Table 1.
Descriptive Characteristics of Participants at Baseline by Random Assignment
| Characteristic | CaD |
Placebo |
P | ||
|---|---|---|---|---|---|
| No. | % | No. | % | ||
| Total No. of participants | 18,176 | 18,106 | |||
| Age, years | .997 | ||||
| 50-59 | 6,726 | 37.0 | 6,696 | 37.0 | |
| 60-69 | 8,276 | 45.5 | 8,243 | 45.5 | |
| 70-79 | 3,174 | 17.5 | 3,167 | 17.5 | |
| Race/ethnicity | .446 | ||||
| White | 15,051 | 82.8 | 15,104 | 83.4 | |
| Black | 1,680 | 9.2 | 1,635 | 9.0 | |
| Hispanic | 785 | 4.3 | 717 | 4.0 | |
| American Indian | 77 | 0.4 | 72 | 0.4 | |
| Asian/Pacific Islander | 370 | 2.0 | 351 | 1.9 | |
| Unknown | 213 | 1.2 | 227 | 1.3 | |
| Education | .986 | ||||
| High school/GED or lower | 4,286 | 23.6 | 4,290 | 23.7 | |
| School after high school | 7,217 | 39.7 | 7,156 | 39.5 | |
| College degree or higher | 6,557 | 36.1 | 6,545 | 36.1 | |
| Body mass index, kg/m2 | .334 | ||||
| < 25 | 4,745 | 26.1 | 4,834 | 26.7 | |
| 25 to < 30 | 6,476 | 35.6 | 6,487 | 35.8 | |
| ≥ 30 | 6,870 | 37.8 | 6,692 | 37.0 | |
| Smoking | .504 | ||||
| Never | 9,325 | 51.3 | 9,428 | 52.1 | |
| Past | 7,255 | 39.9 | 7,133 | 39.4 | |
| Current | 1,405 | 7.7 | 1,356 | 7.5 | |
| NSAID use | .303 | ||||
| Yes | 6,249 | 34.4 | 6,132 | 33.9 | |
| No | 11,927 | 65.6 | 11,974 | 66.1 | |
| Total vitamin D intake (dietary plus supplements), IU | .372 | ||||
| < 200 | 6,842 | 37.6 | 6,678 | 36.9 | |
| 200 to < 400 | 3,373 | 18.6 | 3,419 | 18.9 | |
| 400 to < 600 | 4,180 | 23.0 | 4,293 | 23.7 | |
| ≥ 600 | 3,426 | 18.8 | 3,363 | 18.6 | |
| Total calcium intake (dietary plus supplements), mg | .740 | ||||
| < 400 | 1,318 | 7.3 | 1,273 | 7.0 | |
| 400 to < 800 | 4,790 | 26.4 | 4,732 | 26.1 | |
| 800 to < 1,200 | 4,712 | 25.9 | 4,654 | 25.7 | |
| ≥ 1,200 | 7,001 | 38.5 | 7,094 | 39.2 | |
| Solar radiation of region, Langleys | .999 | ||||
| 300-325 | 5,366 | 29.5 | 5,351 | 29.6 | |
| 350 | 3,920 | 21.6 | 3,880 | 21.4 | |
| 375-380 | 2,012 | 11.1 | 2,009 | 11.1 | |
| 400-430 | 3,018 | 16.6 | 3,015 | 16.7 | |
| 475-500 | 3,860 | 21.2 | 3,851 | 21.3 | |
| US region | .996 | ||||
| Northeast | 4,018 | 22.1 | 4,001 | 22.1 | |
| South | 4,327 | 23.8 | 4,304 | 23.8 | |
| Midwest | 4,429 | 24.4 | 4,399 | 24.3 | |
| West | 5,402 | 29.7 | 5,402 | 29.8 | |
| Total outdoor walking energy expenditure, METs/wk | .964 | ||||
| None | 6,081 | 33.5 | 6,056 | 33.4 | |
| ≤ 3.5 | 3,491 | 19.2 | 3,481 | 19.2 | |
| 3.6-7.0 | 3,241 | 17.8 | 3,233 | 17.9 | |
| > 7.0 | 3,733 | 20.5 | 3,678 | 20.3 | |
| History of cancer | .235 | ||||
| Yes | 745 | 4.1 | 698 | 3.9 | |
| No | 17,431 | 95.9 | 17,408 | 96.1 | |
| History of melanoma cancer | .293 | ||||
| Yes | 92 | 0.5 | 78 | 0.4 | |
| No | 18,084 | 99.5 | 18,028 | 99.6 | |
| History of nonmelanoma skin cancer | .300 | ||||
| Yes | 1,086 | 6.0 | 1,129 | 6.2 | |
| No | 17,090 | 94.0 | 16,977 | 93.8 | |
| Hormone use (CaD baseline)* | .237 | ||||
| Never user | 5,810 | 32.0 | 5,685 | 31.4 | |
| Past user | 3,007 | 16.5 | 2,937 | 16.2 | |
| Current user | 9,359 | 51.5 | 9,484 | 52.4 | |
| HT intervention assignment | .740 | ||||
| Not randomly assigned | 10,122 | 55.7 | 10,071 | 55.6 | |
| Active | 4,039 | 22.2 | 4,078 | 22.5 | |
| Placebo | 4,015 | 22.1 | 3,957 | 21.9 | |
| DM intervention assignment | .299 | ||||
| Not randomly assigned | 5,582 | 30.7 | 5,490 | 30.3 | |
| Intervention | 4,767 | 26.2 | 4,878 | 26.9 | |
| Comparison | 7,827 | 43.1 | 7,738 | 42.7 | |
Abbreviations: CaD, calcium and vitamin D; DM, dietary modification; GED, general educational development; HT, hormone therapy; MET, metabolic equivalent of task; NSAID, nonsteroidal anti-inflammatory drug.
*
HT variables calculated for time of CaD randomization and include hormone use from Women's Health Initiatve HT trial.