Prospective study of breast-feeding in relation to wheeze, atopy, and bronchial hyperresponsiveness in the Avon Longitudinal Study of Parents and Children (ALSPAC)

Breastfeeding, genetic susceptibility, and the risk of asthma and allergic diseases in children and adolescents: a retrospective national population-based cohort study

BACKGROUND

Asthma and allergic diseases (such as allergic rhinitis) are multifactorial chronic respiratory diseases, and have many common pathogenic mechanisms. This study aimed to assess the joint effects of breastfeeding and genetic susceptibility on asthma, allergic disease in children and adolescents and sought to examine whether the effect of breastfeeding was consistent under distinct levels of genetic risk.

METHODS

A total of 351,931 UK Biobank participants were analyzed. Firstly, Cox proportional hazards model was used to evaluate the relation between breastfeeding and asthma, allergic disease and their comorbidity. Next, we incorporated the polygenic risk score as an additional covariate into the model. Then, we explored the role of breastfeeding at each stage of asthma and allergic disease through a multi-state model. Meanwhile, several sensitivity analyses were conducted to evaluate the robustness of our results. Finally, we calculated the attributable protection and population attributable protection of breastfeeding.

RESULTS

Breastfeeding was related to a reduced risk of occurring asthma (adjusted hazard ratio [HR] = 0.89, 95% confidence interval [CI] 0.86 ~ 0.93), allergic disease (HR = 0.89, 95%CI 0.87 ~ 0.91) and comorbidity (HR = 0.89, 95%CI 0.83 ~ 0.94). The effect of breastfeeding was almost unchanged after considering PRS and did not substantially differ across distinct genetic risk levels. Breastfeeding showed a stronger risk-decreased impact on individuals who developed from allergic rhinitis to comorbidity (HR = 0.83, 95%CI 0.73 ~ 0.93). Further, the influence of breastfeeding was robust against covariates considered and the confounding influence of adolescent smoking. Finally, due to breastfeeding, 12.0%, 13.0% or 13.0% of the exposed population would not suffer from asthma, allergic diseases and the comorbidity, while 7.1%, 7.6% or 7.6% of the general population would not suffer from these diseases.

CONCLUSIONS

This study provided supportive evidence for the risk-reduced effect of breastfeeding on asthma, allergic diseases, and the comorbidity in children and adolescents, and further revealed that such an influence was consistent across distinct genetic risk levels.

Atopic diseases-Diagnostics, mechanisms, and exposures

Epidemiological data suggest that atopic diseases begin in early life and that most cases present clinically during early childhood. The diseases are highly prevalent and increase as communities adopt western lifestyles. Disentangling the pathophysiological mechanisms leading to disease debut is necessary to identify beneficial/harmful exposures so that successful prevention and treatment can be generated. The objective of this review is to explore the definition of atopy and mechanisms of atopic diseases, and to investigate the importance of environmental factors in early life, prior to disease development. First, the distribution of sIgE levels in children is investigated, as this is one of the main criteria for the definition of atopy. Thereafter, it is explored how studies of parental atopic status, sensitization patterns, and early debut and severity of atopic dermatitis have substantiated the theory of an early-life window of opportunity for intervention that precedes the development of atopic diseases in childhood. Then, it is examined whether early-life exposures such as breastfeeding, dogs, cats, and house dust mites in the home perinatally constitute important influencers in this crucial time of life. Finally, it is discussed how these findings could be validated in randomized controlled trials, which might prepare the ground for improved diagnostics and prevention strategies to mitigate the current atopic pandemic.

Maternal dietary indexes are not linked to early childhood wheezing or atopic eczema

BACKGROUND

Several recent studies have investigated the association between maternal diet during pregnancy and wheezing or asthma in children. However, whether a specific dietary pattern during pregnancy protects children from wheezing or atopic diseases remains unclear. This study investigated the association between The Alternative Healthy Eating Index for Pregnancy (AHEI-P), the Dietary Inflammatory Index (DII), and the risk for wheezing and atopic eczema in children during the first year of life.

METHODS

This study included 1330 mother-child pairs who attended the Kuopio Birth Cohort (KuBiCo) study and had dietary information during the last trimester and information on children's health in the first year of life. AHEI-P and DII indicate a healthy diet and dietary inflammation potential during pregnancy. The AHEI-P and DII were compared with reported wheezing and doctor-diagnosed atopic eczema in children during the first year of life.

RESULTS

Neither AHEI-P nor DII is associated with wheezing or atopic eczema in children when analyzed by continuous variables and by tertiles. The odds ratio (95% CI) for AHEI-P and wheezing was 0.99 (0.98-1.01), for AHEI-P and atopic eczema1.01 (0.99-1.02), for DII and wheezing 1.02 (0.95-1.09), and for DII and atopic eczema 0.97 (0.91-1.04).

CONCLUSION

In this cohort study, AHEI-P and DII during pregnancy were not associated with wheezing or atopic eczema in the offspring during the first year of life.

Spanish Pediatricians' Positions Regarding Prevention, Diagnosis, Nutritional Management, and Challenges in Cow's Milk Protein Allergy

Management of cow's milk protein allergy (CMPA) can vary depending on the experience and area of expertise of the clinician responsible for the patient's follow-up, which may or may not align with the recently published literature. To analyze the perspectives of Spanish pediatricians on this topic, a survey was conducted. The survey aimed to determine the current opinions and attitudes of 222 primary care and hospital pediatricians toward CMPA prevention and nutritional management. Participating pediatricians completed the questionnaire, providing insights into their daily clinical practices, including access to testing, attitudes with respect to various aspects of CMPA diagnosis, prevention, oral food challenges, and treatment. The findings revealed that pediatricians generally agree on the use of extensively hydrolyzed formulas (eHFs) to prevent CMPA in high-risk atopic children, despite limited evidence supporting the widespread use of this practice. However, consensus was lacking regarding the utility of formulas with prebiotics and probiotics for expediting tolerance development. In most cases, pediatricians preferred eHFs for the nutritional management of CMPA, followed by hydrolyzed rice formulas (HRFs), with amino-acid-based formulas (AAFs) being the third option. Certain issues remained controversial among pediatricians, such as prevention methods, symptom assessment, and the role of probiotics. These variations in management approaches reflect the influence of clinician experience and area of expertise, underscoring the need for standardized guidelines in this field.

Early-life and health behaviour influences on lung function in early adulthood

RATIONALE

Early-life exposures may influence lung function at different stages of the life course. However, the relative importance of characteristics at different stages of infancy and childhood are unclear.

OBJECTIVES

To examine the associations and relative importance of early-life events on lung function at age 24 years.

METHODS

We followed 7545 children from the Avon Longitudinal Study of Parents and Children from birth to 24 years. Using previous knowledge, we classified an extensive list of putative risk factors for low lung function, covering sociodemographic, environmental, lifestyle and physiological characteristics, according to timing of exposure: 1) demographic, maternal and child; 2) perinatal; 3) postnatal; 4) early childhood; and 5) adolescence characteristics. Lung function measurements (forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁), FEV₁/FVC and forced expiratory flow at 25-75% of FVC) were standardised for sex, age and height. The proportion of the remaining variance explained by each characteristic was calculated. The association and relative importance (RI) of each characteristic for each lung function measure was estimated using linear regression, adjusted for other characteristics in the same and previous categories.

RESULTS

Lower maternal perinatal body mass index (BMI), lower birthweight, lower lean mass and higher fat mass in childhood had the largest RI (0.5-7.7%) for decreased FVC. Having no siblings, lower birthweight, lower lean mass and higher fat mass were associated with decreased FEV₁ (RI 0.5-4.6%). Higher lean mass and childhood asthma were associated with decreased FEV₁/FVC (RI 0.6-0.8%).

CONCLUSIONS

Maternal perinatal BMI, birthweight, childhood lean and fat mass and early-onset asthma are the factors in infancy and childhood that have the greatest influence on early-adult lung function.

Potential of Lactoferrin in the Treatment of Lung Diseases

Lactoferrin (LF) is a multifunctional iron-binding glycoprotein that exhibits a variety of properties, such as immunomodulatory, anti-inflammatory, antimicrobial, and anticancer, that can be used to treat numerous diseases. Lung diseases continue to be the leading cause of death and disability worldwide. Many of the therapies currently used to treat these diseases have limited efficacy or are associated with side effects. Therefore, there is a constant pursuit for new drugs and therapies, and LF is frequently considered a therapeutic agent and/or adjunct to drug-based therapies for the treatment of lung diseases. This article focuses on a review of the existing and most up-to-date literature on the contribution of the beneficial effects of LF on the treatment of lung diseases, including asthma, viral infections, cystic fibrosis, or lung cancer, among others. Although in vitro and in vivo studies indicate significant potency of LF in the treatment of the listed diseases, only in the case of respiratory tract infections do human studies seem to confirm them by demonstrating the effectiveness of LF in reducing episodes of illness and shortening the recovery period. For lung cancer, COVID-19 and sepsis, the reports are conflicting, and for other diseases, there is a paucity of human studies conclusively confirming the beneficial effects of LF.

Association between History of Prolonged Exclusive Breast-Feeding and the Lung Function Indices in Childhood

Although the propitious effects of breastfeeding on children's health are indisputable, the impact of exclusive breastfeeding on the lung function later in life remains controversial. Our objective was to explore the possible associations between breastfeeding and the lung function of children who were exclusively breastfed for an extensive period of time. This was a cross-sectional study of children who were exclusively breastfed for more than 12 months. Demographics and anthropometric data were collected; the body mass index (BMI), % body fat, and % central obesity were calculated; and all the participants underwent standard spirometry with reversibility testing. The relationship between breastfeeding duration and spirometric parameters was assessed by Spearman's correlation and multivariable regression, after adjustment for other confounders. Forty-six children (21 boys), aged 9.2 ± 2.4 years, with a reported breastfeeding duration of 27.5 ± 12.5 months (range 12-60 months) were included; 13% were overweight (none were obese) and 21.7% had central obesity. The average FEV1 was 104.7 ± 10.4% and the average FEF25-75 was 107.9 ± 13.3%. The duration of exclusive breastfeeding was positively correlated with FEF25-75% (r = 0.422, p = 0.003). Multivariable linear regression analysis confirmed the above finding (beta coefficient 0.478, p = 0.002), independently of age, overweight, and central obesity. No correlation was noted between the duration of breastfeeding and other spirometric parameters. In addition to its favorable impact on the metabolic profile, prolonged exclusive breastfeeding seems to exert a propitious effect on the function of smaller airways throughout childhood.

Risk Factors Affecting Development and Persistence of Preschool Wheezing: Consensus Document of the Emilia-Romagna Asthma (ERA) Study Group

Wheezing at preschool age (i.e., before the age of six) is common, occurring in about 30% of children before the age of three. In terms of health care burden, preschool children with wheeze show double the rate of access to the emergency department and five times the rate of hospital admissions compared with school-age asthmatics. The consensus document aims to analyse the underlying mechanisms involved in the pathogenesis of preschool wheezing and define the risk factors (i.e., allergy, atopy, infection, bronchiolitis, genetics, indoor and outdoor pollution, tobacco smoke exposure, obesity, prematurity) and the protective factors (i.e., probiotics, breastfeeding, vitamin D, influenza vaccination, non-specific immunomodulators) associated with the development of the disease in the young child. A multidisciplinary panel of experts from the Emilia-Romagna Region, Italy, addressed twelve key questions regarding managing preschool wheezing. Clinical questions have been formulated by the expert panel using the PICO format (Patients, Intervention, Comparison, Outcomes). Systematic reviews have been conducted on PubMed to answer these specific questions and formulate recommendations. The GRADE approach has been used for each selected paper to assess the quality of the evidence and the degree of recommendations. Based on a panel of experts and extensive updated literature, this consensus document provides insight into the pathogenesis, risk and protective factors associated with the development and persistence of preschool wheezing. Undoubtedly, more research is needed to improve our understanding of the disease and confirm the associations between certain factors and the risk of wheezing in early life. In addition, preventive strategies must be promoted to avoid children's exposure to risk factors that may permanently affect respiratory health.

Effects of early life exposure to home environmental factors on childhood allergic rhinitis: Modifications by outdoor air pollution and temperature

BACKGROUND

There is growing evidence that allergic rhinitis (AR) is associated with indoor environmental factors, but their role in childhood AR during early life remains unclear.

OBJECTIVE

To investigate the association of preconceptional, prenatal, early postnatal, and current exposure to home environmental factors with childhood AR, and to further explore whether this association can be interacted by outdoor air pollution and temperature.

METHODS

A retrospective cohort study of 8689 preschool children was conducted during 2019-2020 in Changsha, China. A standard questionnaire was used to collect data on each family's health outcomes and home environments. We considered home environmental exposures during one year before conception, pregnancy, first year of life, and past year. Associations of indoor air pollution and allergens with AR were assessed by multiple logistic regression models.

RESULTS

Pre-birth exposure to indoor air pollution emitted by new furniture or redecoration and dampness related allergen derived from mold/damp stains and mold/damp clothes or bedding during 1 year before conception and pregnancy was significantly associated with increased AR, with adjusted ORs (95% CI) ranging from 1.35 (1.05-1.75) to 1.87 (1.55-2.27). Childhood AR was also significantly related with post-birth exposure to dampness related indoor allergen including mold/damp stains and mold/damp clothes or bedding in first year and past year and pollen allergen including total and nonflowing plants in past year, with a range of ORs (95% CI) from 1.20 (1.01-1.42) to 1.79 (1.42-2.27). We identified that pre-birth, particularly in utero exposure to both indoor air pollution from renovation and dampness related allergens, played a key role in AR development compared to post-birth exposures, and accumulative effect was observed with the highest risk of AR. High exposure to traffic-related air pollution (TRAP) including outdoor PM_2.5, NO₂, CO, and O₃, as well as living near traffic road not only significantly increased adverse effect of home environmental factors but also decreased protective effect of household dogs on childhood AR. Early life exposure to low temperature in pregnancy and high temperature in first year significantly increased AR risk of home environmental exposure. Sensitivity analysis indicated that some sub-groups were more susceptible to AR risk of home environmental exposure.

CONCLUSION

Our study suggests that pre-birth exposure to home environmental factors played an important role in AR development and this effect can be interacted by TRAP and temperature, which supports a hypothesis of "(pre)fetal origin of childhood AR".

The association between duration of breastfeeding and childhood asthma outcomes

BACKGROUND

Postnatal exposures, including breastfeeding, may influence asthma development.

OBJECTIVE

To investigate the association between breastfeeding duration and child asthma.

METHODS

We studied 2021 mother-child dyads in the ECHO PATHWAYS consortium of prospective pregnancy cohorts (GAPPS, CANDLE, TIDES). Women reported the duration of any and exclusive breastfeeding and child asthma outcomes during follow-up at child age 4 to 6 years. Outcomes included current wheeze (previous 12 months), ever asthma, current asthma (having ≥2 of current wheeze, ever asthma, medication use in past 12-24 months), and strict current asthma (ever asthma with either or both current wheeze and medication use in past 12-24 months). We used multivariable logistic regression to assess associations (odds ratios and 95% confidence intervals) between breastfeeding and asthma outcomes adjusting for potential confounders. We assessed effect modification by mode of delivery, infant sex, and maternal asthma.

RESULTS

Among women, 33%, 13%, 9%, and 45% reported 0 to less than 2, 2 to 4, 5 to 6, and more than 6 months of any breastfeeding, respectively. The duration of any breastfeeding had a protective linear trend with ever asthma but no other outcomes. There was a duration-dependent protective association of exclusive breastfeeding and child asthma outcomes (eg, current asthma adjusted odds ratio [95% confidence interval], 0.64 [0.41-1.02], 0.61 [0.38-0.98], and 0.52 (0.31-0.87) for 2to 4 months, 5 to 6 months, and more than 6 months, respectively, compared with <2 months). For exclusive breastfeeding, protective associations were stronger in dyads with children born by vaginal vs cesarean delivery although interactions did not reach statistical significance (Pinteractions 0.12-0.40).

CONCLUSION

Longer duration of exclusive breastfeeding had a protective association with child asthma.

High Insulin in Early Childhood Is Associated with Subsequent Asthma Risk Independent of Body Mass Index

BACKGROUND

Asthma and obesity are major, interconnected public health challenges that usually have their origins in childhood, and for which the relationship is strengthened among those with insulin resistance.

OBJECTIVE

To determine whether high insulin in early life confers increased longitudinal risk for asthma independent of body mass index.

METHODS

The study used data from the Tucson Children's Respiratory Study (TCRS) and the Avon Longitudinal Study of Parents and Children (ALSPAC). Nonfasting insulin was measured in TCRS participants at age 6 years and fasting insulin in ALSPAC participants at age 8 years. Physician-diagnosed active asthma was determined at baseline and at subsequent assessments up to age 36 years in TCRS and 17 years in ALSPAC.

RESULTS

In TCRS, high insulin (upper quartile) at age 6 years was associated with increased odds of having active asthma from ages 8 to 36 years compared with low insulin (odds ratio,1.98; 95% CI, 1.28-3.05; P = .002). Similarly, in ALSPAC, high insulin was associated with a significantly higher risk of active asthma from ages 11 to 17 years compared with low insulin (odds ratio, 1.59; 95% CI, 1.12-2.27; P = .009). These findings were independent of baseline body mass index in both cohorts, and were not related to other demographic and asthma risk factors nor other tested markers of systemic inflammation and metabolic syndrome.

CONCLUSIONS

In 2 separate birth cohorts, higher blood insulin level in early childhood was associated with increased risk of active asthma through adolescence and adulthood, independent of body mass index. High insulin indicates a novel mechanism for asthma development, which may be a target for intervention.

The Role of Breastfeeding on Respiratory Outcomes Later in Childhood

BACKGROUND

Breastfeeding is associated with a lower risk of wheezing in early childhood, but its effect later in childhood remains unclear. We investigated the association of breastfeeding and respiratory outcomes in children aged 11 years.

MATERIALS AND METHODS

We performed an observational longitudinal study including 110 prepubertal children. Information about breastfeeding duration, wheezing and asthma was collected by questionnaires. At 11 years of age, we measured spirometry parameters, lung volumes, diffusing lung capacity, and fractional exhaled nitric oxide. We used logistic and linear regression models to examine the associations of breastfeeding duration with the odds of asthma and lung function measures. All multivariable analyses were adjusted for sex, smoking during pregnancy, gestational age at birth, twins, and mode of delivery (confounder model).

RESULTS

Breastfeeding duration was associated with FEV₁ z-score [β = 0.04, CI 95% (0.02-0.09)], FEF75 z-score [β = 0.06, CI 95% (0.03-0.09)] and FEV₁/FVC z-score [β = 0.03, CI 95% (0.00-0.07)], but not with diffusing lung capacity and fractional exhaled nitric oxide. No association of breastfeeding duration with preschool wheezing, ever asthma and current asthma was documented.

CONCLUSION

We showed that children breastfed for longer time presented higher FEV₁, FEV₁/FVC, and FEF75 z-score values at 11 years of age compared to children breastfed for shorter time, suggesting a protective effect of breastfeeding on airways, and not on lung parenchyma (lung volumes and alveolar capillary membrane) or allergic airway inflammation. The positive effect of breastfeeding duration on lung function lays the foundation to promote breastfeeding more and more as effective preventive measure.

Breastfeeding and risk of childhood asthma: a systematic review and meta-analysis

OBJECTIVE

To investigate the relationship between breastfeeding and the development of paediatric asthma.

METHODS

A systematic review and meta-analysis was conducted with MEDLINE, Embase, CINAHL and ProQuest Nursing and Allied Health source databases. Retrospective/prospective cohorts in children aged <18 years with breastfeeding exposure reported were included. The primary outcome was a diagnosis of asthma by a physician or using a guideline-based criterion. A secondary outcome was asthma severity.

RESULTS

42 studies met inclusion criteria. 37 studies reported the primary outcome of physician-/guideline-diagnosed asthma, and five studies reported effects on asthma severity. Children with longer duration/more breastfeeding compared to shorter duration/less breastfeeding have a lower risk of asthma (OR 0.84, 95% CI 0.75-0.93; I2 = 62.4%). Similarly, a lower risk of asthma was found in children who had more exclusive breastfeeding versus less exclusive breastfeeding (OR 0.81, 95% CI 0.72-0.91; I2=44%). Further stratified analysis of different age groups demonstrated a lower risk of asthma in the 0-2-years age group (OR 0.73, 95% CI 0.63-0.83) and the 3-6-years age group (OR 0.69, 95% CI 0.55-0.87); there was no statistically significant effect on the ≥7-years age group.

CONCLUSION

The findings suggest that the duration and exclusivity of breastfeeding are associated with a lower risk of asthma in children aged <7 years.

The effect of diet in infancy on asthma in young adults: the Merthyr Allergy Prevention Study

INTRODUCTION

Early infant diet might influence the risk of subsequent allergic disease.

METHODS

The Merthyr Allergy Prevention Study (MAPS) was a randomised controlled trial in infants at high risk of allergic disease. The trial determined whether a cow's milk exclusion diet for the first 4 months of life decreased the risk of allergic disease including asthma compared with a normal diet. A soya milk preparation was offered to those in the intervention group. A standardised questionnaire for allergic disease was completed at ages 1, 7, 15 and 23 years, with clinical assessment at 1, 7 and 23 years. The effect of the intervention on the risk of atopy, asthma and wheeze at age 23 years was determined.

FINDINGS

487 subjects entered the study; at age 23 years 299 completed the questionnaire, of which 119 attended clinical assessment. Subjects randomised to the intervention group had a significantly increased risk of atopy (adjusted OR 2.97, 95% CI 1.30 to 6.80; p=0.01) and asthma (OR 2.07, 95%CI 1.09 to 3.91; p=0.03) at age 23 years, but not wheeze (OR 1.43, 95%CI 0.87 to 2.37; p=0.16). Earlier exposure to cow's milk was associated with a decreased risk of wheeze and asthma at age 23 years, while earlier exposure to soya milk was associated with an increased risk of atopy and asthma.

INTERPRETATION

In infants at high risk of allergic disease, either cow's milk exclusion or early soya milk introduction for the first 4 months of life increases the risk of atopy, wheeze and asthma in adulthood.

Breastfeeding and Allergic Diseases: What's New?

Asthma and other allergic disorders, such as atopic dermatitis and food allergies, are common chronic health problems in childhood. The rapid rise in the prevalence of these conditions registered over the last few decades has stressed the need to identify the modifiable risk factors associated with the development of these diseases. Breast milk, recognized as the gold standard for healthy growth and development of the newborn, is one of the major factors associated with a lower incidence of allergic and infectious diseases in childhood and young adulthood. Although the underlying mechanisms for these effects are not well understood, breastfeeding leads to immune system maturation. In this narrative review, we summarize existing evidence on breastfeeding and human milk composition in relation to allergic disease prevention or development.

The Interplay Between Eczema and Breastfeeding Practices May Hide Breastfeeding's Protective Effect on Childhood Asthma

BACKGROUND

Longer duration of breastfeeding may be protective against asthma. However, early manifestations of allergic disease, such as eczema, are risk factors for asthma and can influence the duration of breastfeeding, and hence, may bias observable associations.

OBJECTIVE

To examine the relationship between breastfeeding ever and duration and the development of asthma and allergic asthma phenotypes, stratified by a diagnosis of eczema during or after the breastfeeding period.

METHODS

A total of 3663 children participated in the 6-year-old follow-up of the HealthNuts study, a population-based, longitudinal study of allergic diseases in Australia. At age 1 year, breastfeeding and eczema data were collected and at age 6 years, information on wheeze, medication use, and parental report of doctor-diagnosed asthma were obtained, both via questionnaire. Skin prick test responses to food and aeroallergens at age 6 years further distinguished asthmatic children into allergic and nonallergic phenotypes.

RESULTS

Breastfeeding initiation was not associated with current asthma at age 6 years (adjusted odds ratio, 0.76; 95% CI, 0.45-1.29) when compared with never breastfeeding. Results were similar for length of exclusiveness and overall duration of breastfeeding, and allergic and nonallergic asthma phenotypes. However, increased duration of breastfeeding among children without eczema in infancy was associated with reduced odds of asthma (per month increase, adjusted odds ratio, 0.98; 95% CI, 0.95-1.0; P = .05), which equates to 0.86 (95% CI, 0.74-1.0) reduced odds of asthma for a 6-month increase in breastfeeding. This association was not apparent in children who were diagnosed with eczema during breastfeeding (adjusted odds ratio, 1.03; 95% CI, 0.98-1.08; P = .3).

CONCLUSIONS

Longer duration of breastfeeding was associated with a reduced odds of asthma among children without eczema in the first year of life; this association was masked before stratification by eczema in infancy. Future studies examining breastfeeding practices and the risk of allergic outcomes in later childhood need to consider the presence of early-life allergic manifestations impacting on breastfeeding behavior.

Effect of breastfeeding duration on lung function, respiratory symptoms and allergic diseases in school-age children

BACKGROUND

A positive effect of breastfeeding on lung function has been demonstrated in cohorts of children with asthma or risk for asthma. We assessed the impact of breastfeeding on lung function and symptoms at the age of 6 years in an unselected, healthy birth cohort.

METHODS

We prospectively studied healthy term infants from the Bern-Basel Infant Lung Development (BILD) cohort from birth up to 6 years. Any breastfeeding was assessed by weekly phone calls during the first year of life. Risk factors (eg, smoking exposure, parental history of allergic conditions, and education) were obtained using standardized questionnaires. The primary outcomes were lung function parameters measured at 6 years of age by spirometry forced expiratory volume in 1 second, body plethysmography (functional residual capacity [FRCpleth ], the total lung capacity [TLCpleth ], and the effective respiratory airway resistance [Reff ]) and fractional exhaled nitric oxide (FeNO). Secondary outcomes included ever wheeze (between birth and 6 years), wheeze in the past 12 months, asthma, presence of allergic conditions, atopic dermatitis, rhinitis, and positive skin prick test at the age of 6 years.

RESULTS

In 377 children the mean breastfeeding duration was 36 weeks (SD 14.4). We found no association of breastfeeding duration with obstructive or restrictive lung function and FeNO. After adjustment for confounders, we found no associations of breastfeeding duration with respiratory symptoms or the presence of allergic conditions.

CONCLUSION

This study found no evidence of an association between breastfeeding and comprehensive lung function in unselected healthy children with long-term breastfeeding. Our findings do not support the hypothesis that the duration of breastfeeding has a direct impact on lung function in a healthy population with low asthmatic risk.

Factors Predicting Asthma in Children With Acute Bronchiolitis

OBJECTIVE

The aim of this study was to determine if there is an association between bronchiolitis and future development of asthma in children younger than 2 years.

METHODS

We reviewed the medical records of 1991 patients younger than 2 years presenting to the emergency department from January 2000 to December 2010 who received a clinical diagnosis of acute bronchiolitis. Their demographic information, the number of bronchiolitis episodes, and family history of asthma were recorded. The primary care clinic records of these children were reviewed for a period of 1 year following their presentation to the emergency department to determine if they had received a diagnosis of asthma. A stepwise logistic regression was performed to determine what factors were associated with future asthma development.

RESULTS

We reviewed the medical record of 1991 children with the diagnosis of bronchiolitis for subsequent development of asthma. The following variables were identified as predictors of subsequent asthma: male sex (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.05-1.55), family history of asthma (OR, 1.6; 95% CI, 1.33-1.95), atopy (OR, 1.4; 95% CI, 1.12-1.83), age older than 5 months (OR, 1.4 95% CI, 1.13-1.66), more than 2 episodes of bronchiolitis (OR, 2.4; 95% CI, 1.79-3.07), and allergies (OR1.6; 95% CI, 1.14-2.14).

CONCLUSIONS

In this limited sample, the predictor variables for asthma were male sex, age older than 5 months, more than 2 episodes of bronchiolitis, a history of atopy, and allergies.

Birth Mode, Breastfeeding, Pet Exposure, and Antibiotic Use: Associations With the Gut Microbiome and Sensitization in Children

PURPOSE OF REVIEW

The infant gut microbiota has become a focus of multiple epidemiologic and cohort studies. This microbiome is derived from the mother (via the vaginal canal, maternal skin contact, breastfeeding, and possibly in utero microbial transfer) and is likely influenced by multiple external factors. It is now believed by some experts that colonization and formation of the newborn and alterations of gut microbiota in children are dependent on earlier alterations of the microbiota of mothers during or perhaps even before pregnancy. This review will focus on specific factors (pet keeping, breastfeeding, antibiotic use, and mode of delivery) that influence the infant gut microbiome and atopy.

RECENT FINDINGS

This is a review of recent literature describing how pet keeping, breastfeeding, antibiotic use, and mode of delivery influences and changes the infant gut microbiome and atopy. General trends in gut microbiota differences have emerged in different birth cohorts when each external factor is analyzed, but consistency between studies is difficult to replicate. The aforementioned factors do not seem to confer an overwhelming risk for development of atopy alone. This review provides a comprehensive review of early life environmental factors and their influence on the infant gut microbiome and atopy.

Perinatal factors and the development of childhood asthma

BACKGROUND

Perinatal factors are suspected to have a significant impact on the development of asthma; however, sufficiently powered studies have not been performed to investigate this issue.

OBJECTIVE

To evaluate whether perinatal factors and other risk factors have an independent or combined effect on the development of asthma.

METHODS

This study involved 3,770 children (mean age 9.1 years, range 5.68-12.16 years; 51.9% boys) who were enrolled in the Elementary School Student Cohort (2009-2014) in Ulsan University Hospital (Ulsan, Korea). Subjects were divided into an asthma group (n = 514) and a non-asthma group (n = 3,256).

RESULTS

Multivariate analyses showed that early life (within first week) oxygen therapy (adjusted odds ratio [aOR] 1.864, 95% confidence interval [CI] 1.156-3.004) and breastfeeding (aOR 0.763, 95% CI 0.606-0.960) were 2 significant perinatal factors influencing the development of asthma. Environmental tobacco smoke (aOR 1.634, 95% CI 1.298-2.058) and parental allergic disease (aOR 1.882, 95% CI 1.521-2.328) also were identified as risk factors. Using subgroup analyses, combined effects on asthma development were observed between perinatal factors (early life oxygen therapy and breastfeeding) and other risk factors (vicinity to major roadway [traffic-related air pollution], environmental tobacco smoke, parental allergic disease, and atopy).

CONCLUSION

Early life oxygen therapy and breastfeeding were identified as 2 important perinatal factors influencing the development of asthma. Furthermore, these factors showed combined effects with other risk factors (environmental tobacco smoke, traffic-related air pollution, parental allergic disease, and atopy) on the development of asthma.

Iberian consensus on cow's milk allergy: The CIBAL Study

BACKGROUND

The present study explores the professional opinion of a wide range of experts from the Iberian Peninsula (Spain and Portugal) and their degree of consensus about CMPA's prevention, diagnosis, treatment and progression.

MATERIAL AND METHODS

A 57-item survey divided in four blocks: Prevention (14 items), Diagnosis (10 items), Treatment (19 items) and Progression (14 items) was completed by 160 panellists, experts in CPMA management (116 Spain, 44 Portugal). Each one answered the questionnaire, formulated in Portuguese and Spanish, by individually accessing an online platform in two consecutive rounds. Five possible answers were possible: "completely agree", "agree", "neither agree nor disagree", "disagree" and "completely disagree". A modified Delphi method was used.

RESULTS

Consensus (more than 66% agree) was reached in 39 items (68.4%) and Discrepancy (less than 50% agree) in nine items (15.7%). Block separated analysis offers valuable differences regarding consensus. The Prevention block only reached 50%; the Diagnosis block 90%; the Treatment block 73.68%, showing a high degree of agreement on dietary treatment (15/16 items), and discrepancy or less agreement on immunotherapy treatments. The Progression block reached 71.4% consensus with discrepancy with regard to the time to perform oral food challenge and negatives prognosis consequences of accidental milk ingestion.

CONCLUSIONS

This study displays the current opinions of a wide group of experts on CMPA from the Iberian Peninsula and evidence discussion lines in CMPA management. The questions on which there were situations of discrepancy, provide us with very useful information for promoting new, rigorous research enabling us to draw conclusions on these controversial aspects.

Longitudinal Associations Between Respiratory Infections and Asthma in Young Children

We examined temporal dependencies between repeated assessments of respiratory tract infections (RTIs) and asthma in children in the Leicester Respiratory Cohort, Leicestershire, United Kingdom. Information associated with asthma (i.e., doctor diagnosis, health care visits, wheeze frequency) and RTIs (i.e., cold duration and frequency, cough with colds, ear infections) in the previous 12 months was assessed repeatedly at ages 1, 4, and 6 years for children born between April 1996 and April 1997. We determined associations between contemporaneous and lagged measures of asthma and RTIs, using structural equation modelling. In 1,995 children, asthma was positively associated with contemporaneous infections. Asthma at age 6 years was positively associated with asthma at age 4 years (regression coefficient = 0.87; 95% confidence interval (CI): 0.76, 0.97), but not with asthma at age 1 year (regression coefficient = -0.01; 95% CI: -0.14, 0.11). We found no evidence for direct protective effect of infections at age 1 year on asthma either at age 4 (regression coefficient = -0.20; 95% CI: -0.51, 0.10) or 6 (regression coefficient = 0.24; 95% CI: -0.04, 0.52) years. Adjusting for potential confounders did not qualitatively change those relationships. Based on our findings, we suggest that asthma at age 6 years is directly influenced by asthma history and only indirectly, if at all, by earlier infection episodes. We found little support for a protective effect of preschool infections on asthma at early school age.

Protective effect of breastfeeding on recurrent cough in adulthood

RATIONALE

Breastfeeding protects from respiratory infections in early life but its relationship to recurrent cough and other respiratory outcomes in adult life is not well established.

METHODS

Infant feeding practices were assessed prospectively in the Tucson Children's Respiratory Study, a non-selected birth cohort and categorised into formula from birth or introduced <1 month, formula introduced ≥1 to <4 months and exclusive breastfeeding for ≥4 months. Infant feeding was assessed as an ordinal variable representing an increasing dose of breastmilk across the three categories. Recurrent cough was defined at 22, 26 and 32 years as ≥2 episodes of cough without a cold lasting 1 week during the past year. Covariates included participant sex, race/ethnicity and smoking as well as parental smoking, education, age and asthma. Covariates were evaluated as potential confounders for the relation between infant feeding and adult outcomes.

RESULTS

Of the 786 participants, 19% breastfed <1 month, 50% breastfed ≥1 to <4 months and 31% breastfed ≥4 months. The prevalence of recurrent cough at 22, 26 and 32 years was 17%, 15% and 16%, respectively. Each ordinal increase in breastfeeding duration was associated with a decreased risk of recurrent cough in adult life: adjusted OR=0.71, (95% CI: 0.56 to 0.89), p=0.004. Additional adjustment for concurrent adult asthma, wheeze, smoking and lung volume did not change these results.

CONCLUSION

Longer duration of breastfeeding reduces the risk of recurrent cough in adult life, regardless of smoking and other respiratory symptoms, suggesting long-term protective effects on respiratory health.

Prospective Cohort Study of Breastfeeding and the Risk of Childhood Asthma

OBJECTIVES

To study whether the duration of breastfeeding and time for introduction of complementary foods was associated with the risk of childhood asthma.

STUDY DESIGN

We used data from the Norwegian Mother and Child Study, a nationwide prospective cohort study that recruited pregnant women from across Norway between 1999 and 2008. Children with complete data of breastfeeding up to 18 months and current age >7 years were eligible (n = 41 020). Asthma as the primary outcome was defined based on ≥2 dispensed asthma medications at age 7 years registered in the Norwegian Prescription Database. We used log-binomial regression models to obtain crude relative risks (RRs) in the main analysis, and adjusted for selected confounders in multivariable analyses.

RESULTS

For duration of any breastfeeding, 5.9% of infants breastfed <6 months (adjusted RR [aRR] 1.05, 0.93-1.19) and 4.6% breastfed 6-11 months (aRR 0.96, 0.87-1.07) had dispensed asthma medications at age 7 years compared with 4.6% of infants breastfed ≥12 months (P_trend .62). Infants still breastfed at 6 months, but introduced to complementary foods <4 months and 4-6 months, had an aRR of 1.15 (0.98-1.36) and 1.09 (0.94-1.27) respectively, compared with infants fully breastfed for 6 months (P_trend .09). Ages at introduction of solids or formula separately were not significant predictors (P_trend .16 and .08, respectively).

CONCLUSIONS

We found no association between duration of breastfeeding or age of introduction to complementary foods and asthma at age 7 years.

Duration and exclusiveness of breastfeeding and risk of childhood atopic diseases

BACKGROUND

Breastfeeding may have immune modulatory effects that influence the development of childhood allergic sensitization and atopic diseases. We aimed to examine the associations of breastfeeding with childhood allergic sensitization, inhalant or food allergy and eczema, and whether any association was affected by disease-related modification of the exposure or modified by maternal history of allergy, eczema, or asthma.

METHODS

This study among 5828 children was performed in a population-based prospective cohort from fetal life onwards. We collected information on duration (<2 months, 2-4 months, 4-6 months, and ≥6 months) and exclusiveness (nonexclusive vs exclusive for 4 months) of breastfeeding in infancy by postal questionnaires. At age 10 years, inhalant allergic sensitization and food-allergic sensitization were measured by skin prick tests, and physician-diagnosed inhalant and food allergy by a postal questionnaire. Data on parental-reported eczema were available from birth until age 10 years.

RESULTS

We observed no association of breastfeeding with any allergic sensitization, physician-diagnosed allergy, or combination of these outcomes. Shorter breastfeeding duration was associated with an overall increased risk of eczema (P-value for trend <.05). Nonexclusively breastfed children had an overall increased risk of eczema (adjusted odds ratio [95% confidence interval]: 1.11 [1.01, 1.23]), compared with children exclusively breastfed for 4 months. Risk period-specific sensitivity analyses, additional adjustment for ointment use for eczema at age 2 months, and cross-lagged modeling showed no consistent results for disease-related modification of the exposure. Results were not modified by maternal history of allergy, eczema, or asthma (lowest P-value for interaction=.13).

CONCLUSION

Shorter duration or nonexclusiveness of breastfeeding is associated with a weak overall increased risk of eczema but not allergic sensitization or physician-diagnosed allergy at age 10 years.

Diet and Asthma: Is It Time to Adapt Our Message?

Asthma is a chronic respiratory disorder which is associated with airway inflammation. Environmental factors, in association with genetic susceptibility, play a critical role in asthma pathophysiology. Inhaled allergens, smoke exposure, indoor and outdoor air pollution are common triggers of asthma symptoms. Although the role of diet has clearly established mechanisms in diseases such as cardiovascular disease, type 2 diabetes, and cancer, it is not commonly identified as a causal factor in asthma. However, some dietary patterns, such as the Western diet, which includes a high intake of refined grains, processed and red meats, and desserts, have pro-inflammatory effects. On the contrary, the Mediterranean diet, with high intake of fruits and vegetables has anti-inflammatory properties. The influence of food on asthma outcomes is of growing interest, but dietary habits of asthma patients are not commonly investigated in clinical practice. In this review, we focus on the impact of diet on asthma risk and asthma control. We also detail the influence of diet on obese patients with asthma.

Human Milk and Allergic Diseases: An Unsolved Puzzle

There is conflicting evidence on the protective role of breastfeeding in relation to the development of allergic sensitisation and allergic disease. Studies vary in methodology and definition of outcomes, which lead to considerable heterogeneity. Human milk composition varies both within and between individuals, which may partially explain conflicting data. It is known that human milk composition is very complex and contains variable levels of immune active molecules, oligosaccharides, metabolites, vitamins and other nutrients and microbial content. Existing evidence suggests that modulation of human breast milk composition has potential for preventing allergic diseases in early life. In this review, we discuss associations between breastfeeding/human milk composition and allergy development.

The Potential for Emerging Microbiome-Mediated Therapeutics in Asthma

PURPOSE OF REVIEW

In terms of immune regulating functions, analysis of the microbiome has led the development of therapeutic strategies that may be applicable to asthma management. This review summarizes the current literature on the gut and lung microbiota in asthma pathogenesis with a focus on the roles of innate molecules and new microbiome-mediated therapeutics.

RECENT FINDINGS

Recent clinical and basic studies to date have identified several possible therapeutics that can target innate immunity and the microbiota in asthma. Some of these drugs have shown beneficial effects in the treatment of certain asthma phenotypes and for protection against asthma during early life. Current clinical evidence does not support the use of these therapies for effective treatment of asthma. The integration of the data regarding microbiota with technologic advances, such as next generation sequencing and omics offers promise. Combining comprehensive bioinformatics, new molecules and approaches may shape future asthma treatment.

Timing of food introduction and development of food sensitization in a prospective birth cohort

BACKGROUND

The effect of infant feeding practices on the development of food allergy remains controversial. We examined the relationship between timing and patterns of food introduction and sensitization to foods at age 1 year in the Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort study.

METHODS

Nutrition questionnaire data prospectively collected at age 3, 6, 12, 18, and 24 months were used to determine timing of introduction of cow's milk products, egg, and peanut. At age 1 year, infants underwent skin prick testing to cow's milk, egg white, and peanut. Logistic regression models were fitted to assess the impact of timing of food exposures on sensitization outcomes, and latent class analysis was used to study patterns of food introduction within the cohort.

RESULTS

Among 2124 children with sufficient data, delaying introduction of cow's milk products, egg, and peanut beyond the first year of life significantly increased the odds of sensitization to that food (cow's milk adjOR 3.69, 95% CI 1.37-9.08; egg adjOR 1.89, 95% CI 1.25-2.80; peanut adjOR 1.76, 95% CI 1.07-3.01). Latent class analysis produced a three-class model: early, usual, and delayed introduction. A pattern of delayed introduction, characterized by avoidance of egg and peanut during the first year of life, increased the odds of sensitization to any of the three tested foods (adjOR 1.78, 95% CI 1.26-2.49).

CONCLUSIONS

Avoidance of potentially allergenic foods during the first year of life significantly increased the odds of sensitization to the corresponding foods.

Duration and exclusiveness of breastfeeding and school-age lung function and asthma

BACKGROUND

Breastfeeding reduces the risk of asthma in early childhood, but it is not clear whether its effect on respiratory morbidity is still present in later childhood.

OBJECTIVE

To examine the associations of any breastfeeding, breastfeeding duration, and breastfeeding exclusiveness with lung function and asthma in school-aged children and whether associations were influenced by respiratory tract infections and maternal or child's atopic status.

METHODS

This study of 4,464 children was embedded in a population-based prospective cohort study. Information on breastfeeding was obtained by multiple questionnaires from birth until 1 year of age. At 10 years of age, lung function was measured by spirometry, and information on asthma was obtained by questionnaire. Adjusted linear and logistic regression models were used to examine the associations.

RESULTS

Shorter duration of breastfeeding was associated with a lower forced expiratory volume in 1 second (FEV₁) only (z score change, -0.01; 95% confidence interval [CI], -0.02 to -0.00) per month shorter breastfeeding, but not asthma. When categorized, breastfeeding for 2 to 4 months was associated with a lower forced vital capacity (FVC) (z score change, -0.11; 95% CI, -0.20 to -0.03) compared with breastfeeding for 6 months or longer. Nonexclusive breastfeeding for 4 months was associated with a lower FVC (z score change, -0.08; 95% CI, -0.16 to -0.01) compared with exclusive breastfeeding for 4 months. Results did not materially change after additional adjustment for lower respiratory tract infections and were not modified by maternal history of asthma or atopy, child's eczema, or inhalant allergic sensitization.

CONCLUSION

Shorter duration and nonexclusivity of breastfeeding were associated with a lower FEV₁ and FVC but not asthma at school-age.

Breastfeeding, maternal asthma and wheezing in the first year of life: a longitudinal birth cohort study

The impact of breastfeeding on respiratory health is uncertain, particularly when the mother has asthma. We examined the association of breastfeeding and wheezing in the first year of life.We studied 2773 infants from the Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort. Caregivers reported on infant feeding and wheezing episodes at 3, 6 and 12 months. Breastfeeding was classified as exclusive, partial (supplemented with formula or complementary foods) or none.Overall, 21% of mothers had asthma, 46% breastfed for at least 12 months and 21% of infants experienced wheezing. Among mothers with asthma, breastfeeding was inversely associated with infant wheezing, independent of maternal smoking, education and other risk factors (adjusted rate ratio (aRR) 0.52; 95% CI 0.35-0.77 for ≥12 versus <6 months breastfeeding). Compared with no breastfeeding at 6 months, wheezing was reduced by 62% with exclusive breastfeeding (aRR 0.38; 95% CI 0.20-0.71) and by 37% with partial breastfeeding supplemented with complementary foods (aRR 0.63; 95% CI 0.43-0.93); however, breastfeeding was not significantly protective when supplemented with formula (aRR 0.89; 95% CI 0.61-1.30). Associations were not significant in the absence of maternal asthma (p-value for interaction <0.01).Breastfeeding appears to confer protection against wheezing in a dose-dependent manner among infants born to mothers with asthma.

Breastfeeding and asthma outcomes at the age of 6 years: The Generation R Study

BACKGROUND

Breastfeeding is associated with a lower risk of asthma symptoms in early childhood, but its effect at older ages remains unclear. We examined the associations of duration and exclusiveness of breastfeeding with asthma outcomes in children aged 6 years, and whether these associations were explained by atopic or infectious mechanisms.

METHODS

We performed a population-based prospective cohort study among 5675 children. Information about breastfeeding was collected by questionnaires. At age 6 years, we measured interrupter resistance (Rint) and fractional exhaled nitric oxide (FeNO). Information about wheezing patterns (early (≤3 years only), late (>3 years only), persistent (≤3 and >3 years)), and current asthma at 6 years was derived from repeated questionnaires.

RESULTS

Compared to children who were ever breastfed, those who were never breastfed had lower FeNO levels (sympercent (95% CI): -16.0 (-24.5, -7.5)) and increased risks of late and persistent wheezing (OR(95% CI): 1.69 (1.06, 2.69) and 1.44 (1.00, 2.07), respectively). Shorter duration of breastfeeding was associated with early wheezing and current asthma (1.40 (1.14, 1.73) and 2.19 (1.29, 3.71), respectively). Less exclusive breastfeeding was associated with early wheezing (1.28 (1.08, 1.53)). Breastfeeding duration and exclusiveness were not associated with FeNO or Rint. The associations were not explained by inhalant allergies, partly by lower respiratory tract infections in early life, and to a lesser extent by lower respiratory tract infections in later life.

CONCLUSIONS

Breastfeeding patterns may influence wheezing and asthma in childhood, which seems to be partly explained by infectious mechanisms.

Evaluating the efficacy of breastfeeding guidelines on long-term outcomes for allergic disease

BACKGROUND

WHO guidelines advocate breastfeeding for 6 months, and EAACI guideline recommends exclusive breastfeeding for 4-6 months. However, evidence for breastfeeding to prevent asthma and allergic disease is conflicting. We examined whether following recommended breastfeeding guidelines alters the long-term risks of asthma, eczema, rhinitis or atopy.

METHODS

The effect of nonexclusive (0, >0-6, >6 months) and exclusive breastfeeding (0, >0-4, >4 months) on repeated measures of asthma (10, 18 years), eczema, rhinitis, and atopy (1-or-2, 4, 10, 18 years) risks was estimated in the IoW cohort (n = 1456) using log-linear models with generalized estimating equations. The Food Allergy and Intolerance Research (FAIR) cohort (n = 988), also from the IoW, was examined to replicate results.

RESULTS

Breastfeeding (any or exclusive) had no effect on asthma and allergic disease in the IoW cohort. In the FAIR cohort, any breastfeeding for >0-6 months protected against asthma at 10 years (RR = 0.50, 95% CI = 0.32-0.79, P = 0.003), but not other outcomes, whilst exclusive breastfeeding for >4 months protected against repeated rhinitis (RR = 0.36, 95% CI = 0.18-0.71, P = 0.003). Longer breastfeeding was protective against late-onset wheeze in the IoW cohort.

CONCLUSION

The protective effects of nonexclusive and exclusive breastfeeding against long-term allergic outcomes were inconsistent between these colocated cohorts, agreeing with previous observations of heterogeneous effects. Although breastfeeding should be recommended for other health benefits, following breastfeeding guidelines did not appear to afford a consistent protection against long-term asthma, eczema, rhinitis or atopy. Further research is needed into the long-term effects of breastfeeding on allergic disease.

Relationship between respiratory and food allergy and evaluation of preventive measures

Food allergy and respiratory allergy are two frequently associated diseases and with an increasing prevalence. Several reports show the presence of respiratory symptoms in patients with food allergy, while certain foods may be related to the development or exacerbation of allergic rhinitis and asthma. The present update focuses on this relationship, revealing a pathogenic and clinical association between food and respiratory allergy. This association is even more intense when the food hypersensitivity is persistent or starts in the early years of life. Food allergy usually precedes respiratory allergy and may be a risk factor for allergic rhinitis and asthma, becoming a relevant clinical marker for severe atopic asthma. Furthermore, the presence of co-existing asthma may enhance life-threatening symptoms occurring during a food allergic reaction. Recommendations for dietary restrictions during pregnancy and breastfeeding to prevent the development of respiratory allergy are controversial and not supported by consistent scientific data. Current recommendations from medical societies propose exclusive breastfeeding during the first four months of life, with the introduction of solid food in the fourth to the seventh month period of life. A delayed introduction of solid food after this period may increase the risk of developing subsequent allergic conditions. Further studies are encouraged to avoid unjustified recommendations involving useless dietary restrictions.

Breastfeeding and asthma and allergies: a systematic review and meta-analysis

AIM

To systematically review the association between breastfeeding and childhood allergic disease.

METHODS

Predetermined inclusion/exclusion criteria identified 89 articles from PubMed, CINAHL and EMBASE databases. Meta-analyses performed for categories of breastfeeding and allergic outcomes. Meta-regression explored heterogeneity.

RESULTS

More vs. less breastfeeding (duration) was associated with reduced risk of asthma for children (5-18 years), particularly in medium-/low-income countries and with reduced risk of allergic rhinitis ≤5 years, but this estimate had high heterogeneity and low quality. Exclusive breastfeeding for 3-4 months was associated with reduced risk of eczema ≤2 years (estimate principally from cross-sectional studies of low methodological quality). No association found between breastfeeding and food allergy (estimate had high heterogeneity and low quality). Meta-regression found differences between study outcomes may be attributable to length of breastfeeding recall, study design, country income and date of study inception. Some of the protective effect of breastfeeding for asthma may be related to recall bias in studies of lesser methodological quality.

CONCLUSION

There is some evidence that breastfeeding is protective for asthma (5-18 years). There is weaker evidence for a protective effect for eczema ≤2 years and allergic rhinitis ≤5 years of age, with greater protection for asthma and eczema in low-income countries.

Factors affecting breast milk composition and potential consequences for development of the allergic phenotype

There is conflicting evidence on the protective role of breastfeeding in relation to allergic sensitization and disease. The factors in breast milk which influence these processes are still unclear and under investigation. We know that colostrum and breast milk contain a variety of molecules which can influence immune responses in the gut-associated lymphoid tissue of a neonate. This review summarizes the evidence that variations in colostrum and breast milk composition can influence allergic outcomes in the infant, and the evidence that maternal and environmental factors can modify milk composition. Taken together, the data presented support the possibility that maternal dietary interventions may be an effective way to promote infant health through modification of breast milk composition.

Breast-feeding does not protect against allergic sensitization in early childhood and allergy-associated disease at age 7 years

BACKGROUND

Extended breast-feeding is recommended for newborn children at risk of allergy-associated diseases, but the evidence of a protective effect on sensitization and these diseases remains elusive.

OBJECTIVE

The aim of this study was to investigate the effects of the duration of exclusive breast-feeding on the development of sensitization in preschool children.

METHODS

Information on breast-feeding was gathered by interviews involving 335 children aged 1, 6, and 12 months from the Copenhagen Prospective Study on Asthma in Childhood2000 birth cohort born to mothers with a history of asthma. Skin prick test responses and specific IgE levels against 12 common inhalant and 10 food allergens were assessed longitudinally at ages ½ year, 1½ years, 4 years, and 6 years. Eczema, wheeze/asthma, and allergic rhinitis were diagnosed at the Copenhagen Prospective Studies on Asthma in Childhood clinic at 7 years of age, strictly adhering to predefined algorithms. Associations between duration of exclusive breast-feeding and outcomes were analyzed by logistic regression.

RESULTS

We found no significant association between duration of exclusive breast-feeding and development of sensitization in the first 6 years of life (odds ratio [OR]: ½ year, 1.10 [95% CI, 0.90-1.36]; 1½ years, 1.15 [95% CI, 0.97-1.36]; 4 years, 1.08 [95% CI, 0.93-1.25]; and 6 years, 0.96 [95% CI, 0.84-1.10]) or with current eczema, wheeze/asthma, and allergic rhinitis at age 7 years (OR, 1.07 [95% CI, 0.92-1.24]; OR, 0.97 [95% CI, 0.82-1.14]; and OR, 1.02 [95% CI, 0.84-1.23], respectively). Adjusting for reverse causation by excluding children with eczema, wheeze, or a positive skin prick test response before ending exclusive breast-feeding did not alter the results.

CONCLUSION

Exclusive breast-feeding does not affect sensitization in early childhood or associated diseases at 7 years of age in at-risk children.

Pre- and postnatal risk factors in relation to allergic rhinitis in school-aged children in China

Objective

The objective of this study was to investigate the relationship between prenatal and postnatal risk factors and the prevalence of allergic rhinitis (AR) in Chinese children of specific ages.

Study Design

This study was a cross-sectional survey. Students from 8 metropolitan cities in China were studied in November and December, 2005. There were 20,803 elementary-school Chinese children (49.6% boys, mean age, 9.19 years) enrolled. Questions from the standard questionnaire of the International Study of Asthma and Allergies in Children were completed to enable us to examine the pattern of current AR. The potential confounders and pre-and postnatal risk factors were analyzed using logistic regression.

Results

The overall prevalence of AR was found in this study to be 9.8%. After adjusting for several likely confounders, there was a higher likelihood of AR in school-aged children who were not exclusively breastfed in the first 4 months of their lives (odds ratio [OR]: 1.28; 95% confidence interval [CI]: 1.16–1.41), children who were born post-term (OR: 1.34; 95% CI: 1.12–1.60), children delivered by cesarean section (OR: 1.07; 95% CI: 1.00–1.19), or children born to mothers who experienced depressive symptoms during the pre- and postnatal periods (OR: 1.28; 95% CI: 1.15–1.42).

Conclusions

AR in school-aged children was found to be associated with pre- and postnatal events. These findings indicate that strategies to reduce exposure to risk factors during pre- and postnatal periods for childhood allergies might be warranted.

The role of the early-life environment in the development of allergic disease

A consensus has been reached that the development of allergic disorders is strongly influenced by early life exposures. An overview of several prenatal and early life factors that have been investigated for their associations with development of childhood allergy is presented. Delivery mode, the gut microbiome, vitamin D, folate, breastfeeding, pets, antibiotics, environmental tobacco smoke, and airborne traffic pollutants are discussed. Although many studies suggest an effect, overall, no risk factors clearly increase or reduce the risk of allergic outcomes.

Early origins of chronic obstructive lung diseases across the life course

Chronic obstructive lung diseases, like asthma and chronic obstructive pulmonary disease, have high prevalences and are a major public health concern. Chronic obstructive lung diseases have at least part of their origins in early life. Exposure to an adverse environment during critical periods in early life might lead to permanent developmental adaptations which results in impaired lung growth with smaller airways and lower lung volume, altered immunological responses and related inflammation, and subsequently to increased risks of chronic obstructive lung diseases throughout the life course. Various pathways leading from early life factors to respiratory health outcomes in later life have been studied, including fetal and early infant growth patterns, preterm birth, maternal obesity, diet and smoking, children's diet, allergen exposure and respiratory tract infections, and genetic susceptibility. Data on potential adverse factors in the embryonic and preconception period and respiratory health outcomes are scarce. Also, the underlying mechanisms how specific adverse exposures in the fetal and early postnatal period lead to chronic obstructive lung diseases in later life are not yet fully understood. Current studies suggest that interactions between early environmental exposures and genetic factors such as changes in DNA-methylation and RNA expression patterns may explain the early development of chronic obstructive lung diseases. New well-designed epidemiological studies are needed to identify specific critical periods and to elucidate the mechanisms underlying the development of chronic obstructive lung disease throughout the life course.

Exclusive breastfeeding is associated with reduced cow's milk sensitization in early childhood

BACKGROUND

Although breastfed infants have consistently been reported as having fewer infections and respiratory morbidity during infancy, none have reached a definitive conclusion as to whether breastfeeding is an effective strategy to prevent allergic diseases. This study aims to investigate the relationship between exclusive breastfeeding and sequential changes of several biomarkers of allergy, such as absolute eosinophil count, total IgE level, and specific IgE level during the first 3 yrs of life.

METHODS

This is an unselected, population-based study that is part of a prospective birth cohort called the PATCH (Prediction of Allergy in Taiwanese Children). Blood analysis was performed at ages 6, 12, 18, 24, and 36 months. Clinical records of breastfeeding and detailed questionnaires regarding to allergic diseases were also obtained.

RESULTS

Analysis comparing exclusive breastfeeding ≥4 months with those <4 months and those partially breastfed showed a decreased risk of sensitization toward cow's milk protein up to the age of 2 yr (adjusted OR for cow's milk sensitization at 12 months was 0.2 [95% CI, 0.07-0.5]), at 18 months of age it was 0.2 [95% CI, 0.07-0.5], and at 24 months of age it was 0.2 [95% CI, 0.04-0.7]). In addition, although not significant, children of the exclusive breastfeeding group showed a trend of lower absolute eosinophil counts than their counterparts at all ages, and a lower total IgE level at the age of 3 yr.

CONCLUSIONS

Results of this study suggest that exclusive breastfeeding is associated with a reduced risk of cow's milk protein sensitization during early childhood.

Breastfeeding and introduction of complementary foods during infancy in relation to the risk of asthma and atopic diseases up to 10 years

BACKGROUND

It has been hypothesized that changes in diet during early life may have contributed to the increase in childhood asthma and atopy. The long-term effect of the timing and content of infant feeding on the incidence of asthma and atopic diseases in children is unclear.

OBJECTIVE

To investigate the associations between duration of breastfeeding and the timing of introduction of complementary foods during the first 6 months and parental-reported asthma, wheeze and atopic eczema up to 10 years of age.

METHODS

Infant feeding practices (breastfeeding and introduction of complementary foods) of 1924 singleton children participating in the Study of Eczema and Asthma To Observe the influence of Nutrition (SEATON) birth cohort were prospectively collected up to 6 months with outcomes (wheeze, atopic eczema and asthma) being assessed at 1, 2, 5 and 10 years. Data were analysed using generalized estimating equations and discrete hazards models with adjustment for confounders.

RESULTS

By 6 months, 59% and 35% of mothers had stopped exclusive and total breastfeeding, respectively. Although formula feeding was adversely associated with wheeze in the past 12 months (adjusted OR for no formula feeding: 070, 95% CI 0.50-0.97), and the introduction of biscuits/bread after 5 months of age adversely associated with atopic eczema (adjusted OR 1.34, 95% CI 1.06-1.69), these results lost their statistical significance after adjustment for multiple testing. Stratification of the results by the presence of eczema by 6 months of age and family atopic history did not substantially differ from the results of the whole study population.

CONCLUSION AND CLINICAL RELEVANCE

Our results suggest that the nature of infant feeding during the first 6 months seems not to substantially influence the long-term risk of asthma and atopic diseases in children, nor in children at high risk of atopic disease because of a family history of atopic disease.

Breastfeeding and childhood asthma: systematic review and meta-analysis

Asthma and wheezing disorders are common chronic health problems in childhood. Breastfeeding provides health benefits, but it is not known whether or how breastfeeding decreases the risk of developing asthma. We performed a systematic review and meta-analysis of studies published between 1983 and 2012 on breastfeeding and asthma in children from the general population. We searched the PubMed and Embase databases for cohort, cross-sectional, and case-control studies. We grouped the outcomes into asthma ever, recent asthma, or recent wheezing illness (recent asthma or recent wheeze). Using random-effects meta-analyses, we estimated pooled odds ratios of the association of breastfeeding with the risk for each of these outcomes. We performed meta-regression and stratified meta-analyses. We included 117 of 1,464 titles identified by our search. The pooled odds ratios were 0.78 (95% confidence interval: 0.74, 0.84) for 75 studies analyzing "asthma ever," 0.76 (95% confidence interval: 0.67, 0.86) for 46 studies analyzing "recent asthma," and 0.81 (95% confidence interval: 0.76, 0.87) for 94 studies analyzing recent wheezing illness. After stratification by age, the strong protective association found at ages 0-2 years diminished over time. We found no evidence for differences by study design or study quality or between studies in Western and non-Western countries. A positive association of breastfeeding with reduced asthma/wheezing is supported by the combined evidence of existing studies.

Breastfeeding, introduction of other foods and effects on health: a systematic literature review for the 5th Nordic Nutrition Recommendations

The present systematic literature review is part of the 5th revision of the Nordic Nutrition Recommendations. The overall aim was to review recent scientific data valid in a Nordic setting on the short- and long-term health effects of breastfeeding (duration of both any and exclusive breastfeeding) and introduction of foods other than breast milk. The initial literature search resulted in 2,011 abstracts; 416 identified as potentially relevant. Full paper review resulted in 60 quality assessed papers (6A, 48B, and 6C). A complementary search found some additional papers. The grade of evidence was classified as convincing, probable, limited-suggestive, and limited-no conclusion. The evidence was convincing of a protective dose/duration effect of breastfeeding against overweight and obesity in childhood and adolescence, overall infections, acute otitis media, and gastrointestinal and respiratory tract infections. The evidence was probable that exclusive breastfeeding for longer than 4 months is associated with slower weight gain during the second half of the first year which could be part of the reason behind the reduced risk of later overweight or obesity. There was also probable evidence that breastfeeding is a protective factor against inflammatory bowel disease, celiac disease, and diabetes (type 1 and 2), provides beneficial effects on IQ and developmental scores of children as well as a small reductive effect on blood pressure and blood cholesterol levels in adulthood. Other associations explored were limited-suggestive or inconclusive. In conclusion, convincing and probable evidence was found for benefits of breastfeeding on several outcomes. The recommendation in NNR2004 about exclusive breastfeeding for 6 months and continued partial breastfeeding thereafter can stand unchanged. The relatively low proportion of infants in the Nordic countries following this recommendation indicates that strategies that protect, support and promote breastfeeding should be enhanced, and should also recognize the benefits for long-term health.

Breastfeeding practice and its association with respiratory symptoms and atopic disease in 1-3-year-old children in the city of Riyadh, central Saudi Arabia

BACKGROUND

Saudi Arabia has a declining rate of breastfeeding and increasing levels of childhood asthma and atopic disease. In highly economically developed countries, breastfeeding of children at high risk of atopic disease reduces the likelihood of atopic dermatitis, wheezing associated with respiratory infections, and possibly asthma. This study investigated the prevalence of breastfeeding and its association with wheezing/asthma and atopic disease in 1-3-year-old children in Riyadh, Saudi Arabia.

SUBJECTS AND METHODS

A cross-sectional study of children attending routine "well-baby" clinics in three Saudi State Hospitals in Riyadh. An interviewer administered a questionnaire to collect data on sociodemographics, breastfeeding, wheezing symptoms, asthma, and atopic disease.

RESULTS

In total, 622 children 1-3 years old were recruited. Of these, 75% of children were ever breastfed, and 36% of children were fully breastfed, with 20% of children being fully breastfed for ≥ 3 months. Increasing duration of full breastfeeding was associated with a reduced likelihood of maternal reporting of her child having "ever wheezed," "wheezed' in the last 12 months," and "ever having asthma," with adjusted odds ratio for full breastfeeding ≥ 12 months versus never breastfed of 0.51 (95% confidence interval 0.29-0.90), 0.48 (0.26-0.88), and 0.46 (0.22-0.94), respectively. No associations were demonstrable between full or ever breastfeeding and atopic dermatitis/eczema, irrespective of family history of atopic disease.

CONCLUSIONS

Although breastfeeding does not protect children from developing eczema in Riyadh, full breastfeeding is associated with reduced childhood wheezing and possibly asthma. Further efforts should be made to promote breastfeeding in Saudi Arabia.