Table 2.

Subjects' Anthropomorphic, Laboratory, and Dietary Characteristics

Characteristics	Screening	Study 1	Study 2	Study 3
Anthropomorphic characteristics
Age, years	58 ± 7	—	—	—
Race	17 Caucasian	—	—	—
	2 Black
	2 Hispanic
Body mass index, kg/m2	—	29 ± 5	29 ± 5	29 ± 5
Laboratory characteristics
25(OH)D, ng/mL	—	28 ± 13	36 ± 18	35 ± 16
1,25(OH)2D3, pg/dL	—	47 ± 26	53 ± 24	60 ±18
PTH, pg/mL	—	49 ± 24	50 ± 22	49 ± 20
Serum calcium, mg/dL	—	9.1 ± 0.4	9.2 ± 0.3	9.2 ± 0.4
Serum creatinine, mg/dL	—	0.8 ± 0.1	0.8 ± 0.1	0.8 ± 0.1
Urine calcium, mg/24 h	—	153 ± 67	152 ± 64	146 ± 46
Dietary habits
Kilocaloriesa	2200 ± 340	2100 ± 310	2100 ± 320	2100 ± 300
Calcium, mg	1400 ± 650	1400 ± 650	1400 ± 650	1400 ± 650
Carbohydrates, gb	270 ± 60	250 ± 50	250 ± 50	250 ± 50
Protein, g	88 ± 21	84 ± 20	83 ± 20	83 ± 20
Fat, g	87 ± 22	85 ± 22	85 ± 23	85 ± 23
Fiber, g	24 ± 11	23 ± 10	22 ± 9	23 ± 10
Vitamin D, IUc	160 ± 100	150 ± 100	150 ± 100	150 ± 100
Sodium, mga	3400 ± 890	3300 ± 820	3300 ± 810	3300 ± 820
Magnesium, mg	360 ± 110	360 ± 120	360 ± 110	360 ± 110
Iron, mg	16 ± 5	16 ± 6	16 ± 6	16 ± 6
Caffeine, mg	170 ± 150	160 ± 110	160 ± 110	160 ± 110
Oxalate, servings	1.2 ± 1.0	1.1 ± 1.0	1.2 ± 1	1.4 ± 1

Note: Fractional calcium absorption studies 1, 2, and 3 occurred at baseline, 39 ± 17 days, and 64 ± 2 days later, respectively. We used analysis of variance with a Bonferroni correction to compare within-subject changes in laboratory characteristics and dietary habits during study visits. Four dietary parameters were statistically different during inpatient visits compared with subjects' usual dietary intake based on 7-day diet diaries secondary to incomplete meal consumption.

^ap < .0001.

^bp = .0015.

^cp = .005.