Table 1 Variable definition and descriptive statistics (n = 2145)

Longevity

Age of the older adult at the time of death

93.41

9.18

91.76

10.01

Number of children

Total number of children

3.67

1.84

3.50

1.64

Number of sons

Total number of sons

2.42

1.45

2.36

1.34

Number of daughters

Total number of daughters

2.14

1.56

1.93

1.39

Having a son

Whether the number of sons is greater than 0; if yes, it is assigned 1; otherwise, it is 0

94

0.22

97

0.17

Having a daughter

Whether the number of daughters is greater than 0; if yes, it is assigned 1; otherwise, it is 0

87

0.33

89

0.31

Having sons and daughters

If the older adult has at least one son and one daughter, the value is 1; otherwise, it is 0

84

0.37

86

0.34

Age at first birth

The age when the first child was born

24.1

5.71

24.21

4.43

Age at last birth

The age at which the youngest child was born

37.42

6.89

35.67

6.11

Marital status

With spouse assigned 1, and without spouse assigned 0

0.76

76

0.42

68

0.47

Ethnic group

Han nationality is assigned 0, the Hui, Mongolian, and other nationalities as minorities are assigned 1

16

0.37

6

0.23

Education status

Formal education is assigned 1, otherwise, it is 0

35

0.48

61

0.48

Living with family

Whether living alone, if yes, it is 0; if no, it is 1

71

0.45

64

0.48

Hypertension

If the participant suffers from this disease, it is assigned 1; if no, it is 0

28

0.45

37

0.48

Diabetes

If the participant suffers from this disease, it is assigned 1; if no, it is 0

5

0.22

6

0.24

Cardiovascular disease

If the participant suffers from this disease, it is assigned 1; if no, it is 0

20

0.40

26

0.44

Apoplexy

If the participant suffers from this disease, it is assigned 1; if no, it is 0

13

0.34

20

0.41

Respiratory disease

If the participant suffers from this disease, it is assigned 1; if no, it is 0

13

0.34

19

0.39

Cancer

If the participant suffers from this disease, it is assigned 1; if no, it is 0

10

0.30

19

0.39

Medical insurance

If the participant participates in one of the insurances, the value is assigned 1; the value is 0 otherwise

90

0.30

86

0.34

Public older adult insurance

If the participant participates in public older adult insurance, the value is assigned 1; the value is 0 otherwise

23

0.42

5

0.35

Smoking

If the participant ever smokes, the value is assigned 1; otherwise, the value is assigned 0

7

0.25

1

0.08

Clean energy in the kitchen

If the participant uses clean energy, the value is assigned 1; otherwise, it is assigned 0

53

0.50

74

0.43