Mammographic Breast Density, Body Mass Index, Menopausal Status, and Breast Cancer Risk
Menée à partir de données coréennes portant sur 7 millions de femmes âgées d'au moins 40 ans et ayant réalisé un dépistage mammographique entre 2009 et 2013, cette étude analyse, en fonction du statut ménopausique, l'association entre la densité mammaire, l'indice de masse corporelle et le risque de cancer du sein (65 282 cas)
Elevated breast density and overweight or obesity are well-established risk factors for breast cancer in both premenopausal and postmenopausal women. Breast density represents the amount of fibroglandular (dense) tissue relative to fatty (nondense) tissue on a mammogram. Furthermore, breast density and body mass index (BMI) are inversely related and act as confounders to each other’s effects. In the study by Tran et al, the authors sought to better elucidate the interactions between breast density and BMI in breast cancer risk using a population of millions of Korean women aged 40 years or older, who underwent mammography screening between 2009 and 2013. Tran and colleagues reported that breast density was an independent risk factor for breast cancer for premenopausal and postmenopausal women, but obesity was only associated with breast cancer risk in postmenopausal women. Moreover, when compared with underweight women categorized as Breast Imaging Reporting and Data System (BI-RADS) category 1 (breasts almost entirely fat), obese women with very dense breasts (BI-RADS category 4) showed the highest risk of breast cancer, with a 2-fold increase in risk for premenopausal women and a 6-fold increase for postmenopausal women. Furthermore, interactions in both the additive and multiplicative scales were considered, with the authors reporting a small or nonsignificant multiplicative interaction between BMI and breast density on breast cancer risk, but a positive additive interaction in both premenopausal and postmenopausal women. A positive additive interaction means that the combined effect size of the 2 risk factors is greater than the sum of each risk factor independently. Considering that additive interactions use the absolute risk they are more relevant for public health and clinical decision-making.
JAMA Network Open , éditorial en libre accès, 2020