Table 1 Operationalization of the study variables and their categorization for analyses

Study Outcomes: Xerostomia

Self-reported mouth dryness:

'1' never,

'2' sometimes,

'3' often,

'4' always

'1' never/sometimes,

'2' often/always

'1' control group,

'2' xerostomia group

Sicca syndrome

'1' Sicca syndrome

'2' Non-Sicca syndrome

'1' Objective symptoms of Sicca syndrome

'2' No objective symptoms of Sicca syndrome

Indicators:

Gender

1) males, 2) females

'1' males, '2' females

'1' males, '2' females

Age

In full years

'1′ 35–46 years, '2′ 47–60 yrs.; '3′ 61–74 yrs

'1′ 35–60 yrs.;

'2′ 61–74 yrs

Residence

Location of residence:

'1' urban;

'2' peri-urban;

'3' rural

‘1’ urban; ‘2’ peri-urban; ‘3’ rural

'1' urban;

'2' peri-urban/rural

Education

In full years

'1' ≤ secondary; '2' college; '3' university + 

'1' secondary or less;

'2' college/university or more

Systemic diseases

(Total number)

Any systemic condition

'1' none; '2' one, '3' two or more conditions

'1' none;

'2' one or more

Medications

(Total number)

Any medication

'1' none; '2' one, '3' two or more

'1' none;

'2' one or more

Perceived stress Total stress score (%)

10 questions (responses: '0' never; '1' rarely; '2' sometimes; '3' often; '4' very often. calculated from responses 3 and 4 and adjusted for the number of answers

'1' low; '2' medium, '3' high/very high

'1' low;

'2' medium/high/very high

Body Mass Index (BMI)

Based on weight & height

(BMI = kg/m²)

'1' BMI ≤ 25.0; '2' BMI 25.1–29.9; '3' BMI ≥ 30

'1' underweight/normal;

'2' overweight/obese

Smoking

'1' no; '2' yes

'1' no; '2' yes

'1' no

'2' yes;

Daily alcohol use in units¹

Alcohol consumed in the past month: '0' none; '1' one unit; '2' two units, '3' units; '4' units; '5' five or more

'1' no; '2' yes

'1' no;

'2' yes