Abstract PD12-04: PD12-04 Impact of Race and Body Mass Index on Breast Cancer Diagnoses
Authors: Chung Victoria , Maini Ruby , Cattie Rabia , Olet Susan , Sheen Melanie 
Published: March 2023

Background Breast cancer (BC) is the most common cancer among women and the second most common cause of cancer-related mortality among women. Much attention has been paid to factors that increase the risk of developing BC. Among these are weight, typically defined by body mass index (BMI), and race. Elevated BMI has not only been shown to increase the risk of BC in some patients but has also been associated with increased rates of hormone receptor (HR) positive BC, particularly among postmenopausal patients. In premenopausal patients, an inverse relationship has been established between obesity and BC. In fact, a 2008 meta-analysis of obesity and malignancy evaluated almost 8,000 cases of premenopausal BC and showed a BC risk reduction of 8% for every 5 kg/m2. However, this study was not inclusive of African American (AA) patients. AA women are more likely to be obese than any other racial group in the US. They are also at higher risk of aggressive breast cancers, and at an earlier age. We sought to evaluate the relative risk of breast cancer diagnosis among obese vs nonobese patients of different races, as well as the rate of HR positivity in patients diagnosed with BC.

Methods BMI, age, and self-declared race were collected from the electronic health record for all female patients presenting to our health system located in Louisiana and Mississippi between 2012 and 2022. This same data was collected for female patients who were diagnosed with BC in the same time period (n=9123), as well as HR positivity vs HR negativity. Patients less than 50 years old were considered premenopausal, and patients greater than 50 years old were considered postmenopausal. BMI greater than 30 was used to define obesity. The relative risk of BC was calculated for demographic groups according to premenopausal or postmenopausal status, White or Black/African American race, and BMI less than or greater than 30. The relative risk of HR positive BC was calculated among the same demographic groups.

Discussion Data collected across the largest health system in Louisiana and Mississippi shows that a higher BMI is linked to an increased risk of BC, regardless of age or race. This was seen across both stratifications and was statistically significant except in postmenopausal AA women. This is contrary to what is frequently published in the literature that premenopausal obesity is protective against BC. Additionally, this data demonstrates that there is not a link between obesity and HR+ BC. This data did show that obesity in younger white patients may be protective against HR+ BC, which is aligned with prior research.

Conclusion The association between obesity and BC incidence has been well-described in the literature, primarily in the postmenopausal setting. This large, retrospective analysis confirms that association, but also shows a strong association in premenopausal patients. Unlike other studies, this review did not show an association between obesity and HR positivity, and additionally did not show significant differences between AA patients and White patients. This provides needed insight into the inequities faced by AA women with BC. Further studies should be done to evaluate the association of socioeconomic status with BC subtypes.

Table 1: Breast cancer cases (5/1/2012-5/1/2022) among women by BMI, age group, and race

Table 2: Hormone receptor positivity (5/1/2012-5/1/2022) among women with breast cancer by BMI, age group, and race

Citation Format: Victoria Chung, Ruby Maini, Rabia Cattie, Susan Olet, Melanie Sheen. PD12-04 Impact of Race and Body Mass Index on Breast Cancer Diagnoses [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD12-04.