Table 3.

Subgroup analysis results of QSM values based on age and gender differences.

Brain region	Subgroup	SMD (95%CI)	p-valuea	I2 (%)b/Phetrogenity	kc
Putamen	Age
	≤ 69	0.68 (0.39, 0.96)	0.06	0.00/0.31	4
	> 69	1.73 (0.69, 2.77)		89.69/0.00	4
	Sex (male%)
	≤ 30%	1.51 (0.61, 2.40)	0.41	84.70/0.00	4
	>30%	0.98 (0.11, 1.85)		89.66/0.00	4
	Geographic Distribution
	Asia	1.33 (0.54, 2.12)	0.53	90.56/0.00	6
	Non Asia	0.95 (0.08, 1.82)		65.19/0.09	2
	Risk of bias (ROB)
	High ROB	1.01 (0.15, 1.86)	0.46	88.91/0.00	4
	Low ROB	1.48 (0.55, 2.42)		86.35/0.00	4
Globus pallidus	Age
	≤ 69	0.26 (−0.04, 0.56)	0.09	0.00/0.43	3
	> 69	1.37 (0.14, 2.60)		89.62//0.00	3
	Sex (male%)
	≤ 30%	0.65 (0.08, 1.22)	0.72	64.21/0.07	3
	>30%	0.94 (−0.57, 2.46)		94.70/0.00	3
	Risk of bias (ROB)
	High ROB	0.80 (−0.29, 1.88)	0.99	93.17//0.00	3
	Low ROB	0.81 (−0.14, 1.76)		76.44/0.04	3
Caudate nucleus	Age
	≤ 69	0.53 (0.25, 0.81)	0.02	0.00/0.52	4
	> 69	1.20 (0.72, 1.69)		14.32/0.28	2
	Sex (male%)
	≤ 30%	0.73 (0.38, 1.07)	0.91	0.00/0.28	3
	>30%	0.77 (0.13, 1.41)		73.24//0.03	3
	Geographic distribution
	Asia	0.90 (0.54, 1.26)	0.04	38.61/0.18	4
	Non Asia	0.30 (−0.16, 0.76)		0.00/0.70	2
	Risk of bias (ROB)
	High ROB	0.77 (0.34, 1.20)	0.71	58.94/0.07	3
	Low ROB	0.60 (−0.16, 1.37)		57.99//0.12	3
Thalamus	Age
	≤ 69	−0.08 (−0.61, 0.44)	0.12	47.27/0.17	2
	> 69	1.57 (−0.48, 3.62)		97.46//0.00	4
	Sex (male%)
	≤ 30%	2.53 (−2.01, 7.06)	0.34	97.61/0.00	2
	>30%	0.31 (−0.18, 0.81)		70.26//0.02	4
	Risk of bias (ROB)
	High ROB	0.19 (−0.43, 0.81)	0.26	73.03/0.02	2
	Low ROB	1.88 (−0.97, 4.72)		98.00/0.00	4

AD, Alzheimer’s disease; CI, confidence interval; QSM, quantitative susceptibility mapping; SMD, standardized mean difference.

^aTest of group differences, p-value < 0.05.

^bA statistical measure of study heterogeneity.

^cNumber of studies.