Figure 1From: Serum 25-hydroxyvitamin D concentrations and postmenopausal breast cancer risk: a nested case control study in the Cancer Prevention Study-II Nutrition CohortRestricted cubic spline showing the fully adjusted associations between serum 25(OH)D levels and breast cancer risk in 1032 participants in the Cancer Prevention Study-II Nutrition Cohort. The reference value is less than 36.7 nmol/L. The knots are defined by the quintile cut points for 25-hydroxyvitamin D (25(OH)D) and are 36.7, 49.8, 60.8, and 73.2.Back to article page