Likewise for those who started with T-scores of less than -20 , mean change of spine bone mineral density at 2 years did not differ significantly between the exemestane and anastrozole treatment groups ( 211 % , 95 % CI -084 to 506 vs 372 % , 95 % CI 154 to 589 ; p = 026 ) , nor did hip bone mineral density ( 209 % , 95 % CI -145 to 563 vs 00 % , 95 % CI -367 to 366 ; p = 028 ) .