Abstract 146: WCRF/AICR recommendation adherence and breast cancer incidence among postmenopausal women with non-modifiable risk factors.
Authors: Oppeneer Sarah , Inoue-Choi Maki , Lazovich DeAnn , Robien Kim 
Published: August 2014

Taller height, family history of breast and ovarian cancer, younger age at menarche, and older age at menopause are non-modifiable breast cancer risk factors. In previous studies, adherence to the 2007 World Cancer Research Fund (WCRF)/ American Institute for Cancer Research (AICR) diet and physical activity recommendations were associated with lower cancer risk. We hypothesized that guideline adherence would be associated with lower breast cancer risk, and that the recommendations might be more beneficial among women with non-modifiable risk factors.

This analysis included data from 36,626 postmenopausal women in the Iowa Women's Health Study with no history of cancer at baseline. Data from the 1986 baseline questionnaire were used to create scores for the WCRF/AICR recommendations for BMI, physical activity, and intake of fruits and vegetables, fiber, alcohol, red and processed meat, sugary beverages and sodium. One point was assigned for complete adherence, 0.5 points for partial adherence and 0 points for non-adherence. Points were summed to create an overall adherence score (max. = 8). Multivariate-adjusted Cox regression was used to evaluate associations between the overall score and single recommendation adherence with breast cancer risk (n = 3189, baseline - 2010). Stratified analyses were used to evaluate whether associations differed by height (&lt;66 in./≥66 in.), family history of breast or ovarian cancer (yes/no), and ages at menarche (quartiles) and menopause (quartiles).

The mean adherence score was 5.0 (range: 0.5 - 8.0). Overall, a higher score was associated with a lower breast cancer risk (HR: 0.94, 95% CI: 0.91-0.97). Alcohol intake (HR: 0.81, 95% CI: 0.70 - 0.94) and BMI (HR: 0.79, 95% CI: 0.72 - 0.87) were the only specific recommendations significantly associated with breast cancer risk. The association between adherence score and breast cancer risk did not differ significantly across strata for any of the non-modifiable risk factors. Alcohol intake was more strongly associated with breast cancer risk in taller women (HR: 0.72, 95% CI: 0.55 - 0.93 vs. HR: 0.85, 95% CI: 0.71 - 1.03 for shorter women; pinteraction = 0.46), while a stronger association with BMI was observed in shorter women (HR: 0.75, 95% CI: 0.67 - 0.84 vs. HR: 0.86, 95% CI: 0.86 - 1.01 for taller women; pinteraction = 0.12). High physical activity was associated with lower breast cancer risk in women who where younger at menarche (HR: 0.77, 95% CI: 0.61 - 0.97 vs. HR: 1.05, 95% CI: 0.88 - 1.25 for older age at menarche; pinteraction = 0.01).

Alcohol intake &lt;10g/day and maintaining a BMI between 18.5 - 25 were most strongly associated with lower breast cancer risk among all women. The results suggest women with non-modifiable risk factors may not receive additional benefit, but that limiting alcohol intake, maintaining a healthy BMI and regular physical activity may be important recommendations for these women.

Citation Format: Sarah Oppeneer, Maki Inoue-Choi, DeAnn Lazovich, Kim Robien. WCRF/AICR recommendation adherence and breast cancer incidence among postmenopausal women with non-modifiable risk factors. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 146. doi:10.1158/1538-7445.AM2013-146