IGF1 and breast cancer: When we examined the association of 25(OH)D with breast cancer risk by IGF-1 levels at baseline, the ORs for the third tertile were 0.62 (95% CI = 0.30 to 1.28) in the below-median stratum and 0.79 (95% CI = 0.39 to 1.62) in the above-median stratum.