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Table 2 Descriptive statistics showing covariates and exposures in the analysis of Alzheimer’s disease and Multiple sclerosis, 45-84 years old, 1994-1998

From: Road proximity, air pollution, noise, green space and neurologic disease incidence: a population-based cohort study

Level

Covariates

 

Alzheimer’s disease (N= 13498)

Multiple Sclerosis (N=7232)

Case (N= 1227)

Control (N = 12271)

Case (N= 658)

Control (N = 6574)

   

Count

%

Count

%

Count

%

Count

%

Individual

Comorbiditya

No

642

52.3

7164

58.4

527

80.1

5300

80.6

Yes

585

47.7

5107

41.6

131

19.9

1274

19.4

Neighborhood

Household income

Lowest

312

25.4

2948

24.0

113

17.2

1071

16.3

Low

238

19.4

2368

19.3

136

20.7

1166

17.6

Middle

200

16.3

2275

18.6

130

19.8

1293

19.7

Upper middle

253

20.6

2235

18.2

140

21.2

1483

22.6

Upper

224

18.3

2445

19.9

139

21.1

1561

23.8

Education

Less than secondary

275

22.4

2886

23.5

130

20.8

1415

21.5

Secondary

327

26.7

3314

27.0

159

24.2

1755

26.7

Post-secondary

625

50.9

6071

49.5

369

55.0

3404

51.8

Chinese

<10% of population in Neighborhood

699

57.0

5890

48.0

337

51.2

3147

47.9

> 10% of population in Neighborhood

528

43.0

6381

52.0

321

48.3

3427

52.1

South Asian

<10% of population in Neighborhood

513

41.8

6125

49.9

329

50.0

3030

46.1

> 10% of population in Neighborhood

714

58.2

6146

50.1

329

50.0

3544

53.9

Visible minority

<10% of population in Neighborhood

959

78.2

9625

78.4

518

78.7

5138

78.2

> 10% of population in Neighborhood

268

21.8

2646

21.6

140

21.3

1436

21.8

Exposures

  

Alzheimer’s disease (N= 13498)

Multiple Sclerosis (N=7232)

  

Case (N= 1227)

Control (N = 12271)

Case (N= 658)

Control (N = 6574)

Road proximity

  

Count

%

Count

%

Count

%

Count

%

Highway <50m

No

1203

98.1

12064

98.3

640

97.3

6434

97.9

Yes

24

1.9

207

1.7

18

2.7

140

2.1

Highway <150m

No

1169

95.3

11728

95.5

615

93.5

6194

94.2

Yes

58

4.7

545

4.5

43

6.5

380

5.8

Major road <50m

No

1134

92.4

11543

94.1

591

89.8

6082

92.5

Yes

93

7.6

728

5.9

67

10.2

492

7.5

Major road <50m or Highway <150m

No

1082

88.2

11060

90.1

556

84.5

5759

87.6

Yes

145

11.8

1211

9.9

102

15.5

815

12.4

Air pollution

 

Minimum

Medium

Maximum

Interquartile

Minimum

Medium

Maximum

Interquartile

Minimum

Medium

Maximum

Interquartile

Minimum

Medium

Maximum

Interquartile

PM2.5 (μg/m³)

0.7

4.0

10.2

1.5

0.0

4.0

10.2

1.5

0.6

4.1

10.2

1.5

0.0

3.9

10.4

1.7

Black carbon (μg/m³)

0.0

1.0

5.0

1.2

0.0

1.0

5.0

1.1

0.0

1.0

5.0

1.3

0.0

1.0

5.0

0.9

NO2 (ppb)

16.4

28.5

57.5

8.2

12.2

30.5

62.4

9.0

14.4

30.1

57.6

8.0

11.8

29.6

58.0

8.8

NO (ppb)

13.2

27.5

108.1

10.4

6.8

29.2

126.0

13.9

11.0

29.6

71.3

14.5

7.1

28.1

108.9

13.4

Noise (Lden dB(A))

 

44.5

60.6

77.2

5.6

32.2

60.7

85.8

5.8

36.2

60.3

82.5

5.4

33.4

60.6

84.4

5.6

Greenness (NDVI)

 

-0.0

0.3

0.6

0.1

-0.1

0.3

0.6

0.1

0.0

0.3

0.5

0.1

-0.1

0.3

0.6

0.1

  1. aComorbidities include traumatic brain injury, diabetes, hypertension, stroke, coronary heart disease, congestive heart failure and arrhythmia