Table 1. Participant characteristics overall and by quartile of fibroblast growth factor-23 level.

Characteristics	Overall	Quartile 1	Quartile 2	Quartile 3	Quartile 4	P trend
		(< 53 RU/ml)	(53–69 RU/ml)	(70–100 RU/ml)	(> 100 RU/ml)
Weighted N	27,994	6,860	6,971	6,897	7,266
Age (years)	65.0 (0.3)	62.1 (0.5)	64.0 (0.5)	66.4 (0.6)	67.3 (0.5)	<0.001
Male (%)	45	58	46	46	31	<0.001
Black (%)	41	46	38	45	35	<0.001
Household income < $20,000/yr (%)	16	14	11	18	21	<0.001
Education < high school (%)	12	11	10	12	16	<0.001
Coronary heart disease (%)	17	12	11	15	27	<0.001
Stroke (%)	6	4	6	4	9	<0.001
Diabetes (%)	21	17	15	22	27	<0.001
Dyslipidemia (%)	59	56	60	59	61	<0.001
Current Smoking (%)	14	12	9	14	20	<0.001
Alcohol consumption (%)						<0.001
None (0 drinks/d)	63	56	61	63	70
Moderate*	33	37	35	33	27
Heavy **	4	7	4	4	3
Physical activity frequency (%)***						<0.001
None	34	31	30	31	43
1–3 times/week	36	40	38	33	34
>4 times/week	30	29	32	36	23
UACR (mg/g)	7.1 [4.6, 14.4]	6.4 [4.2, 11.6]	6.6 [4.2, 11.4]	7.2 [4.9, 14.0]	9.3 [4.9, 25.2]	<0.001
eGFR (ml/min/1.73m2)	85.9 (0.7)	93.5 (1.1)	88.9 (1.1)	85.3 (1.2)	76.4 (1.5)	<0.001
CKD stage 3a (eGFR 45–59 ml/min/1.73 m2), %	6.1	2.2	2.9	6.6	12.2	<0.001
CKD stage 3b (eGFR 30–44 ml/min/1.73 m2), %	2.7	0.1	1.9	1.3	7.0	<0.001
CKD stage 4 (eGFR 15–29 ml/min/1.73m2), %	0.5	0	0	0.1	1.7	<0.001
CKD stage 5 (eGFR < 15 ml/min/1.73m2), %	0.3	0	0	0	1.2	<0.001

Data are given as mean (standard error), median [interquartile range] or frequencies.

Abbreviations: UACR, urinary albumin to creatinine ratio; eGFR, estimated glomerular filtration rate.

* (≤7 and 14 drinks/d for women and men, respectively)

**(>7 and 14 drinks/d for women and men, respectively)

***In answer to “How many times per week do you engage in intense physical activity, enough to work up a sweat?”