Breastfeeding, asthma, and atopic disease: an epidemiological review of the literature

Physiologic changes in serotonin concentrations in breast milk during lactation

OBJECTIVES

Serotonin (5-hydroxytryptamine; 5-HT) plays an important role in milk volume homeostasis in the mammary glands during lactation, and 5-HT in milk also may affect infant development. The aim of this study was to investigate changes in 5-HT concentration in breast milk according to the duration of lactation and evaluate whether the 5-HT concentration varied before and after nursing.

METHODS

Healthy nursing Japanese women who had a natural delivery or underwent a cesarean delivery at Iwate Medical University Hospital were included in this study.

RESULTS

The mean 5-HT concentration in milk was obtained from multiparous mothers 6 to 7 d after delivery (colostrum) and was significantly higher compared with primiparous mothers (24.3 ± 2.63 versus 18.5 ± 2.60 ng/mL). Additionally, mean 5-HT concentration increased with increasing lactation duration in primiparous women (colostrum: 18.5 ± 2.60; 1 mo postdelivery: 19.8 ± 2.46; 3 mo postdelivery: 22.7 ± 2.55 ng/mL); in particular, the mean 5-HT concentration in breast milk 3 mo after delivery was significantly higher than in colostrum. The mean 5-HT concentrations in breast milk in primiparous mothers immediately before nursing, 1 to 2 h after nursing, and immediately before the next nursing event were 23.6 ± 1.48, 22.82 ± 1.65, and 21.84 ± 1.31 ng/mL, respectively; mean 5-HT concentrations in multiparous women were 25.4 ± 1.65, 23.6 ± 2.20, or 22.4 ± 2.09 ng/mL, respectively. There was no significant difference in 5-HT concentrations at each time point between the groups.

CONCLUSION

This information may be useful in determining the role of 5-HT in breast milk on infant development and growth.

Asthma co-morbidities in Nigerian children: prevalence, risk factors and association with disease severity and symptoms control

Introduction

Prompt recognition and management of co-morbidities is an important step in ensuring optimal childhood asthma symptoms control. This study sets out to determine the prevalence, predictive factors and association of co-morbidities with asthma severity, lung functions and symptoms control in Nigerian children.

Methods

Children (aged 2 to 15 years) with physician-diagnosed asthma at the Wesley Guild Hospital, Nigeria were consecutively recruited. Asthma co-morbidities, severity and levels of symptoms control were assessed using standard definitions. Lung functions of children ≥ 6 years were also measured. Factors predictive of asthma co-morbidities and association of co-morbid conditions with asthma severity, lung functions and symptoms control were determined using univariate and multivariate analyses.

Results

A total of 186 children (male: female 1.4:1) were recruited and the majority (81.0%) had mild intermittent asthma. Forty (21.5%) had suboptimal symptoms control and 112 (60.2%) had associated co-morbidities. Allergic rhinitis and/or conjunctivitis (41.4%) were the most common co-morbidities. Predictors of concomitant presence of allergic rhinitis among the children were older age group ≥ 6 years (OR = 2.488; 95%CI 1.250-4.954; p = 0.036) and lack of exclusive breastfeeding (OR = 2.688; 95%CI 1.199 -5.872; p = 0.020) while obesity/overweight (OR = 6.300; 95%CI 2.040-8.520; p = 0.003) and Allergic rhinitis (OR = 2.414; 95%CI 1.188-6.996; p = 0.049) were determinants of persistent asthma. Suboptimal symptoms control was associated with having concomitant allergic rhinitis (p = 0.018), however no comorbid condition predicted lung function impairment.

Conclusion

About two-thirds of children with asthma had co-morbidities and allergic rhino-conjunctivitis was the most common. School age group and early introduction to breast milk substitutes predict the presence of these co-morbidities which also affect asthma severity and control.

Long-term Breastfeeding in the Prevention of Allergic Rhinitis: Allergic Rhinitis Cohort Study for Kids (ARCO-Kids Study)

OBJECTIVES

There is a great deal of interest in the possibility that environmental factors may influence the risk of developing allergic rhinitis (AR) in early life. We investigated the simultaneous effects of mode of delivery and duration of breastfeeding on the development of AR in children.

METHODS

Data from 1,374 children participating in the Allergic Rhinitis Cohort Study for kids (ARCO-kids study) was analyzed. All subjects were divided into AR or non-allergic rhinitis (NAR) groups. Data on environmental factors, mode of delivery and duration of breastfeeding were collected using a questionnaire.

RESULTS

Compared with short-term breastfeeding (<6 months), long-term breastfeeding (≥12 months) was significantly associated with a lower prevalence of AR (adjusted odds ratio [aOR], 0.54; 95% confidence interval [CI], 0.34 to 0.88). Children in the AR group also had a higher cesarean delivery rate than those in the NAR group (39.1% vs. 32.8%, P=0.05). Regarding the combined effects of mode of delivery and duration of breastfeeding, long-term breastfeeding with a vaginal delivery strongly suppressed the development of AR, compared to short-term breastfeeding with a cesarean delivery (aOR, 0.47; 95% CI, 0.30 to 0.73).

CONCLUSION

Long-term breastfeeding (≥12 months) and a vaginal delivery are associated with a lower risk of developing childhood AR.

The effect of family policies and public health initiatives on breastfeeding initiation among 18 high-income countries: a qualitative comparative analysis research design

BACKGROUND

The objective of this study is to examine the effects of macro-level factors - welfare state policies and public health initiatives - on breastfeeding initiation among eighteen high-income countries.

METHODS

This study utilizes fuzzy-set Qualitative Comparative Analysis methods to examine the combinations of conditions leading to both high and low national breastfeeding initiation rates among eighteen high-income countries.

RESULTS

The most common pathway leading to high breastfeeding initiation is the combination of conditions including a high percentage of women in parliament, a low national cesarean section rate, and either low family spending, high rates of maternity leave, or high rates of women working part-time. The most common pathway leading to low breastfeeding initiation includes the necessary condition of low national adherence to the Baby-Friendly Hospital Initiative.

CONCLUSION

This research suggests that there is a connection between broad level welfare state polices, public health initiatives, and breastfeeding initiation. Compliance with the WHO/UNICEF initiatives depends on welfare regime policies and overall support for women in both productive and reproductive labor.

Diet Hypotheses in Light of the Microbiota Revolution: New Perspectives

From an evolutionary standpoint, allergy has only recently emerged as a significant health problem. Various hypotheses were proposed to explain this, but they all indicated the importance of rapid lifestyle changes, which occurred in industrialized countries in the last few decades. In this review, we discuss evidence from epidemiological and experimental studies that indicate changes in dietary habits may have played an important role in this phenomenon. Based on the example of dietary fiber, we discuss molecular mechanisms behind this and point towards the importance of diet-induced changes in the microbiota. Finally, we reason that future studies unraveling mechanisms governing these changes, along with the development of better tools to manipulate microbiota composition in individuals will be crucial for the design of novel strategies to combat numerous inflammatory disorders, including atopic diseases.

Analysis of serotonin concentrations in human milk by high-performance liquid chromatography with fluorescence detection

Serotonin (5-hydroxytryptamine, 5-HT) plays an important role in milk volume homeostasis in the mammary gland during lactation; 5-HT in milk may also affect infant development. However, there are few reports on 5-HT concentrations in human breast milk. To address this issue, we developed a simple method based on high-performance liquid chromatography with fluorescence detection (HPLC-FD) for measuring 5-HT concentrations in human breast milk. Breast milk samples were provided by four healthy Japanese women. Calibration curves for 5-HT in each sample were prepared with the standard addition method between 5 and 1000 ng/ml, and all had correlation coefficients >0.999. The recovery of 5-HT was 96.1%-101.0%, with a coefficient of variation of 3.39%-8.62%. The range of 5-HT concentrations estimated from the calibration curves was 11.1-51.1 ng/ml. Thus, the HPLC-FD method described here can effectively extract 5-HT from human breast milk with high reproducibility.

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.

Maternal dietary fat and fatty acid intake during lactation and the risk of asthma in the offspring

AIM

To explore the association between maternal dietary fat and fatty acid (FA) intake during lactation, and the risk of asthma in the offspring by the age of 5 years.

METHODS

The subjects comprised 1798 mother-child pairs from the Type 1 Diabetes Prediction and Prevention (DIPP) Nutrition Study. Dietary intake was assessed by a validated 181-item food frequency questionnaire, which covered the third month of lactation. The cumulative incidence of asthma was assessed at the age of 5 years with a questionnaire modified from the International Study of Asthma and Allergies in Childhood (ISAAC). Cox proportional hazards regression was used for statistical analysis.

RESULTS

The maternal use of margarines during lactation was associated with a marginally increased risk of asthma [hazard ratio (HR) for user vs. nonuser 1.96, 95% confidence interval (CI) 1.01-3.82, p = 0.047] after adjusting for putative confounders. The maternal intakes of n-3 polyunsaturated FA (PUFA) and fish during lactation were not associated with the risk of asthma.

CONCLUSION

Maternal use of margarines during lactation was weakly associated with an increased risk of asthma in the offspring at the age of 5 years. Other fats or FAs during lactation were not associated with the risk of asthma. However, the nonadherence to dietary recommendations regarding especially fats of our study population may restrict the generalizability of our results.

A systematic review of structured versus non-structured breastfeeding programmes to support the initiation and duration of exclusive breastfeeding in acute and primary healthcare settings

EXECUTIVE SUMMARY

Background: Breastfeeding has many important health benefits for the woman and her baby. Despite evidence of benefit from a large number of well conducted studies, breastfeeding uptake and the duration of exclusive breastfeeding remain low in many countries. In order to improve breastfeeding rates, policy and guidelines at global, individual country level and in local healthcare settings have recommended that structured programmes to support breastfeeding should be introduced. The objective of this review was to consider the evidence of outcomes of structured compared with non-structured breastfeeding programmes in acute maternity care settings to support initiation and duration of exclusive breastfeeding.

REVIEW METHODS

The definition of structured programme used included a multi-faceted or single intervention approach to support breastfeeding; definition of non-structured included support offered within standard care. The review considered quantitative and qualitative studies which addressed outcomes following the introduction of a structured programme in acute healthcare settings to support breastfeeding compared with no programme. The primary outcomes of interest were uptake of breastfeeding and duration of exclusive breastfeeding (only breast milk, including milk expressed). Studies which only considered community based interventions were not included.

SEARCH STRATEGY

A search of the literature published between 1992 and 2010 was conducted, which followed a four step process. After a limited search of MEDLINE and CINAHL to identify key words contained in the title or abstract and index terms to describe relevant interventions, a second extensive search was undertaken using identified key words and index terms. The third step included a search of reference lists and bibliographies of relevant articles and the fourth step included a search of grey and unpublished literature and national databasesMethodological quality: Methodological quality was assessed using checklists developed by the Joanna Briggs Institute. Two independent reviewers conducted critical appraisal and data extraction.

RESULTS

Twenty-six articles were included; one randomised controlled trial, two non randomised trials, one cross-sectional study, five systematic reviews, 15 cohort studies and two descriptive studies. Due to the poor quality of evidence presented and clinical and methodological heterogeneity of study designs, including definitions of breastfeeding and duration of follow-up, it was not possible to combine studies or individual outcomes in meta-analyses, therefore findings are presented in a narrative form.In most studies the structured programme of interest reflected some or all of the Baby Friendly Hospital Initiative 'Ten Steps'. Most studies found a statistically significant improvement in initiation of breastfeeding following introduction of a structured breastfeeding programme, although effect sizes varied widely.The impact of introducing a structured programme on the duration of exclusive breastfeeding and duration of any breastfeeding was also evident, although not all studies found statistically significant differences. At hospital discharge or within the first week post-birth, implementation of a structured programme appeared to increase duration of exclusive breastfeeding and the duration of any breastfeeding compared with usual care. After hospital discharge and up to six months post-birth, use of structured programmes also appeared to support continued duration of exclusive and any breastfeeding although differences in outcomes were not reported across all included studies. At six months, three of five studies which included data on longer-term outcomes showed women were statistically significantly more likely to be exclusively breastfeeding. Only one of these studies compared outcomes following implementation of BFHI.

CONCLUSIONS

Despite the poor overall quality of studies, structured programmes, regardless of content, compared with standard care appear to influence the uptake and duration of exclusive breastfeeding and any breastfeeding. In healthcare settings with low breastfeeding uptake and duration rates, structured programmes may have a greater benefit. In countries where breastfeeding uptake is already high, the benefit is less apparent. The extent to which structured programmes in different maternity acute care settings have a significant effect on the duration of exclusive breastfeeding at six months is less clear. Most of the recommendations of this review were based on observational studies and retrospective data collection. Few studies controlled for any potential confounding factors and the impact of bias has to be considered.

IMPLICATIONS FOR PRACTICE

Acute maternity care settings should implement structured programmes to support breastfeeding as part of routine maternity care. Programmes can replicate an existing programme, such as the BFHI, in full or in part, or be specifically developed to support implementation of evidence to reflect the needs and demands of the local healthcare organisation. In healthcare settings which have a high uptake of breastfeeding, resources may be better directed at improving support for duration of exclusive breastfeeding in the community.

IMPLICATIONS FOR RESEARCH

Further high quality RCTs are needed which address the impact of introduction of structured programmes on women's experiences of infant feeding, on the role of the relevant healthcare professionals and on short and longer-term health outcomes. Prospective data capture to inform economic analyses should also be undertaken. Trial interventions need to be well defined and implementation processes described to inform reproducibility across different locations and different country settings. Research is also needed to address the issue of which elements of a structured programme are likely to lead to the most clinical and cost effective use of healthcare resources and to address how sustainable these interventions are in health systems facing increased economic pressures.

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.

Serotonin transport and metabolism in the mammary gland modulates secretory activation and involution

CONTEXT

Serotonin [5-hydroxytryptamine (5-HT)] is an important local regulator of lactation homeostasis; however, the roles for the serotonin reuptake transporter and monoamine oxidase have not been known.

OBJECTIVE

The aim of the study was to determine whether drugs that impact 5-HT affect human lactation physiology.

DESIGN AND SETTING

We conducted laboratory studies of human and animal models and an observational study of the onset of copious milk secretion in postpartum women at a university medical center.

PARTICIPANTS

We studied women expecting their first live-born infant; exclusion criteria were: referred to the medical center for another medical condition, known contraindication to breastfeed, and less than 19 yr of age and unable to obtain parental consent.

INTERVENTION(S)

The mothers were interviewed. The cell and animal studies consisted of a variety of biochemical, pharmacological, and genetic interventions.

MAIN OUTCOME MEASURE(S)

The human subjects outcome was prevalence of delayed onset of copious milk secretion. The cell and animal outcomes were physiological and morphological.

RESULTS

Inhibiting serotonin reuptake in mammary epithelial cells altered barrier function, and the effects were amplified by coadministering a monoamine oxidase inhibitor. Direct delivery of fluoxetine by slow-release pellets caused localized involution. TPH1 knockout mice displayed precocious secretory activation. Among a cohort of 431 women, those taking SSRI were more likely (P = 0.02) to experience delayed secretory activation.

CONCLUSIONS

Medications that perturb serotonin balance dysregulate lactation, and the effects are consistent with those predicted by the physiological effects of intramammary 5-HT bioactivity. Mothers taking serotonergic drugs may need additional support to achieve their breastfeeding goals.

Neonatal innate immunity in allergy development

PURPOSE OF REVIEW

The neonate is born with a distinct immune system that is biased against the production of T-helper cell 1 (Th1) cytokines. Birth imposes a great challenge on the neonatal immune system, which is confronted with an outside world rich in foreign antigens. Exposure to these antigens shapes the developing neonatal immune system. Inducing Th-1 or Th-2 polarized responses that may extend beyond the neonatal age and counteract or promote allergic sensitization. This review describes how engagement of the innate immune system might contribute to the development of allergy in children.

RECENT FINDINGS

The exact role of innate immune stimulation in the development of allergies is a controversial area. Epidemiological literature suggests that microbial exposure in early childhood protects against the development of allergies, whereas a large amount of experimental data demonstrates that innate immune stimulation enhances Th2 responses upon primary and secondary antigen exposure.

SUMMARY

Dose, site and timing of allergen exposure are likely to modulate the innate immune response, polarizing the maturing neonatal immune system towards Th1 or Th2-type responses, thereby protecting from or predisposing to asthma and allergies. Modulation of neonatal innate immune responses may be a novel approach to prevent asthma and allergies.

Risk factors of childhood asthma in Sao Jose do Rio Preto, Sao Paulo, Brazil

BACKGROUND

Epidemiological studies have shown increased prevalence of asthma over the last decades and a considerable variation in these rates between different countries, mainly developed. Changes in lifestyle of different populations could explain the increasing prevalence of asthma and its different rates in different communities.

OBJECTIVES

A case-control study was conducted to investigate some risks factors associated to asthma in schoolchildren in São José do Rio Preto, São Paulo, Brazil.

CASUISTIC AND METHODS

A total of 3793 self-administered written questionnaire (WQ) was filled in by parents of 6-7-year-old schoolchildren, applying the International Study of Asthma and Allergies in Childhood (ISAAC) protocol. Additionally, was added a supplementary WQ evaluating risk factors: gender, personal history of rhinitis and atopic eczema, familial history of atopy, older siblings, day care, breastfeeding, and exposure to pets and to cigarette smoking. Children whose parents responded affirmatively to question 'Has your child had wheezing in the past 12 monthsquest;' were identified as having current asthma.

RESULTS

The prevalence of current asthma was 18.3%. In multivariate analysis the following risk factors were associated with asthma: rhinitis (OR = 10.6; 95% CI = 8.27-13.56), atopic eczema (OR = 1.54; 95% CI = 1.00-2.35), father with asthma (OR = 3.49; 95% CI = 1.83-6.67), mother with asthma (OR = 1.84; 95% CI = 1.11-3.05), current exposure to pets (OR = 1.83; 95% CI = 1.45-2.32) and passive tobacco smoking exposure (OR = 1.43; 95% CI = 1.12-1.83).

CONCLUSIONS

Our results show that genetic background, environmental factors and the presence of co-morbidities such as rhinitis and atopic eczema are associated to the genesis of asthma in Brazilian schoolchildren.

Maternal pre-pregnancy obesity and diagnosis of asthma in offspring at age 3 years

OBJECTIVE

The objective of this study was to examine the relationship between maternal pre-pregnancy obesity and a diagnosis of asthma in offspring at age 3 years.

METHODS

A population-based sample of children born in large U.S. cities in 1998-2000 was followed since birth (N=1971). The main outcome measure was whether the mother reported at 3 years that the child had ever been diagnosed with asthma. Multilevel logistic regression models were used to estimate the association between maternal pre-pregnancy obesity and child asthma diagnosis, as well as the extent to which the association can be explained by sociodemographic, medical, obstetric, and behavioral factors associated with both conditions.

RESULTS

Children with obese mothers had 52% higher odds of having an asthma diagnosis by age 3 (OR=1.52; 95% CI: 1.18-1.93). Sociodemographic, medical, obstetric, and behavioral factors explained some, but not all, of the association.

CONCLUSIONS

Maternal pre-pregnancy obesity is associated with diagnosis of asthma in offspring at age 3 years. The results from this study are preliminary and need to be replicated and further explored, but are suggestive of a complex intergenerational linkage between obesity and asthma.

Motherhood meets epidemiology: measuring risk factors for breast–feeding cessation

Objective:

To examine statistical models that have been used to predict the cessation of breast–feeding.

Setting:

In nutritional epidemiology, a knowledge of risk factors that lead to breast-feeding cessation is essential to promote optimal infant health by increasing or sustaining breast–feeding rates. However, a number of methodological issues complicate the measurement of such risk factors. It is important when building multivariate models that variables entered into the model are not intervening variables, factors on the causal pathway or surrogate outcomes. Inclusion of these types of variable can lead to inaccurate models and biased results. A factor often cited to predict breast–feeding is ‘intention to breast–feed’ prior to the birth of the infant, although this factor is directly on the causal decision–making pathway. Another factor often cited is the age of introduction of formula feeding, which is actually part of the outcome variable because formula feeding defines the difference between full, complementary and no breast-feeding. Rather than include these as risk factors in multivariate models, factors removed from the causal pathway such as influences of educational practices, including advice to complementary feed, and beliefs and attitudes of families and health-care practitioners should be measured.

Conclusions:

The accurate quantification of modifiable risk factors is essential for designing public health education campaigns that are effective in sustaining or increasing breast–feeding duration.

Prolonged exclusive breastfeeding is associated with increased atopic dermatitis: a prospective follow-up study of unselected healthy newborns from birth to age 20 years

BACKGROUND

Exclusive breastfeeding for the first 6 months is recommended by the World Health Organization and considered allergy preventive. However, it is not known whether prolonging exclusive breastfeeding for over 6 months provides further benefit in allergy prevention.

OBJECTIVE

The aim of this prospective 20-year follow-up study was to find out whether the allergy protective effect can be enhanced by prolonging strictly exclusive breastfeeding for > or =9 months of age. A total of 200 unselected healthy newborns were enrolled in the study. Their mothers were encouraged to maintain exclusive breastfeeding for as long as possible. The number of infants on strictly exclusive breastfeeding was 167 at 2, 116 at 6, 36 at 9 and 7 at 12 months of age. Of the 200 infants, 42% had a family history of allergy. The children were re-assessed at ages 5 (n=163), 11 (n=150) and 20 years (n=164) with clinical examination, skin prick testing, and parental and personal structured interviews.

RESULTS

Exclusive breastfeeding prolonged for > or =9 months was associated with atopic dermatitis (P=0.002) and symptoms of food hypersensitivity (P=0.02) at age 5 years, and with symptoms of food hypersensitivity at age 11 years (P=0.01), in children with a family history of allergy.

CONCLUSION

Prolonging strictly exclusive breastfeeding for > or =9 months was not helpful in atopy prevention, instead, it was associated with increased atopic dermatitis and food hypersensitivity symptoms in childhood.

Airway hyperresponsiveness and body mass index: the Child Health and Environment Cohort Study in Hesse, Germany

Increased body mass index has been linked to wheezing, a diagnosis of asthma, and morbidity. We investigated the association between body mass index (BMI), breastfeeding, and airway hyperresponsiveness (AHR) in 536 German schoolchildren. We analyzed consecutive surveys in 1994-1995 and 1997, conducted as part of the Child Health and Environment Cohort Study in Hesse, Germany. The questionnaire included questions adapted from the German version of the International Study of Asthma and Allergy in Childhood (ISAAC). A bronchial challenge test using 4.5% hypertonic saline was conducted during the 1997 survey. AHR was defined as a fall in forced expiratory volume in 1 sec (FEV(1)) of > or = 15%. Of 536 children who participated in the 1997 survey (median age, 10.3 years), 82 (15%) tested positive for AHR. In a multivariate analysis, there was no association between AHR determined at age 10 years and the highest quintile of BMI compared to the lowest quintile at age 4 years (odds ratio (OR), 1.4; 95% confidence interval (CI), 0.5-3.6), 7-8 years (OR, 0.6; 95% CI, 0.1-2.5), or 10 years (OR, 1.1; 95% CI, 0.2-4.3). Breastfeeding for 12 weeks or longer protected against AHR (OR, 0.4; 95% CI, 0.2-0.9). However, when children in the highest quintile of BMI at age 4 years had been breastfed for 8 weeks or less, the prevalence of AHR at age 10 years was significantly increased (27.7%, P = 0.01). In conclusion, our results demonstrate a protective effect of breastfeeding against AHR, and reinforce the need to encourage breastfeeding. Although there was no association between BMI and AHR, our finding of an interactive effect of high BMI and short breastfeeding on AHR suggests a complex etiological pathway that needs to be further explored.

Prenatal dichlorodiphenyldichloroethylene (DDE) and asthma in children

Prevalence of asthma increases with increasing dichlorodiphenyldichloroethylene (DDE) levels. However, the effect of early-life exposure, the fundamental window of exposure, is unknown. We assessed the association between prenatal DDE and other organochlorine compounds, and atopy and asthma during infancy. All women presenting for antenatal care in Menorca (Spain) over 12 months starting in mid-1997 were invited to take part in a longitudinal study; 482 children were subsequently enrolled, and 468 (97.1%) provided complete outcome data up to the fourth year of study. Prenatal exposure of organochlorine compounds was measured in cord serum in 405 (83%) children. Asthma was defined on the basis of wheezing at 4 years of age, persistent wheezing, or doctor-diagnosed asthma. We measured specific immunoglobulin-E (IgE) against house dust mite, cat, and grass in sera extracted at 4 years of age. DDE (median = 1.03 ng/mL) was detected in all children, as well as hexachlorobenzene (0.68 ng/mL) and polychlorobiphenyls (0.69 ng/mL). Wheezing at 4 years of age increased with DDE concentration, particularly at the highest quartile [9% in the lowest quartile (< 0.57 ng/mL) vs. 19% in the highest quartile (1.90 ng/mL); relative risk = 2.63 (95% confidence interval 1.19-4.69), adjusting for maternal asthma, breast-feeding, education, social class, or other organochlorines]. The association was not modified by IgE sensitization and occurred with the same strength among nonatopic subjects and among those with persistent wheezing or diagnosed asthma. DDE was not associated with atopy alone. Prenatal exposure to DDE residues may contribute to development of asthma.

Clinical lactation practice: 20 years of evidence

Lactation consultants depend on a vast multidisciplinary knowledge base to support their practices. To coincide with the 20-year anniversary of the International Lactation Consultant Association, the authors sought to highlight the knowledge base to demonstrate how practice has been affected. Using standard databases, they extracted English-language scientific literature related to breastfeeding and maternal and infant health outcomes; factors associated with breastfeeding initiation, exclusivity, and duration; lactation physiology; common breastfeeding challenges; breastfeeding practices within vulnerable populations; health professional support of breastfeeding; and breastfeeding practices in developing countries of Africa. Summaries of research are provided to demonstrate scientific method and knowledge evolution. As the knowledge of the biological, behavioral, and environmental factors that affect breastfeeding continues to grow, researchers and lactation consultants will identify additional research areas. Thus, the cycle of describing and explaining phenomena, testing interventions to improve practice, and ultimately improving breastfeeding outcomes worldwide will continue.

The early origins hypothesis with an emphasis on growth rate in the first year of life and asthma: a prospective study in Chile

BACKGROUND

There is uncertainty about the impact of the programming hypothesis in terms of nutritional status at birth, rate of growth in the first year of life, length of gestation, breast feeding, and episodes of illness on asthma. An analysis was therefore carried out to test this hypothesis.

METHODS

Data were collected on 1232 children born between 1974 and 1978 in a semi-rural area of Chile. Measurements at birth and growth in the first year of life were obtained from a birth registry and clinical notes. Information on asthma was collected using the European Community Respiratory Health Survey questionnaire. Sensitisation to eight allergens and bronchial hyperresponsiveness (BHR) to methacholine were determined. All other information was obtained using a questionnaire. Polytomous logistic analyses were carried out to explore the association of factors at birth and during the first year of life with asthma symptoms, atopy, and BHR.

RESULTS

Weight and length gain in the first year were positively associated with wheeze (odds ratio (OR) 1.004, 95% CI 1.001 to 1.007 and OR 1.11, 95% CI 0.98 to 1.25, respectively). A higher body mass index (BMI) at birth was protective in subjects reporting both wheeze and waking with breathlessness (OR 0.54, 95% CI 0.35 to 0.84). Length rate in tertiles divided by length at birth in tertiles was related to asthma symptoms (OR 1.68, 95% CI 1.19 to 2.37). Most other assessments were not associated with asthma.

CONCLUSION

These results show promising but inconclusive evidence that a rapid rate of growth in length, especially in newborn infants of low length, might be involved in the aetiology of asthma.

A review of the effects of breastfeeding on respiratory infections, atopy, and childhood asthma

The etiology of childhood asthma is not fully understood. Early exposure to certain respiratory infections may be protective for atopy and/or asthma whereas some infections have been suggested to exert the opposite effects. Wheezing lower respiratory illness (LRI) in the first year of life and atopy are independently associated with increased risk for current asthma in childhood and their effects are mediated via different causal pathways. These risk factors are multiplicative when they operate concommitantly within individual children. Exclusive breastfeeding protects against asthma via effects on both these pathways, as well as through other as yet undefined mechanisms. Furthermore, exclusive breastfeeding may protect against asthma and may reduce the incidence of lower respiratory illness, especially respiratory syncytial virus (RSV). We have previously demonstrated a protective effect of exclusive breastfeeding on asthmatic traits in children. The aim of this review was to clarify this protective association from intermediate associations with respiratory infections, atopy, or through other facets of breastfeeding. The bioactivity of breast milk and subsequent pathways that may act upon the development of asthma in children are explored.