human
***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: Only limited data are available about the incidence of asthma  based on longitudinal prospect i ve studies . Further , the results from different studies on incidence vary considerably depending on the age composition of the cohorts under study , the used methods and the criteria for disease . Also among adults high incidence rates have been reported during recent years . The aim of this study was to examine to what extent the incidence of physician-diagnosed asthma could be explained by a real incidence of the disease , and to what extend by an increased diagnostic activity or altered diagnostic praxis . Another aim was to study risk factors for asthma based on incident cases . Three cross-sectional surveys have been performed in the same population sample living in the northern-most province of Sweden , Norrbotten . The first survey was performed in 1986 , and 5698 subjects , 86 % of those invited , responded to a postal question naire . Of these , 4754 subjects ( 83 % ) participated at the third survey in 1996 . After exclusion of all subjects who had reported that they had asthma in 1986 , or had been classified as having asthma in 1986 , 68 men and 98 women ( P=0.02 ) reported in 1996 that they had been diagnosed as having asthma by a physician . Thus , the cumulative incidence for the 10-year period was 3.2 % among men and 4.5 % among women . After correction for subjects who already in 1986 had reported symptoms common in asthma , or had been classified as having chronic bronchitis , 97 subjects with incident asthma remained , which corresponded to an annual incidence rate among men of 1.7 and among women of 2.9/1000 persons year(-1 ) ( P=0.1 ) . Clinical examinations confirmed asthma in a large majority of these 97 subjects . Significant risk factors were family history of asthma , both ex- and current smoking , and female sex . The socio-economic groups manual workers and assistant non-manual employees were associated with incident asthma , although not significantly . The increasing prevalence of asthma among adults during recent 10 - 20 years may to a considerable extent be explained by an increased diagnostic activity or altered diagnostic praxis . Use of different methods when measuring incidence may in part explain the extremely diverging incidence rates of asthma found in different studies 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 The majority of cross-sectional studies have shown a higher prevalence of ventilatory impairment in welders while only few longitudinal studies were able to detect chronic effects on spirometry or bronchial responsiveness . The aim of the study was to determine the incidence of probable occupational asthma ( OA ) , bronchial obstruction and hyperresponsiveness among 286 students entering an apprenticeship programme in the welding profession . This epidemiological prospect i ve cohort study consisted of a baseline assessment survey and two follow-up assessment s. A respiratory symptom question naire was administered at each visit . Spirometry and methacholine bronchial challenge test results , conducted once prior to onset of exposure and later after an average of 15 months of apprenticeship , were available for 194 subjects . The incidence of probable OA was ∼3 % ( 6 of 194 ) . The incidence of bronchial hyperresponsiveness , defined as a ≥3.2‐fold decrease in the provocative concentration causing a 20 % fall in the forced expiratory volume in one second from baseline to the end of the study was 11.9 % . A statistically significant difference was found between the baseline and end of study for the lung function values . In particular , the forced expiratory volume per cent predicted had significantly dropped by 8.4 % on average . The significance of these early pulmonary function changes in relation to possible chronic effects of exposure to welding fumes and gases remains to be explored OBJECTIVE To study the occurrence of bronchial obstructive symptoms and immunoglobulin ( Ig ) E antibodies after respiratory syncytial virus ( RSV ) bronchiolitis in infancy . Previous studies of this subject have mostly been retrospective or without controls , or the controls have not been followed prospect ively . DESIGN This was a prospect i ve cohort study with matched controls . PARTICIPANTS Forty-seven infants had experienced RSV bronchiolitis severe enough to cause hospitalization at a mean age of 3 1/2 months . For each child with RSV infection , two controls were acquired from the local Child Health Center and matched for date of birth , sex , and residence . Only one control was obtained for one RSV child , and the control group thus contained 93 children . METHODS All the children underwent two follow-up examinations , the first one at a mean age of 1 year and the second at a mean age of 3 years . At the first follow-up , a  skin-prick test against egg white  was performed , and serum  IgG antibodies  against RSV were measured . At the second follow-up , serum IgE antibodies  were measured using screening tests for common food and inhalant antibodies , and  skin-prick tests against egg white , cat , birch , and mite allergen were performed . Hereditary and environmental factors ( passive smoking , indoor furred animals ) and duration of breast-feeding were recorded . RESULTS At the first follow-up , 89 % in the RSV group and 27 % in the control group had IgG antibodies against RSV ( P < .001 ) . At the second follow-up , asthma , defined as three episodes of bronchial obstruction verified by a physician , was found in 11 of 47 children ( 23 % ) in the RSV group and in 1 of 93 children ( 1 % ) in the control group ( P < .001 ) . A positive test for IgE antibodies was noted in 14 of 44 ( 32 % ) RSV children and in 8 of 92 ( 9 % ) children in the control group ( P = .002 ) . An analysis of risk factors for the development of asthma and IgE antibodies on the whole group of 140 children showed that RSV bronchiolitis was the most important risk factor , and a family history of atopy or asthma further increased the risk . CONCLUSIONS Respiratory syncytial virus bronchiolitis during the first year of life apparently is an important risk factor for the development of asthma and sensitization to common allergens during the subsequent 2 years , particularly in children with hereditary for atopy/asthma Abstract Objective : To describe the incidence and prognosis of wheezing illness from birth to age 33 and the relation of incidence to perinatal , medical , social , environmental , and lifestyle factors . Design : Prospect i ve longitudinal study . Setting : Engl and , Scotl and , and Wales . Subjects : 18 559 people born on 3 - 9 March 1958 . 5801 ( 31 % ) contributed information at ages 7 , 11 , 16 , 23 , and 33 years . Attrition bias was evaluated using information on 14 571 ( 79 % ) subjects . Main outcome measure : History of asthma , wheezy bronchitis , or wheezing obtained from interview with subjects ' parents at ages 7 , 11 , and 16 and reported at interview by subjects at ages 23 and 33 . Results : The cumulative incidence of wheezing illness was 18 % by age 7 , 24 % by age 16 , and 43 % by age 33 . Incidence during childhood was strongly and independently associated with pneumonia , hay fever , and eczema . There were weaker independent associations with male sex , third trimester antepartum haemorrhage , whooping cough , recurrent abdominal pain , and migraine . Incidence from age 17 to 33 was associated strongly with active cigarette smoking and a history of hay fever . There were weaker independent associations with female sex , maternal albuminuria during pregnancy , and histories of eczema and migraine . Maternal smoking during pregnancy was weakly and inconsistently related to childhood wheezing but was a stronger and significant independent predictor of incidence after age 16 . Among 880 subjects who developed asthma or wheezy bronchitis  from birth to age 7 , 50 % had attacks in the previous year at age 7 ; 18 % at 11 , 10 % at 16 , 10 % at 23 , and 27 % at 33 . Relapse at 33 after prolonged remission of childhood wheezing was more common among current smokers and atopic subjects . Conclusion : Atopy and active cigarette smoking are major influences on the incidence and recurrence of wheezing during adulthood . Key messages Incidence of wheezing illness at all ages was strongly and consistently related to a history of hay fever or eczema ( atopy ) . Associations with maternal smoking during pregnancy , abdominal pain , and migraine were largely confined to those without atopy Active smoking was a powerful and potentially avoidable risk factor for wheeze starting in adult life among both atopic and non-atopic subjects A quarter of the children with a history of asthma or wheezy bronchitis by age 7 reported wheeze in the past year at age 33 Recurrence of wheezing after prolonged remis- sion during late adolescence was strongly associ- ated with atopy and cigarette smoking We conducted a prospect i ve study of a cohort of 3091 nonsmokers , ages 27 to 87 years , to evaluate the association between long-term ambient ozone exposure and  development of adult-onset asthma .  Over a 15-year period , 3.2 % of males and 4.3 % of females reported new doctor diagnoses of asthma .  For males , we observed a significant relationship between report of doctor diagnosis of asthma and 20-year mean 8-h average ambient ozone concentration  ( relative risk (RR)=2.09 for a 27 ppb increase in ozone concentration , 95 % CI=1.03 to 4.16 ) . We observed no such relationship for females . Other variables significantly related to development of asthma were a history of ever-smoking for males ( RR=2.37 , 95 % CI=1.13 to 4.81 ) , and for females , number of years worked with a smoker ( RR=1.21 for a 7-year increment , 95 % CI=1.04 to 1.39 ) , age ( RR=0.61 for a 16-year increment , 95 % CI=0.44 to 0.84 ) , and a history of childhood pneumonia or bronchitis ( RR=2.96 , 95 % CI=1.68 to 5.03 ) . Addition of other pollutants ( PM10 , SO4 , NO2 , and SO2 ) to the models did not diminish the relationship between ozone and asthma for males . These data suggest that long-term exposure to ambient ozone is associated with development of asthma in adult males STUDY OBJECTIVES To examine the prevalence of asthma and hay fever  , and the incidence and temporal relationships of asthma , hay fever , and chronic bron 
    Output:
    
agent
***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: Only limited data are available about the incidence of asthma  based on longitudinal prospect i ve studies . Further , the results from different studies on incidence vary considerably depending on the age composition of the cohorts under study , the used methods and the criteria for disease . Also among adults high incidence rates have been reported during recent years . The aim of this study was to examine to what extent the incidence of physician-diagnosed asthma could be explained by a real incidence of the disease , and to what extend by an increased diagnostic activity or altered diagnostic praxis . Another aim was to study risk factors for asthma based on incident cases . Three cross-sectional surveys have been performed in the same population sample living in the northern-most province of Sweden , Norrbotten . The first survey was performed in 1986 , and 5698 subjects , 86 % of those invited , responded to a postal question naire . Of these , 4754 subjects ( 83 % ) participated at the third survey in 1996 . After exclusion of all subjects who had reported that they had asthma in 1986 , or had been classified as having asthma in 1986 , 68 men and 98 women ( P=0.02 ) reported in 1996 that they had been diagnosed as having asthma by a physician . Thus , the cumulative incidence for the 10-year period was 3.2 % among men and 4.5 % among women . After correction for subjects who already in 1986 had reported symptoms common in asthma , or had been classified as having chronic bronchitis , 97 subjects with incident asthma remained , which corresponded to an annual incidence rate among men of 1.7 and among women of 2.9/1000 persons year(-1 ) ( P=0.1 ) . Clinical examinations confirmed asthma in a large majority of these 97 subjects . Significant risk factors were family history of asthma , both ex- and current smoking , and female sex . The socio-economic groups manual workers and assistant non-manual employees were associated with incident asthma , although not significantly . The increasing prevalence of asthma among adults during recent 10 - 20 years may to a considerable extent be explained by an increased diagnostic activity or altered diagnostic praxis . Use of different methods when measuring incidence may in part explain the extremely diverging incidence rates of asthma found in different studies 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 The majority of cross-sectional studies have shown a higher prevalence of ventilatory impairment in welders while only few longitudinal studies were able to detect chronic effects on spirometry or bronchial responsiveness . The aim of the study was to determine the incidence of probable occupational asthma ( OA ) , bronchial obstruction and hyperresponsiveness among 286 students entering an apprenticeship programme in the welding profession . This epidemiological prospect i ve cohort study consisted of a baseline assessment survey and two follow-up assessment s. A respiratory symptom question naire was administered at each visit . Spirometry and methacholine bronchial challenge test results , conducted once prior to onset of exposure and later after an average of 15 months of apprenticeship , were available for 194 subjects . The incidence of probable OA was ∼3 % ( 6 of 194 ) . The incidence of bronchial hyperresponsiveness , defined as a ≥3.2‐fold decrease in the provocative concentration causing a 20 % fall in the forced expiratory volume in one second from baseline to the end of the study was 11.9 % . A statistically significant difference was found between the baseline and end of study for the lung function values . In particular , the forced expiratory volume per cent predicted had significantly dropped by 8.4 % on average . The significance of these early pulmonary function changes in relation to possible chronic effects of exposure to welding fumes and gases remains to be explored OBJECTIVE To study the occurrence of bronchial obstructive symptoms and immunoglobulin ( Ig ) E antibodies after respiratory syncytial virus ( RSV ) bronchiolitis in infancy . Previous studies of this subject have mostly been retrospective or without controls , or the controls have not been followed prospect ively . DESIGN This was a prospect i ve cohort study with matched controls . PARTICIPANTS Forty-seven infants had experienced RSV bronchiolitis severe enough to cause hospitalization at a mean age of 3 1/2 months . For each child with RSV infection , two controls were acquired from the local Child Health Center and matched for date of birth , sex , and residence . Only one control was obtained for one RSV child , and the control group thus contained 93 children . METHODS All the children underwent two follow-up examinations , the first one at a mean age of 1 year and the second at a mean age of 3 years . At the first follow-up , a  skin-prick test against egg white  was performed , and serum  IgG antibodies  against RSV were measured . At the second follow-up , serum IgE antibodies  were measured using screening tests for common food and inhalant antibodies , and  skin-prick tests against egg white , cat , birch , and mite allergen were performed . Hereditary and environmental factors ( passive smoking , indoor furred animals ) and duration of breast-feeding were recorded . RESULTS At the first follow-up , 89 % in the RSV group and 27 % in the control group had IgG antibodies against RSV ( P < .001 ) . At the second follow-up , asthma , defined as three episodes of bronchial obstruction verified by a physician , was found in 11 of 47 children ( 23 % ) in the RSV group and in 1 of 93 children ( 1 % ) in the control group ( P < .001 ) . A positive test for IgE antibodies was noted in 14 of 44 ( 32 % ) RSV children and in 8 of 92 ( 9 % ) children in the control group ( P = .002 ) . An analysis of risk factors for the development of asthma and IgE antibodies on the whole group of 140 children showed that RSV bronchiolitis was the most important risk factor , and a family history of atopy or asthma further increased the risk . CONCLUSIONS Respiratory syncytial virus bronchiolitis during the first year of life apparently is an important risk factor for the development of asthma and sensitization to common allergens during the subsequent 2 years , particularly in children with hereditary for atopy/asthma Abstract Objective : To describe the incidence and prognosis of wheezing illness from birth to age 33 and the relation of incidence to perinatal , medical , social , environmental , and lifestyle factors . Design : Prospect i ve longitudinal study . Setting : Engl and , Scotl and , and Wales . Subjects : 18 559 people born on 3 - 9 March 1958 . 5801 ( 31 % ) contributed information at ages 7 , 11 , 16 , 23 , and 33 years . Attrition bias was evaluated using information on 14 571 ( 79 % ) subjects . Main outcome measure : History of asthma , wheezy bronchitis , or wheezing obtained from interview with subjects ' parents at ages 7 , 11 , and 16 and reported at interview by subjects at ages 23 and 33 . Results : The cumulative incidence of wheezing illness was 18 % by age 7 , 24 % by age 16 , and 43 % by age 33 . Incidence during childhood was strongly and independently associated with pneumonia , hay fever , and eczema . There were weaker independent associations with male sex , third trimester antepartum haemorrhage , whooping cough , recurrent abdominal pain , and migraine . Incidence from age 17 to 33 was associated strongly with active cigarette smoking and a history of hay fever . There were weaker independent associations with female sex , maternal albuminuria during pregnancy , and histories of eczema and migraine . Maternal smoking during pregnancy was weakly and inconsistently related to childhood wheezing but was a stronger and significant independent predictor of incidence after age 16 . Among 880 subjects who developed asthma or wheezy bronchitis  from birth to age 7 , 50 % had attacks in the previous year at age 7 ; 18 % at 11 , 10 % at 16 , 10 % at 23 , and 27 % at 33 . Relapse at 33 after prolonged remission of childhood wheezing was more common among current smokers and atopic subjects . Conclusion : Atopy and active cigarette smoking are major influences on the incidence and recurrence of wheezing during adulthood . Key messages Incidence of wheezing illness at all ages was strongly and consistently related to a history of hay fever or eczema ( atopy ) . Associations with maternal smoking during pregnancy , abdominal pain , and migraine were largely confined to those without atopy Active smoking was a powerful and potentially avoidable risk factor for wheeze starting in adult life among both atopic and non-atopic subjects A quarter of the children with a history of asthma or wheezy bronchitis by age 7 reported wheeze in the past year at age 33 Recurrence of wheezing after prolonged remis- sion during late adolescence was strongly associ- ated with atopy and cigarette smoking We conducted a prospect i ve study of a cohort of 3091 nonsmokers , ages 27 to 87 years , to evaluate the association between long-term ambient ozone exposure and  development of adult-onset asthma .  Over a 15-year period , 3.2 % of males and 4.3 % of females reported new doctor diagnoses of asthma .  For males , we observed a significant relationship between report of doctor diagnosis of asthma and 20-year mean 8-h average ambient ozone concentration  ( relative risk (RR)=2.09 for a 27 ppb increase in ozone concentration , 95 % CI=1.03 to 4.16 ) . We observed no such relationship for females . Other variables significantly related to development of asthma were a history of ever-smoking for males ( RR=2.37 , 95 % CI=1.13 to 4.81 ) , and for females , number of years worked with a smoker ( RR=1.21 for a 7-year increment , 95 % CI=1.04 to 1.39 ) , age ( RR=0.61 for a 16-year increment , 95 % CI=0.44 to 0.84 ) , and a history of childhood pneumonia or bronchitis ( RR=2.96 , 95 % CI=1.68 to 5.03 ) . Addition of other pollutants ( PM10 , SO4 , NO2 , and SO2 ) to the models did not diminish the relationship between ozone and asthma for males . These data suggest that long-term exposure to ambient ozone is associated with development of asthma in adult males STUDY OBJECTIVES To examine the prevalence of asthma and hay fever  , and the incidence and temporal relationships of asthma , hay fever , and chronic bron 
    Output:
    