Childhood acute lymphoblastic leukemia and indicators of early immune stimulation: a Childhood Leukemia International Consortium study.
Am J Epidemiol
; 181(8): 549-62, 2015 Apr 15.
Article
in En
| MEDLINE
| ID: mdl-25731888
ABSTRACT
The associations between childhood acute lymphoblastic leukemia (ALL) and several proxies of early stimulation of the immune system, that is, day-care center attendance, birth order, maternally reported common infections in infancy, and breastfeeding, were investigated by using data from 11 case-control studies participating in the Childhood Leukemia International Consortium (enrollment period 1980-2010). The sample included 7,399 ALL cases and 11,181 controls aged 2-14 years. The data were collected by questionnaires administered to the parents. Pooled odds ratios and 95% confidence intervals were estimated by unconditional logistic regression adjusted for age, sex, study, maternal education, and maternal age. Day-care center attendance in the first year of life was associated with a reduced risk of ALL (odds ratio = 0.77, 95% confidence interval 0.71, 0.84), with a marked inverse trend with earlier age at start (P < 0.0001). An inverse association was also observed with breastfeeding duration of 6 months or more (odds ratio = 0.86, 95% confidence interval 0.79, 0.94). No significant relationship with a history of common infections in infancy was observed even though the odds ratio was less than 1 for more than 3 infections. The findings of this large pooled analysis reinforce the hypothesis that day-care center attendance in infancy and prolonged breastfeeding are associated with a decreased risk of ALL.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Precursor Cell Lymphoblastic Leukemia-Lymphoma
Type of study:
Observational_studies
/
Risk_factors_studies
/
Systematic_reviews
Limits:
Adolescent
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Child
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Child, preschool
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Humans
Language:
En
Journal:
Am J Epidemiol
Year:
2015
Type:
Article