Table 5.

The robustness test of population urbanization.

Variables	DIFF-GMM
	Eastern region		Central regions		Western regions
	(1)	(2)	(3)	(4)	(5)	(6)
	Morbidity	Mortality	Morbidity	Morbidity	Mortality	Morbidity
Population urbanization	−1.0352*	−2.1906*	−0.8034	−1.4020	−1.1195*	−0.4863
	(−1.853)	(−1.755)	(−1.062)	(−1.259)	(−1.686)	(−0.107)
Population density	1.9029	−5.1416	1.6359	−2.8899	2.4529	6.5785
	(1.642)	(−1.319)	(1.549)	(−0.946)	(1.589)	(1.387)
Age	1.1913	3.1623**	0.2904	57.0209	2.2026	−0.3496
	(1.315)	(1.966)	(0.038)	(1.216)	(0.270)	(−0.103)
rgdp	0.4467**	0.7777*	1.6158**	−1.2548	−0.9862	−0.4307
	(2.026)	(1.689)	(2.097)	(−0.725)	(−1.072)	(−1.175)
Expend	−2.7409	−0.3739	0.8189	1.9069	−0.4761	1.2627
	(−1.128)	(−1.318)	(0.795)	(1.246)	(−1.621)	(1.418)
Medical	−0.3118***	0.0167	−1.8586	−3.4469	8.0402	2.3041
	(−3.072)	(0.200)	(−0.804)	(−1.130)	(1.494)	(1.243)
Air	−0.0220	−0.0677*	−0.5670	0.3371	−0.9307	−0.1791
	(−0.618)	(−1.688)	(−1.074)	(1.121)	(−1.349)	(−1.087)
L.disease	0.5536***	−1.2917**	0.5408***	−1.1777***	−0.9155***	−0.1776***
	(5.062)	(−2.067)	(2.912)	(−3.037)	(−3.321)	(−4.259)
AR_1	0.0519	0.0364	0.0217	0.0926	0.0866	0.0658
AR_2	0.528	0.518	0.1518	0.1422	0.2762	0.2693
Sargan text	0.8934	0.9953	1.0000	1.0000	1.0000	1.0000
Observations	204	204	153	153	170	170

***, **, *The significance level of 1, 5 and 10%, respectively. The numbers with asterisks in the corresponding rows of all variables in the table represent the estimation coefficients, and the values in the parentheses are the corresponding T statistical values, and the P values of AR_1, AR_2, and Sargan test are provided respectively.