ER niacin also significantly increased HDL apoA-I pool size ( 6,088 292 versus 5,675 305 mg ; P < 0.001 ) , and this was attributed to a lower HDL apoA-I fractional catabolic rate ( 0.33 0.01 versus 0.37 0.02 pools/d ; P < 0.005 ) , with no significant changes in HDL apoA-I production ( 20.93 0.63 versus 21.72 0.85 mg/kg per day ; P = 0.28 ) .