The most common adverse event reported was arthralgia ( stratum I : 94 placebo and 114 anastrozole ; stratum II : 39 placebo/placebo , 25 placebo/risedronate , 34 anastrozole/placebo , and 34 anastrozole/risedronate ; stratum III : 21 placebo/risedronate , 17 anastrozole/risedronate ) .