Table 1. Demographic and clinical characteristics of ESRD and control groups.

Characteristic	ESRD group(n = 20)	Control group(n = 20)	t value	P value*
Age(y)	37.1±8.6	38.3±6.5	−0.499	0.621
Sex#				1.000
male	15	15
female	5	5
Education(y)	12.0±2.9	12.9±3.2	−0.938	0.354
No. of cigarettes/day▴	13.5±9.2	16.7±12.6	−0.325	0.768
Duration of dialysis(mo)$	10.7±6.4	NA
MMSE score	29.2±0.8	29.5±0.8	−1.189	0.242

Unless otherwise indicated, data are mean±standard deviations.

NA = not applicable. MMSE  =  Mini-mental status examination.

^* P values are two sided.

^#For sex composition, χ² = 0.000 and ν = 1.

^▴There were two patients in the ESRD group and three persons in the control group with a history of smoking.

^$There were 17 inpatients in the ESRD group.