Table 2.

Effects of vitamin D supplementation with or without calcium on obesity and diabetes parameters.

Study	n (gender) y, duration	Vit D suppl.	Ca++ suppl.	Design	Outcomes
Major et al. [104]	63 (F) ~42.6 y, 15 weeks	200 IU/day	600 mg/day	- Double-blind RCT - Oral vit D + oral Ca++ + WRP - Placebo + WRP	- Greater decreases (treatment vs. control) in total cholesterol/LDL, LDL/HDL and LDL - The differences were independent of changes in fat mass and in WC - Nonsignificant effects on BMI, fat mass or WC
Pittas et al. [84]	314 (F, M) 65 y or older, 3 years	700 IU/day	500 mg/day	- Double-blind RCT - Oral vit D + oral Ca++ - Placebo	- Participants with IFG: treatment group had a lower rise in fasting glucose compared with those on placebo and a lower increase in HOMA-IR - These differences were not present in normal fasting glucose subjects - There were no differences in C-reactive protein or IL-6 between groups
de Boer et al. [85]	33,951 (F) 50–79 y, 7 years	400 IU/day	1000 mg/day	- Double-blind RCT - Oral vit D + oral Ca++ - Placebo	- No significant results of dietary treatment on HR for incident diabetes - This null result was robust in subgroup analyses, efficacy analyses accounting for nonadherence, and analyses examining change in laboratory measurements
Nagpal et al. [106]	100 (M) 35 y or older, 6 weeks	360,000 IU/fortnightly	-	- Double-blind RCT - Oral vit D - Placebo	- Increase in postprandial insulin sensitivity in treatment - No changes in secondary outcome (insulin secretion, basal indices of insulin sensitivity, blood pressure or lipid profile) were found
Sneve et al. [107]	445 (F, M) 21–70 y, 12 months	20,000 IU/twice a week (1) 20,000 IU/once a week (2)	500 mg/day	- Double-blind RCT - Oral vit D(1) - Oral vit D(2) + placebo - Placebo	- No significant change in weight, waist-to-hip ratio or % body fat - PTH decrease and 25(OH)D3 increase in treatments groups, and 25(OH)D3 stabilized after 3 months
Zitterman et al. [105]	200 (F, M) 18–70 y, 12 months	3320 IU/day	-	- Double-blind RCT - Oral vit D + WRP - Placebo + WRP	- Weight loss was not affected significantly - More pronounced decrease occurred in treatment group than in the placebo group in PTH, triglycerides, and the inflammation marker TNF-α. Vitamin D increased LDL
Zhou et al. [103]	870 (F) 55 y or older, 4 years	1100 IU/day	1400–1500 mg/day	- Double-blind RCT - Placebo + oral Ca++ - Oral vit D + oral Ca++ - Placebo	- The calcium intervention groups gained less trunk fat and maintained more trunk lean mass when compared to the placebo group, without difference with adding vitamin D - No significant difference was observed for BMI between groups
Rosenmblum et al. [101]	171 (F, M) 18–65 y, 16 weeks	300 IU/day	1050 mg/day	- Double-blind RCT - Oral vit D + oral Ca++ - Placebo	- Treatment group increase decrease significantly more the % of visceral adipose tissue (−13 ± 16 vs. −5 ± 19)
Forsythe et al. [102]	212 (F, M) 20–40; >64 y, 22 weeks	600 IU/day	-	- RCT - Oral vit D - Placebo	- BMI in older adults was negatively associated with the change in 25(OH)D following supplementation. No such associations were apparent in younger adults

RCT: randomized controlled trial; HR: hazard ratio; IFG: impaired fasting glucose; WRP: weight reduction program; BMI: body mass index; WC: waist circumference.