Skip to main content

Table 2 Descriptive statistics of demographic and health characteristics and study variables in the Diabetic Status sample characterized according to amyloid PET positivity status. Data presented are means (standard deviations) or counts (%). Between-group differences tested using 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

 

(N=394)

Diabeticb amyloid PET positivec

(n=6)

Non-diabetic amyloid PET positivec

(n=88)

p

Diabeticb amyloid PET negative

(n=31)

Non-diabetic amyloid PET negative

(n=269)

p

Age (years)

68.0 (7.1)

75.12 (6.4)

71.3 (5.2)

.09

68.7 (7.2)

66.7 (7.2)

.14

Sex (female)

261 (66.2)

4 (66.7)

55 (62.5)

1.0

20 (64.5)

182 (67.7)

.84

Race/ethnic group:

   

.002

  

<.001

White

358 (90.9)

3 (50.0)

84 (95.5)

<.001

21 (67.7)

250 (92.9)

<.001

Black

22 (5.6)

1 (16.7)

3 (3.4)

>.05

8 (25.8)

10 (3.7)

<.001

American Indian, Asian, Hispanic/Spanishd

14 (3.6)

2 (33.3)

1 (1.1)

<.001

2 (6.5)

9 (3.3)

>.05

Education (years)

16.1 (2.4)

17.3 (2.1)

16.1 (2.3)

.18

15.3 (2.2)

16.2 (2.4)

.05

 

n=272

HOMA2-IR

n=1

n=66

 

n=21

n=184

 

HOMA2-IRe

1.1 (0.7)

0.5

1.0 (0.4)

--

1.7 (0.9)

1.1 (0.7)

<.001

 

n=381

Glucose

n=5

n=85

 

n=27

n=264

 

Glucose (mg/dL)

98.5 (14.1)

117.6 (31.7)

96.5 (9.1)

.21

131.0 (21.8)

95.5 (8.6)

<.001

Prediabetesf

100 (25.9)

--

28 (32.9)

 

--

72 (27.3)

 

Diabetic medications:

       

 Diabetics

27 (6.9)

3 (50.0)

--

 

24 (77.4)

--

 

 Non-diabeticsg

4 (1.0)

--

0 (0.0)

 

--

4 (1.5)

 
 

n=379

APOE4 allele status

n=5

n=83

 

n=28

n=263

 

APOE4 allele status:

      

.14

 Non-carrier

228 (60.2)

2 (40.0)

27 (32.5)

1.0

24 (85.7)

175 (66.5)

 

 ε2 ε4

9 (2.4)

0 (0.0)

1 (1.2)

 

1 (3.6)

7 (2.7)

 

 ε3 ε4

120 (31.7)

2 (40.0)

40 (48.2)

 

3 (10.7)

75 (28.5)

 

 ε4 ε4

22 (5.8)

1 (20.0)

15 (8.1)

 

0 (0.0)

6 (2.3)

 

Amyloid PET DVRh

1.17 (0.23)

1.62 (.31)

1.50 (.23)

.25

1.06 (.05)

1.06 (.05)

.72

Tau PET SUVR, ECi

1.12 (0.32)

1.94 (.53)

1.37 (.48)

.006

1.02 (.15)

1.03 (.17)

.83

Tau PET positivej

61 (15.5)

6 (100.0)

37 (42.0)

.007

3 (9.7)

15 (5.6)

.41

Tau PET SUVR, MTLk

1.00 (.27)

1.62 (.49)

1.21 (.40)

.02

.92 (.11)

.93 (.13)

.52

Tau PET SUVR, temporal meta-ROIl

1.15 (.31)

1.70 (.44)

1.37 (.53)

.15

1.06 (.11)

1.08 (.11)

.48

Time to tau PETm (years)

.92 (.94)

.96 (.92)

1.02 (1.05)

.90

.88 (.67)

.90 (.94)

.89

MCIn

23 (5.8)

1 (16.7)

15 (17.0)

1.0

2 (6.5)

5 (1.9)

.16

Dementian

6 (1.5)

1 (16.7)

3 (3.4)

.24

1 (3.2)

1 (0.4)

.20

  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. bDiabetes identified by clinician or self-report of diabetes or fasting glucose ≥ 126 mg/dL
  4. cAmyloid PET positive: average Pittsburgh Compound B (PiB) DVR > 1.19 from 8 bilateral regions at PiB PET closest in time to tau PET
  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