Association between age at first oral contraceptive use and breast cancer in women-Nouakchott, Mauritania, May - October 2021

Abstract

Introduction: In Mauritania, breast cancer affects 44.9 women per 100,000 inhabitants in 2020 and is the most common cancer. In a context where two- thirds of women use oral contraceptives and nearly one-third of marriages are early, this study examines the association between the age of first use of oral contraceptives and breast cancer among women in Mauritania. Methods: A case-control study (192 cases for 192 controls) was conducted at the Nouakchott Oncology Center from 01 May 2021 to 31 October 2021. A case was defined and so was a witness. A logistic regression was performed with SAS® 9.4 software to estimate the odds ratio of breast cancer associated with age of first oral contraceptive use independent of other characteristics. Results: Half of the patients were from Nouakchott (50.5%), 41.7%, 57.8% and 85.4% were married, uneducated and housewives, respectively. The median age was similar in cases and controls. About 11% of cases and 18.7% of controls used oral contraceptives for the first time before the age of 24, and more than 64% had never used oral contraceptives. After adjusting for possible confounders, age at first oral contraceptive use (<24 years) was significantly associated with breast cancer (adjusted OR = 3.07, 95% CI 1.09-8.82; p = 0.0372) independently of other characteristics. Conclusions: The study shows that the age of first use of oral contraceptives, less than 24 years, is a risk factor for breast cancer in women followed at the Nouakchott Oncology Center. Sensitization of women on alternative contraceptive methods and early marriage is recommended.