Oxidative balance score and serum γ-glutamyltransferase level among Korean adults: a nationwide population-based study.

PURPOSE: The oxidative balance score (OBS) comprises dietary and non-dietary lifestyle pro-oxidants and antioxidants. Elevated serum γ-glutamyltransferase (GGT) level has currently emerged as a biomarker of oxidative stress. In this study, we examined whether OBS was inversely associated with serum GGT level and whether OBS could be a useful marker to predict GGT among Korean adults. METHODS: This cross-sectional study was based on data obtained from the 2010 and 2011 Korea National Health and Nutrition Examination Survey. 2087 men and 2071 women were included in final analysis. The OBS was divided into five equal interval categories, and GGT was dichotomized into low and high using its sex-specific median value. Multiple logistic regression analysis was conducted to assess the association between OBS categories and high GGT. RESULTS: Compared with the lowest OBS category as reference, the multivariable adjusted ORs (95% CIs) for the highest OBS category of men and women were 0.05 (0.01-0.19) and 0.27 (0.09-0.78), respectively (p for trend <0.01). CONCLUSION: A higher OBS that indicates a predominance of antioxidant over pro-oxidant exposure was strongly inversely associated with GGT level among Korean adults.

Association between Salivary Mitochondrial DNA Copy Number and Chronic Fatigue according to Combined Symptoms in Korean Adults.

BACKGROUND: We examined the association between salivary mitochondrial DNA (mtDNA) copy number and chronic fatigue combined with depression and insomnia. METHODS: This cross-sectional study included 58 healthy adults with moderate to severe fatigue (Brief Fatigue Inventory [BFI] ≥4) for longer than 6 months. Subjects were classified as those without combined symptoms, with either depression (Beck Depression Inventory [BDI] ≥13) or insomnia (Pittsburgh Sleep Quality Index [PSQI] ≥5), or with both depression and insomnia. Salivary mtDNA copy number was measured by real-time quantitative polymerase chain reaction. The association was evaluated using a general linear model. RESULTS: About 76% of participants had either depression or insomnia as additional symptoms. These subjects were predominately female, drank more alcohol, and exercised less than those without combined symptoms (P<0.05). The group with both depression and insomnia exhibited significantly higher BFI and lower mtDNA copy number than those without combined symptoms (P<0.05). After adjusting for confounding factors, significant negative associations between mtDNA copy number and usual fatigue were found in the group without combined symptoms, whereas the negative associations in the group with combined symptoms were attenuated. BDI and PSQI were not associated with mtDNA copy number. CONCLUSION: Chronic fatigue is negatively associated with salivary mtDNA copy number. Salivary mtDNA copy number may be a biological marker of fatigue with or without combined symptoms, indicating that a separate approach is necessary.

Alcoholic liver disease: focus on prodromal gut health.

Alcoholic liver disease (ALD) is implicated in gut disturbances, both functionally and structurally. It has been noticed that the gut-liver interaction is an important feature in the prevention of systemic inflammation as well as liver health. The optimal functioning of the gut-liver axis depends on gut health. Therefore, gut problems may be important for estimating liver inflammation, while our knowledge of ALD could also provide an insight into gut health. Gut problems accompanied by ALD include gut motility and absorption problems, mucosal damage and the dysbiosis of gut microbiota and gastrointestinal carcinogenesis. Moreover, there is emerging evidence that besides direct inflammatory injury caused by alcohol, gut problems related to ALD play a crucial role in the pathogenesis of cardiovascular and immunological disorders. In this regard, we should consider ALD in relation to both gut health and chronic systemic low-grade inflammation. Accordingly, integrative therapeutic strategies are warranted for treating and preventing ALD and systemic inflammation as well as alcohol-related gut problems.

Smokers With Adequate Vitamin C Intake Show a Preferable Pulmonary Function Test.

OBJECTIVE: Airflow obstruction often results from the chronic inflammation caused by cigarette smoke. It has been concluded that cigarette smoke-induced oxidative damage is prevented by ascorbic acid on a cellular level. The purpose of the current study was to explore the effect of vitamin C intake on pulmonary function in established smokers (100 or more cigarettes) and never-smokers in a Korean population. METHODS: The 2974 enrolled men and women over the age of 40 in the Korea National Health and Nutrition Examination Survey IV 2008 were divided into 4 groups based on smoking patterns (never-smoker vs established smoker) and vitamin C intake from dietary assessment (higher vs lower; median value: 77.18 mg/day). RESULTS: Univariate analysis showed associations between forced expiratory volume in 1 second (FEV1), FEV/forced vital capacity (FVC) and age, gender, body mass index (BMI), pack-years, vitamin C intake, and additional micronutrient intake. On multiple logistic regression analysis, the odds ratios (95% confidence interval) for FEV1 < 80% predicted were 1.000 (never-smokers, higher vitamin C intake), 1.067 (0.823, 1.383; never-smokers, lower vitamin C intake), 1.224 (0.871, 1.721; established smokers, higher vitamin C intake), and 1.479 (1.057, 2.072; established smokers, lower vitamin C intake). The odds ratios for FEV1/FVC < 0.70 were 1.177 (0.821, 1.687; never-smokers, lower vitamin C intake), 1.637 (1.094, 2.445; established smokers, higher vitamin C intake), and 2.093 (1.403, 3.122; established smokers, lower vitamin C intake) after adjusting for confounding factors (p < 0.001). CONCLUSIONS: Korean smokers with adequate vitamin C intake showed a preferable pulmonary function test.

The association between coronary calcification and adenomatous polyps of colon in Korean adults.

BACKGROUND AND OBJECTIVE: Adenomatous polyps of colon is a precancerous lesion. Many studies have shown that the adenomatous polyps of colon and cardiovascular disease share several common risk factors. This cross-sectional study aimed to investigate whether coronary calcification is associated with the adenomatous polyps of colon. METHODS: Among 1637 Korean adults, we examined the association between coronary calcium score (CCS) as a measurement of coronary calcification and the presence of adenomatous polyps of colon via multi-detected row computed tomography (MDCT) and colonoscopy, respectively. CCS values were categorized as follows: 0, 1-17, 18-105, or≥106. The odds ratios (ORs) and 95% confidence intervals (CIs) for the presence of adenomatous polyps of colon were calculated across CCS groups. RESULTS AND CONCLUSIONS: After adjusting for confounding variables, the adjusted ORs (95% CIs) for the presence of adenomatous polyps of colon in each of the four CCS groups were 1.00 (reference), 1.44 (0.91-2.33), 1.88 (1.15-3.01) and 3.61 (2.23-5.74). And higher CCS values were associated with multiple polyps (P≤0.001), villous histologic features or high-grade dysplasia (P=0.02), and advanced adenomatous polyps (P≤0.001). A higher level of CCS was found to be strongly and independently associated with the presence of adenomatous polyps of colon in Korean adults. This finding suggests that people at high risk for coronary atherosclerosis through MDCT should be considered for further evaluation of adenomatous polyps.

Chronic liver inflammation: clinical implications beyond alcoholic liver disease.

Chronic alcohol exposure can lead to alcoholic liver disease, including hepatitis, cirrhosis and hepatocellular carcinoma, and chronic inflammation can simultaneously cause systemic medical illness. Recent evidence suggests that alcoholic liver disease is a predictor for liver-related diseases, cardiovascular disease, immunologic disease, and bone disease. Chronic inflammation in alcoholic liver disease is mediated by a direct inflammatory cascade from the alcohol detoxification process and an indirect inflammatory cascade in response to gut microflora-derived lipopolysaccharides (LPS). The pathophysiology of alcoholic liver disease and its related systemic illness is characterized by oxidative stress, activation of the immune cascade, and gut-liver interactions. Integrative therapeutic strategies for alcoholic liver disease include abstaining from alcohol consumption; general anti-inflammatories such as glucocorticoid, pentoxifylline, and tumour necrosis factor-α antagonist; antioxidants such as N- acetylcysteine; gut microflora and LPS modulators such as rifaximin and/or probiotics. This review focuses on the impact of chronic liver inflammation on systemic health problems and several potential therapeutic targets.

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 χ(2) 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, ß = 0.021) and 47.3%, 51.9%, 50.0%, and 48.9% among women (P for trend = 0.017, ß = -0.015). The respective prevalences of obesity were 26.0%, 32.4%, 35.1%, and 36.3% among men (P for trend = 0.006, ß = 0.018) and 26.5%, 29.3%, 28.0%, and 27.6% among women (P for trend = 0.143, ß = -0.008). During the same period, the respective prevalences of grade 2 obesity (BMI ≥30 kg/m(2)) were 1.7%, 2.8%, 3.6%, and 3.8% among men (P for trend = 0.075, ß = 0.005) and 3.0%, 3.5%, 3.4%, and 4.0% among women (P for trend = 0.398, ß = 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.

Relationship between blood mercury concentrations and serum γ-glutamyltranspeptidase level in Korean adults using data from the 2010 Korean National Health and Nutrition Examination Survey.

BACKGROUND: Mercury and serum γ-glutamyltranspeptidase (GGT) play an important role in anti-oxidant mechanisms. This study aimed to investigate the association between blood mercury concentrations and GGT in Korean men and women. METHODS: A nationwide cross-sectional study was conducted to examine the relationship between blood mercury concentration and serum GGT among 1959 subjects (aged 20-87 y; 965 men, 994 women), using data from the 2010 Korean National Health and Nutrition Examination Survey. The odds ratios (ORs) and 95% confidence intervals (CIs) for high GGT (≥ 75 th percentile) for both men and women were calculated across blood mercury quartiles using multiple logistic regression analyses. RESULTS: The mean values of BMI, waist circumference, diastolic blood pressure, total cholesterol, and triglycerides were highest in the highest quartile of blood mercury concentrations in both sexes. GGT levels gradually increased in accordance with blood mercury quartiles. Compared to the lowest quartile of blood mercury concentrations, the adjusted OR (95% CI) for high GGT of the highest quartile was 2.59 (1.51-4.43) in men and 2.03 (1.13-3.67) in women. CONCLUSION: We found a positive relationship between blood mercury concentration and serum GGT level in a representative population 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.

Prevalence of metabolic syndrome in children and adolescents - the recent trends in South Korea.

BACKGROUND: Although the metabolic syndrome (MetS) in childhood is increasing worldwide and becoming a significant public health problem, some countries report trends for stabilization. After 2005, the Health Plan 2010 of the Korean Ministry of Health and Welfare has carried out the standardization of school lunch provisions for all students and reinforced nutritional and physical education in schools. Thus, an investigation of changes in the prevalence of MetS in Korean children and adolescents is important and intriguing in the aspect of evaluating the national public health intervention. METHODS: We investigated trends in the prevalence of MetS among a nationally representative sample of 5652 children and adolescents aged 10-18 years from the Korean National Health and Nutrition Examination Surveys (KNHANES) I (1998), II (2001), III (2005), and IV (2008). RESULTS: Prevalence trends in MetS were 7.5%, 9.8%, 10.9%, and 6.7% in the KNHANES I through IV, respectively (p<0.001). Among the five components of MetS, the prevalence of low high-density lipoprotein (HDL) cholesterol increased most over the 1998-2005 period and decreased over the 2005-2008 period. CONCLUSION: The prevalence of MetS has decreased since 2005 mainly because of changes in the prevalence of low levels of HDL cholesterol.

Body composition and its association with cardiometabolic risk factors in the elderly: a focus on sarcopenic obesity.

Important changes in body composition with aging are a progressive loss of muscle mass and increase of fat mass. Despite their enormous clinical importance, body composition changes such as sarcopenic obesity in the elderly are under-recognized. This study aimed to examine the relationship of body composition with a wide variety of cardiometabolic risk factors among 2943 subjects (1250 men and 1693 women) aged 60 years or older from Korean National Health Examination and Nutrition Survey (KNHANES). Sarcopenia was defined as an appendicular skeletal muscle mass (ASM) divided by weight (%) of < 1 SD below the sex-specific mean for young adults. Obesity was defined as a body mass index (BMI) ≥ 25 kg/m(2). Body composition was categorized into four non-overlapping groups: the sarcopenic obese, sarcopenic nonobese, nonsarcopenic obese, and nonsarcopenic nonobese groups. A wide variety of cardiometabolic risk factors, including blood pressure (BP), glucose tolerance indices, lipid profiles, inflammatory markers, and vitamin D level, were compared according to body composition group. The prevalence of sarcopenic obesity was 18.4% in men and 25.8% in women. In both sexes, the prevalence of vitamin D deficiency and metabolic syndrome was highly prevalent in the sarcopenic obese group. Serum insulin level, homeostasis model assessment of insulin resistance (HOMA-IR), triglyceride levels, and ferritin levels were the highest in the sarcopenic obese group in both men and women, whereas HDL-cholesterol and 25-hydroxyvitamin D (25(OH)D) levels were the lowest in the sarcopenic obese group. The sarcopenic obese group was more closely associated with insulin resistance, metabolic syndrome, and cardiovascular disease (CVD) risk factors than any other group in this elderly population.

Serum carcinoembryonic antigen level is associated with arterial stiffness in healthy Korean adult.

BACKGROUND: Carcinoembryonic antigen (CEA), a widely used tumor marker, has been reported to be related with atherosclerosis and cardiovascular disease. However, little is known about the relationship between arterial stiffness and CEA level. We assessed whether serum CEA level is related with arterial stiffness by measuring brachial-ankle pulse wave velocity (ba-PWV) in healthy subjects. METHODS: Serum CEA level, ba-PWV and conventional risk factors were measured in 2909 subjects (1767 men and 1142 women) who underwent routine health checkup. We performed correlation, multiple linear regression and multiple logistic regression analyses to divide into quartiles according to CEA level. RESULTS: The mean values of ba-PWV increased gradually by CEA quartile. After correcting for significantly correlated variables, the ba-PWV was independently associated with CEA (P<0.001). The odds ratios (95% CI) for high ba-PWV (>75th percentile; men: 1518 cm/s, women: 1487 cm/s) according to CEA quartile were 1.00 (Q1), 1.044 (0.659-1.652; Q2), 1.075 (0.688-1.681; Q3), and 1.595 (1.009-2.520; Q4) after adjusting for age, blood pressure, BMI, fasting glucose, heart rate, log hs-CRP, LDL-cholesterol, WBC count, alcohol intake, smoking and exercise in men (P<0.001). The odds ratios (95% CIs) in women were 1.00 (Q1), 1.719 (0.971-3.032; Q2), 1.793 (1.019-3.156; Q3), and 2.330 (1.312-4.139; Q4) (P<0.001) after adjusting for age, blood pressure, BMI, fasting glucose, heart rate, log hs-CRP, lipid profile, uric acid, WBC count, alcohol intake, smoking and exercise. CONCLUSIONS: The CEA level is associated with arterial stiffness which measured by ba-PWV in healthy Korean men and women.

The efficacy and safety of a combined alendronate and calcitriol agent (maxmarvil): a postmarketing surveillance study in korean postmenopausal women with osteoporosis.

BACKGROUND: Combined therapy with alendronate and calcitriol may have additive effects on bone density. An observational study was performed to evaluate the efficacy and safety of Maxmarvil, a combinative agent of alendronate (5 mg) and calcitriol (0.5 µg), and to identify factors associated with efficacy. METHODS: A total of 568 postmenopausal women with osteoporosis were enrolled by family physicians in 12 hospitals. The study subjects took Maxmarvil daily for 12 months. Questionnaires about baseline characteristics, socioeconomic status, and daily calcium intake were completed at the first visit. Adverse events were recorded every 3 months and bone mineral density (BMD) in the lumbar spine was measured using dual-energy X-ray absorptiometry at baseline and after 12 months. We evaluated the efficacy and safety of Maxmarvil, and the factors related to BMD improvement. RESULTS: A total of 370 patients were included in final analysis. The median BMD was 0.81 ± 0.12 g/cm(2) at pre-treatment and 0.84 ± 0.13 g/cm(2) after one year. The average BMD improvement was 3.4% ± 6.4% (P < 0.05), and 167 (45.1%) patients showed improvement. Factors associated with improved BMD were continuation of treatment (odds ratio [OR], 2.41; 95% confidence interval [CI], 1.15 to 5.07) and good compliance (OR, 2.54; 95% CI, 1.29 to 5.00). Adverse events were reported by 35 of the 568 patients, with the most common being abdominal pain and dyspepsia. CONCLUSION: Maxmarvil was found to be safe, well tolerated and effective in osteoporosis treatment. Continuation of treatment and good compliance were the factors associated with efficacy.

Comparison of lipid-related ratios for prediction of chronic kidney disease stage 3 or more in Korean adults.

Dyslipidemia is implicated in increased cardiovascular risk associated with chronic kidney disease (CKD) and in the progression of renal damage. This study compared 4 different lipid-related ratios (total cholesterol [TC]/high-density lipoprotein cholesterol [HDL-C], triglyceride [TG]/HDL-C, calculated low-density lipoprotein cholesterol [c-LDL-C]/HDL-C, and non-HDL-C/HDL-C ratio) for prediction of CKD stage 3 or more to investigate the association between them. This cross-sectional study included 8,650 adults who participated in the 2007-2008 Korean National Health and Nutrition Examination Survey. The overall prevalence of CKD stage 3 or more was 6.4%. For TG/HDL-C, the prevalence with CKD stage 3 or more increased with increasing quartile group in both sexes (P value for trend = 0.046 in men, 0.002 in women) while other lipid-related ratios showed increasing prevalence only in women. In comparison with the lowest quartile of the lipid-related ratios, only the fourth quartile of TG/HDL-C was associated with the prevalence of CKD stage 3 or more in both sexes after adjustment for multiple covariates (odds ratio [OR] for TG/HDL-C-Q(4), 1.82; 95% CI [confidence interval], 1.09-3.03 in men, OR 2.45; 95% CI, 1.52-3.95 in women). In conclusion, TG/HDL-C is the only lipid-related ratio that is independently associated with CKD stage 3 or more in both sexes of Koreans.

Effects of Korean Red Ginseng on Cardiovascular Risks in Subjects with Metabolic Syndrome: a Double-blind Randomized Controlled Study.

BACKGROUND: This study investigated the effects of Korean red ginseng (KRG) supplementation on metabolic parameters, inflammatory markers, and arterial stiffness in subjects with metabolic syndrome. METHODS: We performed a randomized, double-blind, placebo-controlled, single-center study in 60 subjects who were not taking drugs that could affect metabolic and vascular functions. Subjects were randomized into either a KRG (4.5 g/d) group or a placebo group for a 12-week study. We collected anthropometric measurements, blood for laboratory testing, and brachial-ankle pulse wave velocity (baPWV) at the initial (week 0) and final (week 12) visits. RESULTS: A total of 48 subjects successfully completed the study protocol. Oral administration of KRG did not significantly affect blood pressure, oxidative or inflammatory markers, or baPWV. CONCLUSION: We found no evidence that KRG had an effect on blood pressure, lipid profile, oxidized low density lipoprotein, fasting blood glucose, or arterial stiffness in subjects with metabolic syndrome. These findings warrant subsequent longer-term prospective clinical investigations with a larger population. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00976274.

High-normal Glucose Levels in Non-diabetic and Pre-diabetic Men Are Associated with Decreased Testosterone Levels.

BACKGROUND: Testosterone levels are decreased in diabetic patients and recent studies have suggested that high-normal fasting glucose is a risk factor for cardiovascular disease. To further elucidate the relationship between plasma glucose and testosterone, we investigated the association between fasting plasma glucose (FPG) and endogenous sex hormones (serum total testosterone, sex hormone binding globulin, estradiol, and the ratio of testosterone to estradiol) in non-diabetic and pre-diabetic men. METHODS: This study included 388 men (age ≥ 40 years) who visited the health promotion center of a university hospital from May 2007 to August 2008. The subjects were divided into quartiles based on their FPG levels and correlation and multiple linear regression analyses were performed. Q1 (65 mg/dL ≤ FPG < 88 mg/dL), Q2 (88 mg/dL ≤ FPG < 94 mg/dL), Q3 (94 mg/dL ≤ FPG < 100 mg/dL) and Q4 (100 mg/dL ≤ FPG < 126 mg/dL). RESULTS: FPG was independently, inversely associated with total testosterone in the non-diabetic population after adjusting for age, body mass index, smoking, and alcohol consumption (ß = -0.082, P < 0.01). Among the quartiles, subjects in the high-normal FPG groups (Q2, Q3, and Q4 with FPG ≥ 88 mg/dL) had significantly decreased testosterone levels when compared with subjects in the normal FPG group (Q1 with FPG < 88 mg/dL, P < 0.005). Sex hormone binding globulin, estradiol and the ratio of testosterone to estradiol were not correlated with FPG. CONCLUSION: Our study indicates that high-normal fasting glucose levels are associated with decreased testosterone levels in non-diabetic and pre-diabetic men.

Low-grade inflammation, metabolic syndrome and the risk of chronic kidney disease: the 2005 Korean National Health and Nutrition Examination Survey.

Either chronic inflammation or metabolic syndrome (MetS) is associated with renal impairment. This cross-sectional study was designed to investigate the relationship between elevated white blood cell (WBC) counts and chronic kidney disease (CKD) stage 3 or more according to the presence of MetS in adult Koreans. In total, 5,291 subjects (≥ 20 yr-old) participating in the 2005 Korean National Health and Nutrition Examination were included. CKD stage 3 or more was defined as having an estimated glomerular filtration rate below 60 mL/min/1.73 m(2), as calculated using the formula from the Modification of Diet in Renal Disease study. The odds ratio (95% confidence interval) for CKD stage 3 or more in the highest WBC quartile (≥ 7,200 cells/µL) was 1.70 (1.17-2.39) after adjusting for MetS and other covariates, compared with the lowest WBC quartile (< 5,100 cells/µL). In subjects with MetS, the prevalence risk for CKD stage 3 or more in the highest WBC quartile was 2.25 (1.28-3.95) even after fully adjusting for confounding variables. In contrast, this positive association between WBC quartile and CKD stage 3 or more disappeared in subjects without MetS. Low-grade inflammation is significantly associated with CKD stage 3 or more in subjects with MetS but not in those without MetS.

The association between the triglyceride to high-density lipoprotein cholesterol ratio with insulin resistance (HOMA-IR) in the general Korean population: based on the National Health and Nutrition Examination Survey in 2007-2009.

AIMS: This study explores the association between the ratio of triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) and insulin resistance according to waist circumference in the general Korean population. METHODS: 7623 participants were selected from the Korean National Health and Nutrition Examination Survey (KNHANES) conducted during 2007-2009 and included in this cross-sectional study. Insulin resistance was defined as the values equal to or greater than the 75th percentile of the homeostasis model assessment of insulin resistance (HOMA-IR). RESULTS: Positive correlation was found between the ratio of TG and HDL-C and other variables such as waist circumference, total cholesterol, and HOMA-IR for both men and women. The odds ratios (ORs) (95% confidence interval) for insulin resistance for the highest quartile of TG/HDL-C were 2.48 in men and 3.05 in women. The significant relationship between the TG/HDL-C ratio and insulin resistance was not only maintained across all quartiles of waist circumference but also seemed to be enhanced in the higher quartiles of waist circumference. CONCLUSION: In the general Korean population, there seems to be a linear association between TG/HDL-C ratio and insulin resistance, regardless of degrees of waist circumference.

High prevalence of vitamin D insufficiency or deficiency in young adolescents in Korea.

Recent studies suggest that vitamin D insufficiency or deficiency is not only a problem of older generations anymore but also an important health concern among younger generations. However, comprehensive data are lacking in Korean adolescents. We investigated the vitamin D (25-hydroxy vitamin D [25(OH)D]) status, the prevalence of vitamin D insufficiency or deficiency, and the association between vitamin D levels and insulin resistance and lipid profiles in a sample of 188 Korean adolescents aged 12-13 years who participated in a general health check-up at a tertiary hospital. Vitamin D deficiency was considered as serum concentrations <20 ng/mL (50 nmol/L); a level of 21-29 ng/mL (52-72 nmol/L) was considered to indicate vitamin D insufficiency, whereas a level of 30 ng/mL or greater (>75 nmol/L) was considered sufficient or optimum. In this cross-sectional study, vitamin D insufficiency or deficiency was found in 98.9 % of boys and 100 % of girls, whereas only 1.1 % of boys and 0 % of girls had a serum 25(OH)D level of greater than 30 ng/mL. In multivariate linear regression analysis, HOMA-IR, triglyceride, and LDL cholesterol were inversely associated with 25(OH)D concentrations. We found that vitamin D insufficiency or deficiency is a very common health problem in Korean adolescents, particularly in girls, and that serum 25(OH)D levels are inversely associated with insulin resistance and lipid profiles. These results suggest that more time spent in outdoor activity for sunlight exposure and higher vitamin D intake may be needed in younger adolescents in South Korea.