Elevated levels of urine isocitrate, hydroxymethylglutarate, and formiminoglutamate are associated with arterial stiffness in Korean adults.

Recent evidence suggests that cellular perturbations play an important role in the pathogenesis of cardiovascular diseases. Therefore, we analyzed the association between the levels of urinary metabolites and arterial stiffness. Our cross-sectional study included 330 Korean men and women. The brachial-ankle pulse wave velocity was measured as a marker of arterial stiffness. Urinary metabolites were evaluated using a high-performance liquid chromatograph-mass spectrometer. The brachial-ankle pulse wave velocity was found to be positively correlated with L-lactate, citrate, isocitrate, succinate, malate, hydroxymethylglutarate, α-ketoisovalerate, α-keto-ß-methylvalerate, methylmalonate, and formiminoglutamate among men. Whereas, among women, the brachial-ankle pulse wave velocity was positively correlated with cis-aconitate, isocitrate, hydroxymethylglutarate, and formiminoglutamate. In the multivariable regression models adjusted for conventional cardiovascular risk factors, three metabolite concentrations (urine isocitrate, hydroxymethylglutarate, and formiminoglutamate) were independently and positively associated with brachial-ankle pulse wave velocity. Increased urine isocitrate, hydroxymethylglutarate, and formiminoglutamate concentrations were associated with brachial-ankle pulse wave velocity and independent of conventional cardiovascular risk factors. Our findings suggest that metabolic disturbances in cells may be related to arterial stiffness.

Association of serum 25-hydroxyvitamin D and serum total cholesterol with depressive symptoms in Korean adults: the Fifth Korean National Health and Nutrition Examination Survey (KNHANES V, 2010-2012).

OBJECTIVE: To examine the hypothesis that the association between vitamin D deficiency and depressive symptoms is dependent upon total cholesterol level in a representative national sample of the South Korean population. DESIGN: This was a population-based cross-sectional study. SETTING: The Fifth Korean National Health and Nutrition Examination Survey (KNHANES V, 2010-2012). SUBJECTS: We included 7198 adults aged 20-88 years. RESULTS: The incidence of depressive symptoms in individuals with vitamin D deficiency (serum 25-hydroxyvitamin D<20 ng/ml) was 1·54-fold (95 % CI 1·20, 1·98) greater than in individuals without vitamin D deficiency (serum 25-hydroxyvitamin D ≥20 ng/ml). The relationship was stronger in individuals with normal-to-borderline serum total cholesterol (serum total cholesterol<240 mg/dl; OR=1·60; 95 % CI 1·23, 2·08) and non-significant in individuals with high serum total cholesterol (OR=0·97; 95 % CI 0·52, 1·81) after adjustment for confounding variables (age, sex, BMI, alcohol consumption, smoking status, regular exercise, income level, education level, marital status, changes in body weight, perceived body shape, season of examination date and cholesterol profiles). CONCLUSIONS: The association between vitamin D deficiency and depressive symptoms was weakened by high serum total cholesterol status. These findings suggest that both vitamin D and total cholesterol are important targets for the prevention and treatment of depression.

A cross-sectional study of the association between adipokine levels and bone mineral density according to obesity and menopausal status in Korean women.

Results regarding the association between adipokine levels and bone mineral density (BMD) have been inconsistent; the effects of sex, menopause, and central obesity remain unknown. We evaluated the association between serum leptin, adiponectin, and high-molecular-weight (HMW) adiponectin levels and BMD according to menopause and central obesity status in Korean women. This cross-sectional study comprised 255 women undergoing examinations at the CHA Bundang Medical Center. Participants were divided according to menopause, and central obesity status. We measured serum adipokine levels and BMD using an enzyme-linked immunosorbent assay and dual-energy X-ray absorptiometry, respectively. After adjusting for age, body mass index, alkaline phosphatase levels and the Homeostasis Model Assessment index, leptin levels were negatively associated with non-vertebral BMD (total hip, ß = -0.576, P = 0.006; femoral neck, ß = -0.608, P = 0.007) in postmenopausal women without central obesity. Among women without central obesity, HMW adiponectin levels were positively associated with total hip BMD (ß = 0.240, P = 0.010) in premenopausal women but negatively associated with BMD (lumbar, ß = -0.436, P = 0.012; femoral neck, ß = -0.468, P = 0.007) in postmenopausal women. Thus, the association between adipokine levels and BMD varies according to the menopause and central obesity status.

The association of testosterone, sex hormone-binding globulin, and insulin-like growth factor-1 with bone parameters in Korean men aged 50 years or older.

Testosterone and insulin-like growth factor-1 (IGF-1) are essential factors for the maintenance of bone health in men. However, the results for the association of testosterone and IGF-1 with bone parameters were not consistent in prior studies. We evaluated the relationship of testosterone, sex hormone-binding globulin (SHBG), and IGF-1 with bone mineral density (BMD) and bone turnover markers (BTMs) in Korean men. We enrolled 1227 men aged ≥50 years in this cross-sectional study. Serum levels of total testosterone (TT), SHBG, IGF-1, osteocalcin, and C-terminal cross-linking telopeptide of type I collagen (CTX) were measured. Free testosterone (FT) was calculated using Vermeulen's method. BMD was measured by dual-energy X-ray absorptiometry. TT level was not related to BMD or BTMs in the unadjusted model; however, after adjusting for SHBG and IGF-1, the association between TT and BTMs was significant (ß = -0.139 for osteocalcin and ß = -0.204 for CTX). SHBG levels were negatively associated with lumbar BMD, and positively associated with BTMs in all models. As SHBG level increased, the prevalence of osteopenia or osteoporosis defined by BMD significantly increased (OR of 1SD change, 1.24). IGF-1 levels were significantly related with BMD, but not with BTMs. Meanwhile, FT levels were positively associated with BMD and negatively associated with BTMs. In conclusion, SHBG levels were independently related with bone parameters and osteopenia in men aged ≥50 years. IGF-1 levels were positively associated with BMD, but not with BTMs. SHBG may play a role in regulating age-related bone loss in men after middle-age.

Intermuscular adipose tissue is associated with monocyte chemoattractant protein-1, independent of visceral adipose tissue.

OBJECTIVES: Emerging evidence suggests that intermuscular adipose tissue is a risk factor for insulin resistance, but the underlying mechanism still remains unclear. We investigated whether the levels of leptin, adiponectin, and monocyte chemoattractant protein-1 are associated with intermuscular adipose tissue in obese subjects. DESIGN AND METHODS: A cross-sectional study was performed on 77 obese Korean women. Areas of visceral adipose tissue, subcutaneous adipose tissue, and intermuscular adipose tissue were measured by computed tomography scan, and serum concentrations of adipokines were measured by enzyme-linked immunosorbent assays. Correlation between the levels of adipokines and the fat areas was assessed using Pearson correlation and covariate-adjusted multivariable regression. RESULTS: Leptin was positively correlated with subcutaneous adipose tissue (r=0.452, P<0.001), fasting insulin (r=0.403, P<0.001), and homeostasis model assessment of insulin resistance (r=0.360, P=0.001), whereas monocyte chemoattractant protein-1 was positively correlated with intermuscular adipose tissue (r=0.483, P<0.001). After adjustment for age, height, and other body composition metrics, leptin was still related to subcutaneous adipose tissue (ß=0.390, P=0.001). Monocyte chemoattractant protein-1 was associated with intermuscular adipose tissue (ß=0.433, P=0.001) after adjustment for visceral adipose tissue. CONCLUSIONS: Intermuscular adipose tissue was correlated with monocyte chemoattractant protein-1, suggesting its role in the development of insulin resistance.

Prediction of prevalent but not incident non-alcoholic fatty liver disease by levels of serum testosterone.

BACKGROUND AND AIMS: The association between testosterone level and development of non-alcoholic fatty liver disease (NAFLD) is not well known. We examined the relationship of total testosterone level with development and regression of NAFLD. METHODS: Among the men who had undergone repeated liver ultrasonography in 2 years or more at a health promotion center, subjects with available serum testosterone level at baseline were included in the study. Alcohol consumers (> 20 g/day) were excluded from the study. RESULTS: Among the 1944 men, 44.3% of subjects were diagnosed with NAFLD. Higher level of testosterone significantly lowered the prevalence of fatty liver (odds ratios per SD increase, 0.686 and 0.795 at baseline and follow-up, respectively). During the median 4.2 years follow-up, 22.4% of subjects in the normal group developed fatty liver, and 21.0% of subjects in the NAFLD group recovered at the follow-up. In longitudinal analyses, higher level of testosterone was significantly associated with the development or regression of fatty liver, before adjustment for obesity and metabolic parameters. However, in the full-adjusted model, testosterone level did not influence the development or regression of fatty liver. CONCLUSIONS: Although testosterone level was significantly low in the subjects with NAFLD in cross-sectional analyses, baseline testosterone level did not independently influence the development or regression of fatty liver at the median 4.2 years follow-up. Obesity and metabolic parameters may play key roles in the link between testosterone level and NAFLD.

Decreased muscle mass is not an independent risk factor for metabolic syndrome in Korean population aged 70 or older.

CONTEXT: The association of low muscle mass with cardiometabolic risks is still controversial. OBJECTIVE: The aim of this study was to investigate the relationship between low muscle mass and metabolic syndrome (MetS) according to the various muscle mass indices and to evaluate the influence of muscle mass on MetS independent of fat mass. DESIGN: Cross-sectional study SUBJECTS: About 841 men and 1106 women aged 70 or older from Korea National Health and Nutrition Examination Survey 2008-2010 MEASUREMENTS: We used various muscle mass indices: appendicular skeletal muscle mass (ASM) divided by height squared (ASM/Ht(2) ), ASM divided by body weight (ASM/Wt) and ASM adjusted for height and fat mass (residual). Low muscle mass is defined as ASM/Ht(2) and ASM/Wt below 2 SD of the sex-specific mean for healthy young adults. The sex-specific lowest quintile of the distribution of the residual was regarded as low muscle mass. RESULTS: The prevalence of MetS was higher in the population with low muscle mass defined by ASM/Wt, but lower in those defined by ASM/Ht(2) . However, after stratification according to the central obesity, low muscle mass was barely related with MetS. Meanwhile, when both ASM and fat mass were included in a logistic regression model, the odds ratios of 1 SD change of ASM for MetS were 1·07 (0·85-1·34) for men and 1·24 (1·04-1·47) for women, respectively. CONCLUSIONS: The relationship between low muscle mass and MetS was different according to the various muscle mass indices. After controlling the influence of fat mass, decreased muscle mass was not an independent risk factor for MetS.

Serum zinc concentration is inversely associated with insulin resistance but not related with metabolic syndrome in nondiabetic Korean adults.

Although zinc was known to be associated with insulin metabolism and diabetes, the relationship of serum zinc concentration with insulin resistance (IR) and metabolic syndrome (MetS) was not well investigated in general population. The aim of this study is to evaluate the relationships of serum zinc concentration with IR and MetS in a nondiabetic adult population. This cross-sectional study included 656 men and 825 women who were nondiabetic adults from the fifth Korea National Health and Nutrition Examination Survey conducted in 2010. Serum zinc concentration and metabolic parameters were measured. IR was estimated by homeostatic model assessment (HOMA2). MetS was defined according to the National Cholesterol Education Program Adult Treatment Panel III criteria. Serum zinc concentration was negatively correlated with homeostasis model assessment for insulin resistance (HOMA2-IR) in men (r = -0.104, P = 0.008), but not in women. After adjusting for conventional cardiovascular risk factors, the inverse correlation was significant in both men and women (B = -0.262, SE = 0.060 for men, and B = -0.129, SE = 0.052 for women). However, serum zinc concentration was not different between the groups with and without MetS (P = 0.752 for men and P = 0.371 for women). In conclusion, serum zinc concentration was inversely associated with IR but not related to MetS in nondiabetic adult population.