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

Primary prevention of allergic disease through nutritional interventions

With the rising prevalence of atopic disease, primary prevention may play a role in reducing its burden, especially in high-risk infants. With this in mind, the Adverse Reactions to Foods Committee of the American Academy of Allergy, Asthma & Immunology was charged with the task of developing recommendations for primary care physicians and specialists about the primary prevention of allergic disease through nutritional interventions according to current available literature and expert opinion. Recommendations that are supported by data are as follows. Avoidance diets during pregnancy and lactation are not recommended at this time, but more research is necessary for peanut. Exclusive breast-feeding for at least 4 and up to 6 months is endorsed. For high-risk infants who cannot be exclusively breast-fed, hydrolyzed formula appears to offer advantages to prevent allergic disease and cow's milk allergy. Complementary foods can be introduced between 4 and 6 months of age. Because no formal recommendations have been previously provided about how and when to introduce the main allergenic foods (cow's milk, egg, soy, wheat, peanut, tree nuts, fish, shellfish), these are now provided, and reasons to consider allergy consultation for development of a personalized plan for food introduction are also presented.

Neonatal jaundice is a risk factor for childhood asthma: a retrospective cohort study

BACKGROUND

The association between neonatal jaundice and childhood asthma is a new finding of two reports. The purpose of the study was to verify their results.

METHODS

Data from 11,321 children were collected from the National Health Insurance Research Database. Their claims data were evaluated from birth to 10 yr old. Children were analyzed as case (those with neonatal jaundice) and controls (those without neonatal jaundice). The diagnostic criteria for asthma were as follows: at least four asthma diagnoses at outpatient services and emergency department (ED), or one asthma diagnosis during an admission. In children fitting the asthma criteria, those with no asthma diagnosis after 1 yr of age were excluded. Mantel-Haenszel's odds ratios were calculated after adjustment for the following confounders: preterm/low birth weight, neonatal infection, other respiratory conditions, other birth conditions, and gender. Asthma rate, onset time, the use of drugs, upper respiratory infection and lower respiratory infection (LRI) rates, hospital admission/ED visit rates, and the effect of phototherapy were evaluated.

RESULTS

After adjustment for the confounding factors, the rate of asthma was higher in icteric children (OR: 1.64, 95% CI 1.36-1.98, p < 0.001), and the influence in females was stronger. There still was an association between neonatal jaundice and late onset asthma (asthma onset after 3 yr of age). In asthmatic children, those with neonatal jaundice have increased asthma onset rate before age 6, increased use of inhalant steroids, LRI rates, and ED visits for respiratory disease.

CONCLUSIONS

Neonatal jaundice increased the rate and severity of childhood asthma in subjects aged up to 10 yr and may be a risk factor for childhood asthma.

Associations of different phenotypes of wheezing illness in early childhood with environmental variables implicated in the aetiology of asthma

Rationale

Asthma is a complex heterogeneous disease that has increased in prevalence in many industrialised countries. However, the causes of asthma inception remain elusive. Consideration of sub-phenotypes of wheezing may reveal important clues to aetiological risk factors.

Methods

Longitudinal phenotypes capturing population heterogeneity in wheezing reports from birth to 7 years were derived using latent class analysis in the Avon Longitudinal Study of Parents and Children (ALSPAC). Probability of class membership was used to examine the association between five wheezing phenotypes (transient early, prolonged early, intermediate-onset, late-onset, persistent) and early life risk factors for asthma.

Results

Phenotypes had similar patterns and strengths of associations with early environmental factors. Comparing transient early with prolonged early wheezing showed a similar pattern of association with most exposure variables considered in terms of the direction of the effect estimates but with prolonged early wheezing tending to have stronger associations than transient early wheezing except for parity and day care attendance.

Conclusions

Associations with early life risk factors suggested that prolonged early wheeze might be a severe form of transient early wheezing. Although differences were found in the associations of early life risk factors with individual phenotypes, these did not point to novel aetiological pathways. Persistent wheezing phenotype has features suggesting overlap of early and late-onset phenotypes.

Breastfeeding protects against current asthma up to 6 years of age

OBJECTIVE

To investigate the effects of breastfeeding on wheezing and current asthma in children 2 to 6 years of age.

STUDY DESIGN

Infants (n=1105) were enrolled in a prospective birth cohort in New Zealand. Detailed information about infant feeding was collected using questionnaires administered at birth and at 3, 6, and 15 months. From this, durations of exclusive and any breastfeeding were calculated. Information about wheezing and current asthma was collected at 2, 3, 4, 5, and 6 years. Logistic regression was used to model associations between breastfeeding and outcomes with and without adjustment for confounders.

RESULTS

After adjustment for confounders, each month of exclusive breastfeeding was associated with significant reductions in current asthma from 2 to 6 years (all, P<.03). Current asthma at 2, 3, and 4 years was also reduced by each month of any breastfeeding (all, P<.005). In atopic children, exclusive breastfeeding for ≥ 3 months reduced current asthma at ages 4, 5, and 6 by 62%, 55%, and 59%, respectively.

CONCLUSION

Breastfeeding, particularly exclusive breastfeeding, protects against current asthma up to 6 years. Although exclusive breastfeeding reduced risk of current asthma in all children to age 6, the degree of protection beyond 3 years was more pronounced in atopic children.

Fetal and infant origins of asthma

Previous studies have suggested that asthma, like other common diseases, has at least part of its origin early in life. Low birth weight has been shown to be associated with increased risks of asthma, chronic obstructive airway disease, and impaired lung function in adults, and increased risks of respiratory symptoms in early childhood. The developmental plasticity hypothesis suggests that the associations between low birth weight and diseases in later life are explained by adaptation mechanisms in fetal life and infancy in response to various adverse exposures. Various pathways leading from adverse fetal and infant exposures to growth adaptations and respiratory health outcomes have been studied, including fetal and early infant growth patterns, maternal smoking and diet, children's diet, respiratory tract infections and acetaminophen use, and genetic susceptibility. Still, the specific adverse exposures in fetal and early postnatal life leading to respiratory disease in adult life are not yet fully understood. Current studies suggest that both environmental and genetic factors in various periods of life, and their epigenetic mechanisms may underlie the complex associations of low birth weight with respiratory disease in later life. New well-designed epidemiological studies are needed to identify the specific underlying mechanisms. This review is focused on specific adverse fetal and infant growth patterns and exposures, genetic susceptibility, possible respiratory adaptations and perspectives for new studies.

Breastfeeding and mucosal and cutaneous colonization by Staphylococcus aureus in atopic children

BACKGROUND

Studies on the effects of breastfeeding on the development of Atopic Dermatitis (AD) have shown controversial results. The importance of this condition deserves further studies; in particular, it remains unclear whether colonization of atopic patients by Staphylococcus aureus (S. aureus) through breastfeeding is relevant to the development of AD.

OBJECTIVE

To examine the potential relation between breastfeeding and colonization by S. aureus in atopic patients.

METHOD

Transversal study of atopic patients, aged from 4 to 24 months, both genders, receiving outpatient care and 72 mothers. Data on infant breastfeeding practices and on clinical-epidemiological profile were registered. Swabs of the infants' nares and skin (cubital fossa) and swabs of the mothers' nares were collected. For univariate analysis, X2 (chi-square) and Fischer Exact's test were used.

RESULTS

Among breastfed children, S. aureus was isolated from 8 (25.8%) infants' nares swabs and from 4 (12.9%) skin swabs. Among not breastfed children, S. aureus was isolated from 10 (20.8%) infants' nares swabs and from 11 (22.9%) skin swabs. Sixteen mothers (22.2%) had S. aureus isolated from their nares swabs. There was no significant association between breastfeeding and S. aureus colonization (child skin and/or nares). However, there was a degree of concordance for S. aureus carriage among mothers and infants. Among 72 pairs, 56 (77.8%) were concordant.

CONCLUSION

Breastfeeding was not associated with S. aureus muco-cutaneous colonization in atopic infants.

Breastfeeding, asthma, and allergy: a tale of two cities

BACKGROUND

The effect of breastfeeding duration on subsequent asthma and allergy remains the subject of much controversy.

OBJECTIVE

To investigate whether differences in study design or disease-related exposure modification were the cause of the differences in study findings.

METHOD

The data from two cohorts, the Childhood Asthma Prevention Study (CAPS) from Australia and the Barn Allergi Miljo Stockholm cohort from Sweden, which had reported different findings on the association between breastfeeding and asthma, were combined. For this analysis, the definitions for breastfeeding, asthma, and allergy were harmonized. Subjects were included if they had at least one parent with wheeze or asthma and had a gestational age of more than 36 wks (combined n = 882). The risk of disease-related exposure modification was assessed using survival analysis.

RESULTS

Breastfeeding reduced the risk of asthma at 4/5 and 8 yrs of age in children with a family history of asthma. The effect was stronger in the Swedish cohort. Breastfeeding had no effect on the prevalence of sensitization to inhaled allergens in this cohort with a family history of asthma but was a risk factor for sensitization to cow's milk, peanuts, and eggs in the CAPS cohort at 4/5 yrs and in the combined cohort at 8 yrs. There was no evidence to support the existence of disease-related exposure modification in either cohort.

CONCLUSION

These findings point to the importance of harmonization of features of study design, including subject selection criteria and variable definitions, in resolving epidemiological controversies such as those surrounding the impact of breastfeeding on asthma and allergic sensitization.

Perinatal programming of asthma: the role of gut microbiota

Perinatal programming, a dominant theory for the origins of cardiovascular disease, proposes that environmental stimuli influence developmental pathways during critical periods of prenatal and postnatal development, inducing permanent changes in metabolism. In this paper, we present evidence for the perinatal programming of asthma via the intestinal microbiome. While epigenetic mechanisms continue to provide new explanations for the programming hypothesis of asthma development, it is increasingly apparent that the intestinal microbiota plays an independent and potentially interactive role. Commensal gut bacteria are essential to immune system development, and exposures disrupting the infant gut microbiota have been linked to asthma. This paper summarizes the recent findings that implicate caesarean delivery, breastfeeding, perinatal stress, probiotics, and antibiotics as modifiers of infant gut microbiota in the development of asthma.

Systematic review and meta-analysis investigating breast feeding and childhood wheezing illness

There is conflicting evidence concerning the relationship between breast feeding and wheezing illness. The objective of this study was to investigate whether there is any association between breast feeding and wheezing in children aged over 5 years and to discover possible sources of heterogeneity. An electronic search of MEDLINE and EMBASE databases was conducted from January 2000 to June 2010. In addition, reference lists from relevant publications were searched. Birth cohort, cross-sectional and case-control studies were included if they measured any breast feeding or exclusive breast feeding for 3 or 4 months. Wheezing illness, including asthma, was identified based on symptoms, reported diagnosis or objective criteria. Thirty-one publications were identified for meta-analysis. There was no association found between any or exclusive breast feeding and wheezing illness, although there was a high level of heterogeneity between the studies. Subgroup analysis revealed that any breast feeding slightly lowers the odds of wheeze (pooled odds ratio 0.92 [0.86, 0.98]) but slightly increases the odds of asthma defined by specific criteria (pooled odds ratio 1.10 [1.00, 1.22]). This meta-analysis does not provide evidence that breast feeding is protective against wheezing illness in children aged 5 years and over. The difference in the effects of breast feeding according to the nature of the wheezing illness highlights the importance of the heterogeneity of illness phenotypes.

The influence of environment, as represented by diet and air pollution, upon incidence and prevalence of wheezing illnesses in young children

PURPOSE OF REVIEW

The purpose of this review is to consider the collective influence of factors affecting recurrent wheezing in young children.

RECENT FINDINGS

Specific allergen sensitization, upper respiratory infections, genetic polymorphisms and environmental factors have collectively been reported in the prevalence of and induction of recurrent wheezing in young children. Two examples of environmental factors are diet and exposure to air pollution, both of which are potentially modifiable. Recent investigations provide evidence that a 'Mediterranean diet' and a diet that emphasizes polyunsaturated fatty acids during pregnancy and early infancy, as well as breastfeeding, may be protective for wheezing, and that exposure to traffic-related pollution may be an independent factor in the incidence of wheezing in young children.

SUMMARY

Recent studies of early childhood wheezing demonstrate a potentially protective effect of diet and exposure to air pollution as a significant risk factor. An evaluation of collective factors influencing the presence of disease may help to broaden the clinical assessment and give parents and physicians the opportunity to potentially modify circumstances that promote the incidence of recurrent wheezing in infants and preschool aged children.

Early life patterns of common infection: a latent class analysis

Early life infection has been implicated in the aetiology of many chronic diseases, most often through proxy measures. Data on ten infectious symptoms were collected by parental questionnaire when children were 6 months old as part of the Avon Longitudinal Study of Parents and Children, United Kingdom. A latent class analysis was used to identify patterns of infection and their relationship to five factors commonly used as proxies: sex, other children in the home, maternal smoking, breastfeeding and maternal education. A total of 10,032 singleton children were included in the analysis. Five classes were identified with differing infectious disease patterns and children were assigned to the class for which they had a highest probability of membership based on their infectious symptom profile: ‘general infection’ (n = 1,252, 12.5%), ‘gastrointestinal’ (n = 1,902, 19.0%), ‘mild respiratory’ (n = 3,560, 35.5%), ‘colds/ear ache’ (n = 462, 4.6%) and ‘healthy’ (n = 2,856, 28.5%). Females had a reduced risk of being in all infectious classes, other children in the home were associated with an increased risk of being in the ‘general infection’, ‘mild respiratory’ or ‘colds/ear ache’ class. Breastfeeding reduced the risk of being in the ‘general infection’ and ‘gastrointestinal’ classes whereas maternal smoking increased the risk of membership. Higher maternal education was associated with an increased risk of being in the ‘mild respiratory’ group. Other children in the home had the greatest association with infectious class membership. Latent class analysis provided a flexible method of investigating the relationship between multiple symptoms and demographic and lifestyle factors.

Environmental epigenetics of asthma: an update

Asthma, a chronic inflammatory disorder of the airway, is influenced by interplay between genetic and environmental factors now known to be mediated by epigenetics. Aberrant DNA methylation, altered histone modifications, specific microRNA expression, and other chromatin alterations orchestrate a complex early-life reprogramming of immune T-cell response, dendritic cell function, macrophage activation, and a breach of airway epithelial barrier that dictates asthma risk and severity in later life. Adult-onset asthma is under analogous regulation. The sharp increase in asthma prevalence over the past 2 or 3 decades and the large variations among populations of similar racial/ethnic background but different environmental exposures favors a strong contribution of environmental factors. This review addresses the fundamental question of whether environmental influences on asthma risk, severity, and steroid resistance are partly due to differential epigenetic modulations. Current knowledge on the epigenetic effects of tobacco smoke, microbial allergens, oxidants, airborne particulate matter, diesel exhaust particles, polycyclic aromatic hydrocarbons, dietary methyl donors and other nutritional factors, and dust mites is discussed. Exciting findings have been generated by rapid technological advances and well-designed experimental and population studies. The discovery and validation of epigenetic biomarkers linked to exposure, asthma, or both might lead to better epigenotyping of risk, prognosis, treatment prediction, and development of novel therapies.

Does a short breastfeeding period protect from FTO-induced adiposity in children?

CONTEXT

A number of studies have reported replicable associations between common genetic loci and obesity indices. One of these loci is the fat mass and obesity associated locus (FTO). We aimed to assess whether breastfeeding mediated the known association between FTO and indices of body fatness.

METHODS

This study includes three independent pediatric cohorts, two of Greek origin (the Gene-Diet Attica Investigation: GENDAI, n=1 138 and the "Growth, Exercise and Nutrition Epidemiological Study In preschoolers": the GENESIS study, n=2 374) and one British (the Avon Longitudinal Study of Parents and Children:ALSPAC, n=4 325). Among other information, breastfeeding history was recorded. A DNA sample was ascertained by either blood or saliva. Genotyping for FTO variants was performed in GENDAI and ALSPAC for the rs9939609, while in GENESIS, for the rs17817449 variant.

RESULTS

In all cohorts, multivariate analysis showed that the association between FTO:rs9939609 and measures of obesity was consistent across newly presented cohorts (GENDAI: Body mass index [BMI], β=0.43, p=0.009; Waist Circumference, β=1.067, p=0.019; triceps skinfold, β=0.972, p=0.003; subscapular skinfold, β=0.593, p=0.023; GENESIS: Waist Circumference, β=0.473, p=0.008 and subscapular skinfold, β=0.227, p=0.014). Inclusion of one month of breastfeeding as an interaction term effectively removed these associations with indices of obesity (BMI, Waist-Hip-Ratio and subscapular skinfold). No evidence of such interaction was observed for the independent cohort of British children.

CONCLUSIONS

Our findings indicate that in two moderately sized Greek samples, breastfeeding may exert a modifying effect on the relationship between variants at the FTO locus and indices of adiposity. These findings were not replicated in a larger British collection.

The impact of food allergy on asthma

Food allergy is a potentially severe immune response to a food or food additive. Although a majority of children will outgrow their food allergies, some may have lifelong issues. Food allergies and other atopic conditions, such as asthma, are increasing in prevalence in Western countries. As such, it is not uncommon to note the co-existence of food allergy and asthma in the same patient. As part of the atopic march, many food allergic patients may develop asthma later in life. Each can adversely affect the other. Food allergic patients with asthma have a higher risk of developing life-threatening food-induced reactions. Although food allergy is not typically an etiology of asthma, an asthmatic patient with food allergy may have higher rates of morbidity and mortality associated with the asthma. Asthma is rarely a manifestation of food allergy alone, but the symptoms can be seen with allergic reactions to foods. There may be evidence to suggest that early childhood environmental factors, such as the mother's and child's diets, factor in the development of asthma; however, the evidence continues to be conflicting. All food allergic patients and their families should be counseled on the management of food allergy and the risk of developing co-morbid asthma.

Breast-feeding in relation to asthma, lung function, and sensitization in young schoolchildren

BACKGROUND

The evidence from previous studies on beneficial effects of breast-feeding in relation to development of asthma is conflicting.

OBJECTIVE

To investigate the relation between breast-feeding and asthma and/or sensitization during the first 8 years of life.

METHOD

In a birth cohort, children were followed up to 8 years by questionnaires at ages 2 months and 1, 2, 4, and 8 years to collect information on exposures and health effects. Determination of serum IgE antibodies to common inhalant and food allergens was performed at 4 and 8 years. Longitudinal analyses were applied by using general estimated equations. The study population consisted of 3825 children (93% of the original cohort), of whom 2370 gave blood and 2564 performed lung function measurements at 8 years.

RESULTS

Children exclusively breast-fed 4 months or more had a reduced risk of asthma during the first 8 years of life (adjusted odds ratio [OR], 0.63; 95% CI, 0.50-0.78) compared with children breast-fed less than 4 months. At 8 years, reduced risks of sensitization (adjusted OR, 0.79; 95% CI, 0.64-0.99) and asthma in combination with sensitization (adjusted OR, 0.59; 95% CI, 0.37-0.93) were seen among children exclusively breast-fed 4 months or more. This group also had a significantly better lung function measured with peak expiratory flow.

CONCLUSION

Breast-feeding for 4 months or more seems to reduce the risk of asthma up to 8 years. At this age, a reduced risk was observed particularly for asthma combined with sensitization. Furthermore, breast-feeding seems to have a beneficial effect on lung function.

Breastfeeding and the prevalence of allergic diseases in schoolchildren: Does reverse causation matter?

Infants at higher risk of allergic diseases might be breastfed for longer periods compared with infants at lower risk in the hope that breastfeeding might reduce the risk of atopic disorders. Therefore, this intention could manifest as an apparent allergy-promoting effect of breastfeeding or reverse causation. To analyze the effect of breast feeding on the prevalence of allergic diseases at school age, a large questionnaire survey was administered to the parents of schoolchildren aged 7-15 yrs. 13,215 parents responded (response rate, 90.1%). Prevalence rates of allergic diseases were compared according to the type of feeding in infancy (either complete breastfeeding, mixed feeding or complete artificial feeding). In both univariate and multivariate analysis, compared with those with complete artificial feeding, those with mixed and complete breastfeeding showed a significantly lower prevalence of bronchial asthma (BA) (p = 0.01 and 0.003, respectively). On the other hand, in univariate analysis, the prevalence of atopic dermatitis (AD) and food allergy (FA) were significantly higher in those with complete breastfeeding (p = 0.04 and 0.01, respectively). There was a significantly higher proportion of complete breastfeeding among those with greater risk of allergic diseases (presence of family history, either eczema or wheeze within 6 months after birth, or FA in infancy). Therefore, our multivariate analysis included these risks as confounding factors, and we found that the promoting effects of breastfeeding on AD and FA disappeared. In conclusion, our data clearly showed the inhibitory effect of breastfeeding on the prevalence of BA at school age. The apparent promoting effect of breastfeeding on the prevalence of AD and FA is most likely because of reverse causation.

Clinical practice: Breastfeeding and the prevention of allergy

The increase in allergic disease prevalence has led to heightened interest in the factors determining allergy risk, fueled by the hope that by influencing these factors one could reduce the prevalence of allergic conditions. The most important modifiable risk factors for allergy are maternal smoking behaviour and the type of feeding. A smoke-free environment for the child (to be), exclusive breastfeeding for 4-6 months and the postponement of supplementary feeding (solids) until 4 months of age are the main measures considered effective. There is no place for restricted diets during pregnancy or lactation. Although meta-analyses suggest that hypoallergenic formula after weaning from breastfeeding grants protection against the development of allergic disease, the evidence is limited and weak. Moreover, all current feeding measures aiming at allergy prevention fail to show effects on allergic manifestations later in life, such as asthma. In conclusion, the allergy preventive effect of dietary interventions in infancy is limited. Counselling of future parents on allergy prevention should pay attention to these limitations.

Regulatory T cells and asthma

Airway inflammation in asthma is characterized by activation of T helper type-2 (Th2) T cells, IgE production and eosinophilia. In many cases, this process is related to an inappropriate T cell response to environmental allergens, and other T cell-dependent pathways may also be involved (such as Th17). Regulatory T cells (Tregs) are T cells that suppress potentially harmful immune responses. Two major subsets of Treg are CD25(hi), Foxp3(+)Tregs and IL-10-producing Tregs. There is evidence that the numbers or function of both subsets may be deficient in patients with atopic allergic disease. Recent work has extended these findings into the airway in asthma where Foxp3 expression was reduced and CD25(hi) Treg-suppressive function was deficient. In animal models of allergic airways disease, Tregs can suppress established airway inflammation and airway hyperresponsiveness, and protocols to enhance the development, recruitment and function of Tregs have been described. Together with studies of patients and in vitro studies of human T cells, these investigations are defining potential interventions to enhance Treg function in the airway in asthma. Existing therapies including corticosteroids and allergen immunotherapy act on Tregs, in part to increase IL-10 production, while vitamin D3 and long-acting beta-agonists enhance IL-10 Treg function. Other possibilities may be enhancement of Treg function via histamine or prostanoid receptors, or by blocking pro-inflammatory pathways that prevent suppression by Tregs (activation of Toll-like receptors, or production of cytokines such as IL-6 and TNF-alpha). As Tregs can also suppress the potentially beneficial immune response important for controlling infections and cancer, a therapeutic intervention should target allergen- or site-specific regulation.

Diet and asthma: looking back, moving forward

Asthma is an increasing global health burden, especially in the western world. Public health interventions are sought to lessen its prevalence or severity, and diet and nutrition have been identified as potential factors. With rapid changes in diet being one of the hallmarks of westernization, nutrition may play a key role in affecting the complex genetics and developmental pathophysiology of asthma. The present review investigates hypotheses about hygiene, antioxidants, lipids and other nutrients, food types and dietary patterns, breastfeeding, probiotics and intestinal microbiota, vitamin D, maternal diet, and genetics. Early hypotheses analyzed population level trends and focused on major dietary factors such as antioxidants and lipids. More recently, larger dietary patterns beyond individual nutrients have been investigated such as obesity, fast foods, and the Mediterranean diet. Despite some promising hypotheses and findings, there has been no conclusive evidence about the role of specific nutrients, food types, or dietary patterns past early childhood on asthma prevalence. However, diet has been linked to the development of the fetus and child. Breastfeeding provides immunological protection when the infant's immune system is immature and a modest protective effect against wheeze in early childhood. Moreover, maternal diet may be a significant factor in the development of the fetal airway and immune system. As asthma is a complex disease of gene-environment interactions, maternal diet may play an epigenetic role in sensitizing fetal airways to respond abnormally to environmental insults. Recent hypotheses show promise in a biological approach in which the effects of dietary factors on individual physiology and immunology are analyzed before expansion into larger population studies. Thus, collaboration is required by various groups in studying this enigma from epidemiologists to geneticists to immunologists. It is now apparent that this multidisciplinary approach is required to move forward and understand the complexity of the interaction of dietary factors and asthma.

Tolerance and safety of Lactobacillus paracasei ssp. paracasei in combination with Bifidobacterium animalis ssp. lactis in a prebiotic-containing infant formula: a randomised controlled trial

The addition of probiotics to infant formula has been shown to be an efficient way to increase the number of beneficial bacteria in the intestine in order to promote a gut flora resembling that of breast-fed infants. The objective of the present study was to evaluate the safety and tolerance of a combination of two probiotic strains in early infancy. A group of 126 newborns were randomised to receive a prebiotic-containing starter formula supplemented with Lactobacillus paracasei ssp. paracasei and Bifidobacterium animalis ssp. lactis or the same formula without probiotics for the first 3 months of life. A total of eighty infants continued the study until they were aged 6 months. Growth measurements were taken monthly at healthy baby clinics. Diaries were used to monitor behaviour, infections, use of antibiotics, as well as stool characteristics. Normal growth occurred in all infants and no statistically significant differences were detected between the probiotics group and the control group for gain in weight, length and head circumference. Infants in the probiotics group produced softer and more frequent stools during the first 3 months of life. No differences were found in crying and sleeping hours, number of parent-diagnosed infections, antibiotic use, visits to the general practitioner and number of adverse events. The use of a prebiotic-containing starter formula supplemented with L. paracasei ssp. paracasei and B. animalis ssp. lactis in early infancy is safe, well tolerated and has no adverse effects on growth and infant behaviour.

Advances in pediatric asthma in 2008: where do we go now?

This year's summary focuses on recent advances in pediatric asthma as reported in Journal publications in 2008. New National Asthma Education and Prevention Program asthma guidelines were released in 2007 with a special emphasis on asthma control. Attention was redirected to methods that could reduce impairment, specifically symptom control, and minimize risk, including exacerbations. Journal theme issues in 2008 focused on several relevant asthma topics including asthma exacerbations, exercise-induced bronchospasm, asthma and obesity, and occupational asthma. This review highlights Journal articles and related articles that reinforce principles of the guidelines and also direct us to new information that will advance asthma care for children. A major step forward will be finding ways to implement the asthma guidelines.

American Academy of Pediatrics recommendations on the effects of early nutritional interventions on the development of atopic disease

PURPOSE OF REVIEW

To review the American Academy of Pediatrics statement on the effects of early nutritional interventions on the development of atopic disease in infants and children.

RECENT FINDINGS

Recent findings suggest that restriction of maternal diet during pregnancy and lactation does not play a major role in the development of allergic disease. In high-risk infants, exclusive breastfeeding for at least 4 months prevents or delays atopic dermatitis, cow milk allergy, and wheezing early in life. There is evidence that supplementing breastfeeding with a hydrolyzed formula protects against atopic disease, especially atopic dermatitis in at-risk infants. Finally, there is little evidence that delaying the introduction of complementary foods beyond 4-6 months of age has any protective effect against allergy. There is insufficient data that any dietary intervention beyond 4-6 months of age has any protective effect against developing atopic disease.

SUMMARY

In high-risk infants, there is evidence that exclusive breastfeeding for at least 4 months, and delaying of complementary foods until 4-6 months, prevent the development of allergy. There is some evidence that supplementing hydrolyzed formulas in high-risk infants may delay or prevent allergic disease. There is no convincing evidence that maternal manipulation of diet during pregnancy or lactation, use of soy products, or infant dietary restrictions beyond 4-6 months has any effect on the development of atopic disease.

Breastfeeding and allergies: time for a change in paradigm?

PURPOSE OF REVIEW

This review examines recent studies of the relationships between breastfeeding and the epidemiology of allergic diseases, especially atopic dermatitis in infants and asthma in early and later childhood.

RECENT FINDINGS

Results from observational birth cohort studies, case-control studies, and one cluster randomized intervention trial have generally failed to demonstrate a protective effect of breastfeeding on outcomes of atopic dermatitis, allergic sensitization, wheezing, or asthma. Difficulties in interpretation relate to the absence of nonbreastfed control or reference groups in some studies, meaning outcomes can only be compared between different durations of breastfeeding. Studies with a nonbreastfed control group suggest there is an increased risk for atopy and asthma associated with breastfeeding and that prolonged breastfeeding may eventually reduce this increased risk. The family history, sex of the child, and the presence of other risk factors for allergy and asthma also influence the outcome.

SUMMARY

Although breastfeeding is strongly recommended for its multiple benefits on child health, most recent studies do not confirm the 'conventional wisdom' that breastfeeding is protective against allergy and asthma. Early reduction in childhood wheezing may reflect protection from viral infections, but allergies and asthma at later ages may be increased.