Association between treatment of diabetes and breast cancer in 30-79 years old women from metropolitan area of San Juan, Puerto Rico

Background and Objectives: Breast cancer (BC) and diabetes are two of the most prevalent chronic diseases affecting Puerto Rican women. They both cause a worldwide burden in quality of life and productivity on affected women. Recent studies have been pointing the possible relationship between a frequently used diabetic control drug “metformin®” and BC risk modification. Our aim was to evaluate the relationship between BC and metformin® in 30-79 years old women from San Juan, PR. Methods:Case-control study was conducted using type 2 diabetic women fromthe study Epidemiology of breast cancer in Puerto Rico(Atabey). A telephone interview was performed to assess exposure to metformin®. BC risk factors variables were obtain from Atabey database. Logistic regression analysis was performed to determine factors associated with BC risk.Results: Significant difference by BC diagnosis was observed for the use of hormone replacement therapy (P=0.07).Results from the unadjusted logistic regression analysis suggeststhe possibility of been diagnosed with BC in women who didn’t use “metformin®”is 6.0% (POR: 1.06, 95% CI: 0.18-5.97) the possibility in women that were using “metformin®”. When stratified by age we found adecrease riskin women older than 64y/o using metformin® (OR: 0.83, IC95%:0.071- 10.34).Conclusions:Our study suggests that metformin® is protective for BC in women older than 64 y/o. The magnitude of the association and the lack of statistical significance may be explained by our greatest limitation, the small sample size. Future studies to further assess the association between metformin® and BC are needed. Aknowledgments: The content is solely the responsibility of the authors.