Role of adiposity and lipid biomarkers in postmenopausal breast cancer risk: causal mediation analysis
A causal mediation analysis based on a nationwide cohort study in South Korea evaluated the role of adiposity and lipid biomarkers in postmenopausal breast cancer risk. The analysis included data from 2,088,751 postmenopausal women who underwent national health screenings in 2009 and 2010 and were followed through 2021. During follow-up, 18,364 breast cancer cases were diagnosed. Compared with body mass index < 23 kg/m2, the HR was 1.84 (95% CI 1.72-1.97) for BMI ≥ 30 kg/m2. Compared with waist circumference ≤ 80 cm, HR was 1.45 (95% CI 1.39-1.51) for WC ≥ 88 cm. Mediation analyses showed that HDL and LDL cholesterol contributed less that 5.5%, while most of the association was explained by direct effects. The authors conclude that this study confirmed that obesity, particularly central adiposity, is a strong independent risk factor for postmenopausal breast cancer, with minimal mediation by lipid biomarkers.