Novel breast cancer risk factors in Nigeria: the findings of Nigerian breast cancer risk factor study

INTRODUCTION: The potential roles of alcohol consumption and family history of breast cancer in breast cancer etiology have not been widely studied in Nigeria. Moreover, no African study has investigated the relationship between Light Exposure at Night (LEAN), interpregnancy gap, and breast cancer risk. This study investigated the association between LEAN alcohol consumption, family history of breast cancer, interpregnancy gap, and breast cancer risk among Nigerian women. METHODS: A semi-structured questionnaire was used to collect relevant data from 372 cases and 403 controls in five public hospitals in Nigeria. The participants were interviewed in person between October 2016 and May 2017. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CI). RESULTS: After adjusting for relevant confounders, frequent LEAN (OR 1.87, 95% CI: 1.09, 3.21), average interpregnancy gap (AIG) > 3 years (compared to AIG < 1.5 years) (OR 2.21, 95% CI:1.07, 4.57), having a regular history of alcohol consumption (OR 1.67, 95% CI:1.04, 2.69), and family history of breast cancer (OR 2.11, 95% CI:1.14, 3.93) and were significantly associated with an increased risk of breast cancer. CONCLUSION: We hypothesized that LEAN, longer interpregnancy gap, regular alcohol consumption, and family history of breast cancer increase the risk of breast cancer among Nigerian women.