INTRODUCTION: Little is known about how modifiable lifestyle factors interact with the epigenome to influence disease. Body mass index (BMI, weight kg/height m2) and physical activity are associated with @entity0 , but the mechanisms are not well-understood. We hypothesized that BMI or physical activity may modify the association between markers of global DNA methylation and @entity0 risk. METHODS: Resources from a population-based case-control study (~1300 postmenopausal @entity1 ) were used to construct logistic regression models. We explored whether the association between @entity0 and global methylation, assessed using the luminometric methylation assay (LUMA) and long interspersed elements-1 (LINE-1) methylation in white blood cell DNA, was modified by BMI or recreational physical activity (RPA). RESULTS: The @entity0 association was modified by BMI (multiplicative p=0.03) and RPA (p=0.004). @entity28 @entity1 in the highest quartile of LUMA experienced a greater than two-fold increased risk of @entity0 (BMI<25kg/m2: OR=2.16; 95% CI=1.35, 3.57 and BMI 25-29.9kg/m2: OR=2.96; 95% CI=1.69, 5.19) compared to @entity1 in the lowest LUMA quartile. Similar increases in the @entity0 association were observed among @entity1 who were physically active (moderate RPA: OR=2.62; 95% CI=1.44, 4.75 and high RPA: OR=2.62; 95% CI=1.53, 4.49). Estimates among @entity28 and inactive @entity1 were less pronounced and imprecise. Although we observed statistical interactions (p<0.05) between BMI and RPA with LINE-1, we were unable to discern any clear associations with @entity0 . CONCLUSIONS: The association between LUMA and @entity0 risk may be modified by postmenopausal body size and physical activity.

Global DNA Methylation, Measured by the Luminometric Methylation Assay (LUMA), Associates with Postmenopausal Breast Cancer in Non-Obese and Physically Active XXXX .

@entity1 :: ('9606', 'Species') :: ['women'] @entity0 :: ('MESH:D001943', 'Disease') :: ['LUMA-breast cancer', 'postmenopausal breast cancer', 'breast cancer'] @entity28 :: ('MESH:D009765', 'Disease') :: ['obese', 'Non-obese']
@entity1 :: (9606,Species) :: ['Women']
