Seong-Woo Choi

Cohort Profile: The Namwon Study and the Dong-gu Study

These two cohorts were designed to examine the increasing burden of chronic diseases among Korean populations. The studies investigated determinants for stroke, osteoporosis, dementia and cancer among middle-aged and elderly Korean populations. The Namwon Study baseline survey was performed between 2004 and 2007 (n = 10 667), and followed up 4 years later (n = 8157, follow-up rate = 76.5%). The baseline survey of the Dong-gu Study was administered over 2007-2010 (n = 9260), and will be followed up between 2014 and 2015. Questionnaires included assessment of cognitive function, psychiatric health and lifestyle factors. Clinical examinations, biochemical tests and genotyping focused on evaluating the determinants of target diseases and their intermediate phenotypes. Potential collaborators will be invited to contact the chief investigators.

eGFR is associated with subclinical atherosclerosis independent of albuminuria: The Dong-gu Study

OBJECTIVES This study evaluated the relationships between estimated glomerular filtration rate (eGFR) and carotid atherosclerosis, peripheral arterial disease (PAD), arterial stiffness, and left ventricular hypertrophy, independent of albuminuria. METHODS The study population consisted of 6694 people aged 50 years and older who participated in the baseline survey of the Dong-gu Study conducted in Korea between 2007 and 2009. The common carotid artery intima-media thickness (CCA-IMT), carotid plaque, ankle-brachial index (ABI), brachial-ankle pulse wave velocity (baPWV), and left ventricular mass index (LVMI) of each subjects was assessed. RESULTS After adjustment for risk factors and albumin-creatinine ratio (ACR), kidney dysfunction (eGFR=30-44 ml/min per 1.73 m2) was significantly associated with carotid plaque presence (odds ratio [OR], 1.75; 95% confidence interval [CI], 1.21-2.53) and PAD (OR, 2.64; 95% CI, 1.51-4.62) compared to normal kidney function (eGFR≥60 ml/min per 1.73 m2). Similarly, mean LVMI and baPWV differed significantly according to eGFR after adjustment for other risk factors and ACR; in contrast, no significant difference was observed for CCA-IMT. CONCLUSIONS Independent of albuminuria, eGFR is associated with carotid plaque, PAD, baPWV, and LVMI but not with CCA-IMT in Koreans aged 50 years and older.

The Association Between the Socioeconomic Status and Thyroid Cancer Prevalence; Based on the Korean National Health and Nutrition Examination Survey 2010-2011

The incidence of thyroid cancer has recently increased in most industrialized countries, including Korea. To date, few studies have examined the association between thyroid cancer and socioeconomic status (SES). The current study was based on data collected from a total of 12,276 subjects (5,277 men and 6,999 women) by the Korean National Health and Nutrition Examination Survey (KNHANES) between 2010 and 2011. Univariate and multivariate logistic regression analysis revealed that older age (odds ration [OR], 1.03; 95% confidence interval [CI], 1.00-1.05), being female (OR, 8.16; 95%CI, 2.99-22.24), being overweight (OR, 1.04; 95%CI, 1.01-1.06), monthly household income (OR, 3.27; 95%CI, 1.16-9.20 for medium-highest household income vs lowest household income; OR, 3.30; 95%CI, 1.16-9.34 for highest household income vs lowest household income), educational level (OR, 2.74; 95%CI, 1.16-6.46 for 10-12 yr vs < 7 yr) and alcohol consumption (OR, 1.89; 95%CI 1.08-3.32) were significant risk factors for thyroid cancer. Our results indicate that the recent increase in thyroid cancer is attributable to better early detection rather than to any increase in actual prevalence.

High Prevalence of Vitamin D Deficiency in Adults Aged 50 Years and Older in Gwangju, Korea: the Dong-gu Study

Vitamin D plays an important role in bone metabolism and maintaining bone health. Recently, new evidence has revealed that vitamin D affects chronic diseases such as autoimmune diseases, cardiovascular diseases and certain cancers. The aim of this study was to evaluate the vitamin D status and the prevalence of vitamin D deficiency in an urban Korean population. This study included 8,976 participants (3,587 men and 5,389 women) aged 50 yr and older. Serum 25(OH)D level was measured by chemiluminescent microparticle immunoassay. The prevalence of vitamin D deficiency [25(OH)D < 20 ng/mL] was 59.7% and 86.5% in men and women, respectively. The prevalence of vitamin D deficiency increased significantly with age in men, but not in women and it decreased from April to July, more prominently in men than in women. These results suggest that sun exposure, intake of vitamin D supplement, and regular physical activities is recommended in an urban Koreans, especially in women.

Health Behaviors of Cancer Survivors: The Fourth Korea National Health and Nutrition Examination Survey (KNHANES IV, 2007–09)

OBJECTIVE This study aimed to describe the health behaviors of cancer survivors in the Republic of Korea and to compare them with the health behaviors of two control groups: (i) individuals with no history of cancer but with other chronic diseases and (ii) individuals with no history of cancer or other chronic diseases. METHODS This is a cross-sectional study of 17 311 adults at least 19 years of age who participated in the Fourth Korea National Health and Nutrition Examination Survey (2007-09). Smoking, alcohol drinking, physical activity and cancer screening behaviors of cancer survivors were assessed and compared with those of the two control groups. χ(2) tests and multiple logistic regression analyses were performed to determine the likelihood and predictors of health behaviors. RESULTS The proportion of cancer survivors who were current smokers, heavy drinkers and engaged in physical activity were 9.6, 6.6 and 26.0%, respectively. Cancer screening rates reported among survivors were 44.2, 17.0, 49.8 and 47.7% for stomach, colorectal, breast and cervical cancers, respectively. Cancer survivors showed lower smoking and alcohol drinking rates compared with both control groups after adjusting for sex, age, marital status, education, household income and health insurance. Cancer survivors also showed stomach, breast and cervical cancer screening rates that differed from both control groups. However, in multiple analyses, these differences were not significant. CONCLUSIONS Cancer survivors are more likely to adopt good health behaviors than individuals without a history of cancer. Further study is needed to determine the factors that lead to continued unhealthy behaviors after cancer diagnosis.

Association between total bilirubin and hemoglobin A1c in Korean type 2 diabetic patients.

Recent studies have shown that bilirubin is negatively associated with hemoglobin A1c (HbA1c) in the general population. The association between bilirubin and HbA1c in serum of diabetes patients has not yet been studied. The aim of the present study was to evaluate the association between total bilirubin and HbA1c in Korean patients with type 2 diabetes. A total of 690 of the 1,275 type 2 diabetes patients registered with the public health centers in Seo-gu, Gwangju and Gokseong-gun, Jeollanam-do participated in this study. Following an overnight fast, venous blood and urine samples were collected and analyzed. The mean HbA1c values differed significantly according to total bilirubin (≤ 0.4 mg/dL, 7.6%; 0.5 mg/dL, 7.3%; 0.6-0.7 mg/dL, 7.2%; and ≥ 0.8 mg/dL, 7.1%; P for trend = 0.016) after we adjusted for other confounding factors. When the odds ratio (OR) was adjusted for other confounding factors, there was a significant association between total bilirubin and HbA1c (OR, 0.4 [95% confidence interval, 0.2-0.8] for total bilirubin ≥ 0.8 mg/dL versus ≤ 0.4 mg/dL. In conclusion, total bilirubin concentrations in serum are negatively associated with HbA1c levels after adjustment for sex, age, and other confounding factors in type 2 diabetes patients.

HbA1c is significantly associated with arterial stiffness but not with carotid atherosclerosis in a community-based population without type 2 diabetes: The Dong-gu study.

OBJECTIVES We examined the associations between HbA1c levels and various atherosclerotic vascular parameters among adults without diabetes from the general population. METHODS A total of 6500 community-dwelling adults, who were free of type 2 diabetes and ≥50 years of age, were included. High-resolution B-mode ultrasound was used to evaluate carotid artery structure, including intima-media thickness (IMT), plaque, and luminal diameter. Brachial-ankle pulse wave velocity (baPWV), which is a useful indicator of systemic arterial stiffness, was determined using an automatic waveform analysis device. RESULTS No significant associations were observed between HbA1c, carotid IMT, plaque, or luminal diameter in a fully adjusted model. However, the odds ratio (95% confidence interval) for high baPWV (defined as the highest quartile) increased by 1.43 (1.19-1.71) per 1% HbA1c increase after adjusting for conventional risk factors in a multivariate logistic regression analysis. In addition, HbA1c was independently associated with baPWV in a multivariate linear regression analysis. CONCLUSIONS High-normal HbA1c level was independently associated with arterial stiffness, but not with carotid atherosclerotic parameters, in the general population without diabetes. Our results suggest that the functional atherosclerotic process may already be accelerated according to HbA1c level, even at a level below the diagnostic threshold for diabetes.

Average Volume of Alcohol Consumed, Drinking Patterns, and Metabolic Syndrome in Older Korean Adults

Background Controversial results have been reported on the relationship between alcohol intake and metabolic syndrome (MetS). We examined the association of average volume of alcohol consumed and drinking patterns with MetS and its components. Methods This study was conducted as a baseline survey for the Dong-gu Study of adults aged 50 years or older. Drinking patterns were assessed using a structured interview, and average volume of alcohol consumed was calculated. MetS was defined according to the updated version of the National Cholesterol Education Program. Results Compared with individuals who never drank, the adjusted odds ratio (OR) for the prevalence of MetS was significantly higher in men who consumed 2.1 to 4.0 drinks/day (OR, 1.53; 95% CI, 1.17–2.00) and greater than 4.0 drinks/day (OR, 1.63; 95% CI, 1.23–2.14), whereas no significant association was observed in women. Significant dose-response relationships between average volume of alcohol consumed and all metabolic components were observed in men. A usual quantity of 5 to 6 drinks/drinking day (OR, 1.57; 95% CI, 1.19–2.09), 7 or more drinks/drinking day (OR, 1.88; 95% CI, 1.45–2.44), and binge drinking on at least 1 occasion/week (OR, 1.33; 95% CI, 1.01–1.76) were associated with a significantly higher OR for prevalence of MetS in men; however, none of these drinking patterns were associated with MetS in women. Conclusions Unhealthy drinking patterns such as high usual quantity and binge drinking were significantly associated with MetS, suggesting that the effect of alcohol consumption on MetS should be considered in the context of drinking pattern, particularly in men.

APOE polymorphism and carotid atherosclerosis in Korean population: The Dong-gu Study and the Namwon Study

OBJECTIVE We evaluated the association between APOE polymorphism and carotid atherosclerosis in two large independent cohorts from South Korea. METHODS The datasets were from the Dong-gu Study (N = 9056) and the Namwon Study (N = 10,158). Carotid ultrasonography was performed to measure carotid intima-media thickness (IMT) and the presence of carotid plaques. The APOE polymorphism was determined by PCR-RFLP. We performed combined and separate analyses for the two datasets. RESULTS In the combined analysis, individuals with E2E2 or E2E3 genotype had a lower common carotid IMT compared with individuals with E3E3 genotype (0.684 mm vs. 0.736 mm, p = 0.007; 0.718 mm vs. 0.736 mm, p < 0.001, respectively). This association was very slightly attenuated but remained statistically significant after adjustment for blood lipids (0.690 mm vs. 0.736 mm, p = 0.033; 0.725 mm vs. 0.736 mm, p = 0.005, respectively). Compared with individuals with E3E3 genotype, individuals with E2E3 genotype had lower risk for carotid plaque (odds ratio (OR) = 0.83, 95% confidence interval (CI) = 0.75-0.93), while individuals with E3E4 genotype had a higher risk for carotid plaque (OR = 1.09, 95% CI = 1.00-1.20). After adjustment for blood lipids, ORs of E2E3 genotype for carotid plaque was slightly attenuated but remained significant (OR = 0.87 95% CI = 0.78-0.97), while OR of E3E4 genotype were slightly attenuated and not significant (OR = 1.08, 95% CI, 0.99-1.18). CONCLUSIONS We found that APOE polymorphism is associated with carotid atherosclerosis and this association was partly mediated through blood lipid. Our results suggest that APOE polymorphism may influence atherosclerosis through non-lipid pathways.

Associations Between Socio-demographic Characteristics and Healthy Lifestyles in Korean Adults: The Result of the 2010 Community Health Survey

Objectives Several previous studies have found that healthy behaviors substantially reduce non-communicable disease incidence and mortality. The present study was performed to estimate the prevalence of four modifiable healthy behaviors and a healthy lifestyle among Korean adults according to socio-demographic and regional factors. Methods We analyzed data from 199 400 Korean adults aged 19 years and older who participated in the 2010 Korean Community Health Survey. We defined a healthy lifestyle as a combination of four modifiable healthy behaviors: non-smoking, moderate alcohol consumption, regular walking, and a healthy weight. We calculated the prevalence rates and odds ratios of each healthy behavior and healthy lifestyle according to socio-demographic and regional characteristics. Results The prevalence rates were as follows: non-smoking, 75.0% (53.7% in men, 96.6% in women); moderate alcohol consumption, 88.2% (79.7% in men, 96.9% in women); regular walking, 45.0% (46.2% in men, 43.8% in women); healthy weight, 77.4% (71.3% in men, 73.6% in women); and a healthy lifestyle, 25.5% (16.4% in men, 34.6% in women). The characteristics associated with a low prevalence of healthy lifestyle were male gender, younger age (19 to 44 years of age), low educational attainment, married, living in a rural area, living in the Chungcheong, Youngnam, or Gwangwon-Jeju region, and poorer self-rated health. Conclusions Further research should be implemented to explore the explainable factors of disparities for socio-demographic and regional characteristics to engage in the healthy lifestyle among adults.