Social Determinants of Active Aging: Differences in Mortality and the Loss of Healthy Life between Different Income Levels among Older Japanese in the AGES Cohort Study

Exploring the association of lifestyle behaviors and healthy ageing among the older adults in India: evidence from LASI survey

BACKGROUND

Understanding health and developing trends among the older population is essential for countries to tackle the challenges of an ageing population and formulate relevant policies. Facilitating healthy ageing is an essential strategy to address the issues arising among the aged. The concept of healthy ageing is defined as "the process of developing and maintaining the functional ability that enables wellbeing in old age (WHO)," where "functional ability comprises the health-related attributes that enable people to be and to do what they have reason to value." People have different ageing pathways depending on their genetic profile and different life course health risk exposures. Therefore, ageing, more specifically healthy ageing, largely depends on individual lifestyle choices. This study examines the association between lifestyle behaviours and healthy ageing among older adults in India.

METHODS

Based on the first round of LASI in 2017-18, we conceptualized healthy ageing within the WHO functional ability framework. We developed a Healthy Ageing Index (HAI), which incorporates physiological health, functional health, cognitive functions, psychological well-being, and social engagement. We used principal component analysis to generate a composite score for HAI. We then used multiple linear regression to demonstrate the association between lifestyle behaviours and HAI.

RESULT

The mean HAI was 82.8%, indicating that the study population is healthier. The study findings show that smoking and drinking are more prevalent among males, rural residents, illiterate individuals, those currently employed, and those belonging to the poorest wealth quintile. Engaging in physical activity is associated with better health outcomes (β = 2.36; 95% CI: 2.16-2.56).

CONCLUSION

This study emphasizes the importance of adopting a healthier lifestyle to achieve healthy ageing. Health behaviours are modifiable, so our results highlight the need for policy interventions to promote a healthier lifestyle from an early age.

Advancing methods for the biodemography of aging within social contexts

Several social dimensions including social integration, status, early-life adversity, and their interactions across the life course can predict health, reproduction, and mortality in humans. Accordingly, the social environment plays a fundamental role in the emergence of phenotypes driving the evolution of aging. Recent work placing human social gradients on a biological continuum with other species provides a useful evolutionary context for aging questions, but there is still a need for a unified evolutionary framework linking health and aging within social contexts. Here, we summarize current challenges to understand the role of the social environment in human life courses. Next, we review recent advances in comparative biodemography and propose a biodemographic perspective to address socially driven health phenotype distributions and their evolutionary consequences using a nonhuman primate population. This new comparative approach uses evolutionary demography to address the joint dynamics of populations, social dimensions, phenotypes, and life history parameters. The long-term goal is to advance our understanding of the link between individual social environments, population-level outcomes, and the evolution of aging.

The effects of patient cost-sharing on health expenditure and health among older people: Heterogeneity across income groups

Despite rapidly rising health expenditure associated with population aging, empirical evidence on the effects of cost-sharing on older people is still limited. This study estimated the effects of cost-sharing on the utilization of healthcare and health among older people, the most intensive users of healthcare. We employed a regression discontinuity design by exploiting a drastic reduction in the coinsurance rate from 30 to 10% at age 70 in Japan. We used large administrative claims data as well as income information at the individual level provided by a municipality. Using the claims data with 1,420,252 person-month observations for health expenditure, we found that reduced cost-sharing modestly increased outpatient expenditure, with an implied price elasticity of  - 0.07. When examining the effects of reduced cost-sharing by income, we found that the price elasticities for outpatient expenditure were almost zero,  - 0.08, and  - 0.11 for lower-, middle-, and higher-income individuals, respectively, suggesting that lower-income individuals do not have more elastic demand for outpatient care compared with other income groups. Using large-scale mail survey data with 3404 observations for self-reported health, we found that the cost-sharing reduction significantly improved self-reported health only among lower-income individuals, but drawing clear conclusions about health outcomes is difficult because of a lack of strong graphical evidence to support health improvement. Our results suggest that varying cost-sharing by income for older people (i.e., smaller cost-sharing for lower-income individuals and larger cost-sharing for higher-income individuals) may reduce health expenditure without compromising health.

Income-based inequality in nationwide general health checkup participation in Japan

OBJECTIVE

In Japan, it is mandatory for employers to provide general health checkup opportunities to employees. Although many companies have subsidized checkups for employees' dependent family members, their participation is low. We assessed income-based inequality in the participation of employees' dependents in the general health checkup.

STUDY DESIGN

This is a cross-sectional descriptive study. Annual participation rate in general health checkup and various factors including income, age, and sex were collected and analyzed to examine the income-based inequality of participation rate in general health checkup.

METHODS

The data for the present study were sourced from the Fukuoka Branch of the Japan Health Insurance Association, a large medical insurer in Japan. We extracted data of 196,057 dependents aged 40-74 years. We conducted a multiple logistic regression analysis using participation from April 2015 to March 2016 as dependent variable and income category ranging from 1 (lowest) to 4 (highest) between April and June 2015 as independent variable (adjusted for sex and age). We computed slope index of inequality (SII) and relative index of inequality (RII) based on income category.

RESULTS

Higher the income, the more likely were dependents to participate in the general health checkup. SII for the participation rate of general health checkup ranged between -0.02 (95% confidence interval [CI]: -0.07 to 0.03) and 0.06 (0.03-0.09) for men; 0.03 (0.01-0.06) and 0.10 (0.09-0.11) for women. RII for the participation rate of general health checkup ranged between -0.19 (95% CI: -0.66 to 0.29) and 0.88 (0.15-1.61) for men; 0.22 (0.05-0.39) and 0.68 (0.60-0.76) for women. The highest inequality existed for men in their 50s and 60s and women in their 50s; the lowest inequality was among men and women aged 70-74 years.

CONCLUSION

There was income-based inequality in participation in the general health checkup among dependents (family members) of the insured persons. The degree of inequality differed with age group. It cannot be explained solely by financial barrier among low-income group, rather it may reflect Japanese unique context in medical insurance system.

Number of functional teeth more strongly predicts all-cause mortality than number of present teeth in Japanese older adults

Aim

Previous studies on the association between intraoral conditions and mortality in community‐dwelling older individuals reported that fewer present teeth (PT) are significant risk factors for mortality. However, how the number of PT relative to the number of functional teeth (FT), including both present and rehabilitated teeth, influences mortality has not been investigated fully. This study examined the impact of the number of FT on mortality among community‐dwelling Japanese older adults.

Methods

This study was a retrospective, observational and population‐based follow‐up study, which examined 1188 older individuals who participated in an annual geriatric health examination from 2009 to 2015. The average follow‐up period was 1697.0 ± 774.5 days. The primary outcome was all‐cause mortality at follow‐up. The numbers of PT and FT of each participant were counted during an oral examination. In addition, demographics, clinical variables, blood nutrient markers, physical functions and perceived masticatory function were measured.

Results

Kaplan–Meier analysis, followed by a log‐rank test, revealed that fewer PT (P < 0.001) and FT (P = 0.002) were significantly associated with a reduced survival rate. Cox's proportional hazard analysis indicated that the number of FT, but not the number of PT, was a significant independent mortality risk factor after adjusting for demographics, clinical variables, nutrient markers and physical functioning (P = 0.036, hazard ratio: 2.089).

Conclusions

Current results suggest that the number of FT more strongly predicts all‐cause mortality than the number of PT among community‐dwelling older adults. Further studies are necessary to consider the confounding of socioeconomic status and disability status. Geriatr Gerontol Int 2020; ••: ••–••.

Domains and Measurements of Healthy Aging in Epidemiological Studies: A Review

Purpose of the Study

Few studies have recommended the essential domains of healthy aging and their relevant measurement to assess healthy aging comprehensively. This review is to fill the gap, by conducting a literature review of domains and measures of healthy aging in epidemiological studies.

Design and Methods

A literature search was conducted up to March 31, 2017, supplemented by a search of references in all relevant articles in English. We made a final selection of 50 studies across 23 countries or regions.

Results

Nineteen studies applied Rowe and Kahn’s three standards to assess healthy aging. Thirty-seven studies measured physical capabilities mainly by (instrumental) activities of daily living. Cognitive functions were included in 33 studies. Nineteen of them applied Mini-Mental State Examination (MMSE). Twenty-six studies considered metabolic and physiological health, but they mainly asked the self-reported absence of diseases. Twenty-four studies assessed psychological well-being by employing diverse scales. Questions about participation in social activities were mainly asked to measure social well-being in 22 studies. Sixteen studies considered individuals’ general health status, which was mainly measured by self-rated health. Security questions were asked in five studies. Health behaviors were taken into account by three studies. Fifteen studies either applied SF-12/36 or developed health indices to assess healthy aging.

Implications

This review summarizes detailed scales or methods that have been used to assess healthy aging in previous epidemiological studies. It also discusses and recommends the essential domains of healthy aging, and the relevant instruments for further epidemiological research to use in the assessment of healthy aging.

Comparing socio-economic inequalities in healthy ageing in the United States of America, England, China and Japan: evidence from four longitudinal studies of ageing

Healthy ageing has become a popular topic worldwide. So far, a consensus measure of healthy ageing has not been reached; and no studies have compared the magnitude of socio-economic inequality in healthy ageing outside Europe. This study aims to create a universal measure of healthy ageing and compare socio-economic inequalities in healthy ageing in the United States of America (USA), England, China and Japan. We included 10,305 American, 6,590 English, 5,930 Chinese and 1,935 Japanese participants for longitudinal analysis. A harmonised healthy ageing index (HAI) was developed to measure healthy ageing multi-dimensionally. Educational, income and wealth rank scores were derived accounting for the entire socio-economic distribution and the sample size of each category of socio-economic indicator. Associations between socio-economic rank scores and HAIs were assessed using multi-level modelling to calculate the Slope Indices of Inequality. Healthy ageing trajectories were predicted based on the full-adjusted age-cohort models. We found that education was a universally influential socio-economic predictor of healthy ageing. Moving from the highest to the lowest educational groups was associated with a 6.7 (5.2–8.2), 8.2 (6.0–10.4), 13.9 (11.4–16.3) and 6.1 per cent (3.9–8.2%) decrease in average HAI at 60 years in the USA, England, China and Japan, respectively. After 60 years, the educational inequality in healthy ageing kept increasing in the USA and China. The educational inequality in healthy ageing in China was also greater than any other socio-economic inequality in the four countries. Wealth was more influential in predicting healthy ageing inequality among American, English and Japanese participants, while income was more influential among Chinese participants. The socio-economic inequality in healthy ageing in Japan was relatively small. Chinese and American participants had worse healthy ageing profiles than Japanese and English participants.

Gender Difference in the Association Between Subjective Socioeconomic Mobility Across Life Course and Mortality at Older Ages: Results From the JAGES Longitudinal Study

Background

Socioeconomic mobility affects health throughout the life course. However, it is not known whether there are gender differences in the association between life-course subjective socioeconomic status (SSS) mobility and mortality at older ages.

Methods

Participants were 16,690 community-dwelling adults aged 65–100 years in the Japan Gerontological Evaluation Study (JAGES). Baseline information including demographic characteristics, depression, and lifestyle factors were collected in 2010. Participants’ vital status was confirmed in 2013 via linkage to death records. We categorized life-course socioeconomic mobility into the following categories: ‘persistently high’, ‘downward mobility’, ‘upward mobility’, and ‘persistently low’. Cox proportional hazard modeling was used to estimate hazard ratios (HR) for all-cause mortality.

Results

Mortality HRs for the ‘downward’ group were 1.37 (95% confidence interval [CI], 1.08–1.74) among men and 1.27 (95% CI, 0.94–1.71) among women in comparison with the ‘persistently high’ group. Compared to the ‘persistently low’ group, the HRs for the ‘upward’ group were 0.54 (95% CI, 0.35–0.83) among women and 0.91 (95% CI, 0.73–1.24) among men. Associations were not changed after adjusting for objective socioeconomic status but were attenuated by depression.

Conclusions

‘Downward’ mobility was associated with mortality among men, but not among women. Depression appeared to mediate the association. A protective effect of upward mobility was observed among women but not among men.

Inequality within a community at the neighborhood level and the incidence of mood disorders in Japan: a multilevel analysis

PURPOSE

This study analyzes whether income inequality within a community at the neighborhood level is associated with incidence of mood disorder in Japan.

METHODS

A retrospective cohort study was performed using the data of 116,658 National Health Insurance beneficiaries aged between 20 and 69 in Chiba City, Japan. To evaluate income inequality within a community, the Gini coefficient within a 30-min walking distance from an individual's residence was calculated using income distribution estimated by the National Census and the Housing and Land Survey 2013. Incidence of mood disorder was determined through insurance claims submitted from April 1, 2013, to March 31, 2016. A multilevel logistic analysis with three levels-the individual, household, and residential district-was performed to evaluate the association.

RESULTS

Income inequality within a community at the neighborhood level was not associated with incidence of mood disorder in the models with and without equivalent household income (p for trend = 0.856 and 0.947, respectively). No difference was observed in the impact of the Gini coefficient among income levels, lower versus higher income groups (p for interaction between Gini coefficient and household income = 0.967). In contrast, lower equivalent income at the household level was significantly associated with higher incidence of mood disorder (p for trend < 0.001).

CONCLUSIONS

While we confirmed that lower income at the household level itself had an adverse effect on mental health, income inequality within a community at the neighborhood level was not a significant factor for incidence of mood disorder in Japan.

Objective and subjective financial status and mortality among older adults in China

The association between financial status and mortality in older adults is well documented. However, it is unclear whether the association may vary by objective and subjective indicators of financial status. To examine this issue, we used the latest four waves (2005, 2008/2009, 2011/2012, and 2014) of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) of community-residing adults aged 65 and older (n = 25,954). Financial status was assessed using eight objective, subjective, and culturally-oriented measures to capture various dimensions of financial resources at older ages. Multivariate hazard models were used to examine how different indicators of financial status were associated with subsequent mortality in all older adults and by age, gender, and urban-rural residence. Results showed that higher financial status-either objective or subjective-was associated with lower risks of mortality. Subjective assessments of financial status had stronger associations with mortality than objective assessments. The patterns were generally similar between young-old (aged 65-79) and the oldest-old (aged 80+), between women and men, and between rural and urban areas. Together, the findings offer new evidence to help improve the socioeconomic gradient in mortality among older adults in China.

Income-Related Inequalities in Access to Dental Care Services in Japan

Background: This study aimed to evaluate whether income-related inequalities in access to dental care services exist in Japan. Methods: The subjects included beneficiaries of the National Health Insurance (NHI) in Chiba City, Japan, who had been enrolled from 1 April 2014 to 31 March 2015. The presence or absence of dental visits and number of days spent on dental care services during the year were calculated using insurance claims submitted. Equivalent household income was calculated using individual income data from 1 January to 31 December 2013, declared for taxation. Results: Of the 216,211 enrolled subjects, 50.3% had dental care during the year. Among those with dental visits, the average number of days (standard deviation) spent on dental care services per year was 7.7 (7.1). Low income was associated with a decreased rate of dental care utilization regardless of age and sex. However, there was a significant inverse linear association between the number of days spent on dental care services and income levels for both sexes. Conclusions: There were income-related inequalities in access to dental care services, regardless of the age group or sex, within the Japanese universal health insurance system.

Impact of geographic accessibility on utilization of the annual health check-ups by income level in Japan: A multilevel analysis

Although both geographic accessibility and socioeconomic status have been indicated as being important factors for the utilization of health care services, their combined effect has not been evaluated. The aim of this study was to reveal whether an income-dependent difference in the impact of geographic accessibility on the utilization of government-led annual health check-ups exists. Existing data collected and provided by Chiba City Hall were employed and analyzed as a retrospective cohort study. The subjects were 166,966 beneficiaries of National Health Insurance in Chiba City, Japan, aged 40 to 74 years. Of all subjects, 54,748 (32.8%) had an annual health check-up in fiscal year 2012. As an optimal index of geographic accessibility has not been established, five measures were calculated: travel time to the nearest health care facility, density of health care facilities (number facilities within a 30-min walking distance from the district of residence), and three indices based on the two-step floating catchment area method. Three-level logistic regression modeling with random intercepts for household and district of residence was performed. Of the five measures, density of health care facilities was the most compatible according to Akaike's information criterion. Both low density and low income were associated with decreased utilization of the health check-ups. Furthermore, a linear relationship was observed between the density of facilities and utilization of the health check-ups in all income groups and its slope was significantly steeper among subjects with an equivalent income of 0.00 yen than among those with equivalent income of 1.01-2.00 million yen (p = 0.028) or 2.01 million yen or more (p = 0.040). This result indicated that subjects with lower incomes were more susceptible to the effects of geographic accessibility than were those with higher incomes. Thus, better geographic accessibility could increase the health check-up utilization and also decrease the income-related disparity of utilization.

Income Related Inequality of Health Care Access in Japan: A Retrospective Cohort Study

The purpose of this retrospective cohort study was to analyze the association between income level and health care access in Japan. Data from a total of 222,259 subjects (age range, 0–74 years) who submitted National Health Insurance claims in Chiba City from April 2012 to March 2014 and who declared income for the tax period from January 1 to December 31, 2012 were integrated and analyzed. The generalized estimating equation, in which household was defined as a cluster, was used to evaluate the association between equivalent income and utilization and duration of hospitalization and outpatient care services. A significant positive linear association was observed between income level and outpatient visit rates among all age groups of both sexes; however, a significantly higher rate and longer period of hospitalization, and longer outpatient care, were observed among certain lower income subgroups. To control for decreased income due to hospitalization, subjects hospitalized during the previous year were excluded, and the data was then reanalyzed. Significant inverse associations remained in the hospitalization rate among 40–59-year-old men and 60–69-year-old women, and in duration of hospitalization among 40–59 and 60–69-year-olds of both sexes and 70–74-year-old women. These results suggest that low-income individuals in Japan have poorer access to outpatient care and more serious health conditions than their higher income counterparts.