Explaining socioeconomic inequality in mortality among South Koreans: an examination of multiple pathways in a nationally representative longitudinal study

Nonlinear associations between the ratio of family income to poverty and all-cause mortality among adults in NHANES study

Socioeconomic status (SES) has been linked to mortality rates, with family income being a quantifiable marker of SES. However, the precise association between the family income-to-poverty ratio (PIR) and all-cause mortality in adults aged 40 and older remains unclear. A cross-sectional study was conducted using data from NHANES III, including 20,497 individuals. The PIR was used to assess financial status, and various demographic, lifestyle, and clinical factors were considered. Mortality data were collected from the NHANES III linked mortality file. The study revealed a non-linear association between PIR and all-cause mortality. The piecewise Cox proportional hazards regression model showed an inflection point at PIR 3.5. Below this threshold, the hazard ratio (HR) for all-cause mortality was 0.85 (95% CI 0.79-0.91), while above 3.5, the HR decreased to 0.66 (95% CI 0.57-0.76). Participants with lower income had a higher probability of all-cause mortality, with middle-income and high-income groups showing lower multivariate-adjusted HRs compared to the low-income group. This study provides evidence of a non-linear association between PIR and all-cause mortality in adults aged 40 and older, with an inflection point at PIR 3.5. These findings emphasize the importance of considering the non-linear relationship between family income and mortality when addressing socioeconomic health disparities.

Educational inequalities in adult mortality: a systematic review and meta-analysis of the Asia Pacific region

OBJECTIVES

In this study, we aim to analyse the relationship between educational attainment and all-cause mortality of adults in the high-income Asia Pacific region.

DESIGN

This study is a comprehensive systematic review and meta-analysis with no language restrictions on searches. Included articles were assessed for study quality and risk of bias using the Joanna Briggs Institute critical appraisal checklists. A random-effects meta-analysis was conducted to evaluate the overall effect of individual level educational attainment on all-cause mortality.

SETTING

The high-income Asia Pacific Region consisting of Japan, South Korea, Singapore and Brunei Darussalam.

PARTICIPANTS

Articles reporting adult all-cause mortality by individual-level education were obtained through searches conducted from 25 November 2019 to 6 December 2019 of the following databases: PubMed, Web of Science, Scopus, EMBASE, Global Health (CAB), EconLit and Sociology Source Ultimate.

PRIMARY AND SECONDARY OUTCOME MEASURES

Adult all-cause mortality was the primary outcome of interest.

RESULTS

Literature searches resulted in 15 345 sources screened for inclusion. A total of 30 articles meeting inclusion criteria with data from the region were included for this review. Individual-level data from 7 studies covering 222 241 individuals were included in the meta-analyses. Results from the meta-analyses showed an overall risk ratio of 2.40 (95% CI 1.74 to 3.31) for primary education and an estimate of 1.29 (95% CI 1.08 to 1.54) for secondary education compared with tertiary education.

CONCLUSION

The results indicate that lower educational attainment is associated with an increase in the risk of all-cause mortality for adults in the high-income Asia Pacific region. This study offers empirical support for the development of policies to reduce health disparities across the educational gradient and universal access to all levels of education.

PROSPERO REGISTRATION NUMBER

CRD42020183923.

The effect of socioeconomic status on mortality among Alzheimer's disease patients: A nationwide population-based cohort study in Korea

To investigate the effects of household income level on all-cause mortality in patients with Alzheimer's disease (AD). Data was obtained from 7,937 participants in the Korean National Health Insurance cohort who was newly diagnosed with Alzheimer's disease using the anti-dementia medication between 2003 and 2013. All individuals were followed-up until December 2013 or death, whichever came first. Individual income was estimated from the national health insurance premium. Information on mortality was obtained from the Korean National Statistical Office. Cox proportional hazard models were used to compare mortality rates between different income groups after adjusting for possible confounding risk factors. Of 7937 participants, 2292 AD patients (28.9%) died. Those with low, middle-low, middle income level were likely to have more increasing risk of mortality (HR 1.142 [1.022-1.276], HR 1.211 [1.045-1.402], and HR 1.158 [1.009-1.328], respectively), compared to those with high income level. The findings of this study indicate that AD patients with low income level have higher risk for mortality. Promotion of targeted policies and priority support for these groups may help reduce the mortality rate in this vulnerable group.

Occupational inequalities in mortality in Korea using nationally representative mortality follow-up data from the late 2000s and after

Many Korean and international studies have found higher mortality rates and poorer health conditions among manual workers than among non-manual workers. However, a recent study using unlinked data argued that since the economic crisis in Korea in the late 2000s, the mortality estimates of male Korean non-manual workers have been higher than those of manual workers. Our work using individually linked data from the late 2000s and after aimed to examine mortality inequality by occupational class. We analyzed Korea National Health and Nutrition Examination Survey data that were individually linked to cause-of-death data. Cox regression analysis was used to identify the hazard ratios for mortality by occupational class. Of 11,766 males aged between 35 and 64, 397 died between 2007 and 2018: 142 died from cancer, 68 from cardiovascular disease, 88 from external causes, and 99 from other causes. After controlling for age, the mortality estimates for manual workers were 1.85 times higher than those for upper non-manual workers (p<0.05). We observed no evidence of reversed mortality inequality among occupational classes in Korea since the 2000s; this previously reported finding might have been due to numerator-denominator bias arising from the use of unlinked data.

Area-based inequalities and distribution of healthcare resources for managing diabetes in South Korea: a cross-sectional multilevel analysis

OBJECTIVES

We aimed to identify area-based socioeconomic inequalities in diabetes management and to examine whether the distribution of healthcare resources could explain area-based inequalities in diabetes management.

DESIGN

Cross-sectional multilevel analysis from national survey data.

SETTING AND PARTICIPANTS

Data were derived from the 2018 Korean Community Health Survey. Study subjects included 23 760 participants aged 30 years or older with diabetes diagnosed by a doctor.

MAIN OUTCOME MEASURES

The dependent variables were self-reported good glycaemic control, haemoglobin A1c (HbA1c) testing, recognition of the term HbA1c, and diabetic complications testing. Area Deprivation Index was used as an area-based measure of socioeconomic position. Factors related to regional healthcare resources-the coefficient of variation (CV) value of clinics and the number of physicians per 1000-were considered as potential mediating variables in explaining the association between diabetes management and area deprivation. A multilevel logistic regression analysis was used.

RESULTS

Compared with the least deprived quintile, the likelihoods of not taking HbA1c tests, not recognising the term HbA1c, and not taking diabetic complication tests in the most deprived quintile were approximately 1.5 times (95% CI 1.25 to 1.80), 2.6 times (95% CI 1.97 to 3.45) and two times (95% CI 1.67 to 2.48) higher, respectively. In the most deprived quintile, CV value of clinics was the highest and the number of doctors was the lowest. Regional healthcare resource factors explained inequalities in managing diabetes by 14%-18%, especially in the most deprived quintile.

CONCLUSIONS

The results in this study suggest that socioeconomic inequalities in diabetes management may be explained by regional healthcare resource disparities. Policy interventions for a more even distribution of healthcare resources would likely reduce the magnitude of regional socioeconomic inequalities in diabetes management.

Contribution of psychosocial factors to socioeconomic inequalities in mortality among older Australian men: a population-based cohort study

BACKGROUND

Among older people, the extent to which psychosocial factors explain socioeconomic inequalities in mortality is debated. We aimed to investigate the potential mediating effect of psychosocial factors on socioeconomic inequalities in mortality.

METHODS

We used data from a prospective population-based cohort (the Concord Health and Ageing in Men Project; baseline recruitment in 2005-2007), in Sydney, Australia. The main outcomes were all-cause and cause-specific mortality. Socioeconomic status (SES; educational attainment, occupational position, source of income, housing tenure, and a cumulative SES score) was assessed at baseline. Measures of structural and functional social support, as well as depressive and anxiety symptoms were assessed three times during follow-ups. Associations were quantified using Cox regression. Mediation was calculated using "change-in-estimate method".

RESULTS

1522 men (mean age at baseline: 77·4 ± 5·5 years) were included in the analyses with a mean (SD) follow-up time of 9·0 (3·6) years for all-cause and 8·0 (2·8) years for cause-specific mortality. At baseline, psychosocial measures displayed marked social patterning. Being unmarried, living alone, low social interactions, and elevated depressive symptoms were associated with higher risk of all-cause and cardiovascular disease (CVD) mortality. Psychosocial factors explained 35% of SES inequalities in all-cause mortality, 29% in CVD mortality, 12% in cancer mortality, and 39% in non-CVD, non-cancer mortality.

CONCLUSION

Psychosocial factors may account for up to one-third of SES inequalities in deaths from all and specific causes (except cancer mortality). Our findings suggest that interventional studies targeting social relationships and/or psychological distress in older men aiming to reduce socioeconomic inequalities in mortality are warranted.

Cumulative Social Risk and Cardiovascular Disease Among Adults in South Korea: A Cross-Sectional Analysis of a Nationally Representative Sample

INTRODUCTION

The Framingham risk score (FRS) is widely used to predict cardiovascular disease (CVD), but it neglects to account for social risk factors. Our study examined whether use of a cumulative social risk score in addition to the FRS improves prediction of CVD among South Korean adults.

METHODS

We used nationally representative data on 19,147 adults aged 19 or older from the Korea National Health and Nutrition Examination Survey 2013-2016. We computed a cumulative social risk score (range, 0-3) based on 3 social risk factors: low household income, low level of education, and single-living status. CVD outcomes were stroke, myocardial infarction, and angina. Weighted logistic regression examined the associations between cumulative social risk, FRS, and CVD. McFadden pseudo-R² and area under receiver operating characteristic curve (AUC) assessed model performance. We conducted mediation analyses to quantify the association between cumulative social risk score and CVD outcomes that is not mediated by the FRS.

RESULTS

A unit increase in social risk was associated with 89.4% higher risk of stroke diagnosis, controlling for the FRS (P < .001). The FRS explained 8.0% of stroke diagnosis (R²) with fair discrimination (AUC = 0.728), and adding the cumulative social risk score enhanced R² and AUC by 2.4% and 0.039. In the association between cumulative social risk and stroke, the proportion not mediated by the FRS was 65% (P < .001). We observed similar trends in myocardial infarction and angina, such that an increase in social risk was associated with increased relative risk of disease and improved disease diagnosis, and a large proportion of the association was not mediated by the FRS.

CONCLUSION

Controlling for the FRS, cumulative social risks predicted stroke, myocardial infarction, and angina among adults in South Korea. Future research is needed to examine non-FRS mediators between cumulative social risk and CVD.

Age moderates the effect of socioeconomic status on physical activity level among south Korean adults: cross-sectional analysis of nationally representative sample

BACKGROUND

In a nationally representative sample of South Korean adults, we investigated the association between socioeconomic status (SES) and physical activity level, and whether this association varied by age group.

METHODS

We used data from 5065 subjects aged ≥19 years who participated in the 6th Korea National Health and Nutrition Examination Survey. Weighted logistic regression examined the SES-physical activity association. Using the International Physical Activity Questionnaire short form, physical activity level was categorized into two groups: meeting the guideline (≥150 min/week of moderate intensity physical activity) and not meeting the guideline. Annual household income quartile (first quartile = highest income) and education (elementary, middle school, high school, and college graduates) were used as SES indicators. Sociodemographic covariates included in the adjusted models were marital status, town type (rural/urban), dwelling type, perceived health, federal allowance support (yes/no), and working- and sleeping-hours.

RESULTS

In unadjusted models, low income and low education were both associated with significantly lower odds of meeting the physical activity guideline. The income-physical activity association was moderated by age group in both unadjusted and adjusted models. Specifically, among those age < 45 years, those in the third quartile group had 41% higher odds (p < 0.01) of meeting the physical activity guideline compared with the first quartile group, after adjusting for covariates. In contrast, among those age ≥ 45 years, those in the third quartile group had 16% lower odds (p < 0.01) of meeting the physical activity guideline compared with the first quartile group, after adjusting for covariates. Furthermore, the education-physical activity association was moderated by age but only in the adjusted model. Specifically, among those age < 45 years, high school graduates had a 21% higher odds of meeting the physical activity guideline compared with college graduates (p = 0.08). In contrast, among those age ≥ 45 years, high school graduates had a 23% lower odds of meeting the physical activity guideline compared with college graduates (p = 0.01).

CONCLUSION

Future policies that aim to address SES-related health disparities in physical activity among adults in South Korea should consider the different patterns of physical activity in accordance with SES and age.

Socioeconomic disparities in psychological health: Testing the Reserve Capacity Model in a population-based sample of Chinese migrants

Based on the Reserve Capacity Model, this study investigated the associations of objective socioeconomic status and subjective social status with psychological health and the underlying psychosocial mechanisms in a population-based sample of Chinese migrants (n = 15,999). Results showed that subjective social status was positively associated with life satisfaction and self-rated health through the mediation of psychological distress and perceived stress. Whereas education showed a very weak association with life satisfaction, income was directly associated with life satisfaction only. The findings suggest that reducing psychosocial vulnerabilities may be a potential impetus to eliminate socioeconomic health disparities among Chinese migrants.

Stress and associated risk factors among the elderly: a cross-sectional study from rural area of Thailand

Background. Stress is a common mental health problem of the elderly population that affects their quality of life. The objective of this study was to determine the level of stress and associated factors among the elderly living in rural areas of Thailand.  Methods. This was a cross-sectional study conducted in two sub-districts of rural Thailand and interviewed 403 elderly persons.  We used simple random sampling technique from a list of registered elderly individuals and conducted face-to-face interviews using a questionnaire. The questionnaire were piloted, validated and pretested beforehand. Multiple linear regression was applied for data analysis. This study was approved by the Ethical Review Committee of the University of Phayao, Thailand. Results. The mean age of the participants was 68 and two thirds (67%) were female. Less than 43% of the participants had moderate, and one third (34%) had high levels of stress. More than half of participants had low level stress management. Stress was significantly associated with alcohol and illness with a predictive power of 3.0% [(R = 0.173, R Square = 0.030) (p<0.05)]. Conclusion. We conclude that risk factors such as alcohol and illness affect elderly population living in rural areas of Thailand to a major extent in terms of stress.

Stress and associated risk factors among the elderly: a cross-sectional study from rural Thailand

Background. Stress is a common mental health problem of the elderly population that affects their quality of life. The objective of this study was to determine the level of stress and associated factors among the elderly living in rural areas of Thailand.  Methods. This was a cross-sectional study conducted in two sub-districts of rural Thailand and interviewed 403 elderly persons.  We used simple random sampling technique from a list of registered elderly individuals and conducted face-to-face interviews using a questionnaire. The questionnaire were piloted, validated and pretested beforehand. Multiple linear regression was applied for data analysis. This study was approved by the Ethical Review Committee of the University of Phayao, Thailand. Results. The mean age of the participants was 68 and two thirds (67%) were female. Less than 43% of the participants had moderate, and one third (34%) had high levels of stress. More than half of participants had low level stress management. Stress was significantly associated with alcohol and illness with a predictive power of 3.0% [(R = 0.173, R Square = 0.030) (p<0.05)]. Conclusion. We conclude that risk factors such as alcohol and illness affect elderly population living in rural areas of Thailand to a major extent in terms of stress.

Quantifying the impact of reducing socioeconomic inequalities in modifiable risk factors on mortality and mortality inequalities in South Korea

OBJECTIVES

We quantified the impact of reducing socioeconomic inequalities in risk factors on mortality and mortality inequalities in South Korea.

METHODS

The mortality risk function from the 12-year mortality follow-up data of the National Health Insurance Service-National Health Screening Cohort, the prevalence of major risk factors from the Korea National Health and Nutrition Examination Survey 2013-2015, and the Health Plan 2020 (HP2020) goals for major risk factors were used to estimate the magnitude of reduction in mortality inequalities by changing the magnitude of income-based inequalities in risk factors in various scenarios under gender-specific models among participants aged 40-79 years.

RESULTS

The greatest reduction in absolute and relative inequalities in mortality would occur if the low-income group achieved the HP2020 goals earlier than the high-income group. A 10-20% reduction in all-cause mortality inequalities was expected if absolute gaps between income groups in risk factors were halved.

CONCLUSIONS

With the practical goal halving the socioeconomic gaps in modifiable risk factors, reducing inequalities in all-cause mortality by 10-20% would be possible. Further reduction in mortality inequalities would need more aggressive policies on social determinants of health.

Objective and Subjective Socioeconomic Status, Their Discrepancy, and Health: Evidence from East Asia

Socioeconomic status (SES) is largely understood to be a fundamental determinant of health. Recently, subjective socioeconomic status (SSS) has emerged as a potentially important predictor of health above and beyond traditional (i.e., objective) SES indicators (OSS). The current study adds to this emerging body of research by examining the potentially important role of status discrepancies for health outcomes. We used nationally representative data from three East Asian countries (China, Japan, and South Korea) (2010 East Asian Social Survey) and a non-linear statistical technique (i.e., diagonal mobility model) to simultaneously model the independent contributions of OSS and SSS and their discrepancy for three health outcomes. Findings showed that SSS does, in fact, explain additional variation in health net of OSS in most cases, and status discrepancy is not associated with any of the three health outcomes. While status discrepancy was not found to be a driving factor in determining the predictive power of SSS net of OSS (at least in East Asia), the present study adds robustness to the accumulating evidence that challenges the social inequality hypothesis and provides a basis from which future research can build and contribute further to the understanding surrounding socioeconomic status and health outcomes.

Health inequalities in old age: the relative contribution of material, behavioral and psychosocial factors in a German sample

Background

Whereas the association between education and health in later life is well described, investigations about the underlying mechanisms of these health inequalities are scarce. This study examines the relative contribution of material, behavioral and psychosocial factors to health inequalities in older Germans.

Methods

Data were drawn from the fifth wave of the Survey of Health, Ageing and Retirement in Europe (SHARE). The analytic sample included 3246 participants aged 60-85 years. We examined the independent and indirect contribution of material, behavioral and psychosocial factors to the association between education and self-rated health based on logistic regression models.

Results

Material factors were most important as they were additionally working through behavioral and psychosocial factors whereas the independent contribution of behavioral and psychosocial factors was much lower than suggested in the separate analyses of the three explanatory pathways.

Conclusions

Policy interventions that focus on the improvement of material living conditions might reduce health inequalities in old age. In studies on the underlying mechanisms of health inequalities, material, behavioral and psychosocial factors should be modeled as inter-related predictors as the separate analysis does not reveal their actual contribution so that the relevance of single explanatory pathways might be overestimated.

The contribution of health behaviors to socioeconomic inequalities in health: A systematic review

Unhealthy behaviors and their social patterning have been frequently proposed as factors mediating socioeconomic differences in health. However, a clear quantification of the contribution of health behaviors to the socioeconomic gradient in health is lacking. This study systematically reviews the role of health behaviors in explaining socioeconomic inequalities in health. Published studies were identified by a systematic review of PubMed, Embase and Web-of-Science. Four health behaviors were considered: smoking, alcohol consumption, physical activity and diet. We restricted health outcomes to cardiometabolic disorders and mortality. To allow comparison between studies, the contribution of health behaviors, or the part of the socioeconomic gradient in health that is explained by health behaviors, was recalculated in all studies according to the absolute scale difference method. We identified 114 articles on socioeconomic position, health behaviors and cardiometabolic disorders or mortality from electronic databases and articles reference lists. Lower socioeconomic position was associated with an increased risk of all-cause mortality and cardiometabolic disorders, this gradient was explained by health behaviors to varying degrees (minimum contribution -43%; maximum contribution 261%). Health behaviors explained a larger proportion of the SEP-health gradient in studies conducted in North America and Northern Europe, in studies examining all-cause mortality and cardiovascular disease, among men, in younger individuals, and in longitudinal studies, when compared to other settings. Of the four behaviors examined, smoking contributed the most to social inequalities in health, with a median contribution of 19%. Health behaviors contribute to the socioeconomic gradient in cardiometabolic disease and mortality, but this contribution varies according to population and study characteristics. Nevertheless, our results should encourage the implementation of interventions targeting health behaviors, as they may reduce socioeconomic inequalities in health and increase population health.

The Association between Socioeconomic Status and Adherence to Health Check-up in Korean Adults, Based on the 2010-2012 Korean National Health and Nutrition Examination Survey

Background

We investigated the association between socioeconomic status and adherence to health check-ups in a Korean population aged 40 years or older.

Methods

This cross-sectional study included 12,311 participants who participated in the 2010–2012 Korean National Health and Nutrition Examination Survey. Self-reported questionnaires were used to assess each participant's socioeconomic status (household income, occupation, and education) and adherence to health check-ups.

Results

Men with a higher income (highest vs. lowest: odds ratio [OR], 1.799; 95% confidence interval [CI], 1.296–2.497) and men with a higher education level (≥12 vs. <6 years: OR, 1.488; 95% CI, 1.078–2.054) and office workers compared with manual workers (men: OR, 1.431; 95% CI, 1.077–1.902; women: OR, 1.783; 95% CI, 1.256–2.532) appeared to undergo more health check-ups. In particular, men and women with a higher income and education appeared more likely to undergo opportunistic health check-ups (men: highest vs. lowest income: OR, 2.380; 95% CI, 1.218–4.653; ≥12 vs. <6 years education: OR, 2.121; 95% CI, 1.142–3.936; women: highest vs. lowest income: OR, 4.042; 95% CI, 2.239–7.297; ≥12 vs. <6 years education: OR, 2.475; 95% CI, 1.283–4.775).

Conclusion

A higher socioeconomic status was associated with a higher rate of participation in health check-ups. More efforts are needed to identify the factors associated with disparity in adherence to health check-ups.

Role of allostatic load and health behaviours in explaining socioeconomic disparities in mortality: a structural equation modelling approach

Background

The relationship between socioeconomic status and mortality has been well established; however, the extent to which biological factors mediate this relationship is less clear, and empirical evidence from non-Western settings is limited. Allostasis, a cumulative measure of physiological dysregulation, has been proposed as the underlying mechanism linking socioeconomic status to adverse health outcomes. The current study aimed to ascertain the contribution of allostatic load (AL) and health behaviours to socioeconomic inequalities in mortality among Korean adults.

Methods

The sample comprised 70 713 middle-aged and older-aged adults, aged 40–79 years from the Korean Metabolic Syndrome Mortality Study. Using structural equation modelling (SEM), mediation analyses were performed to estimate the effects of socioeconomic position (SEP) on mortality over the follow-up and the extent to which AL, physical exercise and non-smoking status mediate the association between SEP and mortality.

Results

A total of 5618 deaths (7.9%) occurred during the mean follow-up of 15.2 years (SD 2.9). SEM confirmed a direct significant effect of SEP on mortality, as well as significant indirect paths through AL, physical exercise and non-smoking status.

Conclusions

Our findings provide support for the mediating role of AL and health behaviours in the link between SEP and mortality. Policies designed to reduce social disparities in mortality in the long term should primarily focus on reducing stress and promoting healthy lifestyles among the socially disadvantaged groups. Future studies should further assess the role of other mediators such as psychosocial factors, which may contribute to socioeconomic inequalities in mortality.

Neo-Marxian social class inequalities in self-rated health among the employed in South Korea: the role of material, behavioral, psychosocial, and workplace environmental factors

BACKGROUND

The aim of this study was to examine the pattern of social inequality in self-rated health among the employed using the Wright's social class location indicator, and to assess the roles of material, behavioral, psychosocial, and workplace environmental factors as mediating factors in explaining the social class inequality in self-rated health in South Korea.

METHODS

This study used data from the 4th Korea National Health and Nutrition Examination Survey from 2007 to 2009. Study subjects included the employed population of 4392 men and 3309 women aged 19-64 years. Subjects were classified into twelve social class positions based on the Wright's social class map. The health outcome was self-rated health. Material, psychosocial, behavioral, and workplace environmental factors were considered as potential mediators in explaining social class health inequality. We calculated prevalence ratios of poor self-rated health according to social class, adjusted for age and mediating factors using Poisson regression models.

RESULTS

Nonskilled workers and petty bourgeoisie reported worse self-rated health than other social classes among men. The age-adjusted prevalence of petty bourgeoisie and nonskilled workers were about four-fold greater than that of managers. Expert supervisors in the contradictory class location had a greater prevalence of poor self-rated health than experts in men. In women, the prevalence of poor self-rated health was greater in most social classes than their male counterparts, while the differences among social classes within women were not statistically significant. Workplace environmental factors explained the social class inequality by from 24 to 31% in nonskilled and skilled workers and nonskilled supervisors, respectively, and material factors showed an explanatory ability of about 8% for both nonskilled workers and petty bourgeoisie in men.

CONCLUSIONS

We showed the inequality in self-rated health according to the Wright's social class in an industrialized Asian country. Policy efforts to improve workplace environments in nonskilled and skilled workers and nonskilled supervisors would have a moderate effect on reducing the magnitude of social class inequality in self-rated health. Furthermore, the means to improve power relations in the workplace should be devised to further reduce the social class inequalities in health.

Explaining socioeconomic inequalities in self-rated health: a systematic review of the relative contribution of material, psychosocial and behavioural factors

BACKGROUND

Material, psychosocial and behavioural factors are important explanatory pathways for socioeconomic inequalities in health. The aim of this systematic review was to summarise the available evidence on empirical studies and to analyse the relative contribution of these factors for explaining inequalities in self-rated health.

METHODS

The study was performed in compliance with PRISMA guidelines. The literature search was conducted in the electronic databases PubMed and Web of Science (1996-2016) as well as by screening of reference lists of obtained articles. Two reviewers performed the search and critical appraisal of the studies. All studies that focus on explaining socioeconomic inequalities in self-rated health, including at least 2 of the 3 main pathways and analysing the relative contribution of these approaches in separate and joint models, were included.

RESULTS

Eleven publications were included. Separate analyses showed that material, psychosocial and behavioural factors contribute to the explanation of socioeconomic inequalities in self-rated health. However, the combined analyses revealed that material factors contributed most to differences in self-rated health because of their higher independent (direct) effect and additional shared (indirect) effect (through psychosocial and behavioural factors). These results were largely independent of age, gender and indicator of socioeconomic status.

CONCLUSIONS

The evidence presented might be used for policymakers to identify and to justify prioritisation in terms of prevention and health promotion. The findings show that multiple factors are important for tackling social inequalities in health. Strategies for reducing these inequalities should focus on material/structural living conditions as they shape conditions of psychosocial resources and health behaviour.

Socioeconomic Inequality in mortality using 12-year follow-up data from nationally representative surveys in South Korea

Background

Investigations into socioeconomic inequalities in mortality have rarely used long-term mortality follow-up data from nationally representative samples in Asian countries. A limited subset of indicators for socioeconomic position was employed in prior studies on socioeconomic inequalities in mortality. We examined socioeconomic inequalities in mortality using follow-up 12-year mortality data from nationally representative samples of South Koreans.

Methods

A total of 10,137 individuals who took part in the 1998 and 2001 Korea National Health and Nutrition Examination Surveys were linked to mortality data from Statistics Korea. Of those individuals, 1,219 (12.1 %) had died as of December 2012. Cox proportional hazard models were used to estimate the relative risks of mortality according to a wide range of socioeconomic position (SEP) indicators after taking into account primary sampling units, stratification, and sample weights.

Results

Our analysis showed strong evidence that individuals with disadvantaged SEP indicators had greater all-cause mortality risks than their counterparts. The magnitude of the association varied according to gender, age group, and specific SEP indicators. Cause-specific analyses using equivalized income quintiles showed that the magnitude of mortality inequalities tended to be greater for cardiovascular disease and external causes than for cancer.

Conclusion

Inequalities in mortality exist in every aspect of SEP indicators, both genders, and age groups, and four broad causes of deaths. The South Korean economic development, previously described as effective in both economic growth and relatively equitable income distribution, should be scrutinized regarding its impact on socioeconomic mortality inequalities. Policy measures to reduce inequalities in mortality should be implemented in South Korea.

Electronic supplementary material

The online version of this article (doi:10.1186/s12939-016-0341-9) contains supplementary material, which is available to authorized users.

Perceived Stress and Elder Abuse: A Population-Based Study of Adult Protective Services Cases in Chicago

OBJECTIVES

To characterize the relationship between perceived stress and Adult Protective Services (APS) elder abuse cases in a population-based sample.

DESIGN

Cross-sectional.

SETTING

Chicago.

PARTICIPANTS

community-dwelling, older adults (N = 8,558; mean age 74 ± 7, 62% female, 64% African American).

MEASUREMENTS

Perceived Stress Scale (PSS), APS database linkage.

RESULTS

Bivariate and adjusted analyses showed that perceived stress was significantly higher in APS clients than in participants without any APS interaction for various subtypes of abuse (e.g., abuse from a perpetrator and self-neglect). This relationship was strongest for those with a confirmed history of abuse from a perpetrator, with a medium-large effect size (t = -5.8, P < .001, Cohen D = -0.6). Those in the highest stress tertile had a likelihood of having confirmed history of abuse from a perpetrator that was nearly three times as great as that of those in lower stress tertiles (odds ratio = 2.7, 95% confidence interval = 1.2-6.2). Analyses of individual PSS items revealed a robust relationship between distress items and APS involvement. Items reflecting coping were inconsistently associated with elder abuse.

CONCLUSION

Clients of APS have higher levels of perceived stress, and abuse from a perpetrator strengthens this relationship. Therefore, victims of abuse from a perpetrator may be at the highest risk of stress-related consequences and should be targeted for intervention efforts that enhance empowerment and effective coping strategies.

Low economic status is identified as an emerging risk factor for diabetes mellitus in korean men aged 30 to 59 years in korean national health and nutrition examination survey 2008 to 2010

BACKGROUND

We compared the association between economic status and the prevalence of diabetes mellitus (DM) using large nationwide datasets covering the previous 10 years in Korea.

METHODS

We analyzed the association between economic status and DM using Korean National Health and Nutrition Examination Survey (KNHANES) data from 2001 to 2010 weighted to represent the Korean population between 30 and 59 years of age. The economic status of participants was classified into quartiles according to monthly family income with an equivalence scale.

RESULTS

In men, the prevalence of diabetes in the lowest income quartile (Q1) was significantly higher than that in the other quartiles in 2008 (age and body mass index-adjusted odds ratio [OR], 1.846; 95% confidence interval [CI], 1.126 to 3.027; P=0.015), 2009 (OR, 1.706; 95% CI, 1.094 to 2.661; P=0.019), and 2010 (OR, 1.560; 95% CI, 1.024 to 2.377; P=0.039) but not in 2001 or 2005. The data indicated that classification in the lowest economic status was an independent risk factor for diabetes even after adjusting for abdominal obesity, dyslipidemia, hypertension and education level in men of KNHANES 2008 to 2010. Although economic status was significantly associated with abdominal obesity, hypertriglyceridemia, and hypertension in women (P<0.001), there was no significant association between economic status and DM in women.

CONCLUSION

Korean men between 30 and 59 years of age with the lowest economic status had a significantly higher prevalence of DM in 2008 to 2010 even after adjusting for other risk factors.

The effects of community environmental factors on obesity among Korean adults: a multilevel analysis

OBJECTIVES:

This study explored multidimensional factors related to obesity by dividing them into individual and environmental factors, and performed multilevel analysis to investigate community environmental effects.

METHODS:

Data from the 2011 and 2012 Community Health Surveys were used for the analysis. Community-level variables, constructed from various regional statistics, were included in the model as environmental factors. Respondents with body mass index (BMI)≥25 were defined as obese, and a multilevel logistic regression analysis was conducted to analyze individual and environmental factors related to obesity. Moreover, a stratified analysis was conducted to compare factors related to obesity between men and women.

RESULTS:

Of 337,136 samples, 82,887 (24.6%) were obese, with BMI≥25. Sociodemographic characteristics at the individual level were mostly significantly related to obesity; however, while there were more obese men subjects among those with high socioeconomic status, there were more obese women among those with low socioeconomic status. There were fewer obese respondents among those who regularly walked and more obese respondents among those who reported short sleep duration or were highly stressed. At the community level, people living in areas with high socioeconomic status, high satisfaction with safety and public transportation, and high accessibility to sports facilities in their community had lower obesity risks.

CONCLUSIONS:

Community-level environmental factors affected obesity, especially perceived community environment, more significant than physical environment. Thus, it is necessary to develop effective obesity prevention and management strategies by considering potential community environmental factors that affect obesity.

The role of health behaviours across the life course in the socioeconomic patterning of all-cause mortality: the west of Scotland twenty-07 prospective cohort study

Background

Socioeconomic differentials in mortality are increasing in many industrialised countries.

Purpose

This study aims to examine the role of behaviours (smoking, alcohol, exercise, and diet) in explaining socioeconomic differentials in mortality and whether this varies over the life course, between cohorts and by gender.

Methods

Analysis of two representative population cohorts of men and women, born in the 1950s and 1930s, were performed. Health behaviours were assessed on five occasions over 20 years.

Results

Health behaviours explained a substantial part of the socioeconomic differentials in mortality. Cumulative behaviours and those that were more strongly associated with socioeconomic status had the greatest impact. For example, in the 1950s cohort, the age-sex adjusted hazard ratio comparing respondents with manual versus non-manual occupational status was 1.80 (1.25, 2.58); adjustment for cumulative smoking over 20 years attenuated the association by 49 %, diet by 43 %, drinking by 13 % and inactivity by only 1%.

Conclusions

Health behaviours have an important role in explaining socioeconomic differentials in mortality.

Rising inequality in mortality among working-age men and women in Sweden: a national registry-based repeated cohort study, 1990-2007

Background

In the past two decades, health inequality has persisted or increased in states with comprehensive welfare.

Methods

We conducted a national registry-based repeated cohort study with a 3-year follow-up between 1990 and 2007 in Sweden. Information on all-cause mortality in all working-age Swedish men and women aged between 30 and 64 years was collected. Data were subjected to temporal trend analysis using joinpoint regression to statistically confirm the trajectories observed.

Results

Among men, age-standardised mortality rate decreased by 38.3% from 234.9 to 145 (per 100 000 population) over the whole period in the highest income quintile, whereas the reduction was only 18.3% (from 774.5 to 632.5) in the lowest quintile. Among women, mortality decreased by 40% (from 187.4 to 112.5) in the highest income group, but increased by 12.1% (from 280.2 to 314.2) in the poorest income group. Joinpoint regression identified that the differences in age-standardised mortality between the highest and the lowest income quintiles decreased among men by 18.85 annually between 1990 and 1994 (p trend=0.02), whereas it increased later, with a 2.88 point increase per year (p trend <0.0001). Among women, it continuously increased by 9.26/year (p trend <0.0001). In relative terms, age-adjusted mortality rate ratios showed a continuous increase in both genders.

Conclusions

Income-based inequalities among working-age male and female Swedes have increased since the late 1990s, whereas in absolute terms the increase was less remarkable among men. Structural and behavioural factors explaining this trend, such as the economic recession in the early 1990s, should be studied further.

Relationship between socioeconomic status and type 2 diabetes: results from Korea National Health and Nutrition Examination Survey (KNHANES) 2010-2012

OBJECTIVE

To examine the relationship between socioeconomic status (SES) and type 2 diabetes using the Korea National Health and Nutrition Examination Survey (KNHANES) 2010-2012.

DESIGN

A pooled sample cross-sectional study.

SETTING

A nationally representative population survey data.

PARTICIPANTS

A total of 14,330 individuals who participated in the KNHANES 2010-2012 were included in our analysis.

PRIMARY OUTCOME

Prevalence of type 2 diabetes.

RESULTS

The relationship between SES and type 2 diabetes was assessed using logistic regression after adjusting for covariates including age, gender, marital status, region, body mass index, physical activity, smoking and high-risk drinking behaviour. After adjustment for covariates, our results indicated that individuals with the lowest income were more likely to have type 2 diabetes than those with the highest income (OR 1.35; 95% CI 1.08 to 1.72). In addition, lower educational attainment was an independent factor for a higher prevalence of type 2 diabetes in Korea.

CONCLUSIONS

These findings suggest the need for developing a health policy to ameliorate socioeconomic inequalities, in particular income and education-related disparities in type 2 diabetes, along with risk factors at the individual level. In addition, future investigations of type 2 diabetes among Koreans should pay more attention to the social determinants of diabetes in order to understand the various causes of the condition.

Perceived stress and mortality in a Taiwanese older adult population

Perceived stress is associated with poor health outcomes including negative affect, increased susceptibility to the common cold and cardiovascular disease; the consequences of perceived stress for mortality, however, have received less attention. This study characterizes the relationship between perceived stress and 11-year mortality in a population of Taiwanese adults aged 53+ years. Using the Survey of Health and Living Status of the Near Elderly and Elderly of Taiwan, we calculated a composite measure of perceived stress based on six items pertaining to the health, financial situation, and occupation of the respondents and their families. Proportional hazard models were used to determine whether perceived stress predicted mortality. After adjusting for sociodemographic factors only, we found that a one standard deviation increase in perceived stress was associated with a 19% increase in all-cause mortality risk during the 11-year follow-up period (hazard ratio, HR = 1.19, 95% confidence interval, CI 1.13-1.26). The relationship was greatly attenuated when perceptions of stress regarding health were excluded, and was not significant after adjusting for medical conditions, mobility limitations and depressive symptoms. We conclude that the association between perceived stress and mortality is explained by an individual's current health; however, our data do not allow us to distinguish between two possible interpretations of this conclusion: (a) the relationship between perceived stress and mortality is spurious, or (b) poor health acts as the mediator.

Invited commentary: On the future of social epidemiology--a case for scientific realism

In their article in this issue of the Journal (Am J Epidemiol. 2013;178(6):843-849), Galea and Link identify important heuristics for our discipline. In this commentary, I build upon their ideas by arguing that (1) social epidemiology has become an Asian, European, Latin American, and African rather than just North American endeavor, (2) realism is better suited to social epidemiology than positivism, (3) more work on social mechanisms (social class relations, racial discrimination) is needed to increase the explanatory power of social epidemiology, (4) increased attention on (social) causal models will generate more innovative social interventions, and (5) social interventions should be conducted in full partnerships with affected populations.

Association between Household Income and Asthma Symptoms among Elementary School Children in Seoul

OBJECTIVES

This study examined the association between socioeconomic factors and asthma symptoms.

METHODS

A total of 6,919 elementary school children in Seoul were enrolled in the study. Data were obtained from a web-based questionnaire survey. The questionnaire was based on the International Study of Asthma and Allergies in Childhood core module. The prevalence of wheeze in the past 12 months and severe asthma symptoms were obtained. The potential risk factors for asthma symptoms included household income and the number of siblings. A multiple logistic regression analysis was used to calculate the odds ratios (OR) and 95% confidence interval (CI) for the risk factors of asthma symptoms.

RESULTS

The prevalence of current wheeze (wheeze in the past 12 months) was 5.2%. Household income and asthma symptoms were inversely associated after adjusting for other potential risk factors (p for trend=0.03). This association was modified by the number of siblings. With two or more siblings, the effect of household income on asthma symptoms was not significant. However, low household income was still a significant variable for patients with fewer than two siblings (OR 1.41; 95% CI, 1.09-1.81).

CONCLUSIONS

It appears that childhood asthma disparity is dependent on household income. Therefore, policies to improve childhood health inequities should be emphasized.

To what extent do biomarkers account for the large social disparities in health in Moscow?

The Russian population continues to face political and economic challenges, has experienced poor general health and high mortality for decades, and has exhibited widening health disparities. The physiological factors underlying links between health and socioeconomic position in the Russian population are therefore an important topic to investigate. We used data from a population-based survey of Moscow residents aged 55 and older (n = 1495), fielded between December 2006 and June 2009, to address two questions. First, are social disparities evident across different clusters of biomarkers? Second, does biological risk mediate the link between socioeconomic status and health? Health outcomes included subscales for general health, physical function, and bodily pain. Socioeconomic status was represented by education and an index of material resources. Biological risk was measured by 20 biomarkers including cardiovascular, inflammatory, and neuroendocrine markers as well as heart rate parameters from 24-h ECG monitoring. For both sexes, the age-adjusted educational disparity in standard cardiovascular risk factors was substantial (men: standardized β = -0.16, 95% CI = -0.23 to -0.09; women: β = -0.25, CI = -0.32 to -0.18). Education differences in inflammation were also evident in both men (β = -0.17, CI = -0.25 to -0.09) and women (β = -0.09, CI = -0.17 to -0.01). Heart rate parameters differed by education only in men (β = -0.10, CI = -0.18 to -0.02). The associations between material resources and biological risk scores were generally weaker than those for education. Social disparities in neuroendocrine markers were negligible for men and women. In terms of mediating effects, biological risk accounted for more of the education gap in general health and physical function (19-36%) than in bodily pain (12-18%). Inclusion of inflammatory markers and heart rate parameters-which were important predictors of health outcomes-may explain how we accounted for more of the social disparities than previous studies.

The contribution of stress to the social patterning of clinical and subclinical CVD risk factors in African Americans: the Jackson Heart Study

It is often hypothesized that psychosocial stress may contribute to associations of socioeconomic position (SEP) with risk factors for cardiovascular disease (CVD). However, few studies have investigated this hypothesis among African Americans, who may be more frequently exposed to stressors due to social and economic circumstances. Cross-sectional data from the Jackson Heart Study (JHS), a large population-based cohort of African Americans, were used to examine the contributions of stressors to the association of SEP with selected cardiovascular (CVD) risk factors and subclinical atherosclerotic disease. Among women, higher income was associated with lower prevalence of hypertension, obesity, diabetes and carotid plaque and lower levels of stress. Higher stress levels were also weakly, albeit positively, associated with hypertension, diabetes, and obesity, but not with plaque. Adjustment for the stress measures reduced the associations of income with hypertension, diabetes and obesity by a small amount that was comparable to, or larger, than the reduction observed after adjustment for behavioral risk factors. In men, high income was associated with lower prevalence of diabetes and stressors were not consistently associated with any of the outcomes examined. Overall, modest mediation effects of stressors were observed for diabetes (15.9%), hypertension (9.7%), and obesity (5.1%) among women but only results for diabetes were statistically significant. No mediation effects of stressors were observed in men. Our results suggest that stressors may partially contribute to associations of SEP with diabetes and possibly hypertension and obesity in African American women. Further research with appropriate study designs and data is needed to understand the dynamic and interacting effects of stressors and behaviors on CVD outcomes as well as sex differences in these effects.

Overcoming barriers in the management of hypertension: the experience of the cardiovascular health program in chilean primary health care centers

Objective. To assess the blood pressure control and cardiovascular risk factors (CVRFs) in a population of hypertensive patients with access to care under a government-financed program, the Cardiovascular Health Program (CHP). Design. A cross-sectional and multicenter study. Setting. 52 primary care centers, metropolitan area of Santiago, Chile. Participants. 1,194 patients were selected by a systematic random sampling from a universe of 316,654 hypertensive patients. Key Measurements. Demographic information, blood pressure (BP) measurements, and CVRF were extracted from medical records of patients followed for a 12-month period. Results. 59.7% of patients reached target BP <140/90 mmHg. More women were captured in the sampling (2.1 : 1), achieving better BP control than men. Diabetic patients (26.4%) had worse BP control than nondiabetics. Antihypertensive medications were used in 91.5%, with multidrug therapy more frequent in patients with higher BP and more difficult control. Conclusions. The success in improving the BP control to values <140/90 mmHg from 45.3% to 59.7% underscores the contribution of this program in the Chilean primary care cardiovascular preventive strategies. However, fewer hypertensive men than women were captured by this program, and it is of concern the underperforming of BP control observed in diabetics.

The changing gender differences in life expectancy in Korea 1970-2005

Women live much longer than men in Korea, with remarkable gains in life expectancy at birth for the past decades. The gender differential has steadily increased over time, reaching a peak of more than 8 years in 1980s, and decreased thereafter to 6.7 years in 2005. Studies to investigate the pattern and contributing factors to changes in the life expectancy gender gap have been mostly from Western countries, and there has been no such study in Asian countries, except in Japan. We therefore aimed to examine age- and cause-specific contributions to the changing gender differentials in life expectancy in Korea, in particular the decline of the gap, using a decomposition method. Between 1970 and 1979 when the gender gap in life expectancy widened, faster mortality decline among women in ages 20-44 explained 66% of the total increase in the gender gap, which would be due to substantial improvements in reproductive health among women and excess male mortality in occupational injuries and transport accidents. Although greater survival advantage among elderly women over 70 contributed to further increase in the gender gap, the contributions from younger ages with the ages 15-64 contributing the most (-2 years) resulted in the overall reduction of the gender gap which began in 1992 and continued to 2005. Among causes of death, liver diseases (-0.5 years, 38% of the total decline), transport accidents (-0.4 years, 31%), hypertensive diseases (-0.3 years, 19%), stroke (-0.1 years, 11%), and tuberculosis (-0.1 years) contributed the most to the overall 1.4 years reduction in the gender gap. However, changes in mortality from lung cancer (+0.3 years), suicide (+0.3 years), chronic lower respiratory diseases (+0.2 years), and ischemic heart diseases (+0.1 years) contributed to widening the gap during the same period. In sum, while smoking-related causes of death have contributed most to the narrowing gap in most other industrialized countries, these causes contributed toward increasing the gender gap in Korea. Instead, liver disease, hypertension-related diseases, and transport accidents were major contributing causes of death to the narrowing of gender differentials in life expectancy in Korea.

The education effect on population health: a reassessment

Demographic research frequently reports consistent and significant associations between formal educational attainment and a range of health risks such as smoking, drug abuse, and accidents, as well as the contraction of many diseases, and health outcomes such as mortality—almost all indicating the same conclusion: better-educated individuals are healthier and live longer. Despite the substantial reporting of a robust education effect, there is inadequate appreciation of its independent influence and role as a causal agent. To address the effect of education on health in general, three contributions are provided: 1) a macro-level summary of the dimensions of the worldwide educational revolution and a reassessment of its causal role in the health of individuals and in the demographic health transition are carried out; 2) a meta-analysis of methodologically sophisticated studies of the effect of educational attainment on all-cause mortality is conducted to establish the independence and robustness of the education effect on health; and 3) a schooling-cognition hypothesis about the influence of education as a powerful determinant of health is developed in light of new multidisciplinary cognitive research.

Do biological measures mediate the relationship between education and health: A comparative study

Despite a myriad of studies examining the relationship between socioeconomic status and health outcomes, few have assessed the extent to which biological markers of chronic disease account for social disparities in health. Studies that have examined this issue have generally been based on surveys in wealthy countries that include a small set of clinical markers of cardiovascular disease. The availability of recent data from nationally representative surveys of older adults in Costa Rica and Taiwan that collected a rich set of biomarkers comparable to those in a recent US survey permits us to explore these associations across diverse populations. Similar regression models were estimated on three data sets - the Social Environment and Biomarkers of Aging Study in Taiwan, the Costa Rican Study on Longevity and Healthy Aging, and the Health and Retirement Study in the USA - in order to assess (1) the strength of the associations between educational attainment and a broad range of biomarkers; and (2) the extent to which these biomarkers account for the relationships between education and two measures of health status (self-rated health, functional limitations) in older populations. The estimates suggest non-systematic and weak associations between education and high risk biomarker values in Taiwan and Costa Rica, in contrast to generally negative and significant associations in the US, especially among women. The results also reveal negligible or modest contributions of the biomarkers to educational disparities in the health outcomes. The findings are generally consistent with previous research suggesting stronger associations between socioeconomic status and health in wealthy countries than in middle-income countries and may reflect higher levels of social stratification in the US. With access to an increasing number of longitudinal biosocial surveys, researchers may be better able to distinguish true variations in the relationship between socioeconomic status and health across different settings from methodological differences.

Relationships of suicide ideation with cause-specific mortality in a longitudinal study of South Koreans

Using 7-year mortality follow-up data (n = 341) from the 1998 National Health and Nutrition Examination Surveys of South Korean individuals (N = 5,414), the authors found that survey participants with suicide ideation were at increased risk of suicide mortality during the follow-up period compared with those without suicide ideation. The cause-specific analyses showed that, in men, suicide ideation was significantly associated with mortality due to cardiovascular disease, external causes, and other causes. However, there was no significant association between suicide ideation and cause-specific mortality in women. The relationship between suicide ideation and cause-specific mortality in men was not fully explained by baseline health status, socioeconomic status, health behavior, or psychosocial factors.

Socioeconomic disparities in behavioral risk factors and health outcomes by gender in the Republic of Korea

BACKGROUND

Few studies have examined socioeconomic disparities in health and behavioral risk factors by gender in Asian countries and in South Korea, specifically. We investigated the relationship between socioeconomic position (education, income, and occupation) and subjective and acute and chronic health outcomes and behavioral risk factors by gender, and compared results from 1998 and 2005, in the Republic of Korea.

METHODS

We examined data from a nationally representative stratified random sample of 4213 men and 4618 women from the 1998 Korea National Health and Nutrition Examination Survey, and 8289 men and 8827 women from the 2005 Korea National Health and Nutrition Examination Survey using General Linear Modeling and multiple logistic regression methods.

RESULTS

Controlling for behavioral risk factors (smoking, drinking, obesity, exercise, and sleep), those in lower socioeconomic positions had poorer health outcomes in both self-reported acute and chronic disease and subjective measures; differences were especially pronounced among women. A socioeconomic gradient for education and income was found for both men and women for morbidity and self-reported health status, but the gradient was more pronounced in women. In 1998, the odds ratios (ORs) of higher morbidity for illiterate vs. college educated females was 5.4:1 and 1.9:1 for females in the lowest income quintile vs. the highest. The OR for education decreased in 2005 to 2.9:1 and that for income quintiles remained the same at 1.9:1. The OR of lower self-reported health status for illiterate vs. college educated females was 2.9:1 and 1.6:1 for females in the lowest income quintile vs. the highest in 1998, and 3.3:1 and 2.3:1 in 2005.

CONCLUSIONS

Among Korean adults, men and women in lower socioeconomic position, as denoted by education, income, and somewhat less by occupation, experience significantly higher levels of morbidity and lower self-reported health status, even after controlling for standard behavioral risk factors. Disparities were more pronounced for women than for men. Efforts to reduce health disparities in South Korea require attention to the root causes of socioeconomic inequality and gender differences in the impact of socioeconomic position on health.

[Analysis for the impact of adulthood and childhood socioeconomic positions and intergenerational social mobility on adulthood health]

OBJECTIVES

There are at least three conceptual models for the effects of the childhood social environment on adult health: the critical period model, the social mobility model, and the cumulative risk model. However, few studies have investigated all three different models within the same setting. This study aims to examine the impact of childhood and adulthood socioeconomic positions and intergenerational social mobility over the life course on the health in adulthood based both on the critical period model and the social mobility model.

METHODS

This study was conducted on 9583 adults aged between 25 and 64 years old and they were the respondents to the Korea Welfare Panel Study (2006). A multivariate logistic regression analysis was carried out, using the critical period model and the social mobility model out of the life course approaches, to look into the impact of childhood and adulthood socioeconomic positions and intergenerational social mobility on the health status in adulthood.

RESULTS

Household income and occupation out of the adulthood socioeconomic position indicators had an independent influence on the adulthood health status. The childhood socioeconomic position indicators, except for the place of childhood residence, affected the adulthood health status even after adjustment for the adulthood socioeconomic position. The effect of intergenerational social mobility was also statistically significant even after adjusting for the adulthood socioeconomic position, but it became insignificant when the childhood socioeconomic position was additionally adjusted for.

CONCLUSIONS

Adulthood health is indeed affected by both the childhood and adulthood socioeconomic positions as well as intergenerational social mobility. This result shows that a life course approach needs to be adopted when dealing with health issues.

Impact of education, income and chronic disease risk factors on mortality of adults: does 'a pauper-rich paradox' exist in Latin American societies?

OBJECTIVES

To test the hypothesis that an inverse association exists between socio-economic position and all-cause mortality in a developing country in Latin America.

STUDY DESIGN

Prospective cohort study carried out in Chile using data from a simple random sample of 920 apparently healthy subjects (weighted population 11,600 aged 30-89 years) followed for 8 years.

METHODS

Education level (0-8 years, 9-12 years and > or = 13 years) and income quartiles were established at the outset of the study, along with behavioural and biological risk factors for chronic diseases: smoking, alcohol use, obesity, diabetes, hypertension, lipids and family history of death by cardiovascular disease. Relative risks of all-cause mortality were estimated using age-adjusted Cox regression models.

RESULTS

During the follow-up period, 46 deaths were observed. Adjusting for age, gender, and behavioural and biological risk factors, the mortality risk for increasing categories of education after controlling for income was 1.0, 0.76 and 0.33 (P for trend<0.01). In contrast, the relative risk for increasing levels of income after controlling for education was 1.0, 0.98, 1.33 and 1.17 (P for trend=0.07).

CONCLUSION

While education level had a protective effect on mortality risk of Chilean adults, income had a slightly unfavourable effect on survival. This finding is described as suggestive of a 'pauper-rich paradox', since the higher income quantiles in this study correspond with the lower income levels in most developed countries. Nevertheless, due to the small number of deaths, additional research is required to assess the validity of these findings.

Associations of income and wealth with health status in the Korean elderly

OBJECTIVES

This study aimed to verify the association between wealth or income level and health status after adjusting for other socio-economic position (SEP) indicators among Korean adults aged 45 and over.

METHODS

Data were obtained from the 1st wave of Korean Longitudinal Study of Ageing (households: 6,171, persons: 10,254). We used self-rated health status and activities of daily living (ADLs) as dependent variables. Explanatory variables included both net wealth measured by savings, immovables, the other valuated assets and total income including pay, transfer, property and so on. Binary logistic regression was conducted to examine the relationships. Also, in order to determine the relative health inequality across economic groups, we estimated the relative index of inequality (RII).

RESULTS

The inequality of health status was evident among various wealth and income groups. The wealthiest group (5th quintile) was much healthier than the poorest group, and this differential increased with age. Likewise, higher income was associated with better health status among the elderly. However, these effects, as measured by the odds ratio and RII, showed that wealth was more important in determining health status of elderly people.

CONCLUSIONS

This study suggests that economic capability plays a significant role in determining the health status and other health-related problems among the elderly. Particularly, our results show that health status of the aged is related more closely to the individual's wealth than income.

Trends in nutritional inequality by educational level: a case of South Korea

OBJECTIVE

There is much evidence of a cross-sectional relation between socioeconomic position and dietary intakes but the trend of this relation is little studied. This study aimed to examine the extent and trend of nutritional inequality by educational level based on the prevalence of inadequate nutrient intakes.

METHODS

Three cross-sectional nationwide surveys (1998, 2001, 2005) of the Korean National Health and Nutrition Examination Survey were used. A total of 20 777 participants > or = 20 y old were included. The socioeconomic position indicator was educational level. Dietary nutrient intakes were assessed by a 24-h recall and inadequacy of intake for nutrients was assessed on the basis of the percentage of attainment of the dietary reference intakes for Koreans. To assess nutritional inequality by educational level, the prevalence ratio, relative index of inequality, and slope index of inequality were used.

RESULTS

Poorer dietary intakes and higher estimated prevalence of nutrient inadequacy were more apparent in the lower education group than the higher education group for both genders and each survey year. Graded patterns of inequalities in nutrient intakes by educational level were generally clear at each survey year. The trend of the relative nutritional inequalities in Korean men and women remained unchanged from 1998 to 2005, with some exceptions.

CONCLUSION

The inequality in nutrient intakes by educational level was persistently apparent for both genders in the Korean adult population, although the relative inequalities did not increase over time.