BACKGROUND: There is considerable interest in the possibility of an infectious etiology for @entity1 @entity0 . Although studies have shown that certain strains of @entity19 transmit @entity5 virus via breast milk, few epidemiologic studies have addressed this topic in @entity1 . METHODS: We evaluated the relationship between having been breast-fed as an @entity1 and @entity0 risk among 8299 @entity1 who participated in a population-based, case-control study of @entity0 in @entity1 aged 50 years or more. Case @entity1 were identified through @entity5 registries in three states (Massachusetts, New Hampshire, and Wisconsin); control @entity1 were identified through statewide driver's license lists (age <65 years) or Medicare lists (ages 65-79 years). Information on epidemiologic risk factors was obtained through telephone interview. We used multiple logistic regression to assess having been breast-fed and maternal history of @entity0 in relation to @entity0 occurrence both in premenopausal @entity1 (205 case @entity1 ; 220 control @entity1 ) and in postmenopausal @entity1 (3803 case @entity1 ; 4071 control @entity1 ). RESULTS: We found no evidence that having been breast-fed @entity0 risk in either premenopausal @entity1 (odds ratio [OR] = 0.65; 95% confidence interval [CI] = 0.41-1.04) or postmenopausal @entity1 (OR = 0.95; 95% CI = 0.85-1.07). In addition, @entity0 risk was not increased by having been breast-fed by a mother who later developed @entity0 . CONCLUSION: Our results do not support the hypothesis that a transmissible agent in breast milk increases @entity0 risk. Because premenopausal @entity1 were not well represented in our study population, our findings with regard to this group may not be generalizable and should be viewed with caution.

Exposure to breast milk in infancy and adult XXXX risk.

@entity1 :: ('9606', 'Species') :: ['women', 'humans', 'human', 'infant'] @entity5 :: ('MESH:D009369', 'Disease') :: ['cancer', 'mammary tumor'] @entity19 :: ('10090', 'Species') :: ['mice'] @entity0 :: ('MESH:D001943', 'Disease') :: ['breast cancer', 'increased breast cancer']
@entity0 :: (MESH:D001943,Disease) :: ['breast cancer']
