The adjusted odds ratios for IFG for green tea consumption of < 1 , 1-15 , 16-30 , and > 30 cups per week were 1.0 ( reference ) , 0.42 ( 95 % confidence intervals ( CI ) 0.27-0 .65 ) , 0.23 ( 95 % CI , 0.12-0 .46 ) , and 0.41 ( 95 % CI , 0.17-0 .93 ) , respectively .