Table 2.
Vitamin D Status and Biochemistries: Overall and by Season
| Measurementa | Overall (n = 100) | Spring (n = 26) | Summer (n = 18) | Autumn (n = 24) | Winter (n = 32) | ANOVA P Value |
|---|---|---|---|---|---|---|
| 25(OH)D < 20 ng/ml | 19 (19) | 4 (15) | 4 (22) | 2 (8) | 9 (28) | .29 |
| 25(OH)D < 30 ng/ml | 54 (54) | 12 (46) | 9 (50) | 13 (54) | 20 (63) | .65 |
| Serum 25(OH)D, ng/mL | 29 ± 10 | 31 ± 11 | 30 ± 12 | 29 ± 6 | 26 ± 11 | .26 |
| Serum PTH, pg/mL | 85 ± 48 | 88 ± 47 | 69 ± 41 | 86 ± 39 | 92 ± 59 | .44 |
| Serum 1,25(OH)2D, pg/mL | 69 ± 24 | 69 ± 25 | 64 ± 22 | 83 ± 36 | 71 ± 26 | .22 |
| Serum calcium, mg/dL | 10.8 ± 1.0 | 10.7 ± 0.6 | 10.7 ± 0.5 | 10.7 ± 0.7 | 10.7 ± 0.7 | .99 |
| GFR, mL/min/1.73 m2 | 84 ± 24 | 88 ± 35 | 80 ± 16 | 81 ± 15 | 85 ± 24 | .74 |
| Serum phosphorous, mg/dL | 3 ± 0.5 | 3 ± 0.5 | 3 ± 0.6 | 3 ± 0.4 | 3 ± 0.4 | .93 |
| Serum albumin, g/dL | 4.5 ± 0.3 | 5 ± 0.3 | 5 ± 0.3 | 4 ± 0.2 | 5 ± 0.3 | .45 |
| Urine calcium, mg/d | 250 ± 144 | 251 ± 127 | 200 ± 137 | 257 ± 136 | 265 ± 163 | .56 |
| CTX, ng/mL | 0.6 ± 0.4 | 0.6 ± 0.3 | 0.6 ± 0.5 | 0.7 ± 0.3 | 0.7 ± 0.4 | .95 |
| BSAP, U/L | 40 ± 19 | 32 ± 15 | 42 ± 3 | 47 ± 18 | 41 ± 12 | .05b |
Data are presented as N (%) or mean ± sd.
a
Normal ranges: 25(OH)D, 30–80 ng/mL; PTH, 10–66 pg/mL; 1,25(OH) 2D, 15–75 pg/mL; calcium, 8.7–10.2 mg/dL; GFR, > 60 mL/min/1.73 m2; phosphorous, 2.5–4.3 mg/dL; albumin, 3.5–5.5 g/dL; urine calcium, 150–300 mg/d; CTX premenopausal range, 0.112–0.738 ng/mL; CTX postmenopausal range, 0.142–1.351 ng/mL; BSAP premenopausal range, 11.5–29.6 U/L; BSAP postmenopausal range 14.2–42.7 U/L.
b
P values: spring vs autumn, P = .01; differences among other seasons were not significant.