TABLE 4.

ICCs and corresponding RIs for select urinary markers by time intervals between 2 collections in KSS participants¹

	HPFS (n = 698), d					NHS (n = 818), d					NHSII (n = 923), d
	Overall	1–7	8–14	15–29	≥30	Overall	1–7	8–14	15–29	≥30	Overall	1–7	8–14	15–29	≥30
n	698	379	168	102	49	818	433	210	91	84	923	403	228	152	140
ICC
Magnesium, mg/d	0.73	0.67	0.82	0.67	0.74	0.76	0.77	0.70	0.78	0.76	0.70	0.73	0.71	0.63	0.66
Residual 1	0.77	0.72	0.86	0.73	0.76	0.77	0.79	0.71	0.79	0.75	0.71	0.74	0.72	0.60	0.66
Residual 2	0.77	0.72	0.86	0.73	0.76	0.77	0.79	0.71	0.78	0.74	0.71	0.74	0.72	0.60	0.65
Phosphate, mg/d	0.58	0.55	0.62	0.58	0.65	0.58	0.56	0.62	0.55	0.55	0.56	0.58	0.50	0.63	0.53
Residual 1	0.51	0.56	0.43	0.47	0.54	0.54	0.55	0.59	0.50	0.45	0.48	0.53	0.40	0.48	0.43
Residual 2	0.52	0.57	0.42	0.48	0.53	0.55	0.55	0.59	0.51	0.45	0.47	0.53	0.40	0.47	0.44
Sulfate, mg/d	0.64	0.64	0.63	0.67	0.62	0.67	0.67	0.67	0.63	0.71	0.55	0.59	0.56	0.52	0.47
Residual 1	0.55	0.60	0.50	0.46	0.47	0.65	0.66	0.63	0.59	0.66	0.50	0.57	0.51	0.41	0.34
Residual 2	0.54	0.60	0.48	0.45	0.46	0.65	0.66	0.63	0.60	0.66	0.50	0.57	0.51	0.40	0.33
Uric acid, mg/d	0.49	0.53	0.48	0.36	0.42	0.59	0.59	0.67	0.62	0.46	0.42	0.44	0.31	0.48	0.44
Residual 1	0.48	0.52	0.43	0.44	0.37	0.55	0.53	0.66	0.61	0.38	0.32	0.34	0.27	0.30	0.36
Residual 2	0.48	0.53	0.44	0.46	0.37	0.55	0.54	0.66	0.62	0.38	0.33	0.35	0.28	0.31	0.35
Calcium, mg/d	0.79	0.79	0.80	0.80	0.71	0.82	0.85	0.80	0.80	0.75	0.74	0.75	0.73	0.76	0.72
Residual 1	0.81	0.80	0.83	0.81	0.70	0.83	0.86	0.82	0.80	0.74	0.75	0.76	0.73	0.76	0.75
Residual 2	0.81	0.81	0.84	0.81	0.67	0.83	0.86	0.82	0.80	0.73	0.76	0.77	0.75	0.77	0.76
Citrate, mg/d	0.82	0.82	0.85	0.74	0.79	0.88	0.89	0.87	0.81	0.86	0.74	0.78	0.71	0.77	0.67
Residual 1	0.86	0.88	0.86	0.81	0.81	0.89	0.91	0.88	0.83	0.87	0.78	0.82	0.76	0.80	0.69
Residual 2	0.86	0.89	0.87	0.81	0.80	0.89	0.91	0.87	0.83	0.86	0.78	0.82	0.77	0.80	0.69
Oxalate, mg/d	0.55	0.54	0.63	0.46	0.53	0.56	0.59	0.58	0.54	0.45	0.56	0.55	0.58	0.56	0.56
Residual 1	0.55	0.57	0.60	0.39	0.56	0.57	0.59	0.55	0.60	0.45	0.55	0.53	0.61	0.55	0.52
Residual 2	0.56	0.57	0.61	0.38	0.54	0.55	0.58	0.54	0.59	0.44	0.54	0.51	0.60	0.53	0.50
RI
Magnesium, mg/d	0.92	0.90	0.95	0.89	0.92	0.93	0.93	0.91	0.94	0.93	0.91	0.92	0.91	0.88	0.89
Residual 1	0.93	0.91	0.96	0.92	0.93	0.93	0.94	0.91	0.94	0.92	0.91	0.92	0.92	0.87	0.89
Residual 2	0.93	0.92	0.96	0.92	0.93	0.93	0.94	0.91	0.94	0.92	0.91	0.92	0.91	0.87	0.89
Phosphate, mg/d	0.86	0.84	0.87	0.86	0.89	0.85	0.85	0.88	0.84	0.84	0.85	0.86	0.81	0.88	0.83
Residual 1	0.82	0.85	0.78	0.80	0.84	0.84	0.84	0.86	0.82	0.79	0.81	0.83	0.76	0.81	0.78
Residual 2	0.83	0.85	0.77	0.81	0.83	0.84	0.84	0.86	0.82	0.79	0.80	0.83	0.76	0.80	0.78
Sulfate, mg/d	0.88	0.88	0.88	0.90	0.87	0.90	0.90	0.90	0.88	0.91	0.84	0.86	0.85	0.83	0.80
Residual 1	0.84	0.87	0.82	0.79	0.80	0.89	0.89	0.88	0.86	0.89	0.82	0.85	0.82	0.76	0.71
Residual 2	0.84	0.87	0.81	0.79	0.79	0.89	0.89	0.88	0.86	0.89	0.82	0.85	0.82	0.76	0.71
Uric acid, mg/d	0.81	0.83	0.81	0.73	0.77	0.86	0.86	0.89	0.87	0.79	0.77	0.78	0.69	0.81	0.78
Residual 1	0.81	0.83	0.78	0.78	0.74	0.84	0.83	0.89	0.87	0.74	0.70	0.71	0.65	0.68	0.73
Residual 2	0.81	0.83	0.78	0.79	0.74	0.84	0.84	0.89	0.87	0.74	0.70	0.72	0.66	0.69	0.72
Calcium, mg/d	0.94	0.94	0.94	0.94	0.91	0.95	0.96	0.94	0.94	0.93	0.92	0.93	0.92	0.93	0.92
Residual 1	0.95	0.94	0.95	0.94	0.91	0.95	0.96	0.95	0.94	0.92	0.93	0.93	0.92	0.93	0.93
Residual 2	0.95	0.95	0.96	0.95	0.90	0.95	0.96	0.95	0.94	0.92	0.93	0.93	0.92	0.93	0.93
Citrate, mg/d	0.95	0.95	0.96	0.92	0.94	0.97	0.97	0.96	0.95	0.96	0.92	0.94	0.91	0.93	0.89
Residual 1	0.96	0.97	0.96	0.94	0.95	0.97	0.98	0.97	0.95	0.96	0.94	0.95	0.93	0.94	0.90
Residual 2	0.96	0.97	0.96	0.95	0.94	0.97	0.98	0.97	0.95	0.96	0.94	0.95	0.93	0.94	0.90
Oxalate, mg/d	0.84	0.84	0.88	0.79	0.83	0.85	0.86	0.86	0.84	0.79	0.85	0.84	0.86	0.85	0.85
Residual 1	0.84	0.85	0.87	0.75	0.85	0.85	0.86	0.84	0.87	0.79	0.84	0.83	0.87	0.84	0.83
Residual 2	0.85	0.85	0.87	0.74	0.84	0.84	0.86	0.84	0.86	0.78	0.84	0.82	0.87	0.83	0.82

¹. Original values of urinary markers 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). HPFS, Health Professionals Follow-Up Study; ICC, intraclass correlation coefficient; KSS, Kidney Stone Study; NHS, Nurses’ Health Study; NHSII, Nurses’ Health Study II; RI, reliability index.