Factors contributing to educational differences in obesity among women: evidence from South Korea.

BACKGROUND: Obesity is more prevalent among less-educated women than highly-educated women around the world. However, little is known about the factors which cause this difference in obesity, and almost nothing is known about how the individual factors which explain differences in education among women alone contribute to obesity. In this study, we identified the factors which help explain the relationship between education and obesity in women, and quantified their separate contributions to obesity. METHODS: We analyzed information on 14,577 women aged 25 years or over using datasets from the Korea National Health and Nutrition Examination Survey (2010-2014). We divided the women into two education groups: women who had, at most, finished high school (less-educated women), and women who had college degrees and beyond (highly-educated women). Using an extended Oaxaca-Blinder method, we decomposed the difference in obesity prevalence between the two education groups into the contributions (%) due to two effects: composition effect and association effect. RESULTS: Obesity was more than twice as prevalent among the less-educated women (34.3%) than it was among the highly-educated women (16.0%). The composition effect-contribution of differences in the distribution of observed characteristics compared to that of the difference in obesity prevalence between the two education groups-was 38.2%. The association effect-contributions of differences in the estimated coefficients of characteristics compared to that of the difference in obesity prevalence between the two education groups-was 55.8%, of which lifestyle factors were the most important contributor (43.6%). Of the separate contributions of each factor, the association effect of the factor related to women's stress exhibited the largest contribution (23.0%). CONCLUSION: We suggest that to effectively mitigate the high prevalence of obesity among less-educated women, it may be necessary to help low-educated women who do not feel stressful develop strategies to combat their higher risk of obesity. We also suggest the need to conduct decomposition studies in countries which show significant relationships between education and obesity among women, and to create targeted policies to reduce this population's overall risk of obesity.

Sex-specific role of education on the associations of socioeconomic status indicators with obesity risk: A population-based study in South Korea.

BACKGROUND: No study of obesity risk for people in developed countries has conducted a multi-dimensional analysis of the association of socioeconomic status with obesity. In this paper, we investigated if education functions as either a confounder or an effect modifier in the association of another socioeconomic status indicator with obesity. METHODS: This cross-sectional study analyzed data of an adult population sample (10,905 men and 14,580 women) from the Korea National Health and Nutrition Examination Survey (2010-2014). The study performed multivariate logistic regression analyses for three education levels and four indicators of socioeconomic status (i.e., marital status, residential area, occupation, and income). RESULTS: The overall prevalence of obesity was 38.1% in men and 29.1% in women (p < 0.001). In men, while education functioned as an effect modifier in the association between marital status and obesity (p for interaction = 0.006), it functioned as both a confounder (p < 0.001) and an effect modifier (p for interaction < 0.001) in the association between residential area and obesity. In contrast, in women, education functioned as a confounder in the association of residential area with obesity (p = 0.010). However, it functioned as both a confounder (p < 0.001) and an effect modifier (p for interaction = 0.012) in the association between income and obesity. A prediction showed that unlike in women, education was positively associated with obesity risk for some socioeconomic indicator groups in men; for example, in a rural resident group, a higher level of education increased the probability of being obese by 19.7%. CONCLUSIONS: The present study suggests the need to examine sex-specific studies regarding the role of education on the association between other socioeconomic status indicators and obesity. This should be considered in planning education policies to reduce the risk of obesity.

Gender-specific interactions between education and income in relation to obesity: a cross-sectional analysis of the Fifth Korea National Health and Nutrition Examination Survey (KNHANES V).

OBJECTIVES: To identify gender-specific associations between education and income in relation to obesity in developed countries by considering both the interaction-effect terms of the independent variables and their main-effect terms. DESIGN: A cross-sectional study. Education and income levels were chosen as socioeconomic status indicators. Sociodemographics, lifestyles and medical conditions were used as covariates in multivariable logistic regression models. Adjusted ORs and predicted probabilities of being obese were computed and adjusted for a complex survey design. SETTING: Data were obtained from the Fifth Korea National Health and Nutrition Examination Survey (2010-2012). PARTICIPANTS: The sample included 7337 male and 9908 female participants aged ≥19 years. OUTCOME MEASURE: Obesity was defined as body mass index of ≥25, according to a guideline for Asians. RESULTS: In models with no interaction-effect terms of independent variables, education was significantly associated with obesity in both men and women, but income was significant only in women. However, in models with the interaction-effect terms, education was significant only in women, but income was significant only in men. The interaction effect between income and education was significant in men but not in women. Participants having the highest predicted probability of being obese over educational and income levels differed between the two types of models, and between men and women. A prediction using the models with the interaction-effect terms demonstrated that for all men, the highest level of formal education was associated with an increase in their probability of being obese by as much as 26%. CONCLUSIONS: The well-known, negative association between socioeconomic status and obesity in developed countries may not be valid when interaction effects are included. Ignoring these effects and their gender differences may result in the targeting of wrong populations for reducing obesity prevalence and its resultant socioeconomic gradients.

Modifying effects of education on the association between lifestyle behaviors and the risk of obesity: evidence from South Korea.

BACKGROUND: No previous study has explored the interactions between education and lifestyle in relation to obesity. This study hypothesized that education may be obesogenic through its interplay with lifestyle behaviors. METHODS: Data for a nationally representative sample (6937 men and 9333 women) from the Korea National Health and Nutrition Examination Survey (2010-2012) were analyzed. Multivariate logistic regressions were performed for three education levels and six lifestyle behaviors, each of which comprised two groups. RESULTS: Interactions between education and lifestyle behaviors in relation to obesity were observed for all lifestyle behaviors in women (p for interaction <0.001) and for three lifestyle behaviors in men. Education appeared obesogenic for three groups of lifestyle behaviors in men (p for trend <0.05), but was protective against obesity for 11 groups in women. Each one-unit increase in education level in men increased the odds of obesity by 1.29-fold among under-reported energy intake groups (95 % confidence interval: 1.16, 1.44). CONCLUSIONS: Education may be a risk factor for obesity through its interplay with lifestyle behaviors. Further research is required to examine these findings in different socio-cultural settings.

The socioeconomic burden of coronary heart disease in Korea.

OBJECTIVES: We aimed to estimate the annual socioeconomic burden of coronary heart disease (CHD) in Korea in 2005, using the National Health Insurance (NHI) claims data. METHODS: A prevalence-based, top-down, cost-of-treatment method was used to assess the direct and indirect costs of CHD (International Classification of Diseases, 10th revision codes of I20-I25), angina pectoris (I20), and myocardial infarction (MI, I21-I23) from a societal perspective. RESULTS: Estimated national spending on CHD in 2005 was $2.52 billion. The majority of the spending was attributable to medical costs (53.3%), followed by productivity loss due to morbidity and premature death (33.6%), transportation (8.1%), and informal caregiver costs (4.9%). While medical cost was the predominant cost attribute in treating angina (74.3% of the total cost), premature death was the largest cost attribute for patients with MI (66.9%). Annual per-capita cost of treating MI, excluding premature death cost, was $3183, which is about 2 times higher than the cost for angina ($1556). CONCLUSIONS: The total insurance-covered medical cost ($1.13 billion) of CHD accounted for approximately 6.02% of the total annual NHI expenditure. These findings suggest that the current burden of CHD on society is tremendous and that more effective prevention strategies are required in Korea.

Why is high-risk drinking more prevalent among men than women? Evidence from South Korea.

BACKGROUND: It is important to identify and quantify the factors that affect gender differences in high-risk drinking (HRD), from both an academic and a policy perspective. However, little is currently known about them. This study examines these factors and estimates the percentage contribution each makes to gender differences in HRD. METHODS: This study analyzed information on 23,587 adults obtained from the Korea National Health and Nutrition Surveys of 1998, 2001, and 2005. It found that the prevalence of HRD was about 5 times higher among men (0.37) than women (0.08). Using a decomposition approach extended from the Oaxaca-Blinder method, we decomposed the gender difference in HRD to an "overall composition effect" (contributions due to gender differences in the distribution of observed socio-economic characteristics), and an "overall HRD-tendency effect" (contributions due to gender differences in tendencies in HRD for individuals who share socio-economic characteristics). RESULTS: The HRD-tendency effect accounted for 96% of the gender difference in HRD in South Korea, whereas gender differences in observed socio-economic characteristics explained just 4% of the difference. Notably, the gender-specific HRD-tendency effect accounts for 90% of the gender difference in HRD. CONCLUSION: We came to a finding that gender-specific HRD tendency is the greatest contributor to gender differences in HRD. Therefore, to effective reduce HRD, it will be necessary to understand gender differences in socioeconomic characteristics between men and women but also take notice of such differences in sociocultural settings as they experience. And it will be also required to prepare any gender-differentiated intervention strategy for men and women.

Differences between the factors affecting high-risk drinking and those affecting smoking in Korea.

This study examines the factors influencing high-risk drinking and cigarette smoking and assesses the differences in those factors between 2 risky behaviors in Korea. A national, cross-sectional health behavior survey was performed on 12,303 households in 2006 and a data set of 2925 adult males was analyzed using bivariate probit estimation model. The likelihood of high-risk drinking rose with an increase in the level of income, whereas that of smoking was lowest in a medium income. White-collar workers were more at risk of high-risk drinking than blue-collar workers. Conversely, blue-collar workers tended to smoke more frequently than white-collar workers. Body mass index showed a positive association with high-risk drinking, but it had no significant relationship with smoking. Significant differences may exist in associations between factors influencing high-risk drinking and those influencing smoking. The comprehensive understanding of these differences would allow for the development of appropriate public health programs.

Estimating the lifetime economic burden of stroke according to the age of onset in South Korea: a cost of illness study.

BACKGROUND: The recently-observed trend towards younger stroke patients in Korea raises economic concerns, including erosion of the workforce. We compared per-person lifetime costs of stroke according to the age of stroke onset from the Korean societal perspective. METHODS: A state-transition Markov model consisted of three health states ('post primary stroke event', 'alive post stroke', and 'dead') was developed to simulate the natural history of stroke. The transition probabilities for fatal and non-fatal recurrent stroke by age and gender and for non-stroke causes of death were derived from the national epidemiologic data of the Korean Health Insurance Review and Assessment Services and data from the Danish Monitoring Trends in Cardiovascular Disease study. We used an incidence-based approach to estimate the long-term costs of stroke. The model captured stroke-related costs including costs within the health sector, patients' out-of-pocket costs outside the health sector, and costs resulting from loss of productivity due to morbidity and premature death using a human capital approach. Average insurance-covered costs occurring within the health sector were estimated from the National Health Insurance claims database. Other costs were estimated based on the national epidemiologic data and literature. All costs are presented in 2008 Korean currency values (Korean won = KRW). RESULTS: The lifetime costs of stroke were estimated to be: 200.7, 81.9, and 16.4 million Korean won (1,200 KRW is approximately equal to one US dollar) for men who suffered a first stroke at age 45, 55 and 65 years, respectively, and 75.7, 39.2, and 19.3 million KRW for women at the same age. While stroke occurring among Koreans aged 45 to 64 years accounted for only 30% of the total disease incidence, this age group incurred 75% of the total national lifetime costs of stroke. CONCLUSIONS: A higher lifetime burden and increasing incidence of stroke among younger Koreans highlight the need for more effective strategies for the prevention and management of stroke especially for people between 40 and 60 years of ages.

Economic burden of injuries in South Korea.

UNLABELLED: BACKGROUND STUDIES: on the cost of injury are useful in setting research and policy priorities and it is valuable to observe differences in the economic burden of injuries across countries. OBJECTIVE: To estimate the treated prevalence rate, economic burden and gender- and age-specific costs of injuries in Korea in 2006. DESIGN: Annual direct healthcare costs associated with injuries were estimated from the National Health Insurance, Medical Aid and Automobile Insurance databases. Annual direct non-health costs were estimated for transport and caregiver's costs. Indirect costs were estimated for premature death, absence from work and disability. Costs were adjusted to 2006 levels using the healthcare component of the Consumer Price Index. MAIN OUTCOME MEASURES: Prevalence-based direct costs, incidence-based indirect costs and total costs for injuries, stratified by gender, age group and type of injury. RESULTS: The treated prevalence rate of injury in 2006 of the Korean population was 26.5 per 100, resulting in an annual economic burden of $39837 million ($4703 million in direct and $35134 million in indirect costs). The cost of medical treatment associated with injuries accounted for 9.5% of the total health expenditure in Korea. The cost of premature death was the largest contributor to the total and automobile-related injuries accounted for 30.3% of total costs. CONCLUSIONS: The estimates were considerably understated because they did not include losses in household production and quality of life. Nevertheless, the size and main components of the injury burden were identified; this information should aid decision-making about research priorities and improve monitoring of the effects of policy initiatives.

Factors influencing gender differences in smoking and their separate contributions: evidence from South Korea.

This paper explores gender differences in smoking using information on 15,277 adults obtained from the Korea National Health and Nutrition Examination Surveys of 2001 and 2005. Applying a decomposition approach extended from the Oaxaca-Blinder method, we obtained factors influencing gender differences in smoking and estimated their separate contributions. According to the outcomes of decomposition analyses, gender differences in smoking-tendency (or inclination to smoke) accounted for 98% of the total gender difference in smoking. When the gender difference in smoking was decomposed into specified factors, the difference in smoking-tendency between married men and women was found to be the most crucial factor as it explained 11% of the total gender difference in smoking. The gender difference in the proportion of persons attaining a low level of education contributed to a 6% reduction of the total gender difference in smoking. Additionally, factors influencing the gender-specific smoking-tendency were found to be important in explaining the gender difference in smoking. We conclude that, understanding separate contributions of sets of factors affecting gender differences in smoking and devising appropriate policies could effectively reduce the smoking rate of a target gender group to the level of that of a reference gender group.

[Socioeconomic inequity in self-rated health status and contribution of health behavioral factors in Korea].

OBJECTIVES: The study is investigated socioeconomic variations in self-rated health status and contribution of health behavioral factors in Korea. METHODS: A nationally representative sample (2,800 men and 3,230 women aged 20-64 years) from the 2005 Korea National Health and Nutrition Surveys was analyzed using logistic regression. RESULTS: Self-rated health was lower among lower socioeconomic groups compared with higher socioeconomic groups, with gender being irrelevant. This association was attenuated when health behavioral and socio-demographic factors were adjusted. When each health behavioral factor was considered separately, mediators such as smoking in men, and stress or exercise in women explained a large part of the decreased socioeconomic health inequalities. CONCLUSIONS: In Korea, subjective health inequalities arise from different socioeconomic status, but this difference is decreased by health behavioral factors. Therefore, socioeconomic inequity in self-rated health status can be corrected more effectively by promotional health behaviors.

The influence of housing tenure and marital status on smoking in South Korea.

OBJECTIVE: This study aimed to identify the most influential socioeconomic indicator of smoking in South Korea. METHODS: This study analyzed a nationally representative sample (6141 men and 7133 women aged 20-65) from the 2001 and 2005 Korea National Health and Nutrition Surveys. Weighted estimates were computed, adjusting for a complex survey design using "surveyfreq" and "surveylogistic" procedures of SAS 9.1 software. RESULTS: The adjusted OR for smoking in renters compared to homeowners was 1.50 (95% CI: 1.32-1.71) in men and 3.21 (95% CI: 2.41-4.27) in women, and larger in the older than younger groups. For non-married versus married individuals, the OR was 1.37 (95% CI: 1.19-1.59) in men and 3.25 (95% CI: 2.48-4.25) in women; the OR in non-married renters compared married homeowners was 1.79 (95% CI: 1.45-2.22) in men and 10.63 (95% CI: 7.31-15.45) in women. CONCLUSION: Housing tenure was a strong predictor of smoking in South Korea and its significance was very pronounced in non-married individuals. Housing policies to encourage homeownership could be effective in reducing smoking in countries such as China, India, and Vietnam where house ownership is regarded as the ultimate financial safeguard, there are numerous, and traditional attitudes toward marriage are undergoing transition.

Factors influencing cigarette smoking and quantified implications for anti-smoking policy: evidence from South Korea.

OBJECTIVES: The aim of this study was to determine the factors that are associated with adult males' smoking in South Korea and simulate the effects of a potential anti-smoking policy. METHODS: We conducted a national, cross-sectional, telephone survey among males aged 20 years and older in 2006 and analyzed a dataset of 2,847 subjects by using the full information maximum likelihood sample selection model. RESULTS: The likelihood of smoking was highest among the wealthy, employed, Christian, or people who exercise regularly. The low rate of smoking participation was associated with either low pure alcohol intake or increased awareness of lung cancer from smoking. We found that policies to reduce cigarette consumption should focus on lowering smoking participation rather than the amount of cigarettes smoked. Compared to the current state, a policy package consisting of mutually reinforcing measures could reduce the probability of smoking and the average number of cigarettes consumed among all adult males by 34 and 51%, respectively. CONCLUSIONS: Understanding the country-specific factors affecting smoking behavior and selecting an appropriate anti-smoking measure could greatly reduce smoking participation and cigarette consumption.

[Socioeconomic costs of stroke in Korea: estimated from the Korea national health insurance claims database].

OBJECTIVES: To estimate the annual socioeconomic costs of stroke in Korea in 2005 from a societal perspective. METHODS: We identified those 20 years or older who had at least one national health insurance (NHI) claims record with a primary or a secondary diagnosis of stroke (ICD-10 codes: I60-I69, G45) in 2005. Direct medical costs of the stroke were measured from the NHI claims records. Direct non-medical costs were estimated as transportation costs incurred when visiting the hospitals. Indirect costs were defined as patients' and caregivers' productivity loss associated with office visits or hospitalization. Also, the costs of productivity loss due to premature death from stroke were calculated. RESULTS: A total of 882,143 stroke patients were identified with prevalence for treatment of stroke at 2.44%. The total cost for the treatment of stroke in the nation was estimated to be 3,737 billion Korean won (KRW) which included direct costs at 1,130 billion KRW and indirect costs at 2,606 billion KRW. The per-capita cost of stroke was 3 million KRW for men and 2 million KRW for women. The total national spending for hemorrhagic and ischemic stroke was 1,323 billion KRW and 1,553 billion KRW, respectively, which together consisted of 77.0% of the total cost for stroke. Costs per patient for hemorrhagic and ischemic stroke were estimated at 6 million KRW and 2 million KRW, respectively. CONCLUSIONS: Stroke is a leading public health problem in Korea in terms of the economic burden. The indirect costs were identified as the largest component of the overall cost.

[Analysis of willingness-to-quit cigarette price among Korean male adults].

OBJECTIVES: The purpose of this study was to estimate the willingness to quit cigarette price among Korean male adults, and to examine he factors affecting the willingness to quit cigarette price. METHODS: The data was collected by a random digit dial telephone survey. 702 samples were analyzed by using t-tests, ANOVA and OLS regression analysis. To estimate the willingness to quit cigarette price, smokers were asked dichotomous questions with open-ended follow-up and the starting point of the price was randomized by one of 5 bid prices elicited from a pilot study. RESULTS: The mean of the willingness to quit cigarette price was 4,287 Won per package, which was about 2,000 Won higher than the mean of the actual price the smokers now paid. About 41% of respondents were willing to quit smoking if the price of cigarette would be increased by 3,000 Won, and if the price would be increased by 20,000 Won, all respondents were willing to quit smoking. The factors associated with the willingness to quit cigarette price were the place of residence, the amount of smoking and the degree of exposure to smoking through the mass media. CONCLUSIONS: The results showed that to get people to quit smoking, increasing the cigarette price would obviously be effective and much higher prices have a greater effect. Furthermore, to enlarge the effect of increased cigarette prices, providing more cessation programs to small towns, reducing the amount of smoking and decreasing or prohibiting advertisements of cigarettes and smoking in the mass media will be efficient.

[The effect of cigarette price on smoking behavior in Korea].

OBJECTIVES: To determine the impact of cigarette prices on the decision to initiate and quit smoking by taking into account the interdependence of smoking and other behavioral risk factors. METHODS: The study population consisted of 3,000 male Koreans aged > or =20. A survey by telephone interview was undertaken to collect information on cigarette price, smoking and other behavioral risk factors. A two-part model was used to examine separately the effect of price on the decision to be a smoker, and on the amount of cigarettes smoked. RESULTS: The overall price elasticity of cigarettes was estimated at -0.66, with a price elasticity of -0.02 for smoking participation and -0.64 for the amount of cigarettes consumed by smokers. The inclusion of other behavioral risk factors reduced the estimated price elasticity for smoking participation substantially, but had no effect on the conditional price elasticity for the quantity of cigarettes smoked. CONCLUSIONS: From the public health and financial perspectives, an increase in cigarette price would significantly reduce smoking prevalence as well as cigarette consumption by smokers in Korea.