Title: The%20Relationship%20between%20Breast-feeding%20and%20the%20Prevalence%20of%20Asthma%20Yousuke%20Takemura,%20MD,%20PhD%20Associate%20Professor%20Dept.%20of%20Family%20and%20Community%20Medicine%20Mie%20University%20School%20of%20Medicine%20Japan
1The Relationship between Breast-feeding and the
Prevalence of AsthmaYousuke Takemura, MD,
PhDAssociate ProfessorDept. of Family and
Community MedicineMie University School of
MedicineJapan
2Yousuke Takemura, MD, PhDAssociate
ProfessorDepartment of Family and Community
MedicineMie University School of Medicine2-174
Edobashi, Tsu, Mie 514-8507JAPAN E-mail
yousuke_at_clin.medic.mie-u.ac.jp
Y. Takemura et al.
3Introduction There is growing evidence that
asthma is becoming more common in the western
countries. Because treatment of asthma is
somewhat difficult, prophylaxes have been sought.
Y. Takemura et al.
4Many risk factors for asthmaage, gender,
parental smoking, and family history of asthma
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5Many studies on the role of breast-feeding in the
prevention of childhood asthma 1. Positive
association2. No association3. Negative
association
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6Y. Takemura et al.
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8Y. Takemura et al.
9Many of these studies were based on relatively
small sample population, and did not adjust for
confounding factors sufficiently. The present
study examines the relationship between
breast-feeding and ever having asthma by
population based case-control study in Japan.
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10Materials and MethodsStudy Population33
public elementary schools (grades 1 6)15
public junior high schools (grades 1 3)25,767
subjects responded to the questionnaire among
28,848 students.(the response rate 89.3)
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11Measurementthe American Thoracic Society and
Division of Lung Diseases, National Heart, Lung,
and Blood Institute (ATS-DLD) questionnaire for
children (Japanese version) The reliability and
validity of the ATS-DLD questionnaire to identify
children with asthma has been well established.
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12Asthma yes response to all of the following
questions (1) Has your child ever had an attack
of wheezing that has caused him/her to
be short of breath? (2) Has your child
had such an attack twice or more? (3) Has
a physician ever informed you that your
child has asthma? and (4) If so, at that time,
did your child have shortness of breath
with wheezing?
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13Total 12,105 boys 11,723 girls,
aged 6 to 15 yrs
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14Feeding patterns from the age of 1 to 3
monthsbreast-feeding only, mixed, or
artificial feeding Parental smoking Having
mother or father who smoked one or more
cigarettes per day Parental history of asthma
Subjects whose mother or father had ever been
treated for asthma
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15Statistical AnalysisThe characteristics of
subjects with or without asthma the
chi-squared test or Students t-testTo control
for confounding factors such as age, gender,
parental smoking, and parental history of
asthma multiple logistic regression analysis
Dose-response relationship test of trend
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16Results
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20Discussion
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21The mechanism of the unfavorable effect of
breast-feeding on asthma1. Fat soluble
chemicals accumulating in breast milk
2. Sensitization through breast milk
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22Fat soluble chemicals in breast milk If this
mechanism is correct, children higher in the
birth order would be more likely to have asthma.
However, additional adjustment for birth order
did not affect the association between asthma and
breast feeding (adjusted odds ratio 1.212 95
percent confidence interval 1.057, 1.389 p lt
0.01).
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23Sensitization through breast milk Foreign
protein antigens can be transmitted in breast
milk. These antigens may provoke
hypersensitivity. In fact, a study showed that
this type of sensitization was seen in 10
percents of breast fed infants.
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24Advantage 1. The large number of subjects 2.
Several aspects of homogeneity 3. Adjustment
for confounding
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25Limitation(1) Parental recall
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26Limitation(2) the small number of the
reference Although the reference is prefer to
large number, we used artificial milk users as
the reference since we would like to know the
effects of any exposure to breast-milk vs none
on the prevalence of asthma.
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27Limitation(3) duration of breast-feeding
We used three months as cut-off point of
duration of breast-feeding since several studies
used three months as the criteria of the
duration.
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28Conclusion Breast-feeding in infancy might be
related to the higher prevalence of asthma during
pre-adolescence.
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29This study was published in American Journal of
Epidemiology 2001154(2)115-119.
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