TABLE 2.

ICCs and corresponding RIs for sodium and potassium in WLVS participants¹

	NHS (n = 336), draws									NHSII (n = 406), draws
	All	1 and 2	2 and 3	3 and 4	1 and 4	1–3	1, 2, and 4	1, 3, and 4	2–4	All	1 and 2	2 and 3	3 and 4	1 and 4	1–3	1, 2, and 4	1, 3, and 4	2–4
ICC
Volume, L/d	0.63	0.61	0.63	0.67	0.63	0.62	0.63	0.64	0.65	0.68	0.67	0.72	0.70	0.69	0.69	0.68	0.67	0.70
Creatinine, mg/d	0.48	0.48	0.51	0.42	0.43	0.49	0.48	0.45	0.49	0.53	0.43	0.59	0.58	0.61	0.50	0.52	0.54	0.59
Sodium, mg/d	0.32	0.23	0.36	0.36	0.26	0.31	0.28	0.33	0.36	0.34	0.27	0.40	0.37	0.38	0.30	0.34	0.32	0.39
Residual 1	0.29	0.20	0.32	0.31	0.27	0.28	0.25	0.31	0.31	0.27	0.26	0.31	0.27	0.28	0.24	0.29	0.22	0.31
Residual 2	0.28	0.20	0.31	0.31	0.25	0.27	0.24	0.30	0.31	0.26	0.25	0.31	0.26	0.27	0.23	0.28	0.20	0.30
Residual 3	0.28	0.19	0.31	0.31	0.25	0.27	0.24	0.30	0.30	0.26	0.25	0.31	0.26	0.27	0.23	0.28	0.20	0.30
Potassium, mg/d	0.48	0.49	0.48	0.46	0.42	0.49	0.48	0.46	0.49	0.49	0.45	0.54	0.51	0.51	0.48	0.49	0.48	0.52
Residual 1	0.52	0.50	0.51	0.54	0.48	0.51	0.51	0.51	0.53	0.53	0.52	0.57	0.53	0.55	0.54	0.54	0.52	0.55
Residual 2	0.51	0.50	0.50	0.54	0.48	0.50	0.51	0.50	0.53	0.51	0.51	0.54	0.51	0.53	0.52	0.52	0.50	0.52
Residual 3	0.51	0.50	0.50	0.54	0.47	0.50	0.51	0.50	0.53	0.51	0.51	0.54	0.51	0.53	0.52	0.52	0.50	0.52
RI
Sodium, mg/d	0.81	0.61	0.73	0.73	0.64	0.76	0.73	0.77	0.79	0.82	0.65	0.76	0.73	0.74	0.75	0.78	0.77	0.81
Residual 1	0.79	0.58	0.69	0.69	0.65	0.73	0.71	0.76	0.76	0.77	0.64	0.69	0.65	0.66	0.69	0.74	0.67	0.75
Residual 2	0.78	0.57	0.69	0.69	0.64	0.73	0.70	0.75	0.75	0.76	0.63	0.69	0.64	0.65	0.68	0.74	0.66	0.75
Residual 3	0.78	0.57	0.69	0.68	0.63	0.72	0.70	0.75	0.75	0.76	0.63	0.69	0.64	0.65	0.68	0.74	0.66	0.75
Potassium, mg/d	0.89	0.81	0.81	0.79	0.77	0.86	0.86	0.85	0.86	0.89	0.79	0.84	0.82	0.82	0.86	0.86	0.86	0.88
Residual 1	0.90	0.82	0.82	0.84	0.80	0.87	0.87	0.87	0.88	0.91	0.83	0.85	0.83	0.84	0.88	0.88	0.88	0.89
Residual 2	0.90	0.81	0.82	0.84	0.80	0.87	0.87	0.87	0.88	0.90	0.82	0.84	0.82	0.83	0.87	0.87	0.87	0.88
Residual 3	0.90	0.81	0.82	0.84	0.80	0.87	0.87	0.87	0.88	0.90	0.82	0.84	0.82	0.83	0.87	0.87	0.87	0.88

¹. Original values of urinary markers and total volumes were log transformed to improve normality. Residual 1 was adjusted for the urinary excretion of creatinine (milligrams per day). Residual 2 was adjusted as for residual 1 and for body weight (kilograms), height (meters), total calories (kilocalories), and total physical activities (metabolic equivalent task hours per week). Residual 3 was adjusted as for residual 2 and for total energy expenditure measured with the use of doubly labeled water (kilocalories per day). ICC, intraclass correlation coefficient; NHS, Nurses’ Health Study; NHSII, Nurses’ Health Study II; RI, reliability index; WLVS, Women’s Lifestyle Validation Study.