Table 1.
Participants’ baseline characteristics by allocation: bone sub-study and fracture study.
|
Bone sub-study
(n = 450 subset) |
Fracture study
(n = 1682) |
||||||
|---|---|---|---|---|---|---|---|
| Overall (n = 450) | Vitamin D arm (n = 228) | Placebo arm (n = 222) | Overall (n = 1682) | Vitamin D arm (n = 829) | Placebo arm (n = 853) | ||
| Mean age, years (SD) | 10.1 (0.7) | 10.2 (0.7) | 10.0 (0.6) | 8.9 (1.4) | 8.9 (1.4) | 8.8 (1.3) | |
| Female sex, n (%) | 234 (52.0) | 116 (50.9) | 118 (53.2) | 880 (52.4) | 437 (52.8) | 443 (51.9) | |
| Ethnic origina | Xhosa, n (%) | 424 (96.4) | 214 (96.0) | 210 (96.8) | 1615 (97.9) | 788 (97.3) | 827 (98.5) |
| Other, n (%) | 16 (3.6) | 9 (4.0) | 7 (3.2) | 35 (2.1) | 22 (2.7) | 13 (1.5) | |
| Type of residence | Brick, n (%) | 230 (51.1) | 121 (53.1) | 109 (49.1) | 867 (51.5) | 423 (51.0) | 444 (52.1) |
| Informal, n (%) | 220 (48.9) | 107 (46.9) | 113 (50.9) | 815 (48.5) | 406 (49.0) | 409 (47.9) | |
| Parental educationa,b | Primary school, n (%) | 24 (5.3) | 16 (7.0) | 8 (3.6) | 60 (3.6) | 34 (4.1) | 26 (3.1) |
| Secondary school or higher, n (%) | 426 (94.7) | 212 (93.0) | 214 (96.4) | 1618 (96.4) | 792 (95.9) | 826 (96.9) | |
| Mean monthly household income, 1000 ZAR (SD) | 1.6 (2.3) | 1.5 (2.7) | 1.6 (1.9) | 1.9 (2.2) | 1.8 (2.1) | 2.0 (2.2) | |
| Mean BMI-for-age z-score (SD)a | 0.2 (1.0) | 0.2 (1.0) | 0.2 (1.0) | 0.3 (1.1) | 0.3 (1.1) | 0.3 (1.0) | |
| Mean height-for-age z-score (SD)a | −0.4 (1.0) | −0.4 (1.0) | −0.4 (0.9) | −0.6 (1.2) | −0.6 (1.3) | −0.5 (1.1) | |
| Calcium intakea | ≤300 mg/d, n (%) | 67 (15.2) | 32 (14.4) | 35 (16.0) | 239 (14.6) | 104 (12.9) | 135 (16.3) |
| >300 & ≤500 mg/d, n (%)- | 208 (47.2) | 98 (44.1) | 110 (50.2) | 672 (41.1) | 328 (40.8) | 344 (41.4) | |
| >500 mg/d, n (%) | 166 (37.6) | 92 (41.4) | 74 (33.8) | 723 (44.2) | 372 (46.3) | 351 (42.3) | |
| Mean serum 25(OH)D3 concentration, nmol/L (SD)a,c | 70.0 (13.5) | 70.4 (12.1) | 69.6 (14.9) | 71.2 (14.8) | 71.2 (14.5) | 71.1 (15.0) | |
| Serum 25(OH)D3 concentration, categorya,c | <25 nmol/L, n (%) | 1 (0.3) | 0 (0) | 1 (0.6) | 1 (0.1) | 0 (0.0) | 1 (0.1) |
| ≥ 25 & < 50 nmol/L, n (%) | 20 (5.5) | 7 (3.7) | 13 (7.4) | 74 (5.4) | 34 (5.1) | 40 (5.8) | |
| ≥ 50 & < 75 nmol/L, n (%) | 214 (59.0) | 114 (61.0) | 100 (56.8) | 787 (57.7) | 394 (58.8) | 393 (56.6) | |
| ≥75 nmol/L, n (%) | 128 (35.3) | 66 (35.3) | 62 (35.2) | 502 (36.8) | 242 (36.1) | 260 (37.5) | |
| Mean BMC at WBLH, g (SD)a | 759.3 (133.8) | 772.4 (137.1) | 745.9 (129.1) | ||||
| Mean BMC at LS, g (SD)a | 23.7 (4.6) | 24.3 (4.8) | 23.2 (4.3) | ||||
| Mean BMD at LS, g/cm2 (SD) | 0.59 (0.08) | 0.60 (.09) | 0.58 (0.08) | ||||
| Mean BMAD at LS, g/cm3 (SD) | 0.09 (0.01) | 0.09 (0.01) | 0.09 (0.01) | ||||
| Mean serum adjusted calcium concentration, mmol/L (SD)a | 2.38 (0.06) | 2.38 (0.06) | 2.38 (0.06) | ||||
| Mean PTH concentration, pmol/L (SD)a | 3.68 (1.43) | 3.79 (1.56) | 3.56 (1.28) | ||||
| Serum PTH concentration, category | <1.6 pmol/L, n (%) | 13 (3.6%) | 3 (1.6%) | 10 (5.7%) | |||
| ≥1.6 & <6.9 pmol/L, n (%) | 336 (93.6%) | 173 (94.5%) | 163 (92.6%) | ||||
| ≥6.9 pmol/L, n (%) | 10 (2.8%) | 7 (3.8%) | 3 (1.7%) | ||||
| Mean total ALP, IU/L (SD)a | 282.02 (75.58) | 281.02 (72.40) | 283.08 (78.98) | ||||
| Mean CTX concentration, μg/L (SD)a | 1.20 (0.41) | 1.18 (0.41) | 1.23 (0.41) | ||||
| Mean P1NP concentration, μg/L (SD)a | 803.85 (265.32) | 814.92 (280.44) | 792.21 (248.72) | ||||
ZAR, South African Rand.
Missing data (for bone sub-study: ethnicity, n = 5 vitamin D arm, n = 5 placebo arm; for calcium intake, n = 6 Vitamin D arm, n = 3 placebo arm; for serum 25(OH)D3 concentration, n = 66 vitamin D arm, n = 62 placebo arm; for serum-adjusted calcium and total ALP concentration, n = 41 vitamin D arm, n = 45 placebo arm; for PTH: n = 42 vitamin D arm, n = 46 placebo arm; for CTX: n = 41 vitamin D arm, n = 46 placebo arm; for P1NP: n = 43 vitamin D arm, n = 46 placebo arm; for fracture study: ethnicity, n = 19 vitamin D arm, n = 13 placebo arm; parental education, n = 3 vitamin D arm, n = 1 placebo arm; BMI-for-age z-score, n = 2 vitamin D arm, n = 0 placebo arm; height-for-age z-score, n = 2 vitamin D arm, n = 0 placebo arm; for calcium intake, n = 25 Vitamin D arm, n = 23 placebo arm; for serum 25(OH)D3 concentration, n = 159 vitamin D arm, n = 159 placebo arm)
bHighest level of education of at least 1 parent.
cDeseasonalized values.