Table 5.

The overall effect of vitamin D supplement on the vitamin D level in patients with diabetes based on continent, age, BMI, diabetes duration, dose of intervention, and follow-up duration.

Variables		Category	No. study	Pooled MSD (95% CI)	Heterogeneity assessment between studies			Heterogeneity assessment between subgroup		Publication bias assessments
					I 2	p value	Q	Q	p value	β	SE	p value
VIT D	Overall SMD		48 (59)	1.78 (1.53–2.04)	91.92%	≤0.001	718.6	—	—	8.12	0.760	≤0.001
	Continent	Europe	9 (16)	1.10 (0.85–1.36)	71.05%	≤0.001	51.81	18.53	≤0.001
		Asia	39 (43)	2.05 (1.70–2.40)	93.48%	≤0.001	644.13
	Age	<60	33 (35)	1.86 (1.51–2.22)	91.71%	≤0.001	410.18	3.73	0.05
		>60	13 (19)	1.38 (1.05–1.72)	87.23%	≤0.001	140.96
	BMI	<30	25 (30)	1.83 (1.45–2.21)	92.35%	≤0.001	379.13	0.54	0.46
		>30	13 (18)	1.62 (1.22–2.02)	88.85%	≤0.001	152.52
	Disease duration	<10	18 (20)	2.00 (1.57–2.42)	91.70%	≤0.001	229.01	8.71	≤0.001
		>10	1 (2)	0.92 (0.35–1.50)	52.24%	0.15	2.09
	Intervention	<50,000	15 (18)	2.36 (1.73–2.99)	94.62%	≤0.001	315.72	29.76	≤0.001
		50,000–100,000	27 (31)	1.78 (1.46–2.09)	91.09%	≤0.001	336.73
		>100,000	7 (10)	0.86 (0.59–1.13)	45.26%	0.06	16.44
	Follow-up duration	4 weeks	1 (1)	2.42 (1.42–3.41)	—	—	—	41.82	≤0.001
		8 weeks	11 (12)	1.48 (1.08–1.88)	84.02%	≤0.001	68.82
		12 weeks	22 (23)	2.15 (1.64–2.67)	94.18%	≤0.001	377.92
		14 weeks	1 (1)	3.03 (2.23–3.84)	—	—	—
		16 weeks	6 (6)	1.26 (0.53–1.99)	87.56%	≤0.001	40.19
		24 weeks	15 (15)	1.85 (1.36–2.33)	92.73%	≤0.001	192.62
		48 weeks	1 (1)	0.27 (−0.30 to 0.85)	—	—	—