Table 2.

List and characteristics of included trials

No.	References	Journal	Country of origin	Percent females	Mean age	Mean initial 25(OH)D  < 50 nmol/l	Study duration	Vitamin D dose (IU)		Health status	Number of participants
								Verum	Placebo
1	[37]	Am J Clin Nutr	Germany	67	48	Yes	12 mo	3300	0	Heart failure	165
2	[16]	J Bone Miner Res	USA	100	27	No	6 mo	4000	400	Healthy/pregnant	228
3	[17, 38]	Ann Intern Med	USA	100	67	Yes	12 mo	3200/4000	0	Healthy	60
4	[18]	BMJ Open	Sweden	73	53	No	12 mo	4000	0	Frequent ARI	124
5	[19]	Am J Clin Nutr	USA	50	14	Yes	6 mo	4000	0	Obese	44
6	[20]	JAMA	USA	35	40	Yes	6 mo	4000	0	Asthma	408
7	[21]	Circulation	USA	32	36	Yes	6 mo	4000	400	Prehypertension	363
8	[22]	Endocr Connect	India	100	22	No	6 mo	4000	0	PCOS	30
9	[23]	Clin Nutr	Mexico	100	57	No	6 mo	4000	0	Diabetes	104
10	[24]	J Am Coll Cardiol	UK	17	69	Yes	12 mo	4000	0	Heart failure	223
11	[25]	JAMA	USA	100	27	No	6 mo	4400	400	Healthy/pregnant	806
12	[10]	Eur Heart J	Germany	21	55	Yes	36 mo	4000	0	Heart failure	400
13	[26]	Osteoporos Int	UK	49	72	No	12 mo	4000	0	Healthy	194
14	[27]	Eur J Clin Microb Infect Dis	Sweden	57	41	Yes	12 mo	4000	0	MRSA carrier	65
15	[28]	New Engl J Med	USA	45	60	No	24 mo	4000	0	Prediabetes	2423
16	[29]	JAMA	USA	40	10	No	9 mo	4000	0	Asthma	192
17	[30]	J Clin Endocrinol Metab	Canada	51	62	No	36 mo	4000	400	Healthy	249
18	[31]	BMJ Nutr Prev Heath	Pakistan	100	26	Yes	6 mo	4000	400	Healthy/pregnant	235
19	[32, 33]	Am J Transplant J Bone Miner Res	Japan	31	52	Yes	12 mo	4000	0	Kidney transplanted	187
20	[34]	Ann Intern Med	USA	42	77	No	6 mo	4000	200	Healthy	325
21	[35]	Am J Clin Nutr	Finland	43	68	No	60 mo	3200	0	Healthy	1663
22	[36]	BMJ Open	UK	67	60	Yes	6 mo	3200	0	Respiratory tract infection	4464

PCOS polycystic ovarian syndrome, ARI acute respiratory tract infection