Table 1.
Characteristics of the Participants at Baseline, According to Randomized Assignment to Vitamin D or Placebo.*
| Characteristic | Total (N = 25,871) | Vitamin D Group (N = 12,927) | Placebo Group (N = 12,944) |
|---|---|---|---|
| Female sex — no. (%) | 13,085 (50.6) | 6,547 (50.6) | 6,538 (50.5) |
| Age — yr | 67.1±7.1 | 67.1±7.0 | 67.1±7.1 |
| Race or ethnic group — no./total no. (%)† | |||
| Non-Hispanic White | 18,046/25,304 (71.3) | 9,013/12,647 (71.3) | 9,033/12,657 (71.4) |
| Black | 5,106/25,304 (20.2) | 2,553/12,647 (20.2) | 2,553/12,657 (20.2) |
| Non-Black Hispanic | 1,013/25,304 (4.0) | 516/12,647 (4.1) | 497/12,657 (3.9) |
| Asian or Pacific Islander | 388/25,304 (1.5) | 188/12,647 (1.5) | 200/12,657 (1.6) |
| American Indian or Alaskan Native | 228/25,304 (0.9) | 118/12,647 (0.9) | 110/12,657 (0.9) |
| Other or unknown | 523/25,304 (2.1) | 259/12,647 (2.0) | 264/12,657 (2.1) |
| Body-mass index‡ | 28.1±5.7 | 28.1±5.7 | 28.1±5.8 |
| Diabetes — no./total no. (%) | 3,537/25,824 (13.7) | 1,804/12,900 (14.0) | 1,733/12,924 (13.4) |
| Parental history of hip fracture — no./total no. (%) | 3,704/23,979 (15.4) | 1,809/11,970 (15.1) | 1,895/12,009 (15.8) |
| Rheumatoid arthritis — no./total no. (%) | 1,118/25,512 (4.4) | 556/12,749 (4.4) | 562/12,763 (4.4) |
| History of fragility fracture — no./total no. (%) | 2,578/25,023 (10.3) | 1,287/12,513 (10.3) | 1,291/12,510 (10.3) |
| Unintentional fall in the past year — no./total no. (%) | 6,921/25,715 (26.9) | 3,521/12,848 (27.4) | 3,400/12,867 (26.4) |
| Current use of osteoporosis medication — no./total no. (%)§ | 1,240/25,690 (4.8) | 609/12,835 (4.7) | 631/12,855 (4.9) |
| Current smoker — no./total no. (%) | 1,835/25,488 (7.2) | 921/12,732 (7.2) | 914/12,756 ( 7.2) |
| Current use of supplemental vitamin D — no. (%)¶ | 11,030 (42.6) | 5,497 (42.5) | 5,533 (42.7) |
| Current use of glucocorticoids — no./total no. (%) | 461/25,427 (1.8) | 239/12,705 (1.9) | 222/12,722 (1.7) |
| Servings of milk per day | 0.71±0.91 | 0.71±0.89 | 0.72±0.92 |
| Baseline 25-hydroxyvitamin D level — ng/ml‖ | 30.7±10.0 | 30.7±10.0 | 30.7±10.0 |
| Baseline calcium level — mg/dl** | 9.00±1.61 | 9.00±1.61 | 9.00±1.61 |
Plus–minus values are means ±SD. Percentages may not total 100 because of rounding.
Race and ethnic group were reported by the participants.
A total of 30.1% of the participants had a normal body-mass index (18.5 to <25), 40.1% were overweight (25 to <30), and 28.9% were obese (≥30).
Osteoporosis medications included alendronate (Fosamax), raloxifene (Evista), risedronate (Actonel), zoledronate (Reclast), denosumab (Prolia), teriparatide injection (Forteo), salmon calcitonin (Miacalcin or Fortical), and other osteoporosis medications not listed above.
The mean 25-hydroxyvitamin D level at baseline was 34.9 ng per milliliter for participants taking vitamin D supplements (total, <800 IU per day) and 27.4 ng per milliliter for participants not taking vitamin D supplements.
Data were available for 16,757 participants.
Data were available for 15,884 participants.