. 2018 Feb 8;13(3):366–374. doi: 10.2215/CJN.07400717

Table 1.

Baseline characteristics of study participants for prevalent cognitive impairment (cross-sectional) analysis by tertiles of baseline serum sodium levels

Variable	Tertile 1 (126–140 mmol/L) (n=1814)	Tertile 2 (141–142 mmol/L) (n=1818)	Tertile 3 (143–153 mmol/L) (n=1803)
Age, yr	74±6	74±6	74±6
Race (% white)^a	89	92	92
Education
High school or less	23	24	27
Some college	24	23	22
College	18	18	18
Some graduate school	11	11	11
Graduate school	25	24	23
Smoking^a
Never smoker	36	38	38
Current smoker	5	3	3
Former smoker	59	59	59
Alcohol intake, ≥12 drinks in past 12 mo^a	68	64	63
BMI category
Underweight	0.2	0.1	0.1
Normal weight	28	27	26
Overweight	51	50	52
Obese	21	23	22
Physical activity score	146±70	147±67	148±68
CKD-EPI eGFR, ml/min per 1.73 m²	76±16	75±15	75±15
Serum glucose, mg/dl^a	109±29	105±23	103±18
CVD	24	24	23
Diabetes^a	14	10	9
Hypertension^a	48	40	42
Stroke	6	5	6
COPD	11	10	11
Excellent or good health status	85	84	86
SF-12 MCS score	55.6±7.1	55.7±6.8	55.4±6.9
Thiazide diuretic use^a	17	11	10
3MS score	93±6	93±6	93±6
Trails B, time, s^a	138±62	133±57	134±58
Serum sodium, mmol/L^a	139±2 139; (138, 140)	142±1; 142 (141, 142)	144±1; 144 (143, 145)

Data are mean±SD, median (interquartile range), or %. Serum glucose is missing for n=141, thiazide diuretic use is missing for n=211, and Trails B time is missing for n=53. P values are comparisons across tertiles made using a chi-squared test for categoric data and ANOVA for continuous variables. BMI, body-mass index; CKD-EPI, Chronic Kidney Disease Epidemiology Collaboration; CVD, cardiovascular disease; COPD, chronic obstructive pulmonary disease; SF-12 MCS score, Medical Outcomes Study 12-Item Short Form Mental Health Composite Score (health-related quality of life); 3MS, modified Mini-Mental Status examination; Trails B, Trail Making Test Part B.

P<0.05 across tertiles by chi-squared test for categoric data and ANOVA for continuous variables.