Hyeonyoung Ko

Health-Related Quality of Life and Cardiovascular Disease Risk in Korean Adults

Background Health-related quality of life (HRQoL) is considered an important outcome measure in chronic diseases, in particular cardiovascular disease (CVD), which is known to be associated with impaired HRQoL. However, few studies have examined HRQoL in individuals at high risk of CVD. Methods Using the Fifth Korea National Health and Nutrition Examination Survey 2010-2012, we analyzed data from 10,307 adults aged ≥30 years. The study subjects were stratified into 3 groups on the basis of their Framingham risk score-a 10-year estimate of CVD risk: <10.0% (low risk), 10.0%-19.9% (moderate risk), and ≥20.0% (high risk). The EuroQol-5D (EQ-5D) was used to evaluate HRQoL. Results A significantly higher proportion of high-risk subjects than low-risk participants had impaired HRQoL (defined as the lowest quartile of the EQ-5D index); this held true even after adjustment for confounding factors in multivariable logistic regression analysis (men: odds ratio [OR], 1.62; 95% confidence interval [CI], 1.24-2.11; women: OR, 1.46; 95% CI, 1.02-2.08). In terms of the 5 EQ-5D dimensions, a 10-year CVD risk ≥20.0% was significantly associated with self-reported problems of mobility in men (OR, 3.15; 95% CI, 2.02-4.90), and of mobility (OR, 1.56; 95% CI, 1.09-2.24), self-care (OR, 2.14; 95% CI, 1.09-4.22), and usual activity problems (OR, 1.80; 95% CI, 1.17-2.78) in women. Conclusion A high CVD risk is associated with impaired HRQoL. After adjustment for demographic and clinical factors, a 10-year CVD risk ≥20.0% is an independent predictor of impaired HRQoL in the general population; in particular, of mobility problems in men, and of mobility, self-care, and usual activity problems in women.

Factors Associated with Depression Assessed by the Patient Health Questionnaire-2 in Long-Term Cancer Survivors

Background This cross-sectional study aimed to evaluate the prevalence of depressive disorders and factors associated in long-term cancer survivors. Methods A total of 702 long-term cancer survivors over 5-years in remission were recruited in a university-affiliated tertiary hospital in Korea. Self-report using the Patient Health Questionnaire-2 and the Fatigue Severity Scale assessed depression and fatigue, respectively. Demographic characteristics, cancer-related clinical characteristics, comorbidity, health behaviors, and physical symptoms were assessed through the review of medical records or a structured self-administered questionnaire. Results We identified 26.1% of patients who had a depressed mood or displayed a loss of interest. The most prevalent primary site of cancer was the stomach (65.2%), followed by lung, breast, colorectal, and thyroid cancer. We also found that 5.7% of subjects experienced double or triple primary cancers. Larger proportion among depressive group (89.1%) complained at least one physical problem than among non-depressive group (53.2%). Physical symptoms including sleep problems, dry mouth, indigestion, pain, decreased appetite, and febrile sense were more frequent in the depressive group than in the non-depressive group. The Fatigue Severity Scale scores were higher in the depressive group than in the non-depressive group (P<0.001). Multiple logistic regression analysis showed that the highest tertile level of fatigue (odds ratio, 7.31; 95% confidence interval, 3.81–14.02) was associated with the increased risk of depression. Conclusion These findings suggest that careful concern about depression is necessary in long-term cancer survivors. Fatigue may be a surrogate sign for depression, and warrants further evaluation.

Educational Inequality in Obesity-Related Mortality in Korea

The prevalence of obesity has been increasing worldwide, which raises concerns about the disease burden associated with obesity. Socioeconomic status (SES) has been suggested to be associated with obesity and obesity related diseases. This study aimed to evaluate the time trend in socioeconomic inequality in obesity-related mortality over the last decade in Korean population. We evaluated the influence of education level, as an indicator of SES, on obesity-related mortality using death data from the Cause of Death Statistics and the Korean Population and Housing Census databases. The rate ratio of the mortality of people at the lowest education level as compared with those at the highest education level (relative index of inequality [RII]) was estimated using Poisson regression analysis. Between 2001 and 2011, RII (95% confidence interval) for overall obesity-related disease mortality increased from 2.10 (2.02–2.19) to 6.50 (6.19–6.82) in men, and from 1.94 (1.79–2.10) to 3.25 (3.05–3.45) in women, respectively. Cause-specifically, the same trend in RII was found for cardiovascular mortality and mortality from diabetes mellitus, whereas the RII of mortality from obesity-related cancers in men did not show the similar trend. Subgroup analysis stratified by age revealed that the RII of obesity-related mortality was much higher in younger people than in older people. In conclusion, there has been persistent socioeconomic inequality in obesity-related mortality in Korea, which was more evident in younger people than in older people and has been deepened over the last decade especially for cardiovascular disease and diabetes.

Validation study for the Korean version of Fear of Cancer Recurrence Inventory

Fear of cancer recurrence (FCR) is one of the most prevalent unmet psychosocial needs. This study aimed to confirm the cultural equivalence, reliability, and validity of the Korean version of Fear of Cancer Recurrence Inventory (K-FCRI). We conducted a forward–backward translation of the English version FCRI to Korean version through meticulous process including transcultural equivalence test. The psychometric property of the K-FCRI was then validated in 444 survivors from cancers at various sites. The Korean translation was accepted well by participants. There was a good cultural equivalence between the Korean version and the English version of FCRI. Confirmatory factor analysis supported the original seven-factor structure with slightly insufficient level of goodness-of-fit indices (comparative fit index = 0.900, non-normed fit index = 0.893, root mean square error of approximation = 0.060). The K-FCRI had high internal consistency (α = 0.85 for total scale and α = 0.77–0.87 for subscales) and test-retest reliability (r = 0.90 for total scale and r = 0.54–0.84 for subscales). The K-FCRI had significant correlations with the Korean version of Fear of Progression Questionnaire, European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Version 3.0, Hospital Anxiety and Depression Scale, and Fatigue Severity Score, supporting the good construct validity and psychometric properties of K-FCRI. The K-FCRI was confirmed as a valid and reliable psychometric test for measuring FCR of Korean survivors from cancers at various sites.

Cross‐sectional association between testosterone, sex hormone‐binding globulin and metabolic syndrome: The Healthy Twin Study

This study evaluated an association between testosterone, sex hormone‐binding globulin (SHBG) and metabolic syndrome (MetS).We also evaluated the genetic and environmental influences on the association.

Heritability of the morphology of optic nerve head and surrounding structures: The Healthy Twin Study

Background Optic nerve head (ONH) and surrounding structures such as β-zone peripapillary atrophy (PPA) are important structures in glaucomatous pathogenesis. Thus, for understanding genetic components in glaucoma pathogenesis, it is necessary to evaluate the heritability of ONH and surrounding structures. The present study investigated the genetic influences on ONH and surrounding structures such as β-zone PPA and retinal vessels. Methods A total of 1,205 adult twins and their family members (362 monozygotic (MZ) twin subjects (181 pairs), 64 dizygotic (DZ) twin subjects (32 pairs), and 779 singletons from 261 families), were part of the Korean Healthy Twin Study. ONH parameters including the vertical cup-to-disc ratio, the presence, the area and the location of β-zone PPA and the angular location of retinal vein were measured. The genetic influences on the structures were evaluated using variance-component methods. Results The intraclass correlation coefficient (ICC) values of axial length were highest among the parameters. The ICCs of the area and location of PPA were similar to those of vertical cup-to-disc ratio. However, retinal vessel angular locations showed low ICC values even in MZ twins. After age and sex adjustment, for axial length, vertical cup-to-disc ratio, the presence, area and location of PPA, the estimated narrow-sense heritability was 0.85, 0.48, 0.76, 0.50 and 0.65 in the right eye and 0.84, 0.47, 0.72, 0.46 and 0.72 in the left eye, respectively. The estimated narrow-sense heritability of angular location of the superior and inferior vein was 0.17 and 0.12 in the right eye and 0.13 and 0.05 in the left eye, respectively. Conclusions ONH and surrounding structures such as vertical cup-to-disc ratio and the presence, the area and the location of β-zone PPA seemed to be determined by the substantial genetic influence, whereas the venous angular location did not.

The Risk of Microalbuminuria by Obesity Phenotypes according to Metabolic Health and Obesity: The Korean National Health and Nutrition Examination Survey 2011–2014

Background The present study aimed at identifying the difference in the risk of microalbuminuria among individuals with various obesity phenotypes in terms of metabolic health and obesity. Methods This cross-sectional study included 15,268 individuals and used data from the National Health and Nutrition Survey conducted from 2011 to 2014. Obesity was defined as body mass index ≥25 kg/m². Metabolically unhealthy was defined as meeting two or more of the following criteria: systolic and diastolic blood pressure ≥130/85 mm Hg or current use of hypertensive drugs; triglyceride level ≥150 mg/dL; high-density lipoprotein level <40/50 mg/dL (in both men and women); and fasting blood glucose level ≥100 mg/dL or current use of oral antidiabetic medications. The participants were further classified into four subgroups: metabolically healthy non-obese (MHNO), metabolically healthy obese (MHO), metabolically unhealthy non-obese (MUNO), and metabolically unhealthy obese (MUO). Results A significant difference was observed in the microalbuminuria ratio among the four groups. The MHNO group was considered as the reference group, and the MHO, MUNO, and MUO groups were at an increased risk for microalbuminuria by 1.42 fold (95% confidence interval [95% CI], 1.03–1.96), 2.02 fold (95% CI, 1.61–2.53), and 3.40 fold (95% CI, 2.70–4.26), respectively, after adjusting confounding factors. Conclusion The MUNO group had a higher risk of developing microalbuminuria than the MHNO group. Thus, based on this result, differences were observed in the risk of developing microalbuminuria among individuals with various obesity subtypes.

Genetic Influence on Accessory Navicular Bone in the Foot: A Korean Twin and Family Study

An accessory navicular bone (AN) is the most common accessory ossicle in the foot. The presence of an AN bone can trigger various foot problems, such as posterior tibial tendon pathology, flattening of the medial longitudinal arch, and medial foot pain. Despite the clinical influence of presence of an AN in foot disease, the research regarding its inheritance is still insufficient. A total of 135 pairs of monozygotic (MZ) twins, 25 pairs of dizygotic (DZ) twins, and 676 singletons from families were enrolled in order to estimate genetic influences on AN. After confirmation of zygosity and family relationship with a tandem repeat marker kit and questionnaires, the presence and type of the AN was classified through bilateral feet radiographic examination. The heritability of an AN was estimated using quantitative genetic analysis based on a variance decomposition model considering various types of family relationships: father-offspring pair, mother-offspring pair, and pooled DZ twin and sibling pairs. As a result, approximately 40.96% of the participants in this study had an AN in either foot, with type II being the most common type. The heritability for the presence of any type of an AN in any foot was estimated as 0.88 (95% CI [0.82, 0.94]) after adjusting for age and sex. Specifically, type II AN showed the highest heritability of 0.82 (95% CI [0.71-0.93]). The high heritability of an AN found in this large twin and family study suggests that an AN is determined by the substantial influence of genetic factor.

Factors associated with alcohol drinking behavior of cancer survivors: The Korean National Health and Nutrition Examination Survey

BACKGROUND This study aimed to evaluate the factors associated with drinking behavior of cancer survivors after cancer diagnosis. METHODS The study subjects were 906 adult cancer survivors who had reportedly drunk alcohol before cancer diagnosis and participated in the Korean National Health and Nutrition Examination Surveys conducted from 2007 to 2013. Among them, 360 abstained from alcohol drinking after cancer diagnosis. We categorized remaining 546 persistent drinkers into high-risk drinker (consuming≥7 glasses of alcohol for men and≥5 glasses of alcohol for women at one sitting at the frequency of at least once a month) or moderate drinker. We used multiple logistic regression analysis to evaluate risk factors associated with drinking behavior. RESULTS The high-risk drinkers occupied 27.1% (148 survivors) of the persistent alcohol drinking survivors. Age increase (OR=0.96; 95% CI 0.93-0.99), female sex (OR=0.15; 95% CI 0.08-0.28), and increase of time lapse (by 1-year) after cancer diagnosis (OR=0.94; 95% CI 0.92-0.97) were associated with a lower risk of high-risk drinking as compared with moderate drinking. Meanwhile,≤9years of education (OR=1.99; 95% CI 1.10-3.60), alcohol-related cancer (OR=2.09; 95% CI 1.23-3.56), and current smoking (OR=1.92; 95% CI 1.03-3.59) were associated with increased risk of high-risk drinking of cancer survivors. CONCLUSIONS These findings suggest that greater efforts for preventing high-risk drinking should be laid on the cancer survivors, with consideration of individual sociodemographic characteristics, especially when the survivors had been diagnosed with alcohol-related cancer.

Comparison of the association of mammographic density and clinical factors with ductal carcinoma in situ versus invasive ductal breast cancer in Korean women

BackgroundIn spite of the increasing incidence of in situ breast cancer, the information about the risk factors of in situ breast cancer (DCIS) is scarce as compared to the information available for invasive ductal breast cancer (IDC), with inconsistent findings regarding the difference in risk factors between DCIS and IDC.MethodsWe enrolled 472 women with IDC and 90 women with DCIS and 1088 controls matching for age and menopausal status. Information on risk factors was collected through self-administered questionnaire. Percent mammographic dense area (PDA), absolute mammographic dense area (ADA), and nondense area were assessed using a computer-assisted thresholding technique. Odds ratio (OR) and 95% confidence intervals (CI) were estimated by conditional logistic regression model with adjustment for covariates.ResultsLater age at menarche and regular physical exercise were associated with decreased risk of IDC, whereas alcohol consumption, previous benign breast disease, and family history of breast cancer were associated with increased risk of IDC. For DCIS, previous benign breast disease and alcohol consumption were associated with the increased risk, and regular physical exercise was associated with decreased risk. Increase of ADA by 1-quartile level and PDA increase by 10% were associated with 1.10 (95% CI: 1.01, 1.21) and 1.10 (95% CI: 1.01, 1.19) times greater risk of IDC, respectively. The increase of ADA by 1-quartile level and PDA increase by 10% were associated with 1.17 (95% CI: 0.91, 1.50) times and 1.11 (95% CI:0.90,1.37) times greater risk of DCIS, respectively, but the associations were not statistically significant. There was no significant difference in the association with risk factors and mammographic density measures between IDC and DCIS (P > 0.1).ConclusionsDifferential associations of DCIS with mammographic density and risk factors as compared with the associations of IDC were not evident. This finding suggests that IDC and DCIS develop through the shared causal pathways.