Table 1.
Characteristics of included studies
| Author Journal Year Country | Sampling method/setting | Interventi on Duration | Ca su pp | Nb of subjects random ized per arm | Nb of subje cts lost to follo w up | Gen der (% Male per arm) | Age Mean (SD) or median (range) (years) | BMI Mean (SD) or median(ra nge) (kg/m2) | Baseli ne 25(O H)D mean (SD) or media n (range) (ng/ml) | Achie ved 25(O H)D mean (SD) or media n (range) (ng/ml) | Vitamin D assay |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Infants | |||||||||||
| Samadp our Eur J Clin Nutr 2011 [23] Iran | Three urban health centers and two health posts | I1: D3 200 IU/d (Foodlet) I2: D3 200 IU/d (Sprinkles) I3: D3 400 IU/d (Drops) Duration: 4 months |
No | I1: 121 I2: 120 I3: 121 |
I1: 28 I2: 16 I3: 17 |
I1: 59.2 I2: 58.7 I3: 55.4 |
Age in months I1: 12.2 (3.6) I2: 12 (3.8) I3: 12.4 (3.3) |
Weight (kg) I1: 9.2 (1.3) I2: 9.2 (1.4) I3: 9.4 (1.3) Height (cm) I1: 74.3 (4.6) I2: 74 (5.3) I3: 74.7 (4.9) |
I1: 86.7 (27.8) I2: 82.0 (28.5) I3: 88.9 (31.1) |
I1: 88.6 (28.4) I2: 87.4 (32.0) I3: 96.4 (32.1) |
RIA (BioSource Europe S.A., Belgium |
| Children and adolescents | |||||||||||
| El Hajj Fuleihan JCEM 20061 [24] Maalouf JCEM 2008 [25] Lebanon | School children and adolescents | I1: D3 1,400 IU/week (= 200 IU/d) I2: D3 14,000 IU/week (=2,000 IU/d) C: Placebo Duration: 12 months |
No | Girls I1:58 I2: 55 C: 55 Boys I1: 56 I2: 60 C: 56 |
Girls I1: 4 I2: 4 C : 3 Boys I1: 3 I2: 4 C : 5 |
I1: 49 I2: 52 C : 50 |
Girls 13.2 (2.1) Boys 13.0 (1.9) |
Girls 20.1 (3.6) Boys 21.1 (4.2) |
Girls I1: 14 (9) I2: 13 (8) C: 14 (7) Boys: I1: 16 (7) I2: 16 (7) C: 16 (6) |
Girls: I1: 17 (6) I2: 38 (31) C: 16 (8) Boys: I1: 20 (7) I2: 35 (9) C: 17 (6) |
DiaSorin RIA (Diasorin, Incstar, Sallugia, Italy) |
| Ghazi Eur J Clni Nutr 2010 [27] Iran | School children (no other details) | I: D3 50,000U/month (=1,667 IU/d)2 C: placebo monthly Duration: 6 months in boys and 5 months in girls |
No | Girls I: 35 C: 35 Boys I: 35 C: 34 |
3 from the whole study | I : 50 C : 49 |
Girls I : 16.0 (1.0) C: 16.2 (1.2) Boys I : 16.5 (1.4) C: 16.6 (1.4) |
Girls I: 21.8 (3.1) C: 20.7 (2.9) Boys I: 22.3 (4.6) C: 21.9 (4.4) |
Girls I: 8.2 (9) C: 7.9 (5.9) Boys I: 17.5 (5.6) C: 15.5 (6.4) |
Girls at 5 mo I1: 19.2 (9.4) C : 8 (5.6) Boys at 6 mo I1: 29 (10.5) C : 15.6 (6.4) |
ELISA kits (Immuno-diagnostic Systems, Boldon, UK) |
| Mayan IMAJ 2015 [26] Israel | Sheba Medical Center | I:D3 2,000 IU/d C: Placebo Duration: 3 months |
No | I : 28 C: 27 |
None | I : 61 C : 67 |
I : 14 (13–15) C: 13 (12–16) |
NA | I : 24.7 (20.4–28.6) C: 25.0 (21.4–28.3) |
I : 29.7 (24.0–35.3) C: 20.6 (18.3–23.1) |
RIA (Diasorin, Stillwater, Minnesota, USA) |
| Neyestani J Hum Nutr Diet 2013 [28] Iran | 6 primary schools | I :D3200 IU/d C: placebo Duration: 3 months |
Yes | I : 67 C: 60 |
I : 6 C: 7 |
I : 24 C: 32 |
I : 10.4 (0.6) C: 9.8 (0.8) |
I : 18.2 (3.3) C: 18.7 (3.9) |
I : 9.5 (4.6) C: 10.1 (4.3) |
I : 17.5 (4.6) C: 9.6 (3.4) |
HPLC |
| Pregnancy3 | |||||||||||
| Sabet Acta Endocrinol 2012 [29] Iran | Mahdieh Hospital | I:D3 100,000 IU/month (=3,333 IU/d) C: Placebo Duration: 27 weeks gestation until delivery |
No | I : 25 C: 25 |
NA | 0 | I : 26.6 (4.7) C: 26 (6.2) |
Weight I : 72 (10) C: 70 (9) |
I : 33.5 (21.4) C: 38.3 (23.2) |
Maternal I : 61.4 (30) C: 29.4 (16) Venous cord I : 52 (40.5) C: 26 (21.3) |
EIA (Immune diagnostic system Ltd, Bolden, UK |
| Dawodu JCEM 2013 [30] United Arab Emirates | Primary health care clinics, affiliated with Tawam Hospital Pregnant women | I1: D3 3,600 IU/d I2: D3 1,600 IU/d C: Placebo All received also 400 IU/d as prenatal vitamins Duration: 12–16 weeks gestation till delivery |
No | I1: 63 I2: 65 C : 64 |
I1 : 8 I2:13 C : 9 |
0 | I1: 25.6 (5.5) I2: 27.3 (4.9) C : 27.5 (5.5) |
I1: 26.3 (5.4) I2: 26.3 (6.4) C : 25.8 (6.3) |
I1:7.8 (3.1) I2:8.2 (4.8) C: 8.6 (5.2) |
I1: 35.9 (12.1) I2: 25.9 (12.2) C : 19.3 (19.3) |
RIA (DiaSorin, Stillwater, Minnesota) |
| Shakiba Sing Med J 2013 [31] Iran | Two primary care clinics | I1: D3 50,000 IU/month (=1,667 IU/d) I2: 50,000 IU every two weeks (=3,571 IU/d)4 Duration: second trimester until delivery |
No | I1: 17 I2: 17 |
0 | 0 | 25 (3) (all arms) | NA | I1: 16 (7.4) I2: 18 (7.8) |
In neonates: I1: 25 (7) I2: 32 (12) |
Chemilumine sce-nce IA (DiaSorin, spA, Via Crescentino, Vercelli, Italy) |
| Soheilykhah Gynecol Endocrinol 2013 [32] Iran | Two prenatal clinics (Mojibian Hospital and Shahid Sadoughi Hospital) | I1: D2 200 IU/d I2: D2 50,000 IU/month (=1,666 IU/d) I3: D2 50,000 IU every 2 weeks (=3,571 IU/d). Duration: 12 weeks gestation until delivery |
No | I1: 40 I2: 40 I3: 40 |
I1: 5 I2: 2 I3: 0 |
0 | I1: 25 (4.3) I2: 26.5 (4.5) I3: 26.3 (4.8) |
I1: 26.2 (4.5) I2: 25 (3.8) I3: 25.9 (4.6) |
I1: 8.3 (7.8) I2: 7.3 (5.3) I3: 7.3 (5.9) |
I1: 17.7 (9.3) I2: 27.2 (10.7) I3: 34.1 (11.5) |
Chemilumine scence assay5 |
| Etemadifar Iran J Neurol 2015 [33] Iran | MS outpatient clinics of Isfahan University of Medical Sciences | I: D3 50,000 IU/week (7,142 IU/d) C: Placebo Duration: form 12 to 16 weeks gestation till delivery |
No | I : 21 C: 22 |
I : 15 C: 13 |
0 | I : 27.7 (2.4) C: 30.0 (3.9) |
NA | I : 15.3 (2.9) C: 18.3 (19) |
I: 33.7 (15.2) C: 14.6 (1.3) (levels checked at 6 months post-partum) |
RIA kit (DiaSorin, Stillwater, MN, USA) |
| Karamali Horm Metabol Res 2015 [34] Iran | Not detailed | I: D3 50,000 IU every 14 days (3,571 IU/d) C: Placebo All were on multivitamins including vitamin D 400 IU/d Duration: from 20 till 32 weeks of gestation |
No | I : 30 C: 30 |
0 | 0 | 27.4 (5.2) both arms | 25.9 (4.6) both arms | I:17 (1.4) C: 17.1(2.2) |
I : 34.9 (2.4) C:17.4 (4.0) |
ELISA kit (IDS, Boldon, UK) |
| Samimi J Hum Nutr Diet 2015 [35] Iran | Women at risk for preeclampsia, and lived approxim ately 20 km or less from the clinic and hospital | I: D3 50,000 IU every 14 days (3,571 IU/d) C: Placebo All were on multivitam ins including vitamin D 400 IU/d and 500 mg of Calcium, and 108 IU/d dietary vitamin D Duration: from 20 till 32 weeks of gestation |
Ye s (only in I arm) | I : 30 C: 30 |
I : 1 C: 1 |
0 | I : 27.3 (3.7) C: 27.1 (5.2) |
I : 27.4 (3.3) C: 25.6 (4.0) |
I : 13.1 (6.4) C: 16.2 (3.5) |
I : 21.3 (8.4) C: 16.3 (4.9) |
ELISA kit (IDS, Boldon, UK |
| Samimi Glob J Health Sci 2016 [38] Iran | Women with unexplained recurrent spontaneous abortion | I : D3 400 IU/d C: Placebo Duration: until 20 weeks gestation |
No | I : 39 C: 38 |
0 | 0 | I : 26.1 (4.3) C: 26.3 (4.4) |
NA | I : 11.6 (3.8) C: 11.5 (2.4) |
I : 13.2 (3.5) C: 11.1 (2.8) |
NA |
| Shahgheibi J Res Med Sci 2016 [36] Iran | Obstetrics and Gynecology section of Be’sat hospital clinic offices | I: D 5,000 IU weekly (714 IU/d) C: Placebo Duration: from the first trimester till 26 weeks of gestation |
No | I : 50 C: 50 |
I : 4 C: 5 |
0 | NA | I : 28.7 (4.63) C: 28.7 (5.46) |
I : 13.5 (7.6) C: 17.4 (14.9)6 |
NA | NA |
| Vaziri Early Hum Dev and BMC Chil 2016 [37] Iran | prenatal care in Hafez teaching hospital in Shiraz, Iran. | I: D3 2,000 IU/d C: Placebo All participants received multivitamins with vitamin D content of 200–400 IU/d Total vitamin D intake, as reported: I : 2345.16 (240.68) C: 430.79 (230.80) Duration: 26–28 weeks of gestation until delivery |
No | I : 78 C: 75 |
I : 16 C: 10 |
0 | I : 26.82 (4.92) C: 26.00 (4.34) |
I : 26.59 (3.97) C: 26.48 (3.60) |
I : 11.62 (5.59) C: 12.72 (8.37) |
I : 18.04 (9.59) C: 12.02 (5.82) |
CLIA |
Abbreviations: EIA: enzyme immunoassay; ELISA: enzyme-linked immunosorbent assay; HPLC: high pressure liquid chromatography; IA: immunoassay; RIA: radio-immunoassay.
1
El Hajj Fuleihan 2006 and Maalouf 2008 are same trial.
2
A third arm was excluded from analysis as vitamin D was given less frequently than once monthly.
3
Section adapted from Chakhtoura et al, BMJ Open. 2016 Mar 8;6(3):e0108
4
A third arm not included as it did not include randomized participants but those who are vitamin D deficient.
5
Manufacturer not mentioned
6
25(OH)D level unit not mentioned