No relation was observed between breast density and the occurrence of a LRR [ hazards ratio ( HR ) 0.87 , 95 % CI 0.45-1 .68 , p = 0.67 ] , a DR ( HR 1.02 , 95 % CI 0.77-1 .35 , p = 0.90 ) , or CBC ( HR 1.31 , 95 % CI 0.63-2 .72 , p = 0.48 ) .