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.


METHODS
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.


CONCLUSIONS
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.
Kull
Inger
I
Institute of Environmental Medicine, Karolinska Institutet, SE-171 76 Stockholm, Sweden. inger.kull@ki.se
Melen
Erik
E
Alm
Johan
J
Hallberg
Jenny
J
Svartengren
Magnus
M
van Hage
Marianne
M
Pershagen
Göran
G
Wickman
Magnus
M
Bergström
Anna
A
D000485:Allergens / Q000009:adverse effects / Q000276:immunology; D001249:Asthma / Q000453:epidemiology / Q000517:prevention & control*; D001942:Breast Feeding; D002648:Child; D002675:Child, Preschool; D005260:Female; D005512:Food Hypersensitivity / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology* / Q000209:etiology; D007073:Immunoglobulin E / Q000097:blood; D015994:Incidence; D007223:Infant; D019570:Inhalation Exposure; D008297:Male; D012129:Respiratory Function Tests; D011795:Surveys and Questionnaires
D000485:Allergens; D007073:Immunoglobulin E