John A. Linton

Fasting Glucose Level and the Risk of Incident Atherosclerotic Cardiovascular Diseases

OBJECTIVE Although diabetes increases the risk of cardiovascular disease (CVD) and mortality, the dose-response relationship between fasting glucose levels below those diagnostic of diabetes with cardiovascular events has not been well characterized. RESEARCH DESIGN AND METHODS A prospective cohort study of more than one million Koreans was conducted with a mean follow-up of 16 years. A total of 1,197,384 Korean adults with no specific medical conditions diagnosed were classified by baseline fasting serum glucose level. Associations of fasting glucose level with CVD incidence and mortality, stroke incidence and mortality, and all-cause mortality were analyzed using multivariate proportional hazards regression. RESULTS The relationships between fasting glucose levels and CVD risks generally followed J-shape curves, with lowest risk in the glucose range of 85–99 mg/dL. As fasting glucose levels increased to >100 mg/dL, risks for CVD, ischemic heart disease, myocardial infarction, and thrombotic stroke progressively increased, but risk for hemorrhagic stroke did not. Fasting glucose levels <70 mg/dL were associated with increased risk of all stroke (hazard ratio 1.06, 95% CI 1.01–1.11) in men and (hazard ratio 1.11, 1.05–1.17) in women. CONCLUSIONS Both low glucose level and impaired fasting glucose should be considered as predictors of risk for stroke and coronary heart disease. The fasting glucose level associated with the lowest cardiovascular risk may be in a narrow range.

Serum ferritin level is associated with the prevalence of metabolic syndrome in Korean adults: the 2007-2008 Korean National Health and Nutrition Examination Survey.

BACKGROUND Increased ferritin concentrations, which reflect body iron stores, contribute to insulin dysfunction and metabolic syndrome (MetS). METHODS This cross-sectional study included 7346 subjects (3229 men and 4117 women) who participated in the 2007-2008 Korean National Health and Nutrition Examination Survey (KNHANES). We adopted the modified Asian criteria for MetS from the American Heart Association/National Heart, Lung, and Blood Institute. RESULTS In comparison with participants in the first serum ferritin quartile, the odds ratio (95% confidence interval) for MetS for participants in the fourth serum ferritin quartile was 1.67 (1.24-2.23) in men and 1.41 (1.06-1.88) in women after adjusting for multiple covariates (including menopausal status in women) except insulin resistance. This association was attenuated, however, after additionally adjusting for insulin resistance [1.46 (1.08-1.98) in men and 1.22 (0.91-1.65) in women]. In particular, higher serum ferritin concentrations were associated with increased triglyceride concentrations in men and glucose intolerance in women. CONCLUSIONS Increased serum ferritin level was positively associated with the prevalence of MetS and with some diagnostic components of MetS, i.e., we found that increased serum ferritin concentrations were associated with high triglyceride and glucose concentrations in men and women, respectively.

Trends in Prevalence of Overweight and Obesity in Korean Adults, 1998–2009: The Korean National Health and Nutrition Examination Survey

Background Although obesity is increasing worldwide and becoming a major public health problem, some countries report a trend toward stabilization. We investigated prevalence trends in overweight/obesity and obesity among Korean adults during a 12-year period. Methods This study was based on the Korean National Health and Nutrition Examination Survey (KNHANES) I (1998), II (2001), III (2005), and IV (2007–2009). The χ2 and ANOVA tests were used to compare the prevalence and mean values for age and BMI, respectively. P-values for trends were determined by linear and logistic regression analyses, with KNHANES phase as the continuous variable. Results The prevalences of overweight/obesity in KNHANES I through IV were 50.8%, 57.4%, 62.5%, and 62.6%, respectively, among men (P for trend = 0.002, β = 0.021) and 47.3%, 51.9%, 50.0%, and 48.9% among women (P for trend = 0.017, β = −0.015). The respective prevalences of obesity were 26.0%, 32.4%, 35.1%, and 36.3% among men (P for trend = 0.006, β = 0.018) and 26.5%, 29.3%, 28.0%, and 27.6% among women (P for trend = 0.143, β = −0.008). During the same period, the respective prevalences of grade 2 obesity (BMI ≥30 kg/m2) were 1.7%, 2.8%, 3.6%, and 3.8% among men (P for trend = 0.075, β = 0.005) and 3.0%, 3.5%, 3.4%, and 4.0% among women (P for trend = 0.398, β = 0.003). Conclusions The prevalences of overweight/obesity and obesity showed an upward trend among men during the 12-year period, whereas the prevalence of overweight/obesity slightly decreased among women from 2001.

Alcohol Consumption and Digestive Cancer Mortality in Koreans: The Kangwha Cohort Study

Background Alcohol consumption is a known risk factor for cancers of the mouth, esophagus, liver, colon, and breast. In this study, we examined the association between alcohol consumption and digestive cancer mortality in Korean men and women. Methods A cohort of 6291 residents of Kangwha County who were aged 55 years or older in March 1985 were followed to 31 December 2005—a period of 20.8 years. We calculated the relative risks of cancer mortality with respect to the amount of alcohol consumed. Cox proportional hazard model was used to adjust for age at entry, smoking, ginseng intake, education status, and pesticide use. Results In men, the risks of mortality from esophageal cancer (relative risk [RR], 5.62; 95% confidence interval [CI], 1.45–21.77) and colon cancer (RR, 4.59; 95% CI, 1.10–19.2) were higher among heavy drinkers, as compared with abstainers. The risks of mortality from colon cancer and bile duct cancer rose with increasing alcohol consumption; these trends were positive and statistically significant (P = 0.04 and P = 0.02, respectively). When participants were stratified by type of alcoholic beverage, soju drinkers had higher risks of mortality from esophageal cancer and colon cancer than makkoli drinkers. In women, the risk of digestive cancer mortality was higher among alcohol drinkers than abstainers, but this difference was not statistically significant. Conclusions Alcohol consumption increases mortality from esophageal cancer and colon cancer in men.

Inverse Association Between Total Bilirubin and Metabolic Syndrome in Rural Korean Women

UNLABELLED Abstract Background: Chronic inflammation and oxidative stress are associated with the development of metabolic syndrome (MetS). Bilirubin is an antioxidant and has a protective effect against cardiovascular disease (CVD). The purpose of this study was to examine the association between total bilirubin levels and the prevalence of MetS in rural Korean women. METHODS This cross-sectional study included 5,266 women (>40 years) enrolled in the Korean Genomic Rural Cohort (KGRC). MetS was defined using the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI) guidelines. Total bilirubin levels were categorized into quartiles. RESULTS Subjects in the upper quartiles of total bilirubin were younger and had lower waist circumferences, systolic blood pressure, and triglyceride levels and higher high-density lipoprotein cholesterol (HDL-C) concentrations. The overall prevalence of MetS was 39.0%. When the participants were categorized into quartiles by total bilirubin level, the prevalence of MetS according to increasing total bilirubin quartiles was 47.9%, 41.2%, 34.3%, and 32.7%, respectively. By comparison to the lowest quartile of total bilirubin (<0.61 mg/dL), the odds ratio (OR) (95% confidence interval [CI]) for MetS in the highest quartile of total bilirubin (≥0.94 mg/dL) was 0.63 (0.52-0.77) after adjusting for menopausal status, C-reactive protein (CRP) levels, insulin resistance, and other covariates. CONCLUSIONS Total bilirubin level appears to be inversely associated with the prevalence of MetS in rural Korean women >40 years of age in the KGRC, even after adjusting for risk factors of MetS, including body mass index (BMI), menopausal status, CRP levels, and homeostasis model assessment of insulin resistance (HOMA-IR).

Trends in the prevalence of chronic kidney disease in Korean adults: the Korean National Health and Nutrition Examination Survey from 1998 to 2009

BACKGROUND Chronic kidney disease (CKD) is associated with a poor quality of life and cardiovascular events and is a great threat to public health. METHODS We investigated the trends of CKD prevalence over 12 years in Korean adults at least 20 years old using sampling weight methods based on the Korean National Health and Nutrition Examination Survey (KNHANES) I (1998), II (2001), III (2005) and IV (2007-09). Of the 135 954 subjects participating in KNHANES I-IV, 33 276 (14 307 men, 18 969 women) were included in the present study. RESULTS The percentage of glomerular filtration rate (GFR) <60 mL/min/1.73 m(2) in KNHANES I-IV was 1.0, 5.4, 3.1 and 2.6% in men and 3.4, 9.7, 10.2 and 4.6% in women, respectively. The percentage of proteinuria ≥ 1+ measured by a dipstick method across KNHANES phases gradually declined in men (3.1, 3.0, 2.8 and 2.2% in KNHANES I-IV, respectively), while those in women rebounded in KNHANES IV after reduction through KNHANES III (3.3, 2.3, 1.4 and 1.9%, respectively). The prevalence of CKD (GFR <60 mL/min/1.73 m(2) or proteinuria ≥ 1+) in KNHANES I-IV was 3.9, 7.9, 5.4 and 4.5% in men and 6.4, 11.3, 12.0 and 6.3% in women, respectively. After stratification by age (20-39 years, 40-59 years and ≥ 60 years), the prevalence trends were similar to those before the stratification by sexes. CONCLUSIONS The prevalence of CKD in Korean adults has decreased since 2001 in men and since 2005 in women.

Sex differences in the relationship between socioeconomic status and metabolic syndrome: The Korean National Health and Nutrition Examination Survey

AIMS To investigate sex differences in the relationship between socioeconomic status (SES) and the prevalence of metabolic syndrome (MetS) in Korean adults. METHODS We examined the relationship between SES, as measured by household income or education level, and the prevalence of MetS in Korean adults who participated in the 2007-2008 Korean National Health Examination and Nutrition Survey (KNHANES). The adjusted odds ratios (ORs) for MetS were calculated using multivariate logistic regression analysis across household income and education level quartiles. RESULTS We found significant differences between men and women in the association between SES and MetS, with a positive association for men and an inverse association for women. The adjusted OR and 95% confidence interval (95% CI) for MetS for the highest vs. lowest quartile of household income was 1.59 (1.15-2.20) in men. The adjusted ORs for MetS for the highest vs. lowest quartile of household income and education level were 0.54 (0.41-0.72) and 0.26 (0.17-0.38) in women, respectively. CONCLUSIONS We found sex differences in the relationship between SES and the prevalence of MetS in Korea. These findings suggest that sex-specific public health interventions that consider SES are needed for the prevention and treatment of MetS.

High-risk drinking is associated with a higher risk of diabetes mellitus in Korean men, based on the 2010–2012 KNHANES

We examined the association between alcohol-drinking pattern and diabetes mellitus (DM) in Korean adults. This cross-sectional study included 12,486 participants (5551 men and 6935 women) who participated in the 2010-2012 Korean National Health and Nutrition Examination Survey. We categorized alcohol-drinking pattern into three groups based on the alcohol-use disorders identification test (AUDIT): low-risk (score: 0-7), intermediate-risk (score: 8-14), and high-risk (score: ≥15). DM was defined as having fasting plasma glucose ≥126 mg/dL or taking glucose-lowering medication, including insulin therapy. In the study population, 25.2% of men and 4.7% of women were high-risk drinkers. DM prevalence was 9.2% in men and 5.4% in women. DM prevalence was 9.0% and 5.7% in the low-risk drinking group, 7.6% and 4.1% in the intermediate-risk drinking group, and 11.2% and 3.5% in the high-risk drinking group in men and women, respectively. Compared to the low-risk drinking group, odds ratios (95% confidence intervals) of men and women in the intermediate-risk drinking group for DM were 1.043 (0.779-1.396) and 1.139 (0.712-1.824), respectively, and 1.480 (1.133-1.933) and 0.827 (0.296-2.311) in the high-risk drinking group, after adjusting for age and other confounding factors. In conclusion, high-risk drinking appears to be associated with a higher risk of DM in men, but not in women.

Reading nutrition labels is associated with a lower risk of metabolic syndrome in Korean adults: the 2007-2008 Korean NHANES.

BACKGROUND AND AIMS Several studies demonstrated that reading nutrition labels was associated with healthier food choices, despite some controversy. This study investigated the association between the use of nutrition labels and metabolic syndrome (MetS) in Korean adults. METHODS AND RESULTS This cross-sectional study included 7756 individuals who participated in the 2007-2009 Korean National Health and Nutrition Examination Survey (KNHANES). A self-reported questionnaire was used to determine participants awareness of nutrition labels. Modified Asian criteria based on a harmonizing definition of MetS were adopted. Individuals in the group that read nutrition labels (the Reading Group) were youngest and leanest, but their daily caloric intake fell between that of the group that did not read nutrition labels (the Non-Reading Group) and the group that did not know about them (the Not-Knowing Group). The prevalence of MetS was 16.8% in the Reading Group, 27.2% in the Non-Reading Group, and 47.3% in the Not-Knowing Group. In comparison to participants in the Reading Group, the odds ratios (95% confidence interval) for MetS in the participants in the Non-Reading Group and Not-Knowing Group were 1.85 (1.60-2.14) and 4.44 (3.79-5.20), respectively, when not adjusted. The relationship between the use of nutrition labels and MetS remained statistically significant even after adjusting for covariates such as age, sex and socioeconomic status including household income and education level [1.27 (1.05-1.53) in the Non-Reading Group and 1.34 (1.05-1.70) in the Not-Knowing Group]. CONCLUSION Reading nutrition labels appeared to be associated with a lower prevalence of MetS in a nationally representative sample of Korean adults.

Relationship between employment status and obesity in a Korean elderly population, based on the 2007-2009 Korean National Health and Nutrition Examination Survey (KNHANES).

We investigated the relationship between employment status and obesity prevalence in an elderly Korean, using a nationally representative sample. This cross-sectional study included 2991 participants (1396 men and 1595 women) aged 60 years or older. Employment status was categorized into full-time employees, part-time employees, and an unemployed group, based on a self-reported questionnaire. According to Asia Pacific regional guidelines from the World Health Organization (WHO) and International Obesity Task Force (IOTF), obesity was defined as a body mass index (BMI)≥25kg/m(2). Mean BMI in women was highest in the unemployed group, whereas the mean BMI in men did not differ significantly between employment groups. The obesity prevalence in full-time employees, part-time employees, and the unemployed group were 25.1%, 25.5%, and 27.1% in men and 36.0%, 37.9%, and 40.4% in women, respectively. Compared to the full-time employees, the odds ratios (ORs) (95% confidence intervals) for obesity were 1.172 (0.765-1.795) and 1.164 (0.843-1.609) in the part-time employees, and 1.451 (1.054-1.999) and 1.399 (1.090-1.795) in the unemployed group, for men and women, respectively, after adjusting for age, lifestyle factors (physical activity, alcohol consumption, smoking status, daily calorie intake), socioeconomic factors (education level and household income), and inflammatory factor (white blood cell (WBC) counts). Unemployment appears to be significantly related to a higher prevalence risk of obesity in an elderly Korean population, regardless of age, lifestyle, socioeconomic factors, and inflammatory factor.