Table 1

Meta-analyses of studies measuring peripheral markers in individuals with AD versus HC

Analyte	Studies	N (AD/HC)	SMD (95% CI)	p-value	X²	I²(%)	Heterogeneity p-value
IL-1β	25	1313/1011	0.727 (0.335 to 1.120)	<0.001	373.46	94.10	<0.001
IL-1 receptor antagonist	4	343/398	−3.661 (−6.692 to 0.631)	0.018	602.6	99.50	<0.001
IL-2	6	336/248	0.878 (0.126 to 1.630)	0.022	74.48	93.30	<0.001
IL-6	40	2295/2498	0.522 (0.240 to 0.804)	<0.001	687.52	94.60	<0.001
IL-18	9	397/379	0.945 (0.143 to 1.748)	0.021	155.11	95.50	<0.001
α1-antichymotrypsin	18	1970/2346	1.564 (0.904 to 2.225)	<0.001	1062.3	98.40	<0.001
CRP	23	2090/2605	0.268 (−0.094 to 0.629)	0.147	446.2	95.70	<0.001
CXCL-10	3	138/144	2.615 (0.082 to 5.148)	0.043	48.59	95.90	<0.001
Epidermal growth factor	5	521/508	2.213 (0.393 to 4.032)	0.017	340.05	98.80	<0.001
Homocysteine	10	362/570	0.535 (0.124 to 0.947)	0.011	75.3	88.00	<0.001
hsCRP	7	896/474	0.551 (0.250 to 0.852)	<0.001	25.64	76.60	<0.001
Interferon-γ	9	382/284	0.461 (0.010 to 0.913)	0.045	46.73	82.90	<0.001
Leptin	9	589/513	−0.433 (−0.846 to 0.020)	0.04	71.63	90.20	<0.001
Soluble TNF-receptor 1	8	668/623	0.760 (0.310 to 1.210)	0.001	97.1	92.80	<0.001
Soluble TNF-receptor 2	5	400/400	0.419 (0.223 to 0.616)	<0.001	6.99	42.70	0.137
TNF-α	44	2433/1984	0.264 (−0.030 to 0.557)	0.078	828.5	94.80	<0.001
TNF-α converting enzyme	3	293/210	0.759 (0.002 to 1.516)	0.049	28.72	93.00	<0.001
Transferrin	4	135/107	−0.270 (−0.538 to 0.002)	0.049	3.18	5.70	0.364
VCAM-1	5	516/290	0.308 (0.018 to 0.598)	0.037	16.65	70.00	0.005

AD, Alzheimer’s disease; CXCL, C-X-C ligand; CRP, C reactive protein; HC, healthy control; hsCRP, high-sensitivity C reactive protein; IL, interleukin; n, number of patients; SMD, standardised mean difference; TNF, tumour necrosis factor; VCAM-1, vascular cell adhesion protein 1.