Assessment of potential risk factors for breast cancer in a population in Southern Brazil

The aim of this study is to assess potential risk factors for breast cancer in a population in Southern Brazil and build a multivariate logistic model using these factors for breast cancer risk prediction.

A total of 4242 women between 40 and 69 years of age without a history of breast cancer were selected at primary healthcare facilities in Porto Alegre and submitted to mammographic screening. They were evaluated for potential risk factors.

In all, 73 participants among the 4242 women had a breast cancer diagnosis during the follow-up of the project (10 years). The multivariate analysis considering all the patients aged 40–69 years showed that older age (OR 1.08, 95% CI 1.04–1.12), higher height (OR 1.04, 95% CI 1.01–1.09), and history of previous breast biopsy (OR 2.66, 95% CI 1.38–5.13) were associated with the development of breast cancer. Conversely, the number of pregnancies (OR 0.87, 95% CI 0.78–0.98) and use of hormone replacement therapy (OR 0.39, 95% CI 0.20–0.75) were considered a protective factor. Additionally, we performed an analysis separating the participants into groups of 40–49 and 50–69 years old, since a risk factor could have a specific behavior in these age groups. No additional risk factors were identified within these age brackets, and some factors lost statistical significance.

The risk prediction model indicates that the following variables should be assessed in this specific population: age, height, having had previous breast biopsies, number of pregnancies, and use of hormone replacement therapy. These findings may help to better understand the causal model of breast cancer in Southern Brazil.