Table 1.
Baseline characteristics of all randomized study participants
| Characteristics | All (n = 180) | Vitamin D (n = 119) | Placebo (n = 61) | p value |
|---|---|---|---|---|
| Age (years) | 26.0 ± 5.0 | 25.4 ± 4.6 | 27.2 ± 5.5 | 0.022 |
| Body-mass index (kg/m2) | 27.6 ± 7.5 | 27.3 ± 7.4 | 28.3 ± 7.8 | 0.453 |
| Waist circumference (cm) | 89.0 (78.3–104.0) | 87.0 (77.0–104.0) | 93.0 (82.0–104.5) | 0.210 |
| Hip circumference (cm) | 102.0 (94.1–116.8) | 101.0 (94.0–115.0) | 105.0 (95.5–118.5) | 0.378 |
| WHR (cm/cm) | 0.87 ± 0.10 | 0.86 ± 0.08 | 0.88 ± 0.12 | 0.245 |
| Systolic BP (mmHg) | 122 ± 13 | 122 ± 13 | 122 ± 13 | 0.803 |
| Diastolic BP (mmHg) | 81 ± 10 | 81 ± 10 | 82 ± 10 | 0.214 |
| Fasting glucose (mg/dL) | 84 ± 8 | 84 ± 8 | 84 ± 7 | 0.859 |
| OGTT glucose 30 min (mg/dL) | 130 ± 26 | 131 ± 27 | 126 ± 23 | 0.247 |
| OGTT glucose 60 min (mg/dL) | 117 ± 37 | 121 ± 39 | 109 ± 32 | 0.044 |
| OGTT glucose 120 min (mg/dL) | 97 ± 25 | 99 ± 24 | 93 ± 25 | 0.150 |
| AUCgluc | 222.09 ± 44.5 | 226.71 ± 46.12 | 213.07 ± 40.03 | 0.051 |
| Fasting insulin (mU/L) | 10.1 (5.8–16.1) | 10.3 (5.7–16.8) | 9.9 (6.3–13.6) | 0.845 |
| HbA1c (mmol/mol) | 34 (31–35) | 33 (31–35) | 34 (32–35) | 0.683 |
| HOMA-IR | 2.07 (1.18–3.47) | 2.10 (1.12–3.59) | 2.04 (1.31–2.80) | 0.825 |
| QUICKI | 0.342 (0.318–0.373) | 0.341 (0.316–0.376) | 0.343 (0.327–0.367) | 0.825 |
| Triglycerides (mg/dL) | 68 (50–94) | 66 (50–92) | 72 (50–109) | 0.388 |
| Total cholesterol (mg/dL) | 175 (154–197) | 173 (157–191) | 176 (149–203) | 0.565 |
| HDL-cholesterol (mg/dL) | 64 ± 19 | 63 ± 19 | 65 ± 20 | 0.720 |
| LDL-cholesterol (mg/dL) | 96 ± 33 | 94 ± 28 | 100 ± 41 | 0.283 |
| CRP (mg/L) | 1.1 (0.0–3.6) | 1.4 (0.0–3.9) | 0.8 (0.0–3.3) | 0.350 |
| 25(OH)D (nmol/L) | 50.4 ± 19.0 | 50.7 ± 19.5 | 49.9 ± 18.3 | 0.798 |
| PTH (pg/mL) | 41.6 (34.1–52.5) | 41.9 (34.4–53.8) | 40.2 (33.0–51.4) | 0.595 |
| Plasma calcium (mmol/L) | 2.36 ± 0.08 | 2.36 ± 0.08 | 2.36 ± 0.07 | 0.944 |
| Total testosterone (nmol/L) | 1.50 (1.10–1.95) | 1.50 (1.10–2.10) | 1.40 (1.10–1.80) | 0.315 |
| Free testosterone (nmol/L) | 0.021 (0.015–0.032) | 0.021 (0.016–0.032) | 0.018 (0.013–0.032) | 0.221 |
| FAI | 3.14 (2.18–5.26) | 3.33 (2.26–5.29) | 2.53 (2.04–5.15) | 0.223 |
| Androstendione (ng/mL) | 3.36 (2.51–4.44) | 3.41 (2.43–4.46) | 3.32 (2.58–4.41) | 0.850 |
| DHEAS (µg/mL) | 1.90 (1.34–2.78) | 1.94 (1.34–2.70) | 1.90 (1.42–2.79) | 0.897 |
| Estradiol (pg/mL) | 60.6 (44.6–96.0) | 59.1 (42.3–91.2) | 64.0 (49.5–118.5) | 0.164 |
| FSH (mU/mL) | 5.97 ± 2.41 | 5.94 ± 2.33 | 6.04 ± 2.59 | 0.783 |
| LH (mU/mL) | 9.56 ± 5.60 | 9.79 ± 5.87 | 9.11 ± 5.05 | 0.437 |
| Menstrual irregularity (%) | 89.4 | 89.9 | 88.5 | 0.801 |
| Oligomenorrhea (%) | 71.7 | 73.1 | 68.9 | 0.549 |
| Hypermenorrhea (%) | 2.2 | 1.7 | 3.3 | 0.605 |
| Amenorrhea (%) | 15.6 | 15.1 | 16.4 | 0.824 |
Data are shown as means with standard deviation, medians and interquartile range, or as percentages, as appropriate. Comparisons of baseline characteristics between the vitamin D and the placebo group were performed using unpaired Student’s t test, Mann–Whitney U test, X2 test, or Fisher’s exact test, as appropriate
25(OH)D 25-hydroxyvitamin D, AUCgluc plasma glucose area under the curve, BP blood pressure, CRP C-reactive protein, DHEAS dehydroepiandrostendione-sulfate, FAI free androgen index, FSH follicle-stimulating hormone, HbA1c glycated hemoglobin, HDL-cholesterol high density lipoprotein-cholesterol, HOMA-IR homeostatic model assessment-insulin resistance, LDL-cholesterol low density lipoprotein-cholesterol, LH luteinizing hormone, OGTT glucose 30 min plasma glucose at 30 min during 75 g oral glucose tolerance test, OGTT glucose 60 min plasma glucose at 60 min during 75 g oral glucose tolerance test, OGTT glucose 120 min plasma glucose at 120 min during 75 g oral glucose tolerance test, PTH parathyroid hormone, QUICKI quantitative insulin sensitivity check index WHR waist-to-hip ratio