The adjusted risk ratios for recurrent adenomas were 0.99 ( 95 % confidence interval [ CI ] , 0.89 to 1.09 ) with vitamin D versus no vitamin D , 0.95 ( 95 % CI , 0.85 to 1.06 ) with calcium versus no calcium , and 0.93 ( 95 % CI , 0.80 to 1.08 ) with both agents versus neither agent .