Table 2 Comparison of participants’ characteristics based on clustering analysis

Age (years)

81.9 ± 8.1

84.7 ± 7.1

Z = 0.864

BMI (kg/m²)

23.4 ± 2.8

20.5 ± 3.4

Z = 2.06

*

Sex

Male

4

3

χ2 (1, n = 23) = 0.35

Female

7

9

Drink milk

habit

3

3

χ2 (1, n = 23) = 0.015

no habit

8

9

Eat yogurt

habit

3

3

χ2 (1, n = 23) = 0.015

no habit

8

9

Exercise

habit

1

1

χ2 (1, n = 22) = 0.018

no habit

9

11

False teeth

with

10

11

χ2 (1, n = 23) = 0.041

without

1

1

Number of colds per year

0

1

2

χ2 (2, n = 16) = 1.04

1

3

4

2

1

5

Number of times brush teeth per day

2

1

3

χ2 (2, n = 23) = 2.18

3

10

8

4

0

1

Diabetes

with

1

1

χ2 (1, n = 22) = 0.011

(DM)

without

10

8

Hypertension

with

3

5

χ2 (1, n = 20) = 0.82

(HT)

without

8

4

Parkinson’s disease

with

0

1

χ2 (1, n = 20) = 0.82

(PD)

without

11

8

Heart diseases

with

2

1

χ2 (1, n = 20) = 0.099

(HD)

without

9

8

Hyperthyroidism

with

0

1

χ2 (1, n = 20) = 0.83

(HO)

without

11

8

Cerebrovascular disease

with

7

3

χ2 (1, n = 20) = 0.92

(CD)

without

4

6

Anti-hypertensive agent

use

6

3

χ2 (1, n = 20) = 0.15

(AH)

no use

5

6

Diuretics

use

0

1

χ2 (1, n = 20) = 0.83

(DR)

no use

11

8

Psychotropic drug

use

2

2

χ2 (1, n = 20) = 0.025

(PS)

no use

9

7

Antidepressants

use

1

0

χ2 (1, n = 20) = 0.69

(AD)

no use

10

9

Methyldopa

use

0

1

χ2 (1, n = 20) = 0.83

(ME)

no use

11

8

H2 blocker

use

1

2

χ2 (1, n = 20) = 0.33

(HB)

no use

10

7

Stimulated saliva flow rate (ml/min)

0.46 ± 0.11

0.59 ± 0.085

Z = 2.81

**

*

IgA concentration (μg/ml)

57.7 ± 30.1

107 ± 27.8

Z = 2.89

**

*

IgA secretion rate (μg/min)

26.4 ± 13.5

63.8 ± 16.2

Z = 3.42

***

*