Benign breast disease and breast cancer risk in African women: A case-control study.

Purpose: To examine the association between benign breast disease (BBD) and breast cancer (BC) in a heterogeneous population of African women.
Methods: BC cases and matched controls were enrolled in three sub-Saharan African countries, Nigeria Cameroon, and Uganda, between 1998-2018. Multivariable logistic regression was used to test the association between BBD and BC. Risk factors dually associated with BBD and BC were selected. Using a parametric mediation analysis model, we assessed if selected BC risk factors were mediated by BBD.
Results: Of 6418 participants, 55.7% (3572) were breast cancer cases. 360 (5.7%) self-reported BBD. Fibroadenoma (46.8%) was the most reported BBD. Women with a self-reported history of BBD had greater odds of developing BC than those without (adjusted odds ratio [aOR] = 1.47, 95% CI: 1.13-1.91). Biopsy-confirmed BBD was associated with BC (aOR = 3.11, 95% CI: 1.78-5.44). BBD did not significantly mediate the effects of any of the selected BC risk factors.
Conclusions: In this study, BBD was associated with BC and did not significantly mediate the effects of selected BC risk factors.
Competing Interests: Declarations Competing Interests Financial interests: Olufunmilayo I. Olopade is a co-founder of CancerIQ, sits on the advisory boards of 54gene and Tempus, and has received research funding from Ayala Pharmaceuticals, Cepheid, Color Genomics, Novartis, and Roche/Genentech. All other authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.