1. Introduction
The World is experiencing rapid urbanization, with significant implications for health. In 2010, the number of individuals living in urban areas crossed the threshold of 50% of the total World population for the first time in history [
1]. It is estimated that by 2050, over 70% of the World population will be living in urban environments [
2]. The continuing process of urbanization worldwide has engendered interest in both policy and academic circles, as its impact on health is often context-specific and difficult to generalize.
On the one hand, living in urban conglomerations intensifies exposures to adverse environmental [
3], epidemiological [
4,
5], and social [
6] factors that tend to impact health negatively, particularly for the urban poor. On the other, the greater wealth and concentration of healthcare services available in urban areas also mean that illnesses can be more effectively managed [
7]. It is empirically unclear which of the two opposing forces on health dominates in any given context. As a result, it is of critical importance to understand whether the adverse health impact of urban residence can be overcome by one of its strongest benefits—the ready access to medical care—in a broad range of disease contexts.
Indeed, methodological and data challenges remain in the literature on place and health. First, existing literature often focuses on individual disease categories, and nationally representative data are scarce [
1]. Differences in the socioeconomic, environmental, and epidemiological contributors to poor health may well emphasize differing aspects of the positive and adverse health factors of urban living, particularly when comparing across disease categories. Second, methodological shortcomings exist when definitions focus primarily on the physical rather than the socioeconomic context of urbanization [
8]. Third, a simple urban-rural dichotomy may also mask health disparities along the urban-rural continuum [
9].
To overcome these challenges, we study the implication of urbanization and health by using a multifactorial definition of urbanization that encompasses both socioeconomic and physical attributes of urban development, as well as data on all deaths in Taiwan from 1971 to 2008. Our primary objective is to trace the temporal trends in mortality from diseases considered to be amenable to public health or medical interventions in Taiwan, disaggregated by four levels of urbanization. In so doing, we aim to investigate whether the mortality benefits of urban residence are overall greater than their social and environmental harms in an export-driven economy such as that of Taiwan.
Our work contributes to the literature in two specific ways. First, there is very limited empirical literature on the impact of urbanization on health in Taiwan. Existing research often focuses on individual disease categories, uses survey samples or small, potentially non-nationally representative samples of death, or considers urbanization as incidental, rather than the primary covariate of interest. A 1998 study finds that more urbanized areas in Taiwan had increasing trends in certain cancer mortalities [
10]. Other studies link urban environmental factors such as pollution, fluoridation, water hardness and arsenic contamination with coronary or cancer moralities [
11,
12,
13,
14,
15,
16,
17]. Yet another study finds higher mortality rates from traffic accidents in rural areas of Taiwan between 1981 and 1990 [
18]. The remainder of the literature on health and place in Taiwan focuses on prevalence or incidence of [
19,
20], rather than mortality from disease, differences in health care utilization patterns [
21,
22,
23,
24], or differences in risk factors [
25] based on the urbanization level of the study population’s residence.
Second, our work contributes to the literature by providing important implications for Taiwanese policymakers in identifying the geographic distribution of different types of mortality. Such knowledge can contribute to a more efficient allocation of scarce healthcare resources depending on the prevalence of different causes of death between rural and urban areas in Taiwan, and may shed further light on the urban-rural health outcome divide in other Asian nations following a similar path of export-driven growth and development.
4. Conclusions
With a few rare and notable exceptions, more urbanized areas in Taiwan had lower ASMRs for both avoidable deaths as well as all-cause mortality. ASMRs were lower historically in more urbanized areas for all-cause mortality, and for appendicitis, asthma, injuries, and maternal mortality. ASMRs in more urbanized areas began higher, but eventually fell to rates lower than those in less urbanized areas for hypertension/ cerebrovascular diseases, lung cancer among men, and cervical cancer among women. Many of the lower ASMRs in more urbanized areas were achieved despite less favorable environmental or epidemiological factors in urban areas. A possible explanation for the lower ASMRs in urbanized areas may be the richer healthcare resources in Taiwan’s cities and towns.
The only cause of death to exhibit higher ASMRs in more urbanized areas throughout the study period is death due to breast cancer. Moreover, among avoidable deaths, only three ASMRs rose in our 38-year study period: breast cancer (for women only) and lung cancer for all levels of urbanization, and ischemic heart disease (for all levels of urbanization among men, and for the most rural areas among women).
These findings imply that policymakers should consider the urban-rural divide evident in almost all causes of mortality in Taiwan when allocating scarce healthcare resources, and make additional investments to combat the three causes of death that rose from 1971 to 2008. In particular, Taiwanese policymakers should consider further encouraging breast cancer screening, and aggressively pursuing anti-tobacco initiatives, especially in rural areas. Future studies should investigate the reasons for greater breast cancer ASMRs in urban areas despite richer healthcare resources in such areas in order to craft a tailored policy response to the growing mortality rates from breast cancer. In addition, further studies should explicitly study the link between healthcare resources and mortality rates in Taiwan for numerically important causes of deaths.