Table 1.
Baseline characteristics by case-control status and across quartiles of 25(OH) vitamin D (nM).
| Control |
Case |
|
1st Quartile Median (range) 37.1 (9.23 − <47.6) |
2nd Quartile Median (range) 54.0 (47.6 − < 60.2) |
3rd Quartile Median (range) 65.1 (60.2 − < 70.7) |
4th Quartile Median (range) 80.4 (70.7 − 121.5) |
||
|---|---|---|---|---|---|---|---|---|
| N (%) Mean (Std) | N (%) Mean (Std) | P-value | N (%) Mean (Std) | N (%) Mean (Std) | N (%) Mean (Std) | N (%) Mean (Std) | P-value | |
| Age (>70) | ||||||||
| Yes | 132 (33.0) | 132 (33.0) | 1.00 | 84 (34.43) | 57 (29.23) | 54 (32.34) | 68 (35.23) | 0.58 |
| Ethnicity (white) | ||||||||
| Yes | 380 (95.0) | 380 (95.0) | 1.00 | 224 (91.80) | 184 (94.36) | 163 (97.60) | 188 (97.41) | 0.02 |
| BMI (kg/m2) | ||||||||
| <25 | 144 (36.09 | 193 (48.61) | 0.001 | 91 (37.45) | 70 (36.27) | 77 (46.11) | 98 (51.04) | 0.002 |
| 25−<30 | 150 (37.59) | 127 (31.99) | 80 (32.92) | 72 (37.31) | 63 (37.72) | 62 (32.29) | ||
| ≥30 | 105 (26.32) | 77 (19.40) | 72 (29.63) | 51 (26.42) | 27 (16.17) | 32 (16.67) | ||
| BMI (kg/m2) | 27.41 (5.13) | 26.04 (5.15) | <0.001 | 27.70 (5.72) | 27.04 (4.76) | 26.14 (4.87) | 25.75 (25.75) | <0.001 |
| HT usage status | ||||||||
| Past user | 98 (24.50) | 95 (23.75) | 0.80 | 57 (23.36) | 44 (22.56) | 48 (28.74) | 43 (22.28) | 0.45 |
| Oral corticosteroid use | ||||||||
| Yes | 3 (0.75) | 14 (3.50) | 0.007 | 7 (2.87) | 3 (1.54) | 1 (0.60) | 6 (3.11) | 0.29 |
| RAND 36 Physical Function (>90) | ||||||||
| Yes | 117 (29.77) | 86 (21.66) | 0.009 | 47 (19.50) | 56 (29.02) | 38 (23.17) | 61 (31.94) | 0.02 |
| Total physical activity (MET-hrs/wk) | 13.86 (15.32) | 10.71 (12.67) | 0.002 | 10.31 (15.09) | 10.69 (10.37) | 12.88 (12.08) | 15.92 (17.0) | <0.001 |
| Frailty† | ||||||||
| Yes | 66 (16.50) | 89 (22.25) | 0.04 | 65 (26.64) | 29 (14.87) | 31 (18.56) | 30 (15.54) | 0.005 |
| Self-reported health status | ||||||||
| Fair/Poor | 42 (10.69) | 61 (15.37) | 0.05 | 44 (18.26) | 24 (12.44) | 17 (10.30) | 18 (9.47) | 0.03 |
| Smoking | ||||||||
| Past smoker | 171 (43.18) | 144 (36.55) | <0.001 | 92 (37.86) | 70 (36.65) | 72 (43.90) | 81 (42.41) | 0.12 |
| Current smoker | 10 (2.53) | 36 (9.14) | 22 (9.05) | 10 (5.24) | 5 (3.05) | 8 (4.19) | ||
| Alcohol intake (drinks/wk) | 3.40 (1.67) | 3.37 (1.60) | 0.84 | 3.29 (1.62) | 3.39 (1.67) | 3.35 (1.63) | 3.51 (1.60) | 0.58 |
| 25 VITD (nM) | 59.60 (18.05) | 55.95 (20.28) | 0.007 | 35.83 (8.33) | 53.95 (3.73) | 65.13 (3.05) | 83.00 (10.80) | <0.001 |
| Vitamin D supplement ever | ||||||||
| Yes | 189 (47.25) | 195 (48.75) | 0.67 | 63 (25.82) | 96 (49.23) | 102 (61.08) | 123 (63.73) | <0.001 |
| Total vitamin D intake (IU/d) | 373 (275) | 383 (396) | 0.71 | 262 (332) | 361 (263) | 439 (403) | 480 (307) | <0.001 |
| Total calcium intake (mg/d) | 1167.01 (683.85) | 1072.47 (694.23) | 0.05 | 906.38 (567.86) | 1087.03 (702.50) | 1215.80 (731.58) | 1341.99 (703.77) | <0.001 |
| History of fracture on/after age 55 | ||||||||
| Yes | 82 (20.50) | 96 (24.0) | 0.23 | 49 (20.08) | 35 (17.95) | 39 (23.35) | 55 (28.50) | 0.07 |
| Parents broke hip | ||||||||
| Yes | 64 (16.0) | 80 (20.0) | 0.14 | 48 (19.67) | 30 (15.38) | 28 (16.77) | 37 (19.17 | 0.63 |
| Geographic region | ||||||||
| Southern < 35 degrees M | 108 (27.0) | 106 (26.50) | 0.25 | 56 (22.95) | 48 (24.62) | 48 (28.74) | 62 (32.12) | 0.01 |
| Middle 35−40 degrees N | 95 (23.75) | 115 (28.75) | 59 (24.18) | 64 (32.82) | 32 (19.16) | 54 (27.98) | ||
| Northern > 40 degrees N | 197 (49.25) | 179 (44.75) | 129 (52.87) | 83 (42.56) | 87 (52.10) | 77 (39.90) | ||
| Bioavailable estradiol (pg/ml) | 7.54 (4.54) | 6.57 (4.34) | 0.002 | 7.79 (4.82) | 7.01 (4.68) | 6.50 (4.0) | 6.64 (4.05) | 0.01 |
| Bioavailable testosterone (pg/ml) | 12.59 (6.98) | 10.90 (6.26) | <0.001 | 12.43 (7.21) | 11.27 (5.68) | 11.43 (6.50) | 11.66 (7.04) | 0.26 |
| Cystatin-C (mg/L) | 1.06 (0.24) | 1.10 (0.30) | 0.02 | 1.12 (0.37) | 1.06 (0.21) | 1.07 (0.23) | 1.04 (0.20) | 0.02 |
| PINP (ng/ml) | 49.64 (23.71) | 51.00 (23.03) | 0.42 | 49.04 (21.44) | 51.65 (21.41) | 51.68 (51.68) | 49.34 (27.89) | 0.53 |
| CTx (ng/ml) | 0.41 (0.19) | 0.45 (0.21) | 0.02 | 0.45 (0.22) | 0.44 (0.19) | 0.43 (0.21) | 0.39 (0.16) | 0.02 |
* Abbreviations: SD, standard deviation; HT, hormone therapy; MET, metabolic equilivant; PINP, amino proterminal procollagen extension propeptide; CTx, serum c terminal telopeptide of type I collagen
†
Frailty was defined a 3 or more of the following criteria: muscle weakness, slow walking speed, exhaustion, low physical activity and unintentional weight loss (25).