Literature review

1.2.1 Definitions of socioeconomic status and its measurement

SES is commonly used in some scientific fields, including sociology, economy, public health and social epidemiology. Viewing from the sociological point, the power and capital are related to SES, which could indicate the extent of one’s access to the desired resources (such as the money, goods, education, health services) and connote one’s position in the social hierarchy. By using this variance, the sociologist is able to quantify the extent of the social stratification or inequality in or between the societies.

Furthermore, it is also could be used to capture and understand the changes of the structure of one society in the sociological researches since the societies are always in dynamic changes. Thirdly, sociologists could use it to forecast the behavior of the individual and group (Adler et al., 1993). Concerning the health related research (such as the public health or social epidemiology), SES is often used as a benchmark to investigate the health inequalities because the health related researchers believe it is an important factor influencing the health and life outcomes of the individual or group.

Generally speaking, the higher status of a person or group commonly means the higher property of a healthier and longer life.

34

To date, there is consensus on the definition of the SES, since researchers conceptualize the definition based on the nature of their own study. Woolfolk defined SES as “the relative standing in society based on income, power, background and prestige” (Woolfolk & Hoy, 2007). Santrock defined it as “the ability to control resources and participate in society's rewards” (Santrock, 2004). Oakes and Rossi defined it as “a construct that reflects one’s access to collectively desired resources, be they material goods, money, power, friendship networks, healthcare, leisure time, or educational opportunities” (Oakes & Rossi, 2003).

Based on these definitions, in my research, SES is defined as a social standing or class of an individual or one group which could be used to indicate the inequities in access to and distribution of the resources.

Although SES cannot be directly measured because it is abstract and unobserved, we can still measure it through the operationalization. During the last many decades, researchers had tried to operationalize the SES, although the measurable things are different. In the 1940s, one of the American anthropologist, Warner measured SES through occupation, income, housing types and neighborhood(Warner et al., 1949). In the 1950s-1960s, scholars used the occupation, education and income to measure the SES. One of the American sociologist, Hollingshead created the “Two factor index of social position” by using the occupation and education (Hollingshead, 1957). Another sociologist, Duncan created the “socioeconomic index” (SEI), a composite of income and education to measure the occupational prestige by using the U.S. census data (Duncan, 1961). In the 1970s, Haller and Portes developed Duncan’s SEI, making the income, occupation and education become the commonly considered factors in establishing SES (Haller & Portes, 1973). It should be noted that although SES is often measured as a combination of education attainment, income and occupational status, which is commonly conceptualized as the social standing or class of an individual or group (American Psychological Association, 2013), some researchers think race or ethnicity should also be included.

In my study, SES is measured by a combination of education and income, with occupation excluded. Occupation is not included from this study since the object of our research is the older persons who are 60 years or over, and generally, they had been already retired from their jobs. Education was assessed by the question “What level of

35

education did you finish”. Income was measured by asking the participants “How much is your household income”.

1.2.2 Definition of mental health and its measurement

World Health Organization (WHO) defines health as a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity (World Health Organization, 1948). Following this definition, researchers often divide health into three parts: physical health, mental health and social health. In this study, we mainly focus on mental health.

WHO defines the mental health as a state of well-being in which every individual realizes his or her own potential, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to her or his community (World Health Organization, 2010). This definition was adopted in this study as it is not only consistent with the nature of this study but also similar to the author’s opinion about the comprehension of mental health.

In this study, mental health was assessed using the Three Health Factors Scale (Hoshi et al., 2012; Hoshi, 2012; Hoshi & Sakurai, 2012), which is composed of nine questions that measure mental health, physical health and social health, respectively. In the scale, mental health was assessed by three questions: (1) “How is your health status this year?”, (2) “Is your health status as good as last year?”, and (3) “Are you satisfied with your life now?”. The Three Health Factors Scale was validated in the elderly in Tokyo and was found to be easy to administer among the Japanese elderly in Hanno city, Saitama Prefecture (Inoue, 2012).

1.2.3 Definition of need for LTC and its measurement

Before the conceptualization of the need for LTC, we need to clarify what the “LTC”

is, since it will be easy to define the former after clarifying the latter one. According to the WHO, LTC refers to the provision of services for persons of all ages who have long-term functional dependency. Dependency is stressed here because it can create the need for a range of services that designed to compensate for their limited capacity on daily living activities and additional emotional needs and strains, and also result in difficulties in accessing health care (World Health Organization, 2003). However, some

36

researchers defined LTC based on the “medical care”. Alan Garber, a medical expert, thought LTC is designed to comfort those who suffer from the disabling effects of diseases and injuries that medical treatment can neither cure nor fully relieve (Garber, 1996). A health economists, Edward Norton, regarded LTC as the care provided to those with chronic medical conditions who require medical and palliative care (Norton, 2000).

While some healthcare management specialists, such as Pratt considered LTC (or chronic care) is used in the context of an extended type of care that is required over a long period of time, with temporary, short-term breaks, but which goes on in most cases, for the remainder of the individual recipients' life (Pratt, 2010).

Although LTC is truly related to the medical care, these two patterns of care are quite different. Firstly, the contents of their caring service are different. LTC mainly provides the support and assistance of routine activities of daily life (ADL, such as eating, bathing, dressing, getting into and out of bed or a chair, and using the bathroom) or instrumental activities of daily living (IADL, such as housekeeping, managing medications, and grocery shopping) to the elderly physically or mentally disabled (Feder et al., 2000; Nielfeld et al., 1999). Medical care generally offers the services or products for the disease preventing, diagnosing, and curing. Secondly, the care provider is different. The provider of the LTC can be generally divided into formal (paid) provider and informal (unpaid) provider. The formal provider, such as the staff of the caring center, is trained before working. As for the informal provider, such as the family members of the needed elderly, there is no training or guidance. However, the medical care is commonly delivered from the highly trained medical professional, such as physician or nurse.

Considering the definitions above and the objects of our study are the older persons, the LTC in this study is defined as: the chronic services and support that provide to the elderly who have functional limitations or cognitive impairments because of their physically or mentally disability. The definition of the need for LTC is the need for such services and support of the older person.

As for the measurement of the NLTC of the Japanese elderly, we used the LTC level certified by the Japanese Ministry of Health, Labor and Welfare. In 2000, Japan implemented the LTCI and classified each applicant into one of six levels (or to reject—about 3 percent in the first round). The lowest level, called “assistance required”

37

(yôshien), is intended for preventive services; the other five levels are collectively called “care required” (yôkaigo)(Campbell & Ikegami, 2000; Ministry of Health Labor and Welfare, 2002). In our analysis, the subjects who were not eligible to use the LTC were scored 0, while the subjects who were eligible to use the LTC were scored 1 to 6, which stood for the LTC level range from lowest to highest, correspondingly. Finally, all the subjects were categorized into three groups: no need (score 0), low need (score 1-3), and high need (score 4-6). Since there was no LTCI in China, the caring time for the needed older persons by the care providers was used to measure the NLTC among the Chinese elderly.

1.2.4 Relationship between SES and mental health

Substantial researches have already been conducted on the relationship between the SES and health, and consistently indicated that SES is an important determinant of health. People with a low SES suffer from more morbidities and live shorter compared with their counterparts (Brennan & Singh, 2012; Fiorillo & Sabatini, 2011; Hwang et al., 2010; Marmot, 2006; Wengler, 2011; Wilkinson & Marmot, 2003). The research on the relationship between SES and health could even be dated back to the ancient Greece, Egypt and China (Krieger et al., 1997; Lynch et al., 1996). Studies revealed that education and income could affect the health status of the Japanese elderly(Hasegawa et al., 2011). It has been reported that the relationship between SES and health status might be the result of a mixture of biological, lifestyle behavioral, environmental, and social factors rather than one single cause (Berkman & Kawachi, 2000b; Marmot & Wilkinson, 1999). Moreover, some researchers found that the more important factors for the association between SES and health status were the ecological level characteristics (Berkman & Kawachi, 2000a; Kawachi & Kennedy, 1997). In detail, the socioeconomic disparities in health do not follow a simple explanation; pathways by which SES affects health can be expressed by differences in access to health services, exposure to occupational hazards and environmental pathogens, low levels of social support and social capital, poor social policy, the cumulative effects of stress and differences in health risk behaviors (Kagamimori et al., 2009). Similar interpretation for the association between SES and health was also made by some researchers as follows: a higher SES can provide people easier access to better medical care, enable individuals

38

to establish and maintain social networks, and offer people resources to reside in a better neighborhood (Mirowsky et al., 2000; Robert & House, 2000).

Specifically, education, as one of the indicators of SES, has played a central role in the analyses of the SES-health gradient since the use of educational attainment as the primary indicator of SES by Kitagawa and Hauser in 1973 (Cutler et al., 2008).

Education could be regarded as the most basic SES component because it does not only shape the future occupational opportunities and earning potential, but also provide knowledge and life skills that allow better-educated individuals to gain more ready access to information and resources to promote health (Ross & Wu, 1995).

As for another indicator of SES, low income is related to many factors contributing to poor health outcomes, including risky health behaviors, lower levels of education, substandard housing, food insecurity, and lack of health insurance coverage. However, income is independently associated with health outcomes, even after controlling for most of these other factors (Lantz et al., 1998). Researchers even labeled income as ‘one of the most profound influences on mortality’(Wilkinson, 1990).

Mental health, one important aspect of health, has been the subject of many studies, especially its relationship with SES. Past studies have consistently showed that the population with lower SES tended to have higher incidence of mental health problem (Gong et al., 2012), while a population with higher SES had better state of mental health (Mavrinac et al., 2009; Sani et al., 2010). Various studies suggested that people who had a higher income tended to be in a better state of mental health than those who were earning less (Huijts et al., 2010; Theodossiou & Zangelidis, 2009), employed men reported better mental health than those who were not employed (Baron-Epel & Kaplan, 2009), and those with low educational attainment had a higher odds ratio of having depressive symptoms (Devi et al., 2007; Pu et al., 2011). Concerning the Japanese population, it was reported that education attainment had a significant linear association with mental health (based on self-rating) among Japanese female, while no association was found among males (Honjo et al., 2006). Among the Chinese elderly, the association between depressive symptoms and SES was also observed among the empty-nest group (Xie et al., 2010).

Based on the concept of SES, there are also many studies focusing on the relationship between subjective social status (SSS) and mental health, and the main results indicated

39

that SSS would influence the odds of experiencing mental health problems (Friestad, 2010; Leu et al., 2008). Moreover, SSS was found to be significantly associated with psychological stress (Kim et al., 2009). Furthermore, SSS and household income were also found to be significantly associated with psychological distress and those with the low SSS had higher odds of experiencing psychological distress among the Japanese population (Sakurai et al., 2010). Women and those with lower family incomes had a higher probability to experience the depressive symptoms in Japanese population.

However, there is no association between education and depression (Inaba et al., 2005).

1.2.5 Association between SES and the need for LTC

According to existing limited researches, higher levels of unmet needs were reported by people living in the most deprived areas (McKevitt et al., 2011). Indicators related to the SES, such as the educational level, working status, household wealth and poverty status were determinants of daily care needs (Hoi le et al., 2011), which means that a lower SES tend to indicate the increase of the propensity and intensity of care utilization (Laporte et al., 2007; Samuelsson et al., 2003) orthe increase of entering the long-term institutional care (Martikainen et al., 2009). As an important issue on the health equity, the racial or ethnic disparities tend to result in different health status and finally showed different levels of need for long-term care indirectly, since Blacks in America with diabetes and low income have higher probabilities of using home health care than their White counterparts (White-Means & Rubin, 2004). Previous studies showed that Hispanic, compared with other race or ethnic, tend to report worse health status and higher demand of long-term care (Becker et al., 2012; Villa et al., 2003). Moreover, socioeconomic status was found to be an important factor affecting the older persons’

preferences of the arrangements of LTC in Taiwan (Wang et al., 2004).

1.2.6 Relationship between mental health and the need for LTC

Previous studies consistently indicated that patients or frail people had a higher probability to experience the mental health problems (such as anxiety and depression), and the researchers highlighted the importance and necessity on the development of long-term care to these populations in the end, such as the stroke survivors (Wolfe et al., 2011), intellectual disabilities group (Reid et al., 2011) and the elderly with dementia

40

(Kim et al., 2011). However, these researches did not show the empirical correlation between mental health and the need for LTC. Some studies conducted in veterans found that the Veteran Affairs’ long-term care facilities in America cannot provide support for veterans with cognitive deficits who can no longer be cared for at home, thus immediate measures need to be taken to strengthen resources to accommodate the future mental health needs of the aging veterans (Sorrell & Durham, 2011). However these studies did not clarify the correlation between the mental health and need for LTC.

In addition, some studies just described the distribution status of the population with mental health problems and found that mental disorders represent 48% of all admissions for nursing home care, followed by somatic disorders (43%) and social/emotional problems (8%) (Helldin et al., 2009). To date, to the best of our knowledge, only Samuelsson found that people with mental disorders were significantly more likely to use formal support compared to people with good mental health: over a 25 years of follow-up, 53% of people with dementia eventually received both home help and institutional care compared to 34% of people with other psychiatric diagnoses and 12%

of people with good mental health among the Sweden population (Samuelsson et al., 2003).

1.2.7 An overview of the previous researches

A lot of studies have assessed the relationship between the SES and mental health, and consistently found the positive relationship between them, which means the higher SES commonly imply the better status of mental health. There is a limited number of studies on the association between the SES and the NLTC, but consistently indicated that people with a low SES tend to have an increased NLTC.

According to Roos & Havens, the key determinants of successful ageing include living to an advanced age, good physical functioning, mental alertness, and a living spouse not residing in a nursing home, which means that to maintain mental health is very important (Roos & Havens, 1991). Furthermore, as we know, suicide is the main cause of death among patients with Huntington disease (HD), but one research found that HD patients perceived suicide as a response to the realities brought out by HD, such as mental health problems and the need for LTC (Halpin, 2012). Mental health and NLTC are important issues. However, as shown in the literature review above, despite

41

the few attempts to understand the relationship between mental health and NLTC, its empirical correlation remained obscure.

Moreover, although structural equation modeling (SEM) is a useful analytical technique of statistics to test and estimate relationships using a combination of statistical data and qualitative causal assumptions, to the best of our knowledge, no research had explored the relationship between SES, mental health and NLTC using SEM, especially using data from a longitudinal study with large-scale participants.

In addition, it is well known that there is a substantial difference between male and female on the health related issues. In general, life expectancy varies by gender since women tend to live longer than men (Liu et al., 2012), while the male elderly had higher mortality rate compared with their female counterparts (Oksuzyan et al., 2014). As for the physical health, older women are more likely to experience functional impairment in mobility and personal self-care than men of the same age (Arber & Cooper, 1999); in other words, women have a higher probability than men to have disability, non-lethal conditions including functioning problems, IADL difficulties and arthritis (Crimmins et al., 2010). In terms of mental health, it is found that women are more vulnerable to depressive symptoms than men (Nolen-Hoeksema et al., 1999); and the risk for posttraumatic stress disorder (PTSD) following traumatic experiences was twofold higher in women than in men (Breslau, 2001). However, it is worth noting that very few existing studies had ever explored the gender difference on the association between SES and mental health, SES and NLTC, and mental health and NLTC; none had investigated the structural relationship between SES, mental health and NLTC. Thus, whether gender difference exists on the structural association between SES, mental health and NLTC will also be investigated in the present study.

Finally, as shown in the literature review, there were few studies conducted in the Chinese population, and no study analyzed the relationship between the SES, mental health and NLTC between Chinese population and the Japanese population. The existing researches mainly focused on the older person from the developed countries, rather than their developing counterparts, although the number of older persons with functional disabilities and cognitive impairment who need for the LTC is growing fast.

It is noteworthy that, although the objective of the present study is to clarify the association between SES, mental health and NLTC, the ultimate goal of all the health

42

related research is to improve the quality of life of the elderly and help them to achieve a successful aging. It is the target of many political initiatives, social welfare systems (including LTCI), and health interventions.

1.3 Objective and hypotheses of the research