Table 3.

Random-effect models of brain volumes and atrophy rates in normal controls and type 2 diabetes mellitus patients, including total volumes and differences between groups

Brain areas	Group	k	No.	Male, %	Age, yr	Volume, cm3	SE	95% CI	Sig	tau2	tau	I 2	QE
Total brain volume	All	30	18,214	42.863	67.392	1120.675	30.243	1,061.400 to 1,179.950	a	27,198.99	164.9212	99.98716	76,018.724
	Normal	15	15,937	42.731	67.328	1132.803	44.902	1,044.797 to 1,220.808	a	30,041.44	173.3247	99.99302	66,446.501
	T2DM	15	2,277	43.786	67.846	1108.552	41.846	1,026.535 to 1,190.569	a	25,986.99	161.2048	99.91959	8,472.641
	T2DM-normal	15	18,214	42.863	67.392	−20.502	5.851	−31.970 to −9.034	a	439.6137	20.96697	99.57289	487.3966
Grey matter volume	All	48	18,592	42.938	66.513	596.956	12.889	571.694 to 622.218	a	7,886.426	88.80555	99.91265	121,045.52
	Normal	24	15,475	42.488	66.608	605.984	18.299	570.119 to 641.849	a	7,947.538	89.14896	99.94295	101,310.41
	T2DM	24	3,117	45.172	66.039	587.935	18.363	551.944 to 623.925	a	8,005.686	89.4745	99.77253	19,310.03
	T2DM-normal	24	18,592	42.938	66.513	−17.433	4.296	−25.853 to −9.013	a	405.1253	20.12772	99.13594	808.9859
White matter volume	All	44	17,056	42.642	67.164	493.281	10.613	472.481 to 514.081	a	4,874.427	69.8171	99.89194	25,351.214
	Normal	22	14,091	42.247	67.330	499.042	14.641	470.346 to 527.739	a	4,645.458	68.1576	99.92809	16,527.384
	T2DM	22	2,965	44.519	66.376	487.500	15.610	456.904 to 518.095	a	5,269.203	72.58927	99.66385	7,907.034
	T2DM-normal	22	17,056	42.642	67.164	−10.733	2.864	−16.347 to −5.119	a	148.5759	12.18917	98.16723	251.0688
Hippocampal volume	All	28	11,254	47.672	62.288	3.318	0.113	3.097 to 3.540	a	0.3543962	0.5953118	99.72612	7,037.232
	Normal	14	9,935	48.676	62.175	3.394	0.161	3.078 to 3.710	a	0.3602119	0.6001765	99.69904	2,707.878
	T2DM	14	1,319	40.106	63.134	3.243	0.162	2.926 to 3.561	a	0.3639983	0.6033227	99.54532	2,151.285
	T2DM-normal	14	11,254	47.672	62.288	−0.151	0.045	−0.239 to −0.063	a	0.02663409	0.1631996	97.89546	401.8367
Thalamus volume	All	8	10,328	47.366	61.983	7.562	0.089	7.388 to 7.736	a	0.05621649	0.2371002	96.45107	123.66
	Normal	4	9,703	46.450	61.861	7.723	0.112	7.503 to 7.942	a	0.04570418	0.2137854	94.21684	25.00385
	T2DM	4	625	61.600	63.878	7.387	0.074	7.242 to 7.532	a	0.01404856	0.1185266	70.47676	10.83599
	T2DM-normal	4	10,328	47.366	61.983	−0.325	0.062	−0.447 to −0.203	a	0.01298164	0.113937	88.01778	20.0754
Caudate volume	All	6	9,929	47.386	61.886	3.353	0.042	3.270 to 3.436	a	0.009062094	0.09519503	93.94834	74.60724
	Normal	3	9,350	46.503	61.793	3.408	0.049	3.312 to 3.504	a	0.005463963	0.07391862	79.6928	12.1904
	T2DM	3	579	61.658	63.392	3.302	0.065	3.174 to 3.430	a	0.011110639	0.10540702	89.75669	20.24112
	T2DM-normal	3	9,929	47.386	61.886	−0.090	0.025	−0.139 to −0.041	a	0.001316991	0.03629038	73.38077	5.694014
Putamen volume	All	6	9,929	47.386	61.886	4.745	0.050	4.647 to 4.843	a	1.21E-02	0.110161803	92.06085	56.336064
	Normal	3	9,350	46.503	61.793	4.814	0.081	4.656 to 4.973	a	1.71E-02	0.13082691	89.303203	11.837765
	T2DM	3	579	61.658	63.392	4.689	0.023	4.644 to 4.735	a	8.96E-05	0.009463786	3.049979	1.536428
	T2DM-normal	3	9,929	47.386	61.886	−0.139	0.062	−0.260 to −0.017	c	0.009963195	0.09981581	88.87643	10.80907
Globus pallidus volume	All	6	9,929	47.386	61.886	1.762	0.016	1.731 to 1.793	a	0.000838993	0.02896537	79.07953	37.0150961
	Normal	3	9,350	46.503	61.793	1.782	0.002	1.778 to 1.786	a	0	0	0	0.5905017
	T2DM	3	579	61.658	63.392	1.766	0.043	1.681 to 1.851	a	0.004061401	0.06372913	81.56729	6.5953594
	T2DM-normal	3	9,929	47.386	61.886	−0.014	0.038	−0.089 to 0.060		0.003180063	0.05639205	91.2341	14.47432
Amygdala volume	All	6	9,929	47.386	61.886	1.299	0.037	1.226 to 1.372	a	0.007582182	0.08707572	97.63179	39.40874
	Normal	3	9,350	46.503	61.793	1.298	0.055	1.190 to 1.405	a	0.008433407	0.09183358	95.38069	21.78316
	T2DM	3	579	61.658	63.392	1.303	0.065	1.175 to 1.431	a	0.011780498	0.108538	95.01308	17.51575
	T2DM-normal	3	9,929	47.386	61.886	−0.003	0.002	−0.007 to 0.002		0	0	0	0.872544
Nucleus accumbens volume	All	6	9,929	47.386	61.886	0.429	0.010	0.409 to 0.448	a	0.000398667	0.01996666	90.67598	107.1207294
	Normal	3	9,350	46.503	61.793	0.446	0.011	0.424 to 0.468	a	0.000247974	0.01574719	68.49809	7.0336341
	T2DM	3	579	61.658	63.392	0.415	0.004	0.406 to 0.423	a	0	0	0	0.7617099
	T2DM-normal	3	9,929	47.386	61.886	−0.035	0.012	−0.059 to −0.012	b	0.000331685	0.01821223	83.76001	12.15621
Nucleus accumbens volume	All	6	9,929	47.386	61.886	0.429	0.010	0.409 to 0.448	a	0.000398667	0.01996666	90.67598	107.1207294
	Normal	3	9,350	46.503	61.793	0.446	0.011	0.424 to 0.468	a	0.000247974	0.01574719	68.49809	7.0336341
	T2DM	3	579	61.658	63.392	0.415	0.004	0.406 to 0.423	a	0	0	0	0.7617099
	T2DM-normal	3	9,929	47.386	61.886	−0.035	0.012	−0.059 to −0.012	b	0.000331685	0.01821223	83.76001	12.15621
Superior temporal gyrus volume	All	10	347	50.432	59.351	20.376	2.597	15.286 to 25.465	a	66.93965	8.181666	99.64734	1,633.6882
	Normal	5	179	49.721	59.856	20.570	3.961	12.807 to 28.333	a	77.96256	8.829641	99.66233	841.5952
	T2DM	5	168	51.190	58.812	20.189	3.827	12.689 to 27.690	a	72.71978	8.527589	99.64757	777.338
	T2DM-normal	5	347	50.432	59.351	−0.183	0.153	−0.482 to 0.116		0	0	0	3.195813
CSF volume	All	20	5,602	44.199	73.170	355.538	42.541	272.159 to 438.917	a	35,986.88	189.7021	99.93566	10,942.665
	Normal	10	4,363	46.161	74.898	353.829	62.682	230.975 to 476.682	a	39,060.57	197.6375	99.91702	5,588.27
	T2DM	10	1,239	37.288	67.084	357.362	60.961	237.881 to 476.844	a	36,975.35	192.2898	99.90901	4,253.568
	T2DM-normal	10	5,602	44.199	73.170	7.145	5.092	−2.835 to 17.126		210.2279	14.49924	93.53862	101.4667
WMH volume	All	24	16,100	46.043	66.355	6.040	1.101	3.882 to 8.198	a	27.38855	5.233407	99.72127	3,723.2096
	Normal	12	14,030	44.647	66.114	6.282	1.509	3.324 to 9.241	a	24.58371	4.958196	99.71089	2,849.344
	T2DM	12	2,070	55.507	67.986	5.824	1.659	2.571 to 9.076	a	32.50942	5.701703	99.54469	873.7837
Atrophy rate (%/year)	All	8	4,283	30.983	74.948	−0.00565	0.00080	−0.00722 to −0.00408	a	4.78E-06	0.00218744	99.34591	256.421
	Normal	4	3,544	27.906	75.651	−0.00537	0.00129	−0.00790 to −0.00285	a	6.32E-06	0.002513821	99.53845	189.94315
	T2DM	4	739	45.737	71.774	−0.00598	0.00116	−0.00825 to −0.00370	a	4.97E-06	0.002228805	98.69538	63.01815
	T2DM-normal	4	4,283	30.983	74.948	−0.00072	0.00006	−0.00083 to −0.00062	a	0.00E+00	0	0	0.8717236

k, number of studies; SE, standard error; CI, confidence interval; Sig, statistical significance; QE, test statistic of Cochran’s test of heterogeneity; T2DM, type 2 diabetes mellitus; CSF, cerebrospinal fluid; WMH, white matter hyperintensity.

^aP<0.001,

^bP<0.01,

^cP<0.05.