Table 3 Robustness test: Regression results of two-stage least squares method

Gender of the first child

−0.270**

0.125

Number of children

−1.645***

(0.254)

Marital status

0.035

5.616***

0.202

(0.989)

Ethnic group

−0.075

0.414

0.172

(0.850)

Education status

0.757***

−5.338***

0.208

(1.970)

Living with family

−0.280*

2.866***

0.157

(0.980)

Hypertension

0.550***

−4.196***

0.150

(1.414)

Diabetes

−0.640**

−3.229

0.299

(2.077)

Cardiovascular diseases

−0.310*

0.174

0.162

(1.074)

Apoplexy

−0.043

−1.864*

0.202

(0.988)

Respiratory diseases

0.198

1.604

0.224

(1.163)

Cancer

0.425

−7.870***

0.355

(1.973)

Medical insurance

0.073

−2.271**

0.201

(0.995)

Public older adult insurance

−0.049

−0.572

0.153

(0.755)

Smoking

2.058

−18.271*

1.776

(10.028)

Clean energy in the kitchen

−0.035

0.392

0.125

(0.619)

Middle region

0.204

−1.254

0.161

(0.886)

West region

−0.098

− 1.645**

0.162

(0.832)

Constant term

3.710***

87.842***

0.300

(8.212)

Obs.

827

827

R-squared

0.158

0.156

Model test