Yang Hyun Kim

Estimate of a predictive cut-off value for serum 25-hydroxyvitamin D reflecting abdominal obesity in Korean adolescents ☆

Vitamin D deficiency is a serious global issue. Although the serum 25-hydroxyvitamin D [25(OH)D] test is generally the most accurate way to assess vitamin D levels, the optimal range of 25(OH)D has yet to be established. Moreover, the optimal level may vary according to race, region, and age. Suboptimal vitamin D status is associated with obesity and metabolic syndrome, which are the major risk factors for cardiovascular disorders; however, these relationships in children and adolescents have yet to be clearly determined. Therefore, we identified the best predictive cut-off value for reflecting abdominal obesity and, based on this value, we investigated the relationship between suboptimal 25(OH)D status and the risk for having abdominal obesity, being overweight or obese, and having metabolic syndrome in Korean adolescents. We performed a cross-sectional analysis of 713 Korean adolescents, between 12-19 years of age, and used data collected from the 2008 Korea National Health and Nutrition Examination Survey (KNHANES). Receiver operation characteristic curve analysis was used to identify the cut-off value that reflected abdominal obesity. The cut-off value of serum 25(OH)D that reflected abdominal obesity in Korean adolescents was 17.6 ng/mL. After making adjustments for gender, age, and regular physical exercise, the group that had lower levels of serum 25(OH)D compared to the cut-off value had a significantly higher risk for abdominal obesity, obesity, and metabolic syndrome than the group with 25(OH)D levels higher than the cut-off value. Suboptimal vitamin D status based on this value is associated with increased risk for abdominal obesity, obesity, and metabolic syndrome among Korean adolescents.

Socioeconomic status and dyslipidemia in Korean adults: The 2008-2010 Korea National Health and Nutrition Examination Survey

OBJECTIVE This study investigated the relationship between socioeconomic status (SES) and dyslipidemia and various parameters of dyslipidemia among Korean adults. METHODS Data from the 2008-2010 Korea National Health and Nutrition Examination Survey were used in this study. A total of 19,041 Korean adults greater than 19years old participated in the study. The SES was assessed by monthly household income and education level. The relationship of SES to the risk of dyslipidemia was assessed with multivariate logistic regression analysis after adjusting for potential confounders. RESULTS The prevalence of dyslipidemia was 37.4% among Korean adults. In men, household income level was positively associated with prevalence and risks of several parameters of dyslipidemia, and education level had positive associations with the risks of dyslipidemia and parameters of dyslipidemia. However, low SES was linked to increased prevalence and risks of dyslipidemia (P for trend<0.05) and parameters of dyslipidemia in women. CONCLUSIONS Socioeconomic disparities in dyslipidemia were found in the Korean population. Also, there were gender differences in the relationship between SES and dyslipidemia. These disparities should be considered when performing risk calculations and screening for dyslipidemia, which will ultimately help prevent cardiovascular disease.

Oral health behaviors and metabolic syndrome: the 2008–2010 Korean National Health and Nutrition Examination Survey

ObjectivesThis study examined whether oral health behaviors are associated with metabolic syndrome (MetS) in Korean adults involved in the 2008–2010 Korea National Health and Nutrition Examination Survey (KNHANES).Materials and methodsA total of 18,742 subjects (8,034 men and 10,708 women) were included. MetS was defined according to the criteria of the American Heart Association/National Heart, Lung, and Blood Institute Scientific Statement for Asians. Oral health behavior was assessed using a questionnaire included in the KNHANES.ResultsSubjects with MetS brushed their teeth less frequently and used fewer secondary oral products than subjects without MetS (p < 0.01). As frequency of toothbrushing and number of secondary oral products increased, body mass index, waist circumference, diastolic blood pressure, fasting plasma glucose, triglyceride, and white blood cell count decreased, but high-density lipoprotein–cholesterol increased (all p for trend <0.01). In the multivariable logistic regression models, as frequency of toothbrushing increased, the odds ratios (ORs) for MetS, abdominal obesity, and hyperglycemia are more than one after adjusting for age, gender, education, income, alcohol and tobacco use, physical activity, and the components of MetS. The ORs for MetS, abdominal obesity, and high blood pressure were more than one in subjects who do not use dental floss after adjusting for all covariates.ConclusionMetS is associated with infrequent daily toothbrushing and disuse of dental floss in South Korean.Clinical relevanceDentists may recommend evaluation for MetS in the patients with infrequent daily toothbrushing and disuse of dental floss.

Relationship Between Intraocular Pressure and Parameters of Obesity in Korean Adults: The 2008-2010 Korea National Health and Nutrition Examination Survey.

Abstract Purpose: To examine the associations of various parameters of obesity including adiposity with intraocular pressure (IOP) using nationally representative data of South Korean adults. Material and methods: This cross-sectional study analyzed the data from the 2008–2010 Korea National Health and Nutrition Examination Survey. A total of 15,271 subjects (6600 men and 8671 women) participated. Body mass index (BMI), waist circumference (WC), total body fat mass, and total and regional body fat percentage were measured as parameters of obesity. Results: IOP showed positive linear associations with BMI, WC, total fat mass, and total and regional body fat percentages in men, and with BMI, WC, total fat mass, and trunk fat percentage in women after adjusting for confounding variables. Men with higher BMI, WC, total fat mass, and total and regional body fat percentages exhibited increasing trends in odd ratios for having IOP ≥ 18 mmHg after adjusting for all confounding factors (p for trend <0.001 for BMI and total fat mass; p for trend = 0.038 for WC; 0.003 for total body fat percentage; 0.002 for trunk fat percentage; 0.004 for leg fat percentage). However, only BMI showed a significantly increasing trend in the risk of IOP ≥18 mmHg in women. Conclusions: In addition to BMI, WC and total fat mass, total and regional body fat percentage in men and trunk fat percentage in women are positively associated with IOP. Increased BMI, WC, and total and regional body fat are positively associated with a risk of higher IOP (IOP ≥18 mmHg), especially in Korean men.

Tooth loss and bone mineral density in postmenopausal South Korean women: The 2008–2010 Korea National Health and Nutrition Examination Survey

PURPOSE The current study aimed to investigate the association between the number of remaining teeth and bone mineral density (BMD) using data from the Korean National Health and Nutrition Examination Survey (KNHANES) 2008-2010. METHODS This study enrolled 7315 Korean subjects (3364 men over 50 years of age and 3951 postmenopausal women). BMD was measured using dual-energy X-ray absorptiometry at three sites: the total femur (TF), femur neck (FN), and lumbar spine (LS). The number of teeth present was categorized into four groups (≤10, 11-20, 21-25, and ≥26 teeth). RESULTS More remaining teeth were significantly associated with a higher BMD at the TF, FN, and LS in postmenopausal women after adjusting for all the covariates, but not in elderly men. In both sexes, subjects with a normal BMD tended to have more remaining teeth than those who were diagnosed with osteopenia and osteoporosis. A lower prevalence of osteoporosis was also significantly associated with more remaining teeth (number of teeth ≥26) in postmenopausal women. This trend was statistically significant in osteoporosis at the FN (p for trend=0.019). CONCLUSION The number of remaining teeth was associated with osteoporosis, especially at the FN, in postmenopausal women.

Normal range albuminuria and metabolic syndrome in South Korea: The 2011-2012 Korean National Health and Nutrition Examination Survey

Background It is well-known that there is a close relationship between metabolic syndrome (MetS) and microalbuminuria. However, some recent studies have found that even normal range albuminuria was associated with MetS and cardiometabolic risk factors. The purpose of this study is to analyze the relationship between MetS and normal range albuminuria and to calculate the cutoff value for albuminuria that correlates with MetS in the representative fraction of Korean population. Methods Data were obtained from the 2011–2012 Korea National Health and Nutrition Examination Survey and included 9,650 subjects aged ≥19 years. We measured metabolic parameters: fasting blood glucose, waist circumference, blood pressure, and lipids, and albumin-to-creatinine ratio (ACR). The optimal ACR cutoff points for MetS were examined by the receiver operating characteristic curve. Multivariate logistic regression was used to obtain the prevalence of MetS and its components according to the ACR levels. Results The first cutoff value of ACR were 4.8 mg/g for subjects with ≥3 components of MetS. There was a graded association between ACR and prevalence of MetS and its components. If ACR was <4 mg/g, there was no significant increase in the prevalence of MetS or its components. From the ACR level of 4–5 mg/g, the prevalence of MetS significantly increased after adjusting for age, sex, body mass index, smoking, alcohol intake, exercise, and medications for diabetes mellitus and hypertension (odds ratio; 95% confidence intervals = 1.416; 1.041–1.926). Conclusions Albuminuria within the normal range (around 5 mg/g) was associated with prevalence of MetS in the Korean population.

Abdominal Obesity Is Associated with Albuminuria in Women: The 2011 Korea National Health and Nutrition Examination Survey

BACKGROUND The effects of obesity on the kidney, apart from diabetes or hypertension, have not drawn much attention. Moreover, only a few studies have reported the relationship between obesity status and albuminuria in Asian countries, including South Korea. Therefore, this study aimed to investigate the association between obesity status and albuminuria in Korean adults. METHODS We analyzed data from the 2011 Korea National Health and Nutrition Examination Survey. Of the 4,979 subjects included in the general-population group, 3,274 were sorted into a nondiabetic and nonhypertensive population group. Obesity status was measured by body mass index and waist circumference. Albuminuria was defined as a urine albumin-to-creatinine ratio ≥30 mg/g. RESULTS Abdominally obese women were at higher risk for albuminuria than were women without abdominal obesity both in the general population (odds ratio [OR], 95% confidence interval [CI]: 2.08 [1.04-4.16]) and in the nondiabetic and nonhypertensive population (OR [95% CI]: 6.96 [2.34-20.64]) after further adjustment for confounders. Among generally nonobese women, abdominally obese women were at higher risk for albuminuria than were women without abdominal obesity both in the general population (OR [95% CI]: 2.82 [1.51-5.29]) and in the nondiabetic and nonhypertensive population (OR [95% CI]: 5.32 [1.47-19.22]). CONCLUSION Abdominal obesity is associated with an increased risk for albuminuria in Korean women, independently of diabetes or hypertension. Screening for abdominal obesity, especially in women, may therefore provide earlier identification of individuals at risk for developing renal disease and cardiovascular disease, even those who are nondiabetic and nonhypertensive.

Tooth Loss and Metabolic Syndrome in South Korea: The 2012 Korean National Health and Nutrition Examination Survey.

AbstractTo evaluate the relationship between tooth loss and metabolic syndrome (MS) in South Korean adults.Subjects and Methods: A total of 3589 adults (1511 men and 2078 women aged over 40 years) from the 2012 Korean National Health and Nutrition Examination Survey were included and divided into 3 groups according to the number of remaining teeth (0–19, 20–27, and 28). We recorded the number of remaining teeth and measured MS components such as waist circumference, systolic and diastolic blood pressure, fasting blood glucose, serum high-density lipoprotein-cholesterol, and triglyceride concentration. We also calculated the number of subjects who met the inclusion criteria of MS in each group. Multiple logistic regression analysis was performed to estimate the prevalence of MS components according to the number of remaining teeth after adjusting for covariates.Women without MS had significantly more teeth than those with MS (24.5 ± 0.2 vs 21.0 ± 0.3). In men, the prevalence of high blood pressure and high fasting blood glucose levels were significantly different among the 3 groups (P = 0.003 and P < 0.001, respectively); however, the prevalence of MS and all MS components were significantly different in women (P < 0.001 for all comparisons). Men with 0 to 19 remaining teeth were most likely to have high blood pressure and high fasting blood glucose, while women with 0 to 19 remaining teeth had the highest prevalence of MS and each MS component. Multiple logistic regression analysis revealed that women with fewer remaining teeth had a higher prevalence of MS and MS components after adjusting for covariates.Having only a few remaining teeth was associated with MS in women in South Korea.

Association of Urinary Sodium Excretion With Insulin Resistance in Korean Adolescents: Results From the Korea National Health and Nutrition Examination Survey 2009-2010.

AbstractHigh sodium intake is a well-known risk factor for elevated blood pressure and is responsible for a higher incidence of cardiovascular events. Reports have suggested an association of sodium intake with insulin resistance (IR) and type 2 diabetes mellitus in adults. However, evidence on an association between sodium intake assessed on the basis of urinary sodium excretion and IR in adolescents is scarce. The present study aimed at investigating the association between urinary sodium excretion and IR among South Korean adolescents.This population-based, cross-sectional study analyzed the data obtained from the Korea National Health and Nutrition Examination Survey (KNHANES) 2009 to 2010. The data of a total of 1353 adolescents (779 boys and 574 girls) were included in the final analysis. Spot urine samples were collected, and urinary sodium excretion was estimated by using the urinary sodium concentration (U[Na+]), U[Na+] to urinary creatinine ratio (U[Na+]/Cr), and U[Na+] to specific gravity unit (SGU) ratio (U[Na+]/SGU). IR was assessed by using the homeostasis model assessment of IR (HOMA-IR). Hierarchical multivariable logistic regression analysis was performed to assess the risk for a high HOMA-IR according to urinary sodium excretion.The mean levels of U[Na+], U[Na+]/Cr, and U[Na+]/SGU were significantly higher in subjects in the highest HOMA-IR quartile (Q4) than in subjects in the lowest, second, or third quartiles (Q1–3) of HOMA-IR. The mean values of HOMA-IR and several cardiometabolic parameters tended to progressively increase with the U[Na+], U[Na+]/Cr, and U[Na+]/SGU quartiles. Q3 of U[Na+] was at a significantly higher risk than Q1 of U[Na+] of an association with Q4 of HOMA-IR, after adjustment for confounding variables. Q3 and Q4 of U[Na+]/Cr and U[Na+]/SGU, respectively, had significantly higher risks, than the respective Q1s, of an association with Q4 of HOMA-IR. The risk of an association with Q4 of HOMA-IR demonstrated significantly increasing trends with increasing quartiles of U[Na+], U[Na+]/Cr, and U[Na+]/SGU irrespective of confounding factors.Urinary sodium excretion was positively associated with IR in South Korean adolescents. The monitoring and control of urinary sodium excretion may be recommended as an important intervention for the prevention of IR and related diseases in adolescents.

Prevalence and control of hypertension and albuminuria in South Korea: focus on obesity and abdominal obesity in the Korean National Health and Nutrition Examination Survey, 2011-2012.

Background Albuminuria is associated with cardiovascular disease, and the relationship between albuminuria and hypertension is well established in many studies. So the control of hypertension is critical for decreasing cardiovascular events and albuminuria. Obesity and abdominal obesity are also associated with hypertension and albuminuria. Therefore, we analyzed the relationship between albuminuria and the prevalence and control of hypertension in the general Korean population according to obesity status. Methods We analyzed data from the 2011–2012 Korea National Health and Nutrition Examination Survey, and 9,519 subjects were included. Subjects were divided into four groups: non-obese/normal waist circumference, non-obese/high waist circumference, obese/normal waist circumference, and obese/high waist circumference. Results Systolic blood pressure and diastolic blood pressure were positively associated with albumin–creatinine ratio in all groups (all p values <0.005). Non-obese/normal waist circumference group were more likely to have hypertension (odds ratios [95% confidential intervals (CIs)] were 3.20 [2.21–4.63] in microalbuminuria level and 3.09 [1.05–9.14] in macroalbuminuria level), and less likely to have controlled hypertension (odds ratios <1 for both albuminuria levels) after adjusting for all covariates. Obese/normal waist circumference group were also more likely to have hypertension (odds ratio [95% CI] were 3.10 [1.56–6.15] in microalbuminuria level and 21.75 [3.66–129.04] in macroalbuminuria level), and less likely to have controlled hypertension in macroalbuminuria level (odds ratio [95% CI], 0.04 [0.01–0.15]). Conclusions Non-obese and normal waist circumference subjects have an increased prevalence and decreased control of hypertension in microalbuminuria and macroalbuminuria levels. Screening for albuminuria may provide helpful information about hypertension and blood pressure control, particularly in the non-obese and normal waist circumference subjects.