Table 2.
Characteristics of white participants (n=1604) by serum 25(OH)D concentration [n (%)*, unless indicated otherwise]*
| < 20 ng/mL | 20–< 30 ng/mL | ≥ 30 ng/mL | |||
|---|---|---|---|---|---|
| Serum 25(OH)D (mean (±SD)ng/mL) | 16.6 (±3.5) | 25.3 (±2.8) | 38.5 (±9.2) | p-value† | |
| n(%) | 294(18%) | 614(38%) | 696(43%) | ||
| Age (mean (±SD)) yrs | 74.8 (±2.9) | 74.9 (±2.9) | 74.6 (±2.8) | 0.15 ‡ | |
| Female | 155 (52.7%) | 285 (46.4%) | 323 (46.4%) | 0.15 | |
| Dietary Vitamin D intake <400 IU/d | 274 (93.2%) | 563 (91.7%) | 607 (87.2%) | 0.004 | |
| mean (±SD) vitamin D intake (IU/d) § | 178 (±122) | 219 (±127) | 235 (±149) | <0.001‡ | |
| Dietary Calcium intake <1000 mg/d | 248 (84.4%) | 465 (75.7%) | 506 (72.7) | <0.001 | |
| mean (±SD) calcium intake (mg/d) § | 719 (±344) | 795 (±353) | 847 (±430) | <0.001‡ | |
| No Multivitamin Supplement use | 243 (82.7%) | 361 (58.8%) | 301 (43.3%) | <0.001 | |
| No Vitamin D-containing supplement use | 281 (95.6%) | 536 (87.3%) | 567 (81.1%) | <0.001 | |
| No Calcium-containing supplement use | 255 (86.7%) | 451 (73.5%) | 449 (64.5%) | <0.001 | |
| Inflammation: CRP¶ >3mg/L | 141 (48.0%) | 285 (46.4%) | 309 (44.4%) | 0.55 | |
| mean(±SD) CRP¶ (mg/L) § | 5.6 (±9.4) | 5.2 (±10.0) | 5.3 (±8.9) | 0.64‡ | |
| Cholesterol ≥200 mg/dl | 163 (55.4%) | 309 (50.3%) | 328 (47.1%) | 0.06 | |
| mean(±SD) cholesterol (mg/dl) | 207 (±40) | 202 (±38) | 200 (±35) | 0.05‡ | |
| Obese BMI¶ (≥30 kg/m2) | 73 (24.8%) | 122 (19.9%) | 84 (12.1%) | <0.001 | |
| mean(±SD) BMI¶ (kg/m2) | 27.6 (±4.6) | 26.7 (±4.0) | 25.7 (±3.8) | <0.001†† | |
| Impaired kidney function | 0.02 | ||||
| (eGFR¶ <60 mL/min) | 76 (25.9%) | 129 (21.0%) | 193 (27.7%) | ||
| mean(±SD) eGFR¶ | 71 (±16) | 71 (±14) | 69 (±14) | 0.002‡ | |
| No Physical activity (0 min/wk) | 140 (47.6%) | 190 (30.9%) | 205 (29.5%) | <0.001 | |
| Education: | <High school | 40 (13.6%) | 71 (11.6%) | 77 (11.1%) | 0.17 |
| High school grad | 109 (37.1%) | 209 (34.1%) | 216 (31.0%) | ||
| >High school | 145 (50.0%) | 334 (54.5%) | 403 (57.9%) | ||
| Alcohol intake: | ≥7 /week | 37 (12.6%) | 69 (11.2%) | 74 (10.6%) | 0.79 |
| 1–7/week | 73 (24.8%) | 164 (26.7%) | 190 (27.3%) | ||
| <1/week | 20 (6.8%) | 46 (7.5%) | 63 (9.1%) | ||
| None | 164 (55.4%) | 335 (54.6%) | 369 (53.0%) | ||
| Smoking: | Never | 114 (38.8%) | 279 (45.4%) | 304 (43.7%) | 0.13 |
| Current | 24 (8.2%) | 34 (5.5%) | 33 (4.7%) | ||
| Former | 156 (53.0%) | 301 (49.0%) | 359 (51.6%) | ||
| Season: | Sep–Nov | 52 (17.7%) | 138 (22.5%) | 208 (30.0%) | <0.001 |
| Dec–Feb | 120 (40.8%) | 196 (31.9%) | 141 (20.3%) | ||
| Mar–May | 99 (33.7%) | 170 (27.7%) | 201 (28.9%) | ||
| Jun–Aug | 23 (7.8%) | 110 (17.9%) | 146 (21.0%) | ||
| Prevalent disease | |||||
| Cardiovascular disease | 100 (34.0%) | 177 (28.8%) | 171 (24.6%) | 0.01 | |
| Diabetes | 59 (20.1%) | 102 (16.6%) | 82 (11.8%) | 0.002 | |
| Osteoporosis | 36 (12.2%) | 70 (11.4%) | 107 (15.4%) | 0.09 | |
| Hypertension | 162 (55.1%) | 313 (51.0%) | 331 (47.6%) | 0.09 | |
| Knee pain/osteoarthritis | 83 (28.1%) | 145 (23.6%) | 164 (23.6%) | 0.25 | |
| Site: Memphis | 146 (49.7%) | 311 (50.7%) | 353 (50.7%) | 0.95 | |
| Pittsburgh | 148 (50.3%) | 303 (49.4%) | 343 (49.3%) | ||
*
percents indicate prevalence within 25(OH)D category
†
p-values are unadjusted based on chi-square analysis, unless otherwise indicated.
‡
p-values are p-for trend based on general linear models, adjusted for age, gender, BMI and season (unless analyzed on that variable); means(±SD) are presented unadjusted
§
a natural log-transformation was applied to the outcome for formal analysis, however means(±SD) are presented in original scale.
¶
CRP = C-reactive protein; BMI = body mass index, eGRF= estimated glomerular filtration rate