***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Abstract Objectives : To investigate the association between the duration of exclusive breast feeding and the development of  asthma related outcomes in children at age 6 years . Design : Prospect i ve cohort study . Setting : Western Australia . Subjects : 2187 children ascertained through antenatal clinics at the major tertiary obstetric hospital in Perth and followed to age 6 years . Main outcome measures : Unconditional logistic regression to model the association between duration of exclusive breast feeding and outcomes related to asthma or atopy at 6 years of age , allowing for several important confounders : sex , gestational age , smoking in the household , and early childcare . Results : After adjustment for confounders , the introduction of milk other than breast milk before 4 months of age was a significant risk factor for all asthma and atopy related outcomes in children aged 6 years : asthma diagnosed by a doctor ( odds ratio 1.25 , 95 % confidence interval 1.02 to 1.52 ) ; wheeze three or more times since 1 year of age ( 1.41 , 1.14 to 1.76 ) ; wheeze in the past year ( 1.31 , 1.05 to 1.64 ) ; sleep disturbance due to wheeze within the past year ( 1.42 , 1.07 to 1.89 ) ; age when doctor diagnosed asthma ( hazard ratio 1.22 , 1.03 to 1.43 ) ; age at first wheeze ( 1.36 , 1.17 to 1.59 ) ; and positive skin prick test reaction to at least one common aeroallergen ( 1.30 , 1.04 to 1.61 ) . Conclusion : A significant reduction in the risk of childhood asthma at age 6 years occurs if exclusive breast feeding is continued for at least the 4 months after birth . These findings are important for our underst and ing of the cause of childhood asthma and suggest that public health interventions to optimise breast feeding may help to reduce the community burden of childhood asthma and its associated traits . Key messages Asthma is the leading cause of admission to hospital in Australian children and its prevalence is increasing Whether breast feeding protects against asthma or atopy , or both , is controversial Asthma is a complex disease , and the relative risks between breast feeding and asthma or atopy are unlikely to be large ; this suggests the need for investigation in a large prospect i ve birth cohort with timely assessment of atopic outcomes and all relevant exposures Exclusive breast feeding for at least 4 months is associated with a significant reduction in the risk of asthma and atopy at age 6 years and with a significant delay in the age at onset of wheezing and asthma being diagnosed by a doctor Public health interventions to promote an increased duration of exclusive breast feeding may help to reduce the morbidity and prevalence of childhood asthma  and BACKGROUND Breast-feeding clearly protects against early wheezing , but recent data suggest that it might increase later risk of atopic disease and asthma . OBJECTIVE We sought to examine the relationship between breast-feeding and later asthma and allergy outcomes by using data from the Avon Longitudinal Study of Parents and Children , a large birth cohort in the United Kingdom . METHODS We used adjusted logistic regression models to evaluate the association between breast-feeding and atopy at age 7 years , bronchial responsiveness to methacholine at age 8 years , and wheeze at ages 3 and 7 1/2 years . Bayesian methods were used to assess the possibility of bias caused by an influence of early wheezing on the duration of breast-feeding , as well as selection bias . RESULTS Breast-feeding was protective for wheeze in the first 3 years of life ( odds ratio [ OR ] of 0.80 [ 95 % CI , 0.70 - 0.90 ] for > or = 6 months relative to never ) but not wheeze ( OR , 0.98 ; 95 % CI , 0.79 - 1.22 ) , atopy ( OR , 1.12 ; 95 % CI , 0.92 - 1.35 ) , or bronchial hyperresponsiveness ( OR , 1.07 ; 95 % CI , 0.82 - 1.40 ) at ages 7 to 8 years . Bayesian models adjusting for the longer duration of breast-feeding among children with wheezing in early infancy produced virtually identical results . CONCLUSIONS We did not find consistent evidence for either a deleterious effect or a protective effect of breast-feeding on later risk of allergic disease in a large prospect i ve birth cohort of children with objective outcome measures and extensive data on potential confounders and effect modifiers . Neither reverse causation nor loss to follow-up appears to have material ly biased our results BACKGROUND Opinions and recommendations about the optimal duration of exclusive breastfeeding have been strongly divided , but few published studies have provided direct evidence on the relative risks and benefits of different breastfeeding duration s in recipient infants . OBJECTIVE We examined the effects on  infant growth and health of 3 compared with 6 mo of exclusive breastfeeding . DESIGN We conducted an observational cohort study nested within a large r and omized trial in Belarus by comparing 2862 infants exclusively breastfed for 3 mo ( with continued mixed breastfeeding through > /= 6 mo ) with 621 infants who were exclusively breastfed for > /= 6 mo .  Regression to the mean , within-cluster correlation , and cluster- and individual-level confounding variables were accounted for by using multilevel regression analyses . RESULTS From 3 to 6 mo , weight gain was slightly greater in the 3-mo group [ difference : 29 g/mo ( 95 % CI : 13 , 45 g/mo ) ] , as was length gain [ difference : 1.1 mm ( 0.5 , 1.6 mm ) ] , but the 6-mo group had a faster length gain from 9 to 12 mo [ difference : 0.9 mm/mo ( 0.3 , 1.5 mm/mo ) ] and a larger head circumference at 12 mo [ difference : 0.19 cm ( 0.07 , 0.31 cm ) ] . A significant reduction in the incidence density of gastrointestinal infection was observed during the period from 3 to 6 mo in the 6-mo group [ adjusted incidence density ratio : 0.35 ( 0.13 , 0.96 ) ] , but no significant differences in risk of respiratory infectious outcomes or atopic eczema were apparent . CONCLUSIONS Exclusive breastfeeding for 6 mo is associated with a lower risk of gastrointestinal infection and no demonstrable adverse health effects in the first year of life OBJECTIVE To estimate the prevalence of  wheezing in the chest among adults , and to explore the effect of some variables on the prevalence of this condition . METHODS This was a prospect i ve cohort study on individuals born in the city of Pelotas ( Southern Brazil ) in 1982 . A total of 4,297 subjects was traced in 2004 - 5 , representing 77.4 % of the original cohort . Data were collected by means of interviews using the ISAAC ( International Study of Asthma and Allergies in Childhood Steering Committee ) question naire . Associations between the outcome ' occurrence of wheezing in the chest within the 12 months prior to the interview ' and the variables of socioeconomic , demographic and birth characteristics were tested by means of multivariable analyses , using Poisson regression . RESULTS The prevalence of wheezing over the preceding year was 24.9 % . Among the individuals reporting wheezing , 54.6 % reported difficulty in sleeping , and 12.9 % reported difficulty in speaking due to wheezing . The prevalence of wheezing in the chest was significantly higher among women . This association was maintained in analyses adjusted for non-white skin color , family history of asthma and low socioeconomic level . Among men , there was no significant association in the analyses adjusted for skin color and family income at birth . Family histories of asthma and poverty throughout life presented significant associations with wheezing in the chest . For both sexes , there were no associations with the variables of birth weight and breastfeeding duration . CONCLUSIONS The prevalence of wheezing in the chest was high , and subjects with low family income at birth were more likely to have had wheezing in the chest over the preceding year The aim of this study was to assess the preventive effect of exclusive breast-feeding and early solid food avoidance on  atopic dermatitis ( AD ) in infancy . This study is part of a dietary clinical trial in a prospect i ve cohort of healthy term newborns at risk of atopy . It was recommended to breast-feed for at least 4 months and to avoid solid food in the same time-period . Eight hundred and sixty-five infants exclusively breast-fed , and 256 infants partially or exclusively formula-fed , were followed-up until the end of the first year following birth . AD and sensitization to milk and egg were considered as study end-points . The 1-year incidence of AD was compared between the two study groups . Adjusted odds ratios ( OR ) with 95 % confidence intervals ( CI ) were calculated by multiple logistic regression . The incidence of AD was calculated in relation to age at introduction of solid food and amount of food given . In the breast-fed group , the adjusted OR for AD was 0.47 ( 95 % CI 0.30 - 0.74 ) . The strongest risk factor was the occurrence of AD in the subject 's core family . The risk of infants with AD to be sensitized to milk was four times higher , and to egg eight times higher , than in infants without AD . Age at first introduction of solid food and diversity of solid food showed no effect on AD incidence . We conclude that in infants at atopic risk , exclusive breast-feeding for at least 4 months is effective in preventing AD in the first year of life The relationship between  breastfeeding , respiratory and other allergic disorders has been controversial . Our aim was to investigate the relationships between  breastfeeding  , respiratory outcomes , eczema and atopy at 15 months of age in a prospect i ve birth cohort in New Zeal and . A total of 1105 children were enrolled at birth , and 1011 ( 91.2 % ) were followed up at 15 months .  Logistic regression was used to model associations between  breastfeeding  duration and respiratory outcomes , eczema and atopy after adjusting for relevant confounding variables : ethnicity , socio-economic status , parity , body mass index , smoking in pregnancy , gender and respiratory infections in the first 3 months of life . Breastfeeding was associated with a significant reduction in the risk of adverse respiratory outcomes at 15 months . After adjustment for confounders , each month of exclusive breastfeeding reduced the risk of doctor-diagnosed asthma by 20 % ( odds ratio 0.80 , 95 % confidence interval 0.71 to 0.90 ) , wheezing by 12 % ( 0.88 , 0.82 to 0.94 ) and inhaler use by 14 % ( 0.86 , 0.78 to 0.93 ) . Associations for both exclusive and additional  breastfeeding duration s , and respiratory outcomes remained independently significant when modelled simultaneously . Although independently associated with all respiratory outcomes , adjusting for parental history of allergic disease or maternal history of asthma did not alter our findings . Breastfeeding was not associated with eczema or atopy at 15 months . In conclusion , there was a significant protective effect of breastfeeding on infant wheezing and other adverse respiratory outcomes that may be early indicators of asthma in New Zeal and children RATIONALE Virus-induced wheezing episodes in infancy often precede the development of asthma . Whether infections with specific viral pathogens confer differential future asthma risk is incompletely understood . OBJECTIVES To define the relationship between specific viral illnesses and early childhood asthma development . METHODS A total of 259 children were followed prospect ively from birth to 6 years of age . The etiology and timing of specific viral wheezing respiratory illnesses during early childhood were assessed using  nasal lavage , culture , and multiplex reverse transcriptase-polymerase chain reaction . The relationships of these virus-specific wheezing illnesses and other risk factors to the development of asthma were analyzed . MEASUREMENTS AND MAIN RESULTS Viral etiologies were identified in 90 % of wheezing illnesses . From birth to age 3 years , wheezing with respiratory syncytial virus ( RSV ) ( odds ratio [ OR ] , 2.6 ) , rhinovirus ( RV ) ( OR , 9.8 ) , or both RV and RSV ( OR , 10 ) was associated with increased asthma risk at age 6 years . In Year 1 , both RV wheezing ( OR , 2.8 ) and aeroallergen sensitization ( OR , 3.6 ) independently increased asthma risk at age 6 years . By age 3 years , wheezing with RV ( OR , 25.6 ) was more strongly associated with asthma at age 6 years than aeroallergen sensitization ( OR , 3.4 ) . Nearly 90 % ( 26 of 30 ) of children who wheezed with RV in Year 3 had asthma at 6 years of age . CONCLUSIONS Among outpatient viral wheezing illnesses in infancy and early childhood , those caused by RV infections are the most significant predictors of the subsequent development of  asthma  at age 6 years in a high-risk birth cohort OBJECTIVE Previous studies of predictors of atopic dermatitis have had limited sample size , small numbers of variables , or retrospective data collection . The purpose of this prospect i ve study was to investigate several perinatal predictors of atopic dermatitis occurring in the first  
    Output:
    
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 method ological quality .
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