzhou were notified to participate in the questionnaire online under the direction of their parents. The results of the physical examination were reported by the schools' medical department. The results of the questionnaire were collected and analyzed by the researchers. The prevalence of asthma, allergic rhinitis, allergic dermatitis, and eczema was identified.

RESULTS

Based on reported 183,449 questionnaires and medical records, the data indicate that the sex, birth weight, neonatal feeding type, delivery mode, and students' father smoking status were significantly associated with the prevalence of all four allergic diseases in primary and middle school children. In further stratified analyses of the children with normal birth weight (2500-4000 g) and without any maternal diseases during pregnancy, the factors of male sex, high birth weight, cesarean delivery, and father smoking status all increased the risk of asthma, dermatitis, rhinitis, and eczema. Also, unlike exclusive breastfeeding, breast plus formula feeding increased these risks, but pure formula feeding had the opposite effect.

CONCLUSION

Prenatal and neonatal factors, including male sex, high birth weight, cesarean delivery, only child, and father smoking status are associated with the risks of allergic diseases in school children.

Pathways linking caesarean delivery to early health in a dual burden context: Immune development and the gut microbiome in infants and children from Galápagos, Ecuador

OBJECTIVES

Global increases in caesarean deliveries are exposing more infants to perinatal environments that are evolutionarily novel and potentially increasing their risks for inflammatory conditions. Yet, the pathways linking caesareans to later health outcomes are not well understood, particularly in dual burden contexts. We test two of the hypothesized pathways, altered immune function and gut microbiota, which may link delivery mode to later health outcomes and test whether these associations persist when controlling for postnatal nutritional and pathogenic exposures.

METHODS

Data come from infants, aged 0 to 2 (n = 41), and young children, aged 2 to 11 (n = 135), from the Galápagos, Ecuador. Differences in morbidity, C-reactive protein (CRP), and gut microbiota by delivery type were tested using linear and logistic regression models adjusted for nutritional and pathogenic exposures and infant age.

RESULTS

Over half of infants and over 40% of children were delivered by caesarean. Morbidity and CRP did not differ between infants or children born by caesarean or vaginally. Microbial taxa abundance differed by delivery mode. Infants born by caesarean had a higher abundance of Firmicutes and a lower relative abundance of Bacteroidales. Children born by caesarean had a higher abundance of Proteobacteria and Enterobacteriales. These differences remained after adjustment for environmental exposure.

CONCLUSIONS

Caesarean delivery is associated with differences in gut microbiota across childhood even in this dual burden context. Our results highlight the importance of examining caesarean delivery across diverse contexts to better understand the impact of perinatal interventions on short- and longer-term health outcomes.

Caesarean delivery, immune function and inflammation in early life among Ecuadorian infants and young children

Caesarean delivery has been linked to a number of inflammatory conditions in childhood and adolescence. Yet the mechanisms underlying these associations and their generalizability across contexts with different postnatal feeding and pathogenic exposures remain unclear. This study tests the association between delivery type and three measures of immune function, inflammation, morbidity and leukocyte proportions, in Ecuadorian infants and children aged 6 months to 2 years. Data were collected from mother-child pairs participating in a nationally representative health and nutrition survey Encuesta Nacional de Salud y Nutricion (ENSANUT-ECU) conducted in 2012. The analytic sample includes 828 mothers and infants with delivery information and measured biomarkers. Poisson regression models were used to examine the association between delivery type and markers of immune function, controlling for maternal and infant characteristics, including age, sex, sociodemographic characteristics and medical indications. 40.8% (n=338) of sample infants and children were delivered by caesarean. Compared to those born vaginally, infants born by caesarean were less likely to have elevated C-reactive protein (CRP) [CRP>2 mg/l; risk ratio (RR): 0.76, 95% confidence interval (CI): 0.58-1.00] and more likely to have illness symptoms (RR: 1.22, 95% CI: 1.01-1.46) and elevated basophils (RR: 1.83, 95% CI: 1.03-3.25). No other immune cell proportions differed by delivery type. The results suggest that differences in the perinatal exposures accompanying caesarean delivery may alter immune development and function, particularly in the inflammatory response to infection and in cells involved in the allergic response, across infancy and early childhood. Understanding the pathways linking perinatal exposures to immune development is important for preventing the development of inflammatory conditions.

Milk Other Than Breast Milk and the Development of Asthma in Children 3 Years of Age. A Birth Cohort Study (2006⁻2011)

Prevalence of asthma in Australian children is amongst the highest in the world. Although breastfeeding positively influences infant immunity, early introduction of Milk Other than Breast Milk (MOTBM) may also play an important role in the development of Asthma. The aim of this study was to investigate the association between the introduction of MOTBM in the first six months after birth and the development of reported persistent asthma in 3-year olds. A sample of 1121 children was extracted from the Environments for Healthy Living longitudinal birth cohort study. Introduction of MOTBM during the first six months after birth increased almost two-fold the risk of development of persistent asthma after adjusting for other covariates (Adjusted Relative Risk (ARR): 1.71, 95% CI: 1.03⁻2.83, p = 0.038). This study indicates that the introduction of MOTBM in the first six months of life is a risk factor for asthma incidence among 3-year old children. This result is important in explaining the benefits of breastfeeding as part of public health interventions to encourage mothers to increase breastfeeding initiation and duration, and avoid the introduction of MOTBM in the first six months after childbirth.

Elective cesarean delivery at term and the long-term risk for respiratory morbidity of the offspring

Maternal morbidity is associated with cesarean deliveries. However, new evidence suggests that short- and long-term neonatal morbidity is also associated. This includes respiratory morbidity with conflicting results. To determine whether mode of delivery has an impact on the long-term risk for respiratory morbidity in the offspring, a population-based cohort analysis was conducted including all singleton term deliveries occurring between 1991 and 2014 at a single tertiary medical center. A comparison was performed between children delivered via elective cesarean delivery (CD) and those delivered vaginally. Multiple gestations and fetuses with congenital malformations were excluded from the analysis as were all cases of urgent CDs. Pediatric hospitalizations involving respiratory morbidity of offspring up to the age of 18 years were evaluated. A Kaplan-Meier survival curve was used to compare cumulative respiratory morbidity incidence and a Cox regression model to control for confounders. During the study period, 132,054 term deliveries met the inclusion criteria; 8.9% were via elective CDs (n = 11,746) and 91.1% (n = 120,308) were vaginal deliveries. Hospitalizations of the offspring involving respiratory morbidity were significantly more common in offspring delivered by CDs (5.2 vs. 4.3% in vaginal deliveries, p < 0.001). The Kaplan-Meier survival curve demonstrated a significantly higher cumulative incidence of respiratory morbidity in the elective CD group (log rank p < 0.001). In a Cox proportional hazards model, while controlling for maternal age, gestational age, and birthweight, CD exhibited a significant and independent association with long-term respiratory morbidity of the offspring (adjusted hazard ratio = 1.22 (CI, 1.12-1.33), p < 0.001).Conclusion: Elective cesarean delivery at term is a significant risk factor for long-term pediatric respiratory morbidity of the offspring. What is Known: • Cesarean delivery is a major surgery with known possible complications. • Cesarean delivery has possible immediate complications for the newborn including respiratory complications. What is New: • Our study shows more long term respiratory morbidity in the CD group including asthma and obstructive sleep apnea. • Different possible explanations have been proposed including exposure to maternal flora during vaginal delivery and the stress hormones secreted during contractions and delivery.

Developments in the field of clinical allergy in 2015 through the eyes of Clinical and Experimental Allergy

In the second of two papers, we describe developments in the field of clinical allergy as documented by Clinical and Experimental Allergy in 2015. Epidemiology, clinical allergy, asthma and rhinitis are all covered.

Low birth weight contributed to increased serum IL-6 levels in infantile respiratory syncytial virus infection

Background

To evaluate the role of serum cytokines in the pathogenesis of respiratory syncytial virus (RSV) infection in infants with low birth weight (LBW).

Methods

A prospective observational study was performed, and hospitalized children with lower respiratory tract infection (LRTI) were recruited. Three hundred fifty-eight patients < 1 year met the inclusion criteria: 116 patients had only RSV infection (RSV group); 242 patients had no RSV or other specific pathogen (non-RSV group). Serum interleukin-2 (IL-2), IL-4, IL-6, IL-10, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ) were detected through flow cytometry.

Results

No significant differences in serum IL-2, 4, 6, 10, and IFN-γ levels were observed between the RSV and non-RSV groups. For RSV infected infants with or without wheezing, delivery mode had no obvious effect on the changes of serum cytokine levels. However, the level of IL-6 in the RSV-infected infants with LBW was significantly higher than that in infants with normal birth weight.

Conclusions

Serum IL-6 level was significantly increased in RSV infected infants with LBW. It is likely that the specific serum cytokine pattern will contribute to our understanding of the pathogenesis of RSV infections, especially in RSV-infected infants with LBW.

Cesarean section without medical indication and risk of childhood asthma, and attenuation by breastfeeding

Background

Previous studies suggest that caesarean section (CS) may increase the risk of asthma in children, but none of them could preclude potential confounding effects of underlying medical indications for CS. We aim to assess the association between CS itself (without medical indications) and risk of childhood asthma.

Methods

We conducted a hospital-based case-control study on childhood asthma with 573 cases and 812 controls in Shanghai. Unconditional logistic regression models in SAS were employed to control for potential confounders.

Results

Our study found that CS without medical indication was significantly associated with elevated asthma risk (adjusted OR = 1.58 [95% CI 1.17–2.13]). However, this risk was attenuated in children fed by exclusive breastfeeding in the first six months after birth (adjusted OR = 1.39 [95% CI 0.92–2.10]). In contrast, the risk was more prominent in children with non-exclusive breastfeeding or bottle feeding (adjusted OR = 1.91 [95% CI 1.22–2.99]).

Conclusions

CS without medical indication was associated with an increased risk of childhood asthma. Exclusive breastfeeding in infancy may attenuate this risk.

Cesarean section without medical indication and risks of childhood allergic disorder, attenuated by breastfeeding

Caesarean section (CS) may increase the risk of asthma and allergic diseases in children, but previous studies could not preclude the potential confounding effect of underlying medical indications for CS. We aim to assess the association between CS itself (without indications) and risks of asthma and allergic rhinitis in children. The 2014 Shanghai Children's Health, Education and Lifestyle Evaluation was a large population-based survey with cluster random probability sampling in 26 primary schools in Shanghai, China, in 2014. The mode of delivery and child history of asthma and allergic rhinitis were reported by parents. We included 12639 children in our analysis. CS without medical indication was associated with an increased risk of childhood asthma. CS without medical indication and CS for fetal complications were associated with increased risks of childhood allergic rhinitis, respectively. In children fed by exclusive breastfeeding or mixed feeding in the first four months after birth, these risks were not significant. In contrast, in children fed by exclusive formula milk, CS was highly significantly associated with childhood asthma and allergic rhinitis. In conclusion, CS without medical indication was associated with increased risks of both childhood asthma and allergic rhinitis. Breastfeeding in early infancy may attenuate these risks.

Caesarean Section is associated with reduced perinatal cytokine response, increased risk of bacterial colonization in the airway, and infantile wheezing

The relationship between cesarean section (CS) and allergic disorders such as asthma and wheezing has been inconsistent, and the mechanisms for their connection remained largely unknown. We aimed to investigate whether CS is associated with infantile wheeze and to explore the connection between CS and several risk factors known to correlate with allergy development. Mononuclear cells were isolated from cord blood and assessed for cytokine responses by ELISA. Bacteria from nasopharyngeal specimens were identified with traditional culture methods. Infant lung function tests were performed at 6 and 12 months of age. IgE levels and clinical outcomes were assessed at 12 months. The result showed that children delivered by CS were associated with increased risk of wheezing (aHR 1.63; 95% CI: 1.01–2.62) and decreased compliance of the respiratory system at 12 months (p = 0.045). In addition, CS was associated with reduced TLR1–2- triggered TNF-α and IL-6 responses at birth. By12 months of age, children delivered by CS had significantly less airway bacterial clearance. Our findings suggested that CS was associated with decreased pro-inflammatory cytokine response to TLR1–2 stimulation, followed by higher abundance of bacterial colonization in the airway during late infancy, thus increasing the risk of infantile wheezing.

Migrant status and childhood hospitalizations for asthma and other wheezing disorders

BACKGROUND

In developed Western settings, asthma is more prevalent among second-generation compared to first-generation migrants. However, these studies are difficult to interpret as they include migrants of various ethnicities and countries of origin.

OBJECTIVE

We assessed the association of parental migrant status with wheezing disorders among children born in Hong Kong, a developed non-Western setting, where many children have migrant parents from mainland China of the same ethnicity.

METHODS

We used Cox regression to examine the adjusted associations of parental migrant status with time to first public hospital admission for asthma, bronchitis and bronchiolitis (International Classification of Diseases, Ninth Version Clinical Modification 466, 490 and 493) from 9 days to 12 years in a population-representative birth cohort of 8327 Chinese children in Hong Kong.

RESULTS

Having both parents as migrants was associated with higher risk of hospitalization for asthma and other wheezing disorders, compared to both parents being Hong Kong born (hazard ratio 1.30, 95% confidence interval 1.05-1.60 from 9 days to 6 years), adjusted for type of hospital at birth, parental history of allergies, mother's age at birth, father's age at birth and highest parental education.

CONCLUSIONS AND CLINICAL RELEVANCE

In the unique, non-Western context of Hong Kong, second-generation migrants had higher risk of hospitalization for childhood wheezing disorders compared to the native population, particularly before 6 years of age. Further study is required to clarify the underlying mechanisms involved.

Gestational Age, Birthweight for Gestational Age, and Childhood Hospitalisations for Asthma and Other Wheezing Disorders

BACKGROUND

Preterm birth, early term birth, and low birthweight are associated with childhood wheezing disorders in developed Western settings, but observed associations could be confounded by socio-economic position. This study aims to clarify such associations in a developed non-Western setting with a different confounding structure.

METHODS

Using Cox regression, we examined the adjusted associations of gestational age and birthweight for gestational age with time to first public hospital admission for asthma, bronchitis, and bronchiolitis (International Classification of Diseases, Ninth Version Clinical Modification 466, 490, and 493) from 9 days to 12 years in a population-representative birth cohort of 8327 Chinese children in Hong Kong, a developed setting with less clear social patterning of prematurity or birthweight. Analyses were adjusted for infant and parental characteristics and socio-economic position.

RESULTS

Children born late preterm (34 to <37 weeks) had higher risk of hospitalisation for asthma and other wheezing disorders [hazard ratio (HR) 1.99, 95% confidence interval (CI) 1.48, 2.67] than children born full term (39 to <41 weeks). Early term births (37 to <39 weeks) had HR 1.01 (95% CI 0.84, 1.22), late term births (41 to <42 weeks) had HR 0.77 (95% 0.59, 1.01), and post-term births (≥42 weeks) had HR 0.56 (95% CI 0.32, 0.98). Large for gestational age was associated with lower risk of hospitalisation (HR 0.76, 95% CI 0.57, 0.99).

CONCLUSION

The association of preterm birth with childhood wheezing could be biologically mediated. We cannot rule out an association for early term births.

Delivery Mode, Duration of Labor, and Cord Blood Adiponectin, Leptin, and C-Reactive Protein: Results of the Population-Based Ulm Birth Cohort Studies

Background

Numerous studies have reported associations between delivery mode and health outcomes in infancy and later life. Previous smaller studies indicated a relationship between delivery mode and newborn inflammation potentially constituting a mediating factor. We aimed to determine the influence of delivery mode and duration of labor on cord blood concentrations of adiponectin, leptin, and high-sensitivity C-reactive protein (hs-CRP).

Methods

In the Ulm SPATZ Health Study, 934 singleton newborns and their mothers were recruited during their hospital stay in the University Medical Center Ulm, Southern Germany, from 04/2012-05/2013. Inflammatory biomarkers were measured by ELISAs (n = 836). Delivery mode was analyzed categorically (elective cesarean (reference), active labor delivery: emergency cesarean, assisted vaginal, and spontaneous vaginal); duration of labor continuously. Following log-transformation, linear regression was used to estimate geometric means ratios (GMR) adjusted for potential confounders for the effects of delivery mode and duration of labor on each biomarker separately. Independent replication was sought in the similarly conducted Ulm Birth Cohort Study recruited from 11/2000-11/2001.

Results

Individually, active labor delivery modes as well as increasing duration of labor were associated with higher leptin and hs-CRP concentrations. After mutual adjustment, the associations with delivery modes were attenuated but those for duration of labor remained statistically significant (GMR (95%CI) 1.10 (1.00; 1.21) and 1.15 (1.04; 1.27) for leptin and hs-CRP per hour of labor, respectively). No significant adjusted associations were observed between delivery modes and adiponectin concentrations. These findings were replicated in an independent birth cohort study.

Conclusions

Cord blood leptin and hs-CRP concentrations were associated with duration of labor rather than delivery mode. Further research is warranted to investigate these associations with additional cytokines involved in inflammatory response to delineate the inflammatory profile. Subsequently, research on determinants of these associations and their role in development of chronic disease is needed.