Mammographic Breast Density, Body Mass Index, and Risk of Breast Cancer in Korean Women Aged 75 Years and Older
Menée à partir de données de l'Assurance maladie coréenne portant sur 483 564 femmes ayant réalisé une mammographie de dépistage sur la période 2009-2014 et âgées d'au moins 75 ans, cette étude analyse l'association entre la densité mammaire, l'indice de masse corporelle et le risque de cancer du sein chez les femmes âgées
Mammographic breast density and body mass index (BMI) are strong risk factors of breast cancer, but few studies have investigated these factors in older women. This study assessed the association between breast density, BMI, and the breast cancer risk among women aged ≥75 years. We included women who underwent breast cancer screening between 2009-2014 and were followed up until 2020. Breast density was measured using Breast Imaging Reporting and Data System. BMI was classified into three groups: <23, 23–24.9, and ≥25. Cox proportional hazards models were used to estimate the association of breast density and BMI with breast cancer risk. In 483,564 women, 1,885 developed breast cancer. The 5-year incidence increased with an increase in breast density and BMI. Increase in breast density was associated with an increased breast cancer risk in all BMI categories: among women with BMI<23, those with heterogeneous/extreme density had a 2.98-fold (95% CI, 2.23–3.80) increased risk of breast cancer compared with those with entirely fatty breasts. An increase in BMI was associated with increased breast cancer risk in women with the same breast density in all density categories. When the combined associations of breast density and BMI on the risk of breast cancer were considered, women with a BMI≥25 and heterogeneous/extreme breast density had a 5.35-fold (95% CI, 4.26–6.72) increased risk of breast cancer compared with women with a BMI<23 and fatty breasts. Women aged ≥75 years, with dense breasts, regardless of BMI status, might benefit from a tailored screening strategy for early detection of breast cancer.