Factors associated with health-related quality of life in Koreans aged over 50 Years: the fourth and fifth Korea National Health and Nutrition Examination Survey

The Korea National Health and Nutrition Examination Survey (KNHANES) is a population-based cross-sectional survey designed to assess the health related behavior, health condition, and nutritional state of Koreans (http://knhanes.cdc.go.kr/). It was conducted as a tri-annual survey for the first 3 cycles, implemented in 1998, 2001, and 2005. Beginning with the 4th cycle of 2007, it was converted to an annual survey. The 2011 data was recently opened to the public, and is free for all researchers who want to use it. The KNHANES provides a rich source of data which are easy to access and can be quickly obtained. Its ethical problems are minimal and there are no adverse effects in conducting the study. Using the KNHANES saves time, money, and personnel that would otherwise be spent collecting data, and provides a larger and higher-quality database beyond the capacity of any one individual researcher. Further, because the study participants are representative of the Korean population, the results have external validity. Therefore, this data is helpful to young investigators. In fact, the portion of submitted articles to the Korean Journal of Family Medicine (KJFM) using the KNHANES as the primary source of data is significant. Specifically, one article in 2007, three articles in 2008, four articles in 2009, three articles in 2010, five articles in 2011, and five articles in 2012 used the KNHANES data as their primary data source, totaling 21 articles (6.2%) among 338 original articles during the previous five years. However, there are several points investigators should keep in mind when using the KNHANES data. First, the KNHANES data are open to the public and there is no systematic process to control the research topic assignment. Many researchers might investigate the same topic simultaneously, especially popular topics like obesity and metabolic syndrome. Before deciding on the study topic, a thorough search of the database like Medline, EMBASE, and the abstracts of related conferences are needed. Once the topic is decided upon, the article should be submitted as soon as possible. Otherwise someone else may publish a similar study from the same dataset before you do. Second, investigators must be familiar with the huge and complex data structure and study design of the KNHANES. Non-response and multi-stage probability sampling should be taken into account by using survey statistics to estimate the data of the whole Korean population. Despite this, lots of studies submitted to KJFM using the KNHANES do not apply sampling weight in their analysis. In such a case the estimated association might be biased and revision is required. Third, the KNHANES is a secondary data source like the Korea Youth Risk Behavior Web-based Survey and the Community Health Survey, and has the same limitations that they have.1) The main purpose of the KNHANES is to produce national statistics, not to answer a specific research question. Therefore, the particular information the investigator wants may not be collected. For these reasons, the dataset should be examined carefully to confirm that it includes the necessary data. There also exists a potential for errors or mistakes in the data, even with its rigorous documents control system. Missing data is also a problem in the KNHANES.2)

Background: There have been few studies reporting the association between health-related quality of life (HRQoL) and osteoarthritis (OA) in female subjects performing aerobic exercise or not. The aim of this study is to compare HRQoL between OA patients and non-OA subjects in middle aged Korean women (40–59 years) with/without aerobic physical activity, and also to identify an association between EQ-5D instrument based HRQoL and OA controlling for aerobic exercise. Methods: This study used the cross-sectional data, the Korea National Health and Nutrition Examination Survey (KNANES) from 2016 to 2017. We only selected those who had completed the evaluations of aerobic physical activity and osteoarthritis diagnosis. In total, 2445 middle aged women were finally selected for this study. The European quality of life-5 dimensions (EQ-5D) was used for the evaluation of HRQoL as a dependent variable. In socio-demographic factors, age, sex, income level, education level, marital status, economic activity, type of insurance and private insurance and behaviour-related factors were included. One-way analysis of variance was conducted to compare the EQ-5D index and multiple linear regression analysis was employed to identify associated factors with the EQ-5D index. Results: In total, 2445 middle aged women were included in this study, in which 2209 participants were normal (90.0%) with aerobic physical activity (no: 55.0%, yes: 45.0%) and 246 participants were diagnosed with osteoarthritis (10.0%) with aerobic physical activity (no: 56.1%, yes: 43.9%). In group 2-2 (OA with aerobic), the moderate level of muscle exercise (less than 5 days per week) showed the highest HRQoL (p < 0.05) and high level exercise showed the lowest HRQoL (p < 0.05). In menopause status, the participants under menopause status showed lower HRQoL (p < 0.05) than those not under menopause status in group 2-2 (OA with aerobic) only. Conclusions: The HRQoL of OA patients was significantly lower than that of normal participants in middle aged Korean women (40–59 years). Especially, OA patients with maintained aerobic physical activity showed significantly higher HRQoL than those without that under controlling covariates such as age, income level, education level, marital status, economic activity, type of insurance, etc.

This study aimed to examine the association between the risk of obstructive sleep apnea (OSA) and health-related quality of life (HRQoL) using nationally representative data from the Korea National Health and Nutrition Examination Survey (KNHANES). We analyzed data from the 2023 KNHANES, including 3968 adults aged 40 years and older. OSA risk was assessed using the STOP-BANG questionnaire, and HRQoL was measured with the HINT-8, a validated instrument developed in Korea. Complex sample linear regression analyses were performed to investigate the relationship between OSA risk categories and the HINT-8 utility index, adjusting for sociodemographic and health-related factors. Sensitivity analyses using multiple imputation and models with continuous variables were also conducted to assess robustness. Participants at moderate risk of OSA had significantly lower HINT-8 utility scores compared to those at low risk (β = -0.009; 95% CI = -0.017 to -0.001). The high-risk group showed a non-significant trend toward lower HRQoL. In a sensitivity analysis additionally adjusted for age and sex, the negative association remained consistent in both magnitude and direction. Overall, the results were robust across multiple analytical approaches. Only the moderate-risk group showed a statistically significant reduction in HRQoL, whereas the high-risk group demonstrated a non-significant trend. The STOP-BANG questionnaire, owing to its simplicity and high sensitivity, may be useful for the early identification of individuals at moderate risk of impaired HRQoL. These findings support the value of integrating OSA risk screening into population-based health strategies to promote HRQoL. Obstructive sleep apnea (OSA) is a common sleep problem where breathing stops during sleep. Many people with OSA are not diagnosed, even though the condition can reduce energy, raise health risks, and lower quality of life. This study was done to find out how the risk of OSA affects how people feel and function in daily life.We used national data from South Korea to examine this. People were grouped by their risk for OSA using the STOP-BANG questionnaire, a simple screening tool. We measured their quality of life using the HINT-8, which looks at physical ability, pain, mental health, and daily functioning.The study found that people with a moderate risk of OSA had lower quality of life than those with low risk. These results remained even after adjusting for age, sex, income, and health conditions.Our findings suggest that people who are at risk for OSA already experience reduced well-being, even if they have not been diagnosed. Simple tools like STOP-BANG can help identify these individuals early so that they can receive care and improve their quality of life.

As persons with stroke are surviving longer, monitoring and managing their quality of life is becoming important. We reviewed the Korea National Health and Nutrition Examination Survey (KNHANES) in order to evaluate the health-related quality of life (HRQoL) in stroke survivors as measured by the Euro Quality of Life-5D (EQ-5D), and to find out influencing factors. A total of 42,500 subjects were enrolled in the KNHANES, and 575 of them were persons with stroke. The EQ-5D index was lower in persons with stroke than those without stroke, when adjusted for age and sex (with stroke: 0.757±0.012, without stroke: 0.948±0.001, p < .0001). Dimension-specific influencing factors of HRQoL were observed in persons with stroke; mobility problems increased with old age; self-care problems increased with old age and depression; usual activity problems increased with old age, low income, absence of economic activity, and depression; pain/discomfort problems increased with low income. The EQ-5D index was lower in stroke survivors with older age, hypertension, diabetes mellitus, and lack of regular exercise. This is the first study to utilize nationally representative data of the Korean population to investigate the effect of stroke on HRQoL and explore the dimension-specific influencing factors. Further development of rehabilitative interventions for post-stroke depression, vocational rehabilitation, and tailored programs for encouraging physical activity may be needed to improve the HRQoL in Korean stroke survivors.

PurposeThis study was conducted to investigate the depressive symptoms and quality of life (QOL) in patients with age-related macular degeneration (AMD) using data obtained from the Korea National Health and Nutritional Examination Survey V-2 (KNHANES V-2) conducted in 2011.MethodsThis was a population-based, cross-sectional study that selected 329 participants from the fifth KNHANES (2011) who were diagnosed with AMD by an ophthalmologist based on fundus photography. The prevalence of depressive symptoms and the health-related QOL (using EuroQol indices) in this cohort were also estimated. Factors associated with depressive symptoms, including socioeconomic status, QOL indices, and associated chronic diseases, were investigated using multivariate regression models.ResultsDepressive symptoms were observed more frequently in AMD patients than in non-AMD controls (p = 0.013). Among the total 329 AMD participants, 65 (19.8%) had depressive symptoms. There were 16 males (24.6%) and 49 females (75.4%). Upon multivariate analysis, significant factors found to be associated with depressive symptoms were female gender (odds ratio [OR], 2.082; 95% confidence interval [CI], 1.001 to 4.330), being in the “dependent” group for activities of daily living (OR, 4.638; 95% CI, 2.061 to 10.435), and having “some problems” in the “anxiety-depression” dimension of the EQ-5D (OR, 7.704; 95% CI, 1.890 to 31.408).ConclusionsFemale gender and being dependent on others for activities of daily living increased the association of depressive symptoms in this cohort of AMD participants. Screening for depressive symptoms in East Asian AMD patients with these characteristics should be an important component of their care.

BackgroundAs the global population ages, disabling hearing impairment (HI) have been increased rapidly. The impact of HI on health-related quality of life (HRQoL) is of great importance to aid the development of strategic plans and to guide therapeutic interventions.PurposeTo evaluate HRQoL in Korean adults with different degrees of HI using EuroQol five-dimensional (EQ-5D) and EQ-visual analogue scale (VAS), the preference-based generic measures of HRQoL.MethodsUsing a representative dataset from the Korea National Health and Nutrition Examination Survey (KNHANES) from January 2010 to December 2012, EQ-5D questionnaire and EQ- VAS scores of subjects with HI were compared with those of subjects without HI. Logistic regression analysis, with adjustment for covariates, was used to evaluate the impact of HI on HRQoL scales. HI was defined according to the hearing thresholds of pure-tone averages at 0.5, 1, 2, and 3 kHz of the better hearing ear as follows; mild HI (26 to < 40 dB) and moderate to severe HI (≥ 40 dB).ResultsOf the 16,449 Korean adults in KNHANES (age, 45.0 ± 0.2 years; male, 49.7%), 1757 (weighted prevalence, 7.6%) had mild HI and 890 (3.6%) had moderate to severe HI. Subjects with HI had impaired HRQoL as compared with subjects without HI (EQ-5D, 0.96 ± 0.00 vs. 0.88±0.00 vs. 0.86 ± 0.01 for control vs. mild HI vs. moderate to severe HI, p < 0.001; EQ-VAS, 75.10 ± 0.18 vs. 67.48 ± 0.63 vs. 66.24 ± 0.92 for control vs. mild HI vs. moderate to severe HI, p < 0.001). After adjusting for socio-demographic factors (age, gender, household income, education level, presence of spouse) and health-related behaviors (smoking status, alcohol intake, regular exercise), psychological stress, and the presence of comorbidities (diabetes, hypercholesterolemia, hypertension, decreased eGFR, and tinnitus), EQ-VAS remained impaired in the moderate to severe HI group (61.72±1.69) as compared with the control group (65.68 ± 1.26, p = 0.004), but EQ-5D impairment disappeared (0.86 ± 0.02 vs.0.88±0.01 for moderate to severe HI vs. control, p = 0.058).ConclusionAfter adjusting for socio-demographic and psychosocial factors and comorbidities, Korean adults with moderate to severe HI rated their health statuses lower than subjects without HI.

The Korea National Health and Nutrition Examination Survey (KNHANES) is a national health survey that is conducted annually to assess the health and and health-related behaviors of Korean population. To utilize KNHANES data to studies of mortality risk factors, the Korea Disease Control and Prevention Agency (KDCA) constructed a database linking KNHANES data to cause-of-death statistics in Statistics Korea, made available to researchers since 2020. The KNHANES data were linked to the Cause of Death Statistics based on resident registration numbers for subjects aged 19 years or older who agreed to link the data. The linkage rate between 2007-2015 National Health and Nutrition Examination Survey and 2007-2019 Cause of Death Statistics was 97.1%. In the linked dataset, the total death rate was 6.6%, of which neoplasms accounted for the highest death rate (32.1%), followed by circulatory system disease (22.7%) and respiratory system disease (11.5%). The linked dataset was made available through the Research Data Center of the KDCA after a review of the research proposal, and will be made available after periodical updates.

The aim of this study was to examine whether dyslipidemia is associated with periodontitis in a representative sample of Korean adults who were involved in the Fourth Korea National Health and Nutrition Examination Survey (KNHANES). A total of 18,210 subjects over 19years of age who participated in KNHANES were examined. Dyslipidemia is defined according to the definition proposed by the Korean Society of Lipidology and Atherosclerosis. The periodontal status of the patients was assessed by the Community Periodontal Index (CPI). Multivariate logistic regression analysis was carried out and adjusted for socio-demographics, oral health behaviours and status and general health behaviour. All analyses considered a complex sampling design, and multivariate analysis was also performed in the subgroups (age, gender and current smoking status). Multivariate logistic regression analysis revealed significant associations between dyslipidemia except pre-hypercholesterolemia and periodontitis. In the subgroup analysis, periodontitis was significantly associated with hypo-HDL-cholesterolemia and had a potential association with hyper- triglycerides (TG) in subjects younger than 40years. The adjusted ORs were greater in the present smoker group than the non-smoker group. Dyslipidemia except pre-hypercholesterolemia is associated with periodontitis.

BackgroundCorrectional institution inmates have reduced access to dental care; however, a quantitative assessment of their oral health condition has not yet been performed in South Korea. Therefore, this study aimed to assess dental caries and compare the prevalence of dental caries and associated factors between inmates and the general South Korean population.MethodsThe dental records of two detention centers in South Korea were retrospectively analyzed to assess the clinical oral health condition of inmates using the Decayed, Missing, and Filled Teeth (DMFT) index and self-reported questionnaire. These data were compared with similar data obtained from the Korea National Health and Nutrition Examination Survey (KNHANES) for the general South Korean population.ResultsIn total, 642 inmates were analyzed and compared with 13,345 KNHANES participants in the KNHANES. The inmate and KNHANES groups demonstrated significant intergroup differences, with a higher prevalence of untreated caries, DMFT, decayed teeth (DT), and missing teeth (MT) values among the inmates. The prevalence of untreated caries decreased according to the history of dental pain in the inmate group but increased in the KNHANES group. The decrease in DMFT with a history of dental pain was significant only in the inmate group. Furthermore, self-rated oral health was significantly associated with prevalence of untreated caries, DMFT, DT, MT, and filled teeth (FT) in the inmate group but with prevalence of untreated caries, DMFT, DT, and MT in the KNHANES group. It was found that this is because there is an interaction effect by the group.ConclusionsThe oral health of the inmate group was significantly poorer than that of the general group. Since DMFT, DT, MT, and FT values and prevalence of untreated caries in the inmate group were significantly related to their self-rated oral health, suggesting that self-rated oral health should be incorporated into the dental health screenings of correctional institution inmates.

CKD and Health-Related Quality of Life: The Korea National Health and Nutrition Examination Survey

Little is known about the effect of sodium intake on health-related quality of life (HR-QOL). In this study, we investigated the association between estimated 24-h urine sodium and HR-QOL in Korean adults. In this cross-sectional study, we analyzed 10,672 participants from Korea National Health and Nutrition Examination Survey (KNHANES) 2010~2011. To assess sodium intake, 24-h urine sodium excretion was estimated from random urine sodium and creatinine using the Kawasaki formula. HR-QOL was assessed using EQ-5D (EuroQol five-dimension) index calculated from Korean version of the EQ-5D questionnaire. Low HR-QOL was defined as the lowest quartile of the EQ-5D index. Participants were divided into three groups according to their estimated 24-h urine sodium level (low, <2.0 g/day; moderate, 2.0~3.9 g/day; high, >4.0 g/day). Adjusted means of EQ-5D index were 0.975, 0.995, and 0.991 in the low, moderate, and high estimated 24-h urine sodium group, respectively (P = 0.003 for low vs. moderate, P = 0.078 for high vs. moderate). In a multiple logistic analysis, the odds ratio (OR) for low EQ-5D index in the low estimated 24-h urine sodium group compared to the moderate group was 1.87 (95% confidence interval (CI), 1.33-2.64; P < 0.001). The OR in the high estimated 24-h urine sodium group compared to the moderate group was 1.09 (95% CI, 0.95-1.24; P = 0.218). Low estimated 24-h urine sodium rather than high estimated 24-h urine sodium was associated with low HR-QOL in representative Korean adults. Further studies are warranted to verify the effect of sodium intake on HR-QOL and the adequate-level sodium restriction in terms of HR-QOL.

Stroke and depression are common diseases that affect quality of life (QoL). Although some recent studies have investigated the association between the two diseases, studies that examined the association between stroke, depression, and QoL are rare, with large-scale national-level studies lacking. We aimed to investigate the association between depression and QoL in stroke patients. Data from the Korea National Health and Nutrition Examination Survey (KNHANES) IV-VII conducted in 2008-2018 were used, and 45,741 adults who were aged >40 years and had no missing data for stroke and depression were included in the analysis. The participants were first grouped by prevalence of stroke, and further divided by prevalence of depression. The overall prevalence of stroke was 3.2%, and the incidence was 9% higher in men than in women. Multiple logistic regression was performed after adjusting for demographic factors, health-related factors, and disease-related factors. The results confirmed that the stroke group with depression had a lower overall health-related quality of life, measured using EQ-5D, score compared to the stroke group without depression (-0.15). Moreover, the concurrent stroke and depression treatment group had the highest OR of 7.28 (95% CI 3.28-16.2) for the anxiety/depression domain. Depression was strongly associated with QoL in stroke patients. This association was more evident in stroke patients undergoing treatment for depression. Thus, clinical approaches that take QoL into consideration are needed for stroke patients with depression.

BackgroundStroke and depression are common diseases that affect quality of life (QoL). Although some recent studies have investigated the association between the two diseases, studies that examined the association between stroke, depression, and QoL are rare, with large-scale national-level studies lacking. We aimed to investigate the association between depression and QoL in stroke patients.MethodsData from the Korea National Health and Nutrition Examination Survey (KNHANES) IV–VII conducted in 2008–2018 were used, and 45,741 adults who were aged >40 years and had no missing data for stroke and depression were included in the analysis. The participants were first grouped by prevalence of stroke, and further divided by prevalence of depression.ResultsThe overall prevalence of stroke was 3.2%, and the incidence was 9% higher in men than in women. Multiple logistic regression was performed after adjusting for demographic factors, health-related factors, and disease-related factors. The results confirmed that the stroke group with depression had a lower overall health-related quality of life, measured using EQ-5D, score compared to the stroke group without depression (-0.15). Moreover, the concurrent stroke and depression treatment group had the highest OR of 7.28 (95% CI 3.28–16.2) for the anxiety/depression domain.ConclusionDepression was strongly associated with QoL in stroke patients. This association was more evident in stroke patients undergoing treatment for depression. Thus, clinical approaches that take QoL into consideration are needed for stroke patients with depression.

The rapid demographic transition toward a super-aged society has made health-related quality of life (HRQOL) a critical issue for older adults. This study examined determinants of HRQOL among Korean adults aged 65 years and older, focusing on lifestyle behaviors, preventive health practices, healthcare utilization, mental health, and digital health literacy. Data were drawn from the 2023 Korea National Health and Nutrition Examination Survey (KNHANES), a nationally representative cross-sectional survey. A total of 2,052 participants were included after applying weights. HRQOL outcomes were assessed using the EQ-5D index, the HINT-8 scale, and self-rated health. Descriptive, bivariate, and multivariate analyses identified significant predictors. Results showed that physical activity and vaccination uptake were positively associated with HRQOL, whereas smoking, high-risk drinking, and depressive symptoms were linked to lower scores. Depressive symptoms exerted the strongest negative effect. Preventive behaviors, including routine health checkups and cancer screening, were also related to improved subjective health. Conversely, rural residence and unmet medical needs emerged as barriers, reflecting healthcare disparities. Digital health literacy moderates positive associations of physical activity and preventive care, suggesting that technology readiness can amplify benefits. These findings underscore the need for integrated approaches combining lifestyle promotion, preventive and mental health services, equitable healthcare access, and digital health strategies to enhance HRQOL in super-aged societies.

The Korea National Health and Nutrition Examination Survey (KNHANES) is a national surveillance system that has been assessing the health and nutritional status of Koreans since 1998. Based on the National Health Promotion Act, the surveys have been conducted by the Korea Centers for Disease Control and Prevention (KCDC). This nationally representative cross-sectional survey includes approximately 10 000 individuals each year as a survey sample and collects information on socioeconomic status, health-related behaviours, quality of life, healthcare utilization, anthropometric measures, biochemical and clinical profiles for non-communicable diseases and dietary intakes with three component surveys: health interview, health examination and nutrition survey. The health interview and health examination are conducted by trained staff members, including physicians, medical technicians and health interviewers, at a mobile examination centre, and dieticians’ visits to the homes of the study participants are followed up. KNHANES provides statistics for health-related policies in Korea, which also serve as the research infrastructure for studies on risk factors and diseases by supporting over 500 publications. KCDC has also supported researchers in Korea by providing annual workshops for data users. KCDC has published the Korea Health Statistics each year, and microdata are publicly available through the KNHANES website (http://knhanes.cdc.go.kr).