Table 1. Baseline characteristics of enrolled subjects (n=1,921).
| Caa) <400 mg (n=1,090) | 400 mg ≤ Caa) <800 mg (n=646) | Caa) ≥800 mg (n=185) | P-value | ||||
|---|---|---|---|---|---|---|---|
| 25(OH)D<20 ng/mL (n=669) | 25(OH)D≥20 ng/mL (n=421) | 25(OH)D<20 ng/mL (n=408) | 25(OH)D≥20 ng/mL (n=238) | 25(OH)D<20 ng/mL (n=97) | 25(OH)D≥20 ng/mL (n=88) | ||
| Serum 25(OH)D (ng/mL) | 14.1±3.5 | 26.2±5.3 | 14.3±3.3 | 25.8±4.6 | 14.6±3.3 | 26.3±5.6 | <0.001 |
| Ca intake/day (mg) | 241.7±90.8 | 238.5±93.5 | 547.2±110.1 | 556.9±110.1 | 1106.6±414.7 | 1087.2±272.9 | <0.001 |
| Age (yr) | 59.7±6.5 | 61.3±6.2 | 58.4±6.7 | 58.9±6.1 | 58.1±6.4 | 59.6±6.3 | <0.001 |
| Femur neck BMD (g/cm2) | 0.610±0.100 | 0.654±0.099 | 0.626±0.107 | 0.655±0.095 | 0.624±0.967 | 0.658±0.102 | <0.001 |
| Lumbar spine BMD (g/cm2) | 0.765±0.115 | 0.822±0.117 | 0.790±0.132 | 0.824±0.132 | 0.798±0.126 | 0.830±0.132 | <0.001 |
| Height (cm) | 154.2±5.4 | 153.6±5.5 | 155.1±5.5 | 154.1±5.1 | 155.2±5.6 | 155.7±5.4 | <0.001 |
| Weight (kg) | 57.89±8.1 | 57.3±8.5 | 58.4±8.3 | 57.7±7.1 | 58.2±8.2 | 58.7±7.2 | 0.374 |
| Waist circumference (cm) | 82.7±9.0 | 83.0±9.0 | 81.6±8.9 | 82.3±8.8 | 81.5±9.1 | 82.1±9.0 | 0.225 |
| BMI (kg/m2) | 24.1±3.0 | 24.3±3.0 | 24.2±2.9 | 24.4±3.4 | 24.5±3.2 | 24.2±3.0 | 0.609 |
| Serum PTH (pg/mL) | 68.4±34.7 | 62.8±38.6 | 65.9±24.2 | 59.1±24.3 | 65.7±26.4 | 61.1±17.8 | 0.002 |
| Age at menopause (yr) | 49.9±3.9 | 49.2±3.8 | 49.3±3.7 | 49.2±3.5 | 50.8±3.6 | 50.2±3.4 | 0.152 |
| Chronic renal disease | 0.332b) | ||||||
| No | 661 (98.8) | 417 (99.0) | 407 (99.8) | 238 (100.0) | 96 (99.0) | 88 (100.0) | |
| Yes | 8 (1.2) | 4 (1.0) | 1 (0.2) | 0 (0) | 1 (1.0) | 0 (0.0) | |
| Diabetes mellitus | 0.172 | ||||||
| No | 576 (86.1) | 345 (81.9) | 359 (88.0) | 210 (88.2) | 82 (84.5) | 73 (83.0) | |
| Yes | 93 (13.9) | 76 (18.1) | 49 (12.0) | 28 (11.8) | 15 (15.5) | 15 (17.0) | |
| Obesity | 0.197 | ||||||
| BMI <18.5 kg/m2 | 14 (2.1) | 15 (3.6) | 5 (1.2) | 2 (0.8) | 3 (3.1) | 0 (0) | |
| 18.5≤ BMI <25 kg/m2 | 355 (53.1) | 228 (54.2) | 273 (66.9) | 152 (63.9) | 61 (62.9) | 58 (65.9) | |
| BMI ≥25 kg/m2 | 300 (44.8) | 178 (42.3) | 130 (31.9) | 84 (35.3) | 33 (34.0) | 30 (34.1) | |
| History of fracture | 0.797 | ||||||
| Yes | 128 (19.1) | 79 (18.8) | 65 (15.9) | 42 (17.6) | 16 (16.5) | 14 (15.9) | |
| No | 541 (80.9) | 342 (81.2) | 343 (84.1) | 196 (82.4) | 81 (83.5) | 74 (84.1) | |
| Smoking history | 0.522 | ||||||
| Current or past smoker | 64 (9.6) | 29 (6.9) | 28 (6.9) | 20 (8.4) | 8 (8.2) | 8 (9.1) | |
| Never | 605 (90.4) | 392 (93.1) | 380 (93.1) | 218 (91.6) | 89 (91.8) | 80 (90.9) | |
| Physical activity | 0.030 | ||||||
| No | 567 (84.8) | 375 (89.1) | 347 (85.0) | 216 (90.8) | 78 (80.4) | 76 (87.4) | |
| Yes | 102 (15.2) | 46 (10.9) | 61 (15.0) | 22 (9.2) | 19 (19.6) | 11 (12.6) | |
| Estrogen therapy | 0.468 | ||||||
| Yes | 123 (18.4) | 69 (16.4) | 87 (21.3) | 39 (16.4) | 16 (16.5) | 18 (20.5) | |
| No | 546 (81.6) | 352 (836) | 321 (78.7) | 199 (83.6) | 81 (83.5) | 70 (79.5) | |
| Femur neck | <0.001 | ||||||
| Normal | 129 (19.3) | 117 (27.8) | 93 (22.8) | 75 (31.5) | 21 (21.6) | 28 (31.8) | |
| Osteopenia | 380 (56.8) | 256 (60.8) | 241 (59.1) | 141 (59.2) | 59 (60.8) | 52 (59.1) | |
| Osteoporosis | 160 (23.9) | 48 (11.4) | 74 (18.1) | 22 (9.3) | 17 (17.6) | 8 (9.1) | |
| Lumbar spine | <0.001 | ||||||
| Normal | 91 (13.6) | 125 (29.7) | 98 (24.0) | 44 (18.5) | 21 (21.6) | 27 (30.7) | |
| Osteopenia | 341 (51.0) | 198 (47.0) | 163 (40.0) | 124 (52.1) | 50 (51.6) | 44 (50.0) | |
| Osteoporosis | 237 (35.4) | 98 (23.3) | 147 (36.0) | 70 (29.4) | 26 (26.8) | 17 (19.3) | |
| Femur neck | <0.001 | ||||||
| Normal | 129 (19.3) | 117 (27.8) | 93 (22.8) | 75 (31.5) | 21 (21.6) | 28 (31.8) | |
| Osteopenia+osteoporosis | 540 (80.7) | 304 (72.2) | 315 (77.2) | 163 (68.5) | 76 (78.4) | 60 (68.2) | |
| Lumbar spine | 0.004 | ||||||
| Normal | 91 (13.6) | 125 (29.7) | 98 (24.0) | 44 (18.5) | 21 (21.6) | 27 (30.7) | |
| Osteopenia+osteoporosis | 578 (86.4) | 296 (70.3) | 310 (76.0) | 194 (81.5) | 76 (78.4) | 61 (69.3) | |
Values are presented as mean±standard deviation or number (%).
Ca, calcium; 25(OH)D, 25-hydroxyvitamin D; BMD, bone mineral density; BMI, body mass index; PTH, parathyroid hormone.
a)Daily calcium intake; b)Fisher's exact test.