Baseline characteristics of randomised participants
| Treatment assignment | ||||||
| Full factorial randomisation | 2 group randomisation* | |||||
| Placebo | Calcium+placebo | Vitamin D+placebo | Calcium+vitamin D | Calcium+placebo | Calcium+vitamin D | |
| N (%) or mean±SD | N (%) or mean±SD | N (%) or mean±SD | N (%) or mean±SD | N (%) or mean±SD | N (%) or mean±SD | |
| Total N | 415 | 419 | 420 | 421 | 295 | 289 |
| Sex | ||||||
| Female | 60 (14.5) | 63 (15.0) | 62 (14.8) | 67 (15.9) | 295 (100) | 289 (100) |
| Male | 355 (85.5) | 356 (85.0) | 358 (85.2) | 354 (84.1) | 0 | 0 |
| Age | 58.2±7.0 | 58.7±7.0 | 58.3±7.0 | 58.7±6.9 | 56.7±6.0 | 57.0±6.6 |
| Race | ||||||
| Caucasian | 357 (88.8) | 354 (87.6) | 364 (90.1) | 350 (86.6) | 238 (86.6) | 237 (87.5) |
| African American | 27 (6.7) | 33 (8.2) | 25 (6.2) | 46 (11.4) | 28 (10.2) | 25 (9.2) |
| Asian/Pacific Islander | 10 (2.5) | 10 (2.5) | 12 (3.0) | 6 (1.5) | 8 (2.9) | 7 (2.6) |
| Other | 8 (2.0) | 7 (1.7) | 3 (0.7) | 2 (0.5) | 1 (0.4) | 2 (0.7) |
| BMI (kg/m2) | 29.0±4.9 | 29.5±5.1 | 29.1±4.6 | 29.0±5.1 | 28.8±6.0 | 28.3±5.4 |
| <25 | 80 (19.3) | 74 (17.7) | 76 (18.1) | 97 (23.0) | 91 (31.0) | 99 (34.4) |
| 25–29.9 | 187 (45.2) | 180 (43.0) | 181 (43.1) | 180 (42.8) | 91 (31.0) | 97 (33.7) |
| ≥30 | 147 (35.5) | 165 (39.4) | 163 (38.8) | 144 (34.2) | 112 (38.1) | 92 (31.9) |
| Smoking status | ||||||
| Never | 187 (45.1) | 212 (50.6) | 217 (51.7) | 204 (48.5) | 205 (69.5) | 169 (58.5) |
| Former | 193 (46.5) | 174 (41.5) | 164 (39.1) | 169 (40.1) | 62 (21.0) | 88 (30.5) |
| Current | 35 (8.4) | 33 (7.9) | 39 (9.3) | 48 (11.4) | 28 (9.5) | 32 (11.1) |
| Alcohol intake (drinks/day) | 0.89 +/- 1.08 | 0.82±1.01 | 0.91±1.11 | 0.89±1.08 | 0.40±0.72 | 0.48±0.69 |
| Dietary fat intake (g/day) | 71.4±34.3 | 71.3±31.6 | 69.0±28.2 | 66.4±25.7 | 53.9±24.2 | 58.2±26.7 |
| Dietary fibre intake (g/day) | 15.5±7.3 | 16.1±7.1 | 15.0±6.7 | 14.9±7.2 | 13.9±6.3 | 14.6±6.4 |
| Red meat intake (servings/day) | 0.8±0.6 | 0.8±0.6 | 0.8±0.7 | 0.7±0.6 | 0.5±0.5 | 0.5±0.5 |
| Processed meat intake (servings/day) | 0.4±0.5 | 0.4±0.5 | 0.4±0.4 | 0.4±0.4 | 0.2±0.3 | 0.3±0.3 |
| Dietary calcium intake (mg/day) | 672±313 | 718±326 | 643±286 | 652±303 | 604±295 | 656±313 |
| Baseline supplemental calcium† (mg/day) | ||||||
| 0 | 201 (51.9) | 199 (50.6) | 207 (52.3) | 212 (53.0) | 64 (24.9) | 56 (22.0) |
| 1–499 | 173 (44.7) | 172 (43.8) | 172 (43.4) | 169 (42.3) | 94 (36.6) | 86 (33.7) |
| ≥500 | 13 (3.4) | 22 (5.6) | 17 (4.3) | 19 (4.8) | 99 (38.5) | 113 (44.3) |
| Dietary vitamin D intake (IU/day) | 138±97 | 146±96 | 131±102 | 130±92 | 124±96 | 134±98 |
| Supplemental vitamin D† (IU/day) | ||||||
| 0 | 204 (52.2) | 203 (52.2) | 209 (52.6) | 210 (52.9) | 84 (34.2) | 71 (30.5) |
| 1–499 | 175 (44.8) | 170 (43.7) | 162 (40.8) | 175 (44.1) | 120 (48.8) | 110 (47.2) |
| ≥500 | 12 (3.1) | 16 (4.1) | 26 (6.6) | 12 (3.0) | 42 (17.1) | 52 (22.3) |
| Serum 25-OH- vitamin D (ng/mL) | 24.24±7.84 | 24.58±8.42 | 24.88±8.09 | 24.45±8.06 | 25.03±8.90 | 24.29±7.71 |
| Aspirin use | ||||||
| <4 days/week | 255 (61.5) | 249 (59.4) | 255 (60.7) | 270 (64.1) | 227 (77.0) | 206 (71.3) |
| ≥4 days/week | 160 (38.6) | 170 (40.6) | 165 (39.3) | 151 (35.9) | 68 (23.1) | 83 (28.7) |
| NSAID use (non-aspirin) | ||||||
| <4 days/week | 372 (89.6) | 367 (87.6) | 379 (90.2) | 388 (92.2) | 261 (88.5) | 253 (87.5) |
| ≥4 days/week | 43 (10.4) | 52 (12.4) | 41 (9.8) | 33 (7.8) | 34 (11.5) | 36 (12.5) |
Numbers for some characteristics may not sum to total N due to missing data.
↵*Participants not randomised to calcium but were given calcium.
↵†Supplemental values in elemental mg/day and include separate supplements and multivitamins. Participants were asked to cease these supplements at enrolment as a condition of study entry.
BMI, body mass index; NSAID, non-steroidal anti-inflammatory drug.