. 2018 May 25;2(7):687–709. doi: 10.1210/js.2017-00472

Table 2.

Characteristics of Included Studies

Study	Place of Study	n	Study Population	Mean Age	% Male	Vitamin D µg (IU)	Other Treatments	Control Group	Duration of Trial	Outcomes Measured	Treated Group		Control Group
Study	Place of Study	n	Study Population	Mean Age	% Male	Vitamin D µg (IU)	Other Treatments	Control Group	Duration of Trial	Outcomes Measured	Baseline 25(OH)D (nmol/L) Cases	Mean Change (nmol/L) Cases	Baseline 25(OH)D (nmol/L) Controls	Mean Change (nmol/L) Controls
Barengolts et al. 2015	US	173	Prediabetes and hypovitaminosis D (12–73 nmol/L) overweight	60	100	10 µg/d (400 IU/d)		Placebo	12 mo	HbA1c^a	36	84	35	50
Davidson et al. 2013	US	109	Prediabetes and 25(OH)D <75, obese and HTN	55	NA	Mean 2221 µg/wk (88,865 IU/wk) adjusted based on BMI and baseline D		Placebo	12 mo	HbA1c^a, FPG, 2HPG, HOMA-IR	55	107	55	55
Oosterwerff et al. 2014	Netherlands	130	Prediabetes and vitamin D deficiency (<50) and obese	42	61	30 µg/d (1200 IU/d)	500 mg/d CaCO₃	Placebo plus CaCO₃	16 wk	HbA1c, HOMA-IR, 2HPG^a	25	35	22	23
Mitri et al. 2011	US	92	Prediabetes and overweight	57	49	50 µg/d (2000 IU/d)		Placebo	16 wk	HbA1c^a, 2HPG^a, FPG^a	61	25	60	−18
Harris et al. 2012	US	89	Prediabetes and obese	55	35	100 µg/d (4000 IU/d)	Calcium 600 mg/d	Placebo	12 wk	HbA1c, HOMA-IR^a, FPG^a, 2HPG	40	41	38	−1
Tuomainen et al. 2015	Finland	73	Prediabetes and vitamin D deficiency (<75) and overweight	70	NA	First arm: 40 µg/d (1600 IU/d); second arm: 80 µg/d (3200 IU/d)		Placebo	5 mo	HbA1c, FPG, 2HPG^a, HOMA-IR	57	45 (80 µg/d) 28 (40 mg/d)	57	4
Sollid et al. 2014	Norway	511	Prediabetes and obese	50	61	500 µg/wk (20,000 IU/wk)		Placebo	1 y	HbA1c, FPG^a, 2HPG, HOMA-IR	60	46	61	3
Dutta et al. 2014	India	136	Prediabetes and 25(OH)D <75 overweight	55	NA	A; 1500 µg/wk (60,000 IU/wk) for 8 wk then monthly	Calcium 500mg/d C; vitamin D–sufficient group got Ca	Placebo	1 y	HbA1c, FPG^a, 2HPG^a, HOMA-IR	42	47 (A)	95	−73 (C)
Forouhi et al. 2016	UK	340	Prediabetes	52	NA	83 µg/d (3300 IU/d) D3		Placebo	4 mo	HbA1c	46	40	46	0
Jorde et al. 2016	Norway	226	Prediabetes	62	64	500 µg/wk (20,000 IU/wk)		Placebo	5 y	HbA1c, FPG, 2HPG, HOMA-IR^a	60	62	61	6
Moreira-Lucas et al. 2016	Canada	63	Prediabetes and vitamin D deficient	46	52	700 µg/wk (28,000 IU/wk)		Placebo	24 wk	FPG, HbA1c, HOMA-IR^a	48	51	48	−2
Salehpour et al. 2013	Iran	77	Premenopausal women and obese	34	0	25 µg/d (1000 IU/d)		Placebo	12 wk	HbA1c^a, FPG^a, 2HPG, HOMA-IR	37	38	47	4
Pittas et al. 2007	US	92	Overweight	71	52	18 µg/d (700 IU/d)	Calcium 500 mg/d	Placebo	3 y	HOMA-IR^a, FPG^a	71	31	81	−8
Ramly et al. 2014	Malaysia	171	Premenopausal women and D deficient (<50)	50	0	1250 µg/wk (50,000 IU/wk) for 2 mo then monthly		Placebo	12 mo	FPG^a, HOMA-IR^a	30	56	30	6
Carrillo et al. 2013	US	23	Overweight and obese	26	48	100 µg/d (4000 IU/d)		Placebo	12 wk	FPG, 2HPG, HOMA-IR	48	36	45	14
Wamberg et al. 2013	Denmark	52	Obese and D deficient (<50)	34	29	175 µg/d (7000 IU/d)		Placebo	26 wk	FPG^a, HOMA-IR	34	76	34	13
Zittermann et al. 2009	Germany	165	Overweight and average 25(OH)D = 30	44	33	83 µg/d (3332 IU/d)		Placebo	12 mo	HbA1c, FPG	30	56	30	12
Asemi et al. 2015	Iran	104	Women with PCOS and vitamin D deficiency (<50) and obese	29	0	1250 µg/wk (50,000 IU/wk)	Plus Ca placebo	Calcium placebo + vitamin D placebo	2 mo	FPG, HOMA-IR^a	29	30	35	1
Gepner et al. 2012	US	109	Postmenopausal women and 25 ≤ 25(OH)D ≤ 150	64	0	63 µg/d (2500 IU/d)		Placebo	4 mo	FPG	76	39	81	−0.5
Grimnes et al. 2011	Norway	94	Vitamin D deficient	53	52	500 µg biweekly (20,000 IU biweekly)		Placebo	6 mo	FPG^a, HbA1c, HOMA-IR	42	100	39	3
Wood et al. 2012	Scotland	305	Postmenopausal women	65	0	25 µg/d (1000 IU/d) or 10 µg/d (400 IU/d)		Placebo	12 mo	FPG, HOMA-IR	32	43 (25 µg/d) 33 (10 mg/d)	36	−3
Sun et al. 2016	Japan	81	Healthy	45	6	11 µg/d (420 IU/d)		Placebo	1 y	FPG^a, HOMA-IR, HbA1c^a	33	28	32	−1
Sharifi et al. 2014	Iran	53	Adults with NAFLD	42	49	1250 µg biweekly (50,000 IU/ biweekly)		Placebo	4 mo	FPG	37	46	44	6
Mousa et al. 2017	Australia	54	Overweight and obese	30	65	2500 µg (100,000 IU bolus) then 100 µg/d (4000 IU/d)		Placebo	4 mo	FPG	31	57	34	2
Osati et al. 2016	Iran	210	Vitamin D deficient	38	23	1250 µg/wk (50,000 IU/wk)		Placebo	2 mo	FPG, HOMA-IR^a	34	35	35	2
Grubler et al. 2016	Austria	185	People with arterial HTN	60	53	70 µg/d (2800 IU/d)		Placebo	2 mo	FPG, HbA1c^a	54	11	51	0
Lorvand Amiri et al. 2016	Iran	73	Patients with NAFLD	42	62	25 µg/d (1000 IU/d)	Hypocaloric diet	Placebo	3 mo	FPG, HOMA-IR^a	25	43	25	2
Vahedpoor et al. 2017	Iran	58	Patients with cervical intraepithelial neoplasia	37	NA	1250 µg biweekly (50,000 IU biweekly)		Placebo	6 mo	FPG^a, HOMA-IR^a	27	40	28	−2

Abbreviations: HTN, hypertension; NA, not available; NAFLD, non-alcoholic fatty liver disease; PCOS, polycystic ovary syndrome.

^{^a}

Significant difference between intervention and placebo groups (P < 0.05).