Why Do Japan and South Korea Record Very Low Levels of Perceived Health Despite Having Very High Life Expectancies?

Socioeconomic inequalities in self-rated health in Japan, 32 European countries and the United States: an international comparative study

AIMS

Japan is known as a country with low self-rated health despite high life expectancy. We compared socioeconomic inequalities in self-rated health in Japan with those in 32 European countries and the US using nationally representative samples.

METHODS

We analysed individual data from the Comprehensive Survey of Living Conditions (Japan), the European Union Statistics on Income and Living Conditions, and the Behavioral Risk Factor Surveillance System (US) in 2016. We used ordered logistic regression models with four ordinal categories of self-rated health as an outcome, and educational level or occupational class as independent variables, controlling for age.

RESULTS

In Japan, about half the population perceived their health as 'fair', which was much higher than in Europe (≈20-40%). The odds ratios of lower self-rated health among less educated men compared with more educated were 1.72 (95% confidence interval (CI) 1.61-1.85) in Japan, and ranged from 1.67 to 4.74 in Europe (pooled; 2.10 (95% CI 2.01-2.20)), and 6.65 (95% CI 6.22-7.12) in the US. The odds ratios of lower self-rated health among less educated women were 1.79 (95% CI 1.65-1.95) in Japan, and ranged from 1.89 to 5.30 in Europe (pooled; 2.43 (95% CI 2.33-2.54)), and 8.82 (95% CI 8.29-9.38) in the US. Socioeconomic inequalities were large when self-rated health was low for European countries, but Japan and the US did not follow the pattern.

CONCLUSIONS

Japan has similar socioeconomic gradient patterns to European countries for self-rated health, and our findings revealed smaller socioeconomic inequalities in self-rated health in Japan compared with those in western countries.

Trends in mortality from major causes and lifestyle factors by per capita prefectural income: Ecological panel data analysis from 1995 to 2016 in Japan

In Japan, trends in mortality and lifestyle have not been fully investigated according to subnational socioeconomic factors. Forty-seven prefectures (subnational units) were divided into quartiles by annual per capita prefectural income. Age-standardized mortality from all causes, cancer, heart disease, and stroke was averaged by quartile in 1995, 2000, 2005, 2010, and 2015. Data from the National Health and Nutrition Survey were obtained for periods 1 (1995-1997), 2 (1999-2001), 3 (2003-2005), 4 (2007-2009), 5 (2012), and 6 (2016). Body mass index (BMI), the intake of vegetables and salt, the number of steps, and the prevalence of current smoking and drinking for the 40-69-year age range were standardized by 10-year age groups in the 2010 Japanese population and were averaged by quartile. Differences in mortality and lifestyle by year and period, and quartile were tested using a two-way analysis of variance. Mortality decreased in both sexes and mortality in men from all causes, cancer, and stroke differed by quartile, with mortality highest in the first (lowest) quartile. BMI in men and smoking prevalence in women increased, whereas remaining lifestyle factors except for the prevalence of drinking decreased in women. BMI and the number of steps in both sexes and current smoking prevalence in women differed by quartile, with lower quartiles showing a higher BMI and fewer step counts. In conclusion, favorable trends and significant differences in mortality from all causes, cancer, and stroke in men and BMI in women were observed by per capita prefectural income level.

Trends and socioeconomic inequalities in self-rated health in Japan, 1986-2016

INTRODUCTION

Despite having very high life expectancy, Japan has relatively poor self-rated health, compared to other high-income countries. We studied trends and socioeconomic inequalities in self-rated health in Japan using nationally representative data.

METHODS

The Comprehensive Survey of Living Conditions was analyzed, every 3 years (n ≈ 0.6-0.8 million/year) from 1986 to 2016. Whereas previous studies dichotomized self-rated health as an outcome, we used four categories: very good, good, fair, and bad/very bad. Proportional odds ordinal logistic regression models are used, with ordinal scale self-rated health as an outcome, and age category, survey year and occupational class or educational level as independent variables.

RESULTS

In 2016, the age-adjusted percentages for self-rated health categorized as very good, good, fair, and bad/very bad, were 24.0, 17.1, 48.7, and 10.2% among working-age men, and 21.6, 17.5, 49.4, and 11.5% among working-age women, respectively. With 1986 as the reference year, the odds ratios (ORs) of less good self-rated health were lowest in 1995 (0.69; 95% Confidence Interval [95% CI]: 0.66-0.71 of working-age men), and highest in 2010 (1.23 [95% CI: 1.19-1.27]). The ORs of male, lower non-manual workers (compared to upper non-manual) increased from 1.12 (95% CI: 1.07-1.17) in 2010 to 1.20 (95% CI: 1.15-1.26) in 2016. Between 2010 and 2016, the ORs of working-age men with middle and low levels of education (compared to a high level of education) increased from 1.22 (95% CI: 1.18-1.27) to 1.34 (95% CI: 1.29-1.38), and from 1.47 (95% CI: 1.39-1.56) to 1.75 (95% CI: 1.63-1.88), respectively. The ORs of working-age women with middle and low levels of education also increased from 1.22 (95% CI: 1.17-1.28) to 1.32 (95% CI: 1.26-1.37), and from 1.74 (95% CI: 1.61-1.88) to 2.03 (95% CI: 1.87-2.21) during the same period.

CONCLUSION

Japan has the unique feature that approximately 50% of the survey respondents rated their self-rated health as fair, but with important variations over time and between socioeconomic groups. In-depth studies of the role of socioeconomic conditions may shed light on the reasons for the high prevalence of poor self-rated health in Japan.

Health Perceptions and Adopted Lifestyle Behaviors During the COVID-19 Pandemic: Cross-National Survey

BACKGROUND

Social isolation measures are requisites to control viral spread during the COVID-19 pandemic. However, if these measures are implemented for a long period of time, they can result in adverse modification of people's health perceptions and lifestyle behaviors.

OBJECTIVE

The aim of this cross-national survey was to address the lack of adequate real-time data on the public response to changes in lifestyle behavior during the crisis of the COVID-19 pandemic.

METHODS

A cross-national web-based survey was administered using Google Forms during the month of April 2020. The settings were China, Japan, Italy, and India. There were two primary outcomes: (1) response to the health scale, defined as perceived health status, a combined score of health-related survey items; and (2) adoption of healthy lifestyle choices, defined as the engagement of the respondent in any two of three healthy lifestyle choices (healthy eating habits, engagement in physical activity or exercise, and reduced substance use). Statistical associations were assessed with linear and logistic regression analyses.

RESULTS

We received 3371 responses; 1342 were from India (39.8%), 983 from China (29.2%), 669 from Italy (19.8%), and 377 (11.2%) from Japan. A differential countrywise response was observed toward perceived health status; the highest scores were obtained for Indian respondents (9.43, SD 2.43), and the lowest were obtained for Japanese respondents (6.81, SD 3.44). Similarly, countrywise differences in the magnitude of the influence of perceptions on health status were observed; perception of interpersonal relationships was most pronounced in the comparatively old Italian and Japanese respondents (β=.68 and .60, respectively), and the fear response was most pronounced in Chinese respondents (β=.71). Overall, 78.4% of the respondents adopted at least two healthy lifestyle choices amid the COVID-19 pandemic. Unlike health status, the influence of perception of interpersonal relationships on the adoption of lifestyle choices was not unanimous, and it was absent in the Italian respondents (odds ratio 1.93, 95% CI 0.65-5.79). The influence of perceived health status was a significant predictor of lifestyle change across all the countries, most prominently by approximately 6-fold in China and Italy.

CONCLUSIONS

The overall consistent positive influence of increased interpersonal relationships on health perceptions and adopted lifestyle behaviors during the pandemic is the key real-time finding of the survey. Favorable behavioral changes should be bolstered through regular virtual interpersonal interactions, particularly in countries with an overall middle-aged or older population. Further, controlling the fear response of the public through counseling could also help improve health perceptions and lifestyle behavior. However, the observed human behavior needs to be viewed within the purview of cultural disparities, self-perceptions, demographic variances, and the influence of countrywise phase variations of the pandemic. The observations derived from a short lockdown period are preliminary, and real insight could only be obtained from a longer follow-up.

A Systematic Review of Sociodemographic, Macroeconomic, and Health Resources Factors on Life Expectancy

This review was aimed at systematically synthesizing and appraising the existing literature of sociodemographic, macroeconomic, and health resources factors on life expectancy. A systematic literature search of English databases, that is, PubMed/MEDLINE were scrutinized for exploring sociodemographic, macroeconomic, and health resources factors on life expectancy. The literature search was conducted in January 2020, covering a total of 46 articles from 2004 to 2019 met the review criteria, which were fully discussed subsequently. Among sociodemographic factors, infant mortality rate, literacy rate, education level, socioeconomic status, population growth, and gender inequality have a significant impact on life expectancy. Gross domestic product, Gini, income level, unemployment rate, and inflation rate are the main macroeconomic factors that significantly correlated with life expectancy. Among various health care resources, health care facilities, the number of the health care profession, public health expenditure, death rates, smoking rate, pollution, and vaccinations had a significant correlation with life expectancy. The systematic review showed general conformity of different studies, with a significant association between life expectancy and factors comprising several sociodemographic, macroeconomic, and various health care variables. This review found that only one study examined factors affecting life expectancy in Arabic countries. More studies on this region to fill this research gap were highly recommended.

Comparing South Korean and US self-rated health using anchoring vignettes

PURPOSE

This study compares the self-rated health (SRH) of South Korean and US respondents, using anchoring vignettes to adjust for reporting heterogeneity, i.e., cross-national differences in use of response categories.

METHODS

Study participants, ages 20 to 59, were recruited from online survey panels retained by Embrain in Korea (N = 1170) and the US (N = 1033). In the analyses, we first examined the two key measurement assumptions of the anchoring vignette method. Response consistency was examined by regressing SRH on vignette ratings and EQ-5D, and was satisfied when the relationship between SRH and vignette ratings was significant and positive. Vignette equivalence was assessed by examining whether respondents correctly rank-ordered vignettes by health status severity. We then compared estimates of the between-country difference in SRH from two models: a standard ordered probit regression, and a hierarchical ordered probit (Hopit) regression, which adjusted for cross-country differences in use of response categories.

RESULTS

The anchoring vignettes satisfied both measurement assumptions. Results from the ordered probit regression indicated that Korean SRH was worse than that in the US. However, results from the Hopit regression revealed that Korean SRH was actually better than that in the US, after adjusting for Korean respondents' significantly higher intercategory thresholds (demarcating between "very bad" and "bad," "bad" and "fair," etc.).

CONCLUSION

The apparently lower SRH of Korean vis-à-vis US respondents is an artifact of Koreans' higher standards for health-related response categories. After adjusting for these different standards, Korean SRH is revealed to be higher than US SRH.

Educational Inequalities in Self-Rated Health in Europe and South Korea

While numerous comparative works on the magnitude of health inequalities in Europe have been conducted, there is a paucity of research that encompasses non-European nations such as Asian countries. This study was conducted to compare Europe and Korea in terms of educational health inequalities, with poor self-rated health (SRH) as the outcome variable. The European Union Statistics on Income and Living Conditions and the Korea National Health and Nutrition Examination Survey in 2017 were used (31 countries). Adult men and women aged 20+ years were included (207,245 men and 238,007 women). The age-standardized, sex-specific prevalence of poor SRH by educational level was computed. The slope index of inequality (SII) and relative index of inequality (RII) were calculated. The prevalence of poor SRH was higher in Korea than in other countries for both low/middle- and highly educated individuals. Among highly educated Koreans, the proportion of less healthy women was higher than that of less healthy men. Korea’s SII was the highest for men (15.7%) and the ninth-highest for women (10.4%). In contrast, Korea’s RII was the third-lowest for men (3.27), and the lowest among women (1.98). This high-SII–low-RII mix seems to have been generated by the high level of baseline poor SRH.

Mind the gaps: age and cause specific mortality and life expectancy in the older population of South Korea and Japan

BACKGROUND

Recent life expectancy gains in high-income Asia-pacific countries have been largely the result of postponement of death from non-communicable diseases in old age, causing rapid demographic ageing. This study compared and quantified age- and cause-specific contributions to changes in old-age life expectancy in two high-income Asia-pacific countries with ageing populations, South Korea and Japan.

METHODS

This study used Pollard's actuarial method of decomposing life expectancy to compare age- and cause-specific contributions to changes in old-age life expectancy between South Korea and Japan during 1997 and 2017.

RESULTS

South Korea experienced rapid population ageing, and the gaps in life expectancy at 60 years old between South Korea and Japan were reduced by 2.47 years during 1997 and 2017. Decomposition analysis showed that mortality reductions from non-communicable diseases in South Korea were the leading causes of death contributing to the decreased gaps in old-age life expectancy between the two countries. More specifically, mortality reductions from cardiovascular diseases (stroke, ischaemic and hypertensive heart disease) and cancers (stomach, liver, lung, pancreatic cancers) in South Korea contributed to the decreased gap by 1.34 and 0.41 years, respectively. However, increased mortality from Alzheimer and dementia, lower respiratory tract disease, self-harm and falls in South Korea widened the gaps by 0.41 years.

CONCLUSIONS

Age- and cause- specific contributions to changes in old-age life expectancy can differ between high-income Asia-pacific countries. Although the gaps in old-age life expectancy between high-income Asia-pacific countries are primarily attributed to mortality changes in non-communicable diseases, these countries should also identify potential emerging threats of communicable diseases and injuries along with demographic ageing in pursuit of healthy life years in old age.