Hee Taik Kang

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.

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.

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

BACKGROUNDnChronic kidney disease (CKD) is associated with a poor quality of life and cardiovascular events and is a great threat to public health.nnnMETHODSnWe 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.nnnRESULTSnThe 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.nnnCONCLUSIONSnThe prevalence of CKD in Korean adults has decreased since 2001 in men and since 2005 in women.

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.

Elevated intraocular pressure is associated with metabolic syndrome in postmenopausal women: the Korean National Health and Nutrition Examination Survey.

ObjectiveThis study aimed to investigate the association between intraocular pressure and metabolic syndrome according to menopause status in nonglaucomatous Korean women. MethodsWe examined the relationship between intraocular pressure and metabolic syndrome in 4,524 nonglaucomatous Korean women (2,866 premenopausal women and 1,658 postmenopausal women) who participated in the 2008 Korean National Health and Nutrition Examination Survey. Multivariate linear regression analysis was used to assess the relationship between metabolic syndrome and intraocular pressure after adjusting for age, body mass index, smoking status, alcohol consumption, regular exercise, hypertension medication, and diabetes medication according to menopause status in women. ResultsThe prevalence of metabolic syndrome was 5.4% for premenopausal women and 28.0% for postmenopausal women. The mean intraocular pressure gradually increased in accordance with the increasing number of components for metabolic syndrome in postmenopausal women (P = 0.002), but not in premenopausal women (P = 0.387). In multivariate regression analysis, intraocular pressure was significantly associated with metabolic syndrome in postmenopausal women (P = 0.015) after adjusting for confounding variables, but not in premenopausal women (P = 0.940). ConclusionsIntraocular pressure was associated with metabolic syndrome in postmenopausal women, but not in premenopausal women. These findings suggest that intraocular pressure changes may be linked to metabolic syndrome in postmenopausal women.

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

Abstract 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.

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-Q4, 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.

Employment is associated with a lower prevalence of metabolic syndrome in postmenopausal women based on the 2007-2009 Korean National Health Examination and Nutrition Survey.

ObjectiveThis study aims to investigate the association between employment status and metabolic syndrome (MetS) in adult Korean women after stratification by menopause status. MethodsWe examined the relationship between employment status and the prevalence of MetS in 5,256 Korean women (3,141 premenopausal women and 2,115 postmenopausal women) who participated in the 2007-2009 Korean National Health Examination and Nutrition Survey. Employment status was classified as unemployed, employed part time, and employed full time based on a self-reported questionnaire. A modified Asian criterion based on a harmonized definition of MetS was adopted. Sampling weights were used to take the complex sampling method into account. ResultsThe prevalences of MetS in the unemployed group, part-time employment group, and full-time employment group were 14.5%, 11.8%, and 12.7% in premenopausal women and 54.9%, 44.0%, and 41.8% in postmenopausal women, respectively. Compared with the unemployed group, the odds ratios (95% CIs) for MetS in the part-time and full-time employment groups were 0.79 (0.52-1.22) and 0.80 (0.56-1.16) in premenopausal women and 0.67 (0.46-0.97) and 0.66 (0.51-0.84) in postmenopausal women, respectively, after adjusting for covariates such as age, inflammatory marker, socioeconomic status, and lifestyle factors. ConclusionsEmployment seems to be significantly related to a lower prevalence of MetS in postmenopausal women, but not in premenopausal women. However, there may not have been adequate statistical power to detect relations in premenopausal women. Further research is warranted to clarify the menopause-specific relationship between employment status and MetS risk.

Association between serum total bilirubin level and leukoaraiosis in Korean adults

OBJECTIVESnLeukoaraiosis is associated with cerebrovascular microangiopathy. Increasing evidence suggests that bilirubin is a potent cytoprotectant in the development of cardiovascular diseases. This study aimed to determine whether total bilirubin is related to leukoaraiosis.nnnMETHODSnWe examined the relationship of total bilirubin with leukoaraiosis in 1005 Korean adults. The odds ratios for leukoaraiosis were calculated using multivariate logistic regression across serum total bilirubin tertiles.nnnRESULTSnIn comparison with the subjects in the reference group (total bilirubin: 15-26 μmol/L), the odds ratio (95% CI) for leukoaraiosis in the 3rd tertile (total bilirubin ≤10 μmol/L) was 5.50 (1.24-24.40) in women after adjusting for confounding variables. However, this inverse association between serum total bilirubin and the prevalence of leukoaraiosis was not found in men after adjusting for the same co-variables.nnnCONCLUSIONnTotal bilirubin level was inversely associated with leukoaraiosis regardless of classical cardiovascular risk factors in Korean women.

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

BACKGROUNDnMercury 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.nnnMETHODSnA 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.nnnRESULTSnThe 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.nnnCONCLUSIONnWe found a positive relationship between blood mercury concentration and serum GGT level in a representative population sample of Korean adults.