TABLE 4.
Participant-data results of the subgroup effects of vitamin D supplementation according to remeasured achieved post-treatment 25(OH)D concentrations1
| Achieved 25(OH)D | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| <75 nmol/L | ≥75 nmol/L | <100 nmol/L | ≥100 nmol/L | <125 nmol/L | ≥125 nmol/L | |||||||
| Effect size (95% CI) | n | Effect size (95% CI) | n | Effect size (95% CI) | N | Effect size (95% CI) | n | Effect size (95% CI) | n | Effect size (95% CI) | n | |
| SBP,2 mm Hg | 0.06 (−1.82, 1.93) | 1032 | −0.47 (−1.90, 0.97) | 1244 | −0.47 (−1.98, 1.04) | 1235 | −0.06 (1.83, 1.70) | 1041 | −0.29 (−1.62, 1.04) | 1391 | 0.24 (−2.24, 2.72) | 885 |
| DBP,2 mm Hg | 0.82 (−0.39, 2.03) | 1033 | −0.13 (−1.02, 0.77) | 1243 | 0.26 (−0.70, 1.22) | 1236 | −0.03 (−1.15, 1.09) | 1040 | 0.19 (−0.66, 1.03) | 1391 | 0.28 (−1.30, 1.86) | 885 |
| Total cholesterol,2 mmol/L | −0.09 (−0.20, 0.02) | 1142 | 0.03 (−0.04, 0.11) | 1577 | −0.07 (−0.15, 0.02) | 1350 | 0.05 (−0.04, 0.13) | 1369 | −0.04 (−0.11, 0.04) | 1537 | 0.09 (−0.01, 0.20) | 1182 |
| HDL cholesterol,2 mmol/L | −0.01 (−0.04, 0.03) | 1142 | 0.01 (−0.01, 0.04) | 1577 | 0.00 (−0.03, 0.03) | 1350 | 0.01 (−0.01, 0.04) | 1369 | −0.00 (−0.02, 0.02) | 1537 | 0.03 (−0.00, 0.04) | 1182 |
| LDL cholesterol,2 mmol/L | −0.10 (−0.20, −0.00)* | 1136 | −0.02 (−0.08, 0.05) | 1572 | −0.10 (−0.18, −0.02)* | 1342 | 0.00 (−0.07, 0.08) | 1366 | −0.07 (−0.14, −0.00)* | 1528 | 0.04 (−0.05, 0.13) | 1180 |
| Triglycerides,3 mmol/L | 1.02 (0.97, 1.07) | 1143 | 1.02 (0.98, 1.05) | 1577 | 1.03 (0.98, 1.07) | 1351 | 1.02 (0.98, 1.05) | 1369 | 1.03 (0.99, 1.07) | 1537 | 0.99 (0.95, 1.04) | 1183 |
| PTH,3 pmol/L | 0.89 (0.85, 0.92)* | 1224 | 0.85 (0.83, 0.87)* | 1608 | 0.89 (0.86, 0.91)* | 1433 | 0.84 (0.81, 0.87)* | 1399 | 0.87 (0.85, 0.90)* | 1619 | 0.84 (0.81, 0.87)* | 1213 |
| HbA1c,3 % | 1.00 (0.99, 1.01) | 948 | 1.00 (1.00, 1.00) | 1431 | 1.00 (0.99, 1.01) | 1131 | 1.00 (0.99, 1.01) | 1248 | 1.00 (0.99, 1.01) | 1312 | 1.00 (0.99, 1.01) | 1067 |
| Fasting glucose,3 mmol/L | 1.00 (0.98, 1.01) | 939 | 0.99 (0.97, 1.00) | 1096 | 0.99 (0.97, 1.00) | 1129 | 0.99 (0.98, 1.01) | 906 | 0.99 (0.98, 1.00) | 1264 | 0.99 (0.96, 1.01) | 771 |
| Fasting insulin,3 mU/mL | 1.00 (0.93, 1.07) | 883 | 0.98 (0.93, 1.04) | 1060 | 1.00 (0.94, 1.05) | 1070 | 0.96 (0.90, 1.04) | 873 | 0.99 (0.94, 1.04) | 1203 | 0.96 (0.86, 1.06) | 740 |
| Fasting C-peptide,2 pmol/L | 11.11 (−46.08, 68.31) | 433 | 14.44 (−23.89, 52.77) | 593 | 6.93 (−34.88, 48.75) | 552 | 19.61 (−27.18, 66.39) | 474 | 12.46 (−23.56, 48.47) | 645 | −12.52 (−92.31, 67.28) | 381 |
| 2-h Glucose,2 mmol/L | 0.23 (−0.24, 0.69) | 507 | −0.08 (−0.36, 0.21) | 719 | 0.04 (−0.29, 0.38) | 637 | −0.14 (−0.48, 0.20) | 589 | −0.05 (−0.33, 0.24) | 747 | 0.03 (−0.48, 0.54) | 479 |
1Results are derived from 1-step linear mixed models with study added as a random effect. Results were adjusted for age, sex, baseline values of the outcome, BMI, serum calcium concentration, and smoking status. *P < 0.05. For conversion of 25(OH)D from nmol/L to ng/mL, divide by 2.496. Participants in the vitamin D group with the relevant achieved 25(OH)D concentrations were compared with all of the participants in the comparator group. The intervention group with the highest dose of vitamin D was used in studies with >1 intervention group [i.e., Tromsø Obesity (33), UCC1 (34), UCC2 (35), and Wicherts et al. (36)]. DBP, diastolic blood pressure; HbA1c: glycated hemoglobin; PTH, parathyroid hormone; SBP, systolic blood pressure; 25(OH)D, 25-hydroxyvitamin D.
2Results represent the regression coefficient β, which is the mean difference in the outcome in the vitamin D group compared with the comparator group.
3Results were back-transformed and therefore the effect estimate is the ratio of geometric means in both treatment groups. The geometric mean resembles the median. Example of interpretation: PTH concentrations are 0.8 times higher after vitamin D supplementation compared with concentrations in the comparator group.