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Table 1 Descriptive statistics of demographic and health characteristics and study variables. Data presented are means (standard deviations) or counts (%). Between-group differences tested using independent samples t-test for continuous variables and Pearson’s chi-square, Fisher’s Exact test, or Fisher-Freeman-Hamilton Exact test for categorical variablesa

From: The relationship of insulin resistance and diabetes to tau PET SUVR in middle-aged to older adults

 

HOMA-IR sample (N=280)

Amyloid PET positiveb

(n=67)

Amyloid PET negative

(n=213)

p

Diabetic Status sample (N=394)

Diabeticc (n=37)

Non-diabetic (n=357)

p

Age (years)

68.1 (6.6)

70.8 (4.9)

67.3 (6.8)

<.001

68.0 (7.1)

69.8 (7.4)

67.8 (7.1)

.11

Sex (female)

186 (66.4)

41 (61.2)

145 (68.1)

.30

261 (66.2)

24 (64.9)

237 (66.4)

.85

Race/ethnic group:

   

1.0

   

<.001

White

263 (93.9)

63 (94.0)

200 (93.9)

 

358 (90.9)

24 (64.9)

334 (93.6)

<.001

Black

12 (4.3)

3 (4.5)

9 (4.2)

 

22 (5.6)

9 (24.3)

13 (3.6)

<.001

American Indian, Asian, Hispanic/Spanishd

5 (1.8)

1 (1.5)

4 (1.9)

 

14 (3.6)

4 (10.8)

10 (2.8)

.01

Education (years)

16.2 (2.2)

16.1 (2.2)

16.2 (2.2)

.75

16.1 (2.4)

15.6 (2.3)

16.2 (2.4)

.19

     

n=272

HOMA2-IR

n=22

n=250

 

HOMA2-IRe

1.1 (0.7)

1.0 (0.4)

1.1 (0.7)

.18

1.1 (0.7)

1.6 (0.8)

1.0 (0.7)

<.001

     

n=381

Glucose

n=32

n=349

 

Glucose (mg/dL)

98.6 (14.7)

96.1 (9.8)

99.4 (15.8)

.12

98.5 (14.1)

128.9 (23.5)

95.7 (8.7)

<.001

Prediabetesf

74 (26.4)

21 (31.3)

53 (24.9)

.30

100 (25.9)

--

100 (28.0)

 

Diabetes

22 (7.9)

1 (1.5)

21 (9.9)

.03

37 (9.4)

37 (100.0)

--

 

Diabetic medications:

        

 Diabetics

15 (5.4)

0 (0)

15 (7.0)

--

27 (6.9)

27 (73.0)

  

 Non-diabeticsg

2 (0.8)

0 (0)

2 (0.9)

--

4 (1.0)

--

4 (1.1)

 
 

n=276

APOE4 allele status

n=66

n=210

 

n=379

APOE4 allele status

n=33

n=346

 

APOE4 allele status:

   

<.001

   

.09

 Non-carrier

170 (61.6)

23 (34.8)

147 (70.0)

<.001

228 (60.2)

26 (78.8)

202 (58.4)

 

 ε2 ε4

7 (2.5)

1 (1.5)

6 (2.9)

>.05

9 (2.4)

1 (3.0)

8 (2.3)

 

 ε3 ε4

86 (31.2)

33 (50.0)

53 (25.2)

<.001

120 (31.7)

5 (15.2)

115 (33.2)

 

 ε4 ε4

13 (4.7)

9 (13.6)

4 (1.9)

<.001

22 (5.8)

1 (3.0)

21 (6.1)

 

Amyloid PET DVRh

1.16 (0.22)

1.50 (0.23)

1.06 (0.05)

<.001

1.17 (0.23)

1.15 (0.24)

1.17 (0.23)

.58

Amyloid PET positiveb

67 (23.9)

67 (100.0)

0 (0)

--

94 (23.9)

6 (16.2)

88 (24.6)

.25

Tau PET SUVR, ECi

1.09 (0.27)

1.30 (0.41)

1.02 (0.15)

<.001

1.12 (0.32)

1.17 (0.42)

1.12 (.31)

.31

Tau PET positivej

38 (13.6)

25 (37.3)

13 (6.1)

<.001

61 (15.5)

9 (24.3)

52 (14.6)

.12

Tau PET SUVR, MTLk

0.98 (.22)

1.15 (.34)

0.93 (.12)

<.001

1.00 (.27)

1.03 (.34)

1.00 (.26)

.51

Tau PET SUVR, temporal meta-ROIl

1.13 (.25)

1.31 (.43)

1.07 (.11)

<.001

1.15 (.31)

1.17 (.31)

1.15 (.31)

.77

Time to tau PETm (years)

1.06 (1.05)

1.12 (1.10)

1.05 (1.03)

.60

.92 (.94)

.89 (.70)

.93 (.97)

.78

MCIn

9 (3.2)

7 (10.4)

2 (0.9)

.001

23 (5.8)

3 (8.1)

20 (5.6)

.47

Dementian

0 (0)

0 (0)

0 (0)

--

6 (1.5)

2 (5.4)

4 (1.1)

.10

  1. Abbreviations: DVR Distribution volume ratio, EC Entorhinal cortex, HOMA2-IR Homeostasis model assessment of insulin resistance, MCI Mild cognitive impairment, MTL Medial temporal lobe, PET Positron emission tomography, ROI, Region of interest, SUVR, Standardized uptake value ratio
  2. aFor categorical variables with >2 cells, p-value for main effect is noted first followed by p-values for statistically significant post hoc pairwise comparisons
  3. bAmyloid PET positive: average Pittsburgh Compound B (PiB) DVR > 1.19 from 8 bilateral regions at PiB PET closest in time to tau PET
  4. cDiabetes identified by clinician or self-report of diabetes or fasting glucose ≥ 126 mg/dL
  5. dThe 3 race/ethnic groups were combined to maintain anonymity for groups with < 3 individuals
  6. eHOMA2-IR has no reference range; a value of 1.0 approximates normal (Wallace, Levy, & Matthews, 2004). HOMA2-IR values in the Diabetic Status sample are from WRAP participants only
  7. fPrediabetes identified by fasting glucose ≥ 100 mg/dL (American Diabetes Association, 2010)
  8. gOff-label use of metformin in non-diabetics
  9. hValue represents average PiB PET DVR across 8 bilateral regions
  10. iValue represents average tau PET SUVR from bilateral entorhinal cortex
  11. jTau PET positive: average tau PET SUVR > 1.27 from bilateral entorhinal cortex
  12. kValue represents average tau PET SUVR from bilateral entorhinal cortex, hippocampus, and amygdala
  13. lValue represents average tau PET SUVR from bilateral parahippocampal gyrus, amygdala, fusiform cortex, and inferior and middle temporal gyrus
  14. mTime between predictor (HOMA2-IR or diabetic status) and tau PET
  15. nDiagnosed using NIA-AA criteria and consensus conference
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Alzheimer's Research & Therapy

ISSN: 1758-9193