Glymphatic function and its influencing factors in different glucose metabolism states

Table 1 Demographic and clinical characteristics of the study population

Characteristics	NGM (n = 22)	Prediabetes (n = 20)	T2DM (n = 22)	P value	Bonferroni-adjusted P value
Age (years)	51.27 ± 6.80	49.70 ± 7.62	49.36 ± 7.42	0.653	1
Female, n (%)	11 (50)	9 (45)	10 (45)	0.942	1
Education (years)	14.50 ± 3.21	15.25 ± 3.00	14.41 ± 2.54	0.443	1
BMI (kg/m2)	23.38 ± 2.11	25.33 ± 3.35	25.75 ± 3.83	0.041	1
Weight (kg)	62.39 ± 8.05	68.43 ± 13.59	69.30 ± 12.66	0.111	1
Height (cm)	163.11 ± 5.29	163.78 ± 10.88	163.73 ± 7.14	0.961	1
Waist (cm)	82.91 ± 5.13	87.88 ± 10.21	92.07 ± 10.09	0.0041	0.166
Hip (cm)	95.42 ± 3.90	96.43 ± 7.16	96.38 ± 7.19	0.841	1
Waist-to-hip ration	0.87 ± 0.07	0.91 ± 0.07	0.95 ± 0.09	0.0043	0.151
Systolic BP (mmHg)	119.86 ± 15.63	124.10 ± 10.75	135.14 ± 23.94	0.0263	1
Diastolic BP (mmHg)	71.77 ± 13.80	76.25 ± 10.37	87.32 ± 21.32	0.0093	0.3792
TC (mmol/L)	5.27 ± 1.03	5.37 ± 0.93	5.73 ± 1.53	0.553	1
TG (mmol/L)	1.82 ± 1.11	2.00 ± 1.60	3.15 ± 2.98	0.033	1
HDL (mmol/L)	1.48 ± 0.40	1.34 ± 0.37	1.30 ± 0.32	0.323	1
LDL (mmol/L)	2.88 ± 0.94	3.10 ± 0.89	3.18 ± 0.82	0.543	1
FPG (mmol/L)	4.88 ± 0.28	5.54 ± 0.84	9.43 ± 7.39	< 0.0013	< 0.001
2hPG (mmol/L)	6.05 ± 1.21	9.20 ± 0.94	16.28 ± 6.72	< 0.0013	< 0.001
Fasting insulin (pmol/L)	56.09 ± 22.19	89.27 ± 59.74	101.32 ± 1.31	0.043	1
HbA1c [mmol/mol (%)]	5.64 ± 0.42	6.01 ± 0.51	8.51 ± 3.42	< 0.0013	< 0.001
HOMA-IR	2.04 ± 0.87	3.87 ± 3.42	6.16 ± 5.29	0.0023	0.002
MMSE	29.77 ± 0.53	29.80 ± 0.41	29.00 ± 1.38	0.023	0.79

¹ANOVA test.

²Pearson’s χ² test.

³Kruskal-Wallis rank sum test.

Continuous variables are expressed as mean ± SD and categorical variables are expressed as frequencies. NGM: Normal glucose metabolism; T2DM: Type 2 diabetes mellitus; BMI: Body mass index; BP: Blood pressure; TC: Total cholesterol; TG: Triglycerides; HDL: High-density lipoprotein; LDL: Low-density lipoprotein; FPG: Fasting plasma glucose; 2hPG: 2-hour postprandial glucose; HbA1c: Glycosylated hemoglobin; HOMA-IR: Homeostatic insulin resistance model; MMSE: Mini-mental state examination.

Table 2 Correlations between clinical features and biomarkers of the glymphatic system in prediabetes and type 2 diabetes mellitus

Characteristic	Prediabetes (n = 20)			T2DM (n = 22)
	L-DTI-ALPS (95%CI)	R-DTI-ALPS (95%CI)	Mean-DTI-ALPS (95%CI)	L-DTI-ALPS (95%CI)	R-DTI-ALPS (95%CI)	Mean-DTI-ALPS (95%CI)
Age	-0.215 (-0.540, 0.234)1	-0.353 (-0.660, 0.076)1	-0.357 (-0.642, -0.020)1	-0.136 (-0.525, 0.244)1	-0.068 (-0.460, 0.344)1	-0.105 (-0.510, 0.277)1
Education years	0.242 (-0.385, 0.732)2	0.108 (-0.552, 0.600)2	0.227 (-0.457, 0.737)2	0.214 (-0.327, 0.676)2	0.027 (-0.510, 0.496)2	0.048 (-0.483, 0.544)2
BMI	-0.075 (-0.514, 0.404)1	-0.146 (-0.593, 0.394)1	-0.140 (-0.590, 0.326)1	0.161 (-0.245, 0.501)1	0.115 (-0.250, 0.516)1	0.147 (-0.270, 0.549)1
Weight	0.169 (-0.386, 0.477)1	-0.104 (-0.499, 0.466)1	0.034 (-0.450, 0.406)1	0.327 (0.005, 0.558)1	0.323 (0.068, 0.586)1	0.357 (0.095, 0.579)1
Height	0.332 (-0.364, 0.653)1	0.100 (-0.547, 0.540)1	0.264 (-0.434, 0.636)1	0.554 (-0.142, 0.822)1,b	0.621 (0.096, 0.828)1,b	0.651 (0.016, 0.853)1,b
Waist	-0.153 (-0.583, 0.314)1	-0.198 (-0.567, 0.441)1	-0.220 (-0.582, 0.298)1	0.376 (-0.022, 0.667)1	0.130 (-0.190, 0.481)1	0.255 (-0.129, 0.576)1
Hip	-0.077 (-0.469, 0.393)1	0.184 (-0.264, 0.581) 1	0.073 (-0.346, 0.478)1	0.370 (0.011, 0.661)1	0.230 (-0.139, 0.639)1	0.316 (-0.002, 0.651)1
Waist-to-hip ratio	-0.152 (-0.658, 0.349)2	-0.495 (-0.784, 0.017)2,a	-0.467 (-0.770, 0.067)2,a	0.326 (-0.147, 0.671)2	0.124 (-0.388, 0.547)2	0.298 (-0.275, 0.673)2
Systolic BP (mmHg)	-0.204 (-0.634, 0.276)2	-0.168 (-0.551, 0.277)2	-0.203 (-0.701, 0.261)2	0.086 (-0.410, 0.536)2	0.152 (-0.380, 0.587)2	0.105 (-0.437, 0.560)2
Diastolic BP (mmHg)	-0.029 (-0.436, 0.515)2	-0.242 (-0.634, 0.188)2	-0.147 (-0.563, 0.323)2	0.193 (-0.338, 0.581)2	-0.162 (-0.653, 0.326)2	0.004 (-0.521, 0.460)2
TC	-0.567 (-0.831, -0.152)2,a	-0.107 (-0.584, 0.389)2	-0.411 (-0.734, 0.042)2	0.043 (-0.442, 0.510)2	-0.098 (-0.577, 0.434)2	-0.056 (-0.559, 0.454)2
TG	0.035 (-0.527, 0.555)2	-0.160 (-0.654, 0.323)2	-0.140 (-0.675, 0.390)2	0.151 (-0.296, 0.581)2	0.093 (-0.447, 0.538)2	0.128 (-0.353, 0.614)2
HDL	-0.294 (-0.720, 0.235)2	0.214 (-0.302, 0.637)2	-0.039 (-0.564, 0.416)2	-0.544 (-0.792, -0.109)2,a	-0.409 (-0.717, 0.070)2	-0.544 (-0.802, -0.013)2,a
LDL	-0.545 (-0.801, -0.022)2,a	-0.186 (-0.674, 0.338)2	-0.443 (-0.792, 0.022)2	0.148 (-0.408, 0.573)2	-0.047 (-0.530, 0.484)2	0.046 (-0.474, 0.506)2
FPG	-0.270 (-0.681, 0.372)2	-0.343 (-0.712, 0.113)2	-0.410 (-0.750, 0.134)2	0.138 (-0.228, 0.573)2	0.235 (-0.234, 0.567)2	0.226 (-0.217, 0.555)2
2hPG	0.582 (0.192, 0.830)2,a	0.193 (-0.428, 0.673)2	0.477 (-0.103, 0.797)2,a	-0.182 (-0.657, 0.332)2	-0.348 (-0.689, 0.254)2	-0.380 (-0.731, 0.151)2
HbA1c	-0.325 (-0.690, 0.227)2	-0.662 (-0.867, -0.122)2,b	-0.725 (-0.886, -0.398)2,b	-0.036 (-0.439, 0.376)2	0.251 (-0.329, 0.653)2	0.175 (-0.326, 0.513)2
Fasting insulin	0.152 (-0.298, 0.550)2	-0.265 (-0.646, 0.156)2	-0.057 (-0.503, 0.363)2	0.091 (-0.384, 0.463)2	-0.069 (-0.519, 0.420)2	-0.006 (-0.473, 0.415)2
HOMA-IR	0.115 (-0.339, 0.582)2	-0.286 (-0.640, 0.201)2	-0.100 (-0.525, 0.367)2	0.140 (-0.347, 0.576)2	0.035 (-0.455, 0.474)2	0.094 (-0.419, 0.505)2
MMSE	-0.197 (-0.678, 0.450)2	-0.336 (-0.725, 0.355)2	-0.350 (-0.740, 0.540)2	-0.117 (-0.596, 0.316)2	0.106 (-0.411, 0.595)2	0.065 (-0.420, 0.515)2

^aP < 0.05.

^bP < 0.01.

¹Pearson correlation coefficient.

²Spearman correlation coefficient.

Results are expressed as correlation coefficients and 95%CI. DTI-ALPS: Diffusion tensor image analysis method along the perivascular space; L-DTI-ALPS: Diffusion tensor image analysis method along the perivascular space index of the left cerebral hemisphere in prediabetes and type 2 diabetes; R-DTI- ALPS: Diffusion tensor image analysis method along the perivascular space index of the right cerebral hemisphere of prediabetes and type 2 diabetes; Mean-DTI-ALPS: Mean diffusion tensor image analysis method along the perivascular space index in both cerebral hemispheres; T2DM: Type 2 diabetes mellitus; NGM: Normal glucose metabolism; BMI: Body mass index; BP: Blood pressure; TC: Total cholesterol; TG: Triglycerides; HDL: High-density lipoprotein; LDL: Low-density lipoprotein; FPG: Fasting plasma glucose; 2hPG: 2-hour postprandial glucose; HbA1c: Glycosylated hemoglobin; HOMA-IR: Homeostatic insulin resistance model; MMSE: Mini-mental state examination.