borderline significantp = 0.054
The fully adjusted model (model 3) showed a borderline significant decreased risk of BC for optimal values of 25(OH)D (≥75 nmol/L) (HR 0.69, 95% CI 0.47–1.01, p = 0.054), and a significant decreased risk of high optimal values of 25(OH)D (≥100 nmol/L) (HR 0.35, 95% CI 0.19–0.64, p = 1.0·10 −3 ), compared to the insufficient category (50–74 nmol/L).