1. Introduction
Since the 1990s, both the speed and scale of China’s urbanization have accelerated [
1]. During this period, the urbanization rate in China has increased rapidly from 30.48% to 60.60%, an increase of nearly 31%. It has been reported that the urbanization rate in China will reach 75% by 2030 (The China urbanization 2.0 report). According to that result, it can be seen that, in several decades, China will have achieved the urbanization progress that occurred in western countries over hundreds of years [
2]. Such rapid urbanization growth poses large challenges to public health. Specifically, quick urbanization leads to serious problems of environmental pollution and unhealthy lifestyles [
3]. Among these problems, the most widespread impact has been on air pollution [
4], for example, increased levels of industrial sulfur dioxide [
5] and particulate matter (PM
10, PM
2.5) pollution [
6]. PM
2.5 pollution has had a particular impact, according to a previous study; both long-term and short-term exposure to PM
2.5 increased the probability of chronic diseases for residents, such as respiratory disease and cardiovascular morbidity [
7]. It is even reported that 48.6% of the Chinese population (nearly 100 million people) suffer from obstructive pulmonary disease (COPD), and 18.7% of COPD deaths are attributable to environmental PM
2.5 exposure (China Pulmonary Health Study). At the same time, the hazards of wastewater to human health cannot be ignored [
8]. Current research indicates that water pollution is associated not only with acute waterborne diseases (cholera, diarrhea) [
9] but also with cancer risk in severe cases [
10]. The poor lifestyles and unhealthy diets resulting from urbanization also introduce many risks for residents’ health [
11], such as obesity [
12], hypertension [
13], and heart disease [
14]. Despite the negative impacts of urbanization, it also leads to an improved standard of living, better healthcare resources, increased job opportunities, and higher education levels, which lead to greatly improved public health [
6]. However, the most sensitive of the impacted groups are middle-aged and older adults. According to statistics, China’s elderly population accounted for 18.1% of the total population in 2019, and the proportion is expected to rise to 20% by 2030. At that time, China will enter a heavily aging society. Furthermore, with an accelerating rate of increase in the proportion of the population that is aged [
15], chronic diseases among the elderly are a particular problem in China [
16]. According to statistics, nearly 80% of deaths in the elderly population are caused by chronic diseases, and the elderly are 3.2 times more likely to suffer from chronic diseases than other groups [
17], with environmental pollution factors increasing the probability of chronic diseases in the elderly. Researchers have shown that in Wuhan, China, a 10 µg/m
3 increase in NO
2 is associated with a 1.6% increase in CVD mortality in the elderly [
18]. Some scholars have even predicted the future trend of CVD in China; by 2030, the number of CVD events per year in China will increase by more than 50% due to population aging and population growth alone [
19], of which environmental pollution is a factor that cannot be ignored. These statistics demonstrate the importance of studying the health effects of urbanization on middle-aged and elderly people in China. Based on this, are the positive or negative effects of urbanization on the health of older adults greater?
The influence that urbanization has on health is complex [
20,
21]. Some scholars argue that urbanization adversely affects the health of residents [
20,
22]. Previous research has considered the negative health effects of single factors such as changes in environmental pollution [
3,
23], unhealthy lifestyles, and socioeconomic status [
22] caused by urbanization. Among these factors, researchers reported that environmental pollution has the greatest influence on health. Other scholars believe that in the process of urbanization rising living standards, improved healthcare resources, more job opportunities, and higher educational levels have dramatically enhanced public health [
6,
24]. In particular, it should be noted that the advancement of sanitary conditions brought about by urbanization has made it easier for people to enjoy the latest achievements in medical technology and to obtain better medical care, which has benefited city residents and promoted their health. In conclusion, it can be seen that there are disparate impacts of urbanization on health.
In studies of the implications of urbanization for health, most of the scholars have focused on single indexes such as the demographic urbanization rate [
25], constructing the urbanization indicators of broad community characteristics [
22], nighttime light data [
26], and so on. Even when researchers have taken into account the complexity and multidimensionality of urbanization, they have only briefly adopted multiple indexes or have used data that were not representative. For example, Liu et al. [
27] considered the effects of differing levels and rates of urbanization on health by using indexes of land-use transitions, the growth of the economy, population clustering, and health services, and Chen et al. [
26] adopted nighttime databases to assess the effects of urbanization of different dimensions, development speed, and level of health in county-level regions. However, only some scholars consider the multidimensionality of urbanization and employ the entropy method [
28] or the fully arrayed polygonal graphical indication method [
29] to divide urbanization into the urbanization of the population, urbanization of the economy, urbanization of residential environments, and urbanization of residential conditions. Although the selected methods and indicators can objectively reflect the urbanization of all of China, most of them are only analyzed at the provincial level and not at the urban level. More importantly, these measurements of urbanization do not apply to the impact of urbanization on health. Therefore, this paper adopts the fully arrayed polygonal graphical indication method to reconstruct the comprehensive urbanization index for China’s prefecture-level cities and incorporate it into a model of urbanization and health, as well as dividing it into four aspects: demographic urbanization, economy urbanization, residential surroundings urbanization, and residential condition urbanization.
Most scholars studying healthcare service indicators use single indexes, such as healthcare expenditures [
30], the number of hospital beds [
31,
32], and the number of doctors in hospitals [
33]. However, medical resources are not only a reflection of these singular indexes, but are also closely related to financial resources, material resources, and manpower for healthcare. Therefore, some researchers have employed the entropy method [
34] to comprehensively evaluate healthcare resources, but these methods are mostly applied at the provincial scale in China; the data are not easily available at the municipal level. Thus, taking into account the availability of data and the applicability of the method, this paper employs the fully arrayed polygonal graphical indication method [
29] to comprehensively evaluate the level of medical and health resources by selecting three indicators: the number of hospital beds per thousand people, the number of medical and health institutions per thousand people, and the number of hospitals per hundred square kilometers.
To summarize, this paper adopts the fully arrayed polygonal graphical indication method to calculate composite urbanization indexes and healthcare indicators. In this method, we construct the comprehensive urbanization indicators based on the four dimensions of demographic urbanization, economy urbanization, residential surroundings urbanization, and residential condition urbanization. Next, the urbanization indicators, the health service indicators, and the interaction terms of environmental pollution and health services are incorporated into an ordered logistic model to explore the advantages and disadvantages that change in healthcare conditions and environmental pollution caused by urbanization and see what effect they have on the health of middle-aged and elderly people. The heterogeneity of urbanization in multidimensionality, regional differences, and city types are considered as well. The primary contributions of this paper are as follows: First, we incorporate urbanization, environmental pollution, healthcare services, and health into the same research framework to analyze the dual effects and the magnitude of the impacts of environmental pollution and the improvement of healthcare service caused by urbanization. Then, the comprehensive urbanization and healthcare service indexes measured by the fully arrayed polygonal graphical indication method are integrated into an ordered logistics model of the impact of urbanization on health, and the interaction term between the environmental pollution and healthcare service is introduced to study the negative and positive impacts of urbanization on health and the extent of those effects. Finally, the comprehensive urbanization indicators calculated by the fully arrayed polygonal graphical indication method are used to divide the integrated urbanization into four dimensions: urbanization of the population, urbanization of the economy, urbanization of residential environment, and urbanization of residential conditions. This is then used to explore the heterogeneity of the influence of urbanization on health based on the different dimensions of urbanization, the regional variability of urbanization, and the variability of city types. The manuscript is arranged as follows: the second part contains the data and methods, the third part contains the results and discussion, and the last part contains the conclusion and policy implications.
4. Conclusions
This paper employs the fully arrayed polygonal graphical indication method to construct comprehensive urbanization indicators (based on the four dimensions of demographic urbanization, economy urbanization, residential surroundings urbanization, and residential conditions urbanization) and a medical treatment index. Then, we incorporate urbanization indicators, environmental pollution indicators, healthcare, and the interaction terms of environmental pollution and healthcare into the ordered-logistics model to explore the magnitude of the impacts of urbanization on health, including the negative impact of environmental pollution and the positive impact of improved medical care. We also study the heterogeneity effects based on multidimensional urbanization, regional differences, and different city types. Based on this analysis, we conclude the following:
- (1)
The comprehensive urbanization index was constructed by applying the fully arrange polygon graphical index method from four dimensions: the urbanization of the population, the urbanization of economy, the urbanization of residential environment, and the urbanization of residential conditions. The results indicate that integrated urbanization can significantly decrease the rate of chronic diseases among the middle-aged and elderly. However, although the enhancement of healthcare conditions can significantly reduce the prevalence of chronic diseases induced by industrial sulfur dioxide and industrial soot and dust, it cannot offset the health damage caused by PM2.5.
- (2)
Each city has different development directions in the process of urbanization, which can be considered by the four dimensions of demographic urbanization, economy urbanization, residential surroundings urbanization, and residential conditions urbanization. When the main development direction is economic urbanization, although the medical care still does not fully counteract the health risks from PM2.5, the health damage is the lowest, with an increase in the morbidity of chronic diseases among middle-aged and elderly adults of only 12.4%. In addition, the mitigation effect of healthcare for health hazards caused by industrial soot and dust is the highest, with the largest decrease in the incidence of chronic diseases at 18.4% in the primary stage of urbanization. When the development direction is residential surroundings urbanization, the healthcare service has the greatest mitigating effect on the health problems caused by industrial sulfur and dioxide, reducing the incidence of chronic diseases in middle-aged and elderly people by 14.9%. With residential condition urbanization, healthcare can significantly decrease the incidence of chronic diseases caused by industrial wastewater, and the significance level is 1%.
- (3)
Referring to Nelson’s classification in the United States, the study cities are separated into three categories: industrial, commercial, and mixed-economy cities. The results suggest that although medical treatment cannot counteract the health risks induced by PM2.5, at 13.2%, the commercial cities have the lowest overall increase in the incidence of chronic diseases among middle-aged and elderly people. The greatest reduction in the incidence of chronic diseases in middle-aged and elderly people induced by industrial sulfur dioxide and industrial soot and dust is seen in mixed-economy cities, with incidences decreased by 27.3% and 16.4%, respectively.
- (4)
In order to consider the regional imbalance of urban development in China, the sample is divided into three sections: eastern, central, and western China. The regression results suggest that in eastern China, although healthcare does not offset the health damage caused by PM2.5, the overall health risks are lowest, with the incidence of chronic diseases increase by 0.5%. The mitigation of health hazards caused by industrial sulfur and dioxide is the lowest in eastern China, with the prevalence of chronic diseases decreased by 7.4%. However, the reduction influence of medical treatment on health risks caused by industrial soot and dust is the largest in the central part of China, which shows an 18.6% decrease in the prevalence of chronic diseases. Healthcare can significantly decrease the incidence of chronic diseases induced by industrial wastewater.
In light of these conclusions, this paper argues that local governments should focus on controlling air pollutants (particularly PM2.5) and industrial wastewater pollution. First, with regard to PM2.5, local governments can compensate for the health hazards of PM2.5 by enhancing the economic development level and narrowing the development levels between regions. Furthermore, the government should take into account improving the living environment and economic level, balancing the development of secondary and tertiary industries, and strengthening the configuration of medical facilities to tackle the industrial sulfur dioxide and industrial soot and dust pollution. Finally, when treating industrial wastewater pollution, the local government can take some measures to improve the living environment and living conditions, balance the development of industries, and improve other measures to focus on the treatment of eastern and central China and cities dominated by the secondary and tertiary industries.
Although this study explores the dual impact that urbanization has on health through improved healthcare and increased environmental pollution by incorporating healthcare services, environmental pollution, urbanization, and health into the same framework, the data studied are cross-sectional and do not account for changes in dynamics. In future studies, other types of data may be considered to more precisely examine the relationship between the dynamics of urbanization and health.