Table 1 Description of explanatory variables

 Smoking

0 = No

Question: What is your current smoking status?

1 = Yes

 Smoking quantity

0 = No smoking

According to the smoking index (smoking index = number of cigarettes per day * number of years of smoking), the smoking amount is divided into light, moderate and heavy.

1 = Low (light smoking)

2 = Moderate

3 = High (heavy smoking)

 Drinking

0 = No

Question: Did you drink in the past six months?

1 = Yes

 Drinking volume

0 = No drinking

Judging whether to drink too much according to the 2007 standard of China chronic disease and its risk factors monitoring report.

1 = Non-excessive drinking

2 = Excessive drinking

 Smoking and drinking

0 = No smoking or no drinking

1 = Both smoking and drinking

We extended a new dependent variable, both smoking and drinking, according to whether to smoke and whether to drink.

  Age, years

1 = 15–45

Question: Year of birth.

2 = 46–59

3 = ≥60

  Sex

0 = Male

Question: What is your gender?

1 = Female

  Number of siblings

1 = ≤2

Question: What is your household registration number?

2 = 3 or 4

3 = ≥5

  Marital status

1 = Unmarried

Question: What is your present marital status?

2 = Married

3 = Divorced/widowed/other

  Place of residence

0 = Urban

Question: Where do you live? Urban or rural areas?

1 = Rural

  Social health insurance

0 = No

Question: Do you participate in social medical insurance?

1 = Yes

 Income level

1 = Very low(≤12,453)

Yearly household income divided by the number of household members; first household member with a weight of 1, all following household members with a weight of 0.5.

2 = Low(12,453 ~ 20,000)

3 = Middle(20,000 ~ 29,284)

4 = High(29,284 ~ 43,773)

5 = Very high(≥43,773)

 Education

1 = Primary school

Question: What’s the highest level of education in last waves?

2 = Junior school

3 = High school

4 = University or higher

 Employment status

1 = Employed

Question: What is your present employment situation?

2 = Retired

3 = Unemployed

 Type of occupation

1 = Unskilled labor

Question:What is your occupation type?

2 = Skilled labor

3 = Other or unemployed

 Poor or low-security household

0 = No

Question: Is your family listed as a local poor or low-income family?

1 = Yes

 Chronic disease

0 = No

Question: Have you had a chronic disease diagnosed by your doctor?

1 = Yes

 Multiple chronic diseases

0 = No

“Yes” is defined as having two or more chronic diseases, and “no” is defined as not suffering from chronic diseases.

1 = Yes

 EQ-5D

0 = Complete health

“Complete health” is defined as EQ-5D score equal to one point, while “incomplete health” is defined as EQ-5D score less than one point.

1 = Incomplete health

 Health status (VAS, self-reported)

1 = Poor (0–40)

Health status on a 20 cm vertical scale with end points of 0 and 100 was asked on the day of the interview.

2 = Moderate (41–60)

3 = Good (41–80)

0 = Excellent (81–100)

 Physical examination

0 = No

Question: have you had a physical examination in the past 12 months? (excluding examination due to illness)

1 = Yes

 Physical exercise (no. times per week)

1 = 0

Question: on average, how many times a week do you exercise in the past 1 month?

2 = 1 or 2

3 = 3–5

4 = ≥6

 Wave

1 = 2008

2 = 2013

3 = 2018