Yeong Sook Yoon

Effects of exercise-induced weight loss on acylated and unacylated ghrelin in overweight children

Objective  Controversial data on ghrelin concentration during exercise in human subjects have been published. We tested the hypothesis that exercise could affect acylated ghrelin (AG) and unacylated ghrelin (UAG), which could partly explain the previously reported inconsistent findings on the association of exercise with changes in ghrelin.

Adipokines, insulin resistance, metabolic syndrome, and breast cancer recurrence: a cohort study.

IntroductionSeveral in vitro studies have suggested the effects of adipokines and insulin resistance on breast cancer cell proliferation and survival. However, little is known about the clinical significance of these findings.MethodsWe examined associations between breast cancer recurrence and adiponectin, leptin, insulin resistance, and metabolic syndrome (MetS) in a cohort of 747 patients from 2001 to 2004.ResultsAdjusted hazard ratios showed an inverse trend across the quartiles for serum adiponectin concentration in estrogen receptor (ER)/progesterone receptor (PR) -negative patients (P for trend = 0.027) but not in ER/PR-positive patients. Compared to the highest quartile for adiponectin level, the lowest quartile showed a hazard ratio of 2.82 (1.03 to 7.68). Homeostasis model assessment for insulin resistance (HOMA-IR) showed a positive trend for recurrence in the ER/PR-negative group (P for trend = 0.087) and a negative trend in the ER/PR-positive group (P for trend = 0.081). Leptin did not show any associations (P for trend >0.05). A linear trend was observed with the number of components of MetS in ER/PR-negative patients (P for trend = 0.044). This association disappeared when adjusted for adiponectin and HOMA-IR.ConclusionsAdiponectin and HOMA-IR have prognostic significance in breast cancer recurrence and interventions related to these factors may protect against recurrence in ER/PR-negative patients. These findings were not observed in the case of ER/PR-positive patients. Further evaluation of these insignificant associations is needed because it might be biased by adjuvant chemotherapy or other confounders.

Cigarette Smoking Increases Abdominal and Visceral Obesity but Not Overall Fatness: An Observational Study

Background Cigarette smoking and obesity are leading public health concerns. Both increase the risk for cardiovascular disease, cancer, and metabolic abnormalities. This study was conducted to assess the association between cigarette smoking and different types of obesity. Methodology/Principal Findings Two hundred eighty-three visitors to university hospitals located in four main provinces of South Korea were participated. All participants were classified as either current/past or never smokers and were divided into quartiles according to the total pack-years. Body mass index, waist circumference, total body fat percentage, and area of visceral and abdominal subcutaneous fat were measured. These results of each groups were compared. Waist circumference, and visceral fat area showed a J- or U-shaped association with total smoking amount during a lifetime. After restricting the analyses to past/current smokers, we found significant dose-dependent associations of smoking pack-years with abdominal and visceral obesity. Overall obesity measured by body mass index and total body fat percentage did not show such associations. Although current smokers clearly showed significant associations, we could not demonstrate these in past smokers, possibly because of the limited sample size. Conclusions/Significance Although smokers did not show significant difference in mean body mass index than those who never smoked, they showed more metabolically adverse fat distributions with increasing smoking amounts. This finding suggests that smoking is not beneficial for weight control. Therefore, smoking cessation and avoidance of smoking commencement should be addressed as important public health issues in preventing obesity and related complications.

Dairy Product Intake Is Inversely Associated with Metabolic Syndrome in Korean Adults: Anseong and Ansan Cohort of the Korean Genome and Epidemiology Study

The objective of this study was to examine the relationship between dairy product intake and the incidence of metabolic syndrome (MetS) and its components among middle-aged Koreans. We examined 7,240 adults aged 40-69 yr without MetS at baseline over a 45.5-month follow-up period. They were taken from the Anseong and Ansan cohort of the Korean Genome and Epidemiology Study. Dairy product intake including milk, yogurt, and cheese was assessed with food frequency questionnaire. At the follow-up, the incidence of MetS was 17.1%. The incidences of MetS components were as follows: low HDL cholesterol (16.2%), abdominal obesity (14.0%), hypertriglyceridemia (13.8%), hyperglycemia (13.3%), and hypertension (13.1%). Adjusting for potential confounders, dairy product consumption frequency was inversely associated with the risk of MetS and abdominal obesity. Hazard ratio (HR) (95% confidence interval) for dairy product consumption more than 7 times/week compared to never was 0.75 (0.64-0.88, P for trend < 0.001) for MetS and 0.73 (0.61-0.88, P for trend < 0.001) for abdominal obesity. HR for milk intake was 0.79 for MetS and 0.82 for abdominal obesity. The results of this study suggest that daily intake of dairy products protects against the development of MetS, particularly abdominal obesity, in middle-aged Koreans.

Eradication of Helicobacter pylori Increases Ghrelin mRNA Expression in the Gastric Mucosa

It has been suggested that Helicobacter pylori eradication may influence production of some peptides in the stomach, which can affect appetite. This hypothesis is controversial. To verify the hypothesis, we conducted this randomized controlled trial using H. pylori infected subjects without any gastrointestinal symptoms. The treatment group received triple H. pylori eradication therapy for 7 days and the control group received no medication. We measured ghrelin, obestatin and the tumor necrosis factor-α (TNF-α) mRNA levels in endoscopic biopsy specimens and the changes from baseline to follow-up. The plasma active n-octanoyl ghrelin and obestatin levels were measured in both groups. The ghrelin/obestatin ratios in plasma and gastric mRNA expression were calculated at baseline and follow-up. Ghrelin mRNA expression in the fundic mucosa after H. pylori eradication increased significantly compared to the control group (4.47±2.14 vs. 1.79±0.96, P=0.009), independent of inflammatory changes. However, obestatin mRNA expression decreased in the antral mucosa (-0.57±1.06 vs. 0.41±0.72, P=0.028). The treatment group showed a marginal increase (P=0.060) in plasma ghrelin/obestatin ratio. The TNF-α mRNA expression also decreased significantly with treatment. This randomized controlled trial demonstrates that H. pylori eradication increases ghrelin mRNA expression, independent of inflammatory cell changes.

Obesity and metabolic syndrome–related chronic kidney disease in nondiabetic, nonhypertensive adults

Metabolic syndrome (MS) is associated with chronic kidney disease (CKD). The objective of this study is to examine the association between obesity and MS-related CKD in nondiabetic, nonhypertensive Korean adults. Korea National Health and Nutrition Examination Survey III data from 3771 nondiabetic, nonhypertensive Koreans were analyzed. Metabolic syndrome was defined according to the National Cholesterol Education Program-Adult Treatment Panel III, and CKD was diagnosed at an estimated glomerular filtration rate less than 60 mL/(min 1.73 m(2)). The crude and multivariate-adjusted odds ratios (ORs) of CKD associated with MS and its individual components were calculated using logistic regression models in a study population stratified by obesity. The prevalence of MS and CKD was 13.4% and 3.2%, respectively. The association between MS and CKD was significant in obese (OR, 2.91; 95% confidence interval [CI] = 1.34-6.34), but not nonobese (OR, 1.38; 95% CI = 0.60-3.17), subjects. In obese subjects, impaired fasting glucose (OR, 2.47; 95% CI = 1.10-5.57) and high triglyceride levels (OR, 2.42; 95% CI = 1.01-5.83) were risk factors for CKD, whereas no components were significantly associated with CKD in nonobese subjects. Our findings suggest that even in nondiabetic, nonhypertensive Korean adults, early detection and prevention of CKD in obese subjects with MS are critical.

Measurement of antioxidant capacity using the biological antioxidant potential test and its role as a predictive marker of metabolic syndrome

Background/Aims Oxidative stress increases the risk of cardiovascular complications of metabolic syndrome (MetS). This study was conducted to examine the difference in antioxidant capacity according to the presence of MetS, and to characterize the association between antioxidant capacity and MetS-related factors. Methods We used the biological antioxidant potential (BAP) test to estimate antioxidant capacity. The BAP test has recently been used as an indicator of antioxidant capacity. We measured BAP levels in 45 patients with MetS (mean age, 44.6 ± 1.1 years) and 47 age- and sex-matched controls (mean age, 42.7 ± 1.1 years). To evaluate the association between antioxidant capacity and MetS, adiponectin, high-sensitivity C-reactive protein (hs-CRP), interleukin-6, tumor necrosis factor-α, and homeostatic model assessment for insulin resistance (HOMA-IR), linear regression and logistic analyses were performed. Results The mean BAP of the MetS group (1,937.3 ± 36.5 µmol/L) was significantly lower than that of the non-MetS group (2,101.7 ± 29.5 µmol/L). Also, the mean BAP was low in persons having low high density lipoprotein and high triglyceride. Reduced antioxidant capacity was significantly associated with adiponectin, HOMA-IR and hs-CRP after adjusting for age and sex. The odds ratios for MetS with BAP, log adiponectin, log HOMA-IR, and log hs-CRP were 0.63 (95% confidence interval [CI], 0.49 to 0.82), 0.22 (0.10 to 0.51), 14.24 (4.35 to 46.58), and 1.93 (1.36 to 2.75), respectively. Conclusions Persons with MetS showed reduced antioxidant capacity. We identified relationships between antioxidant capacity measured by BAP test and MetS, as well as MetS-related factors, such as insulin resistance, hs-CRP, and adiponectin.

Differences in the associations of anthropometric measures with insulin resistance and type 2 diabetes mellitus between Korean and US populations: Comparisons of representative nationwide sample data

BACKGROUNDS Variation among ethnic groups in the association between obesity and insulin resistance (IR)/diabetes has been suggested, but studies reported inconsistent results. We evaluated ethnic differences in the association between obesity and insulin resistance (IR)/diabetes. METHODS We conducted a cross-sectional analysis using Korea (n=18,845) and the USA (n=4657) National Health and Nutrition Examination Survey(NHANES) 2007-2010. We performed statistical comparisons of AUC-ROC (area under the curve in a receiver operating characteristic curve) values for body mass index (BMI), waist circumference (WC) and homeostasis model assessment of insulin resistance (HOMA-IR) to predict IR or diabetes among different ethnic groups. RESULTS AUC-ROC values for BMI and WC for predicting IR were highest in Whites (0.8324 and 0.8468) and lowest in Koreans (0.7422 and 0.7367). Whites showed the highest AUC-ROC values for BMI (0.6869) and WC (0.7421) for predicting diabetes, while the AUC-ROC for HOMA-IR was highest in Koreans (0.8861). Linear regression showed significant interactions between ethnicity and the main effects (all P<0.0001). Increases in BMI were associated with a larger increase in HOMA-IR in Whites (β=0.0719) and WC in Hispanics (β=0.0324), while BMI was associated with a larger increase in fasting glucose in Koreans (β=0.8279) and WC in Blacks (β=0.4037). In addition, the slope for fasting glucose with increasing HOMA-IR was steeper in Koreans (β=16.5952, P<0.001) than in other groups. CONCLUSION The ability of BMI and WC to predict IR and diabetes was highest in Whites, while the ability of HOMA-IR to predict diabetes was highest in Koreans.

Recent Shift of Body Mass Index Distribution in Korea: a Population-based Korea National Health Insurance Database, 2002–2013

We investigated trends of obesity prevalence among adult Koreans. Data from 110,280,952 participants who underwent medical examination provided by the National Health Insurance System from 2002–2013 were analyzed. The prevalence of moderate obesity (body mass index [BMI] 25.0–29.9 kg/m2) was slightly increased from 2002 (30.7%) through 2010 (33.1%) and reached a plateau since 2010 among men but continuously decreased from 22.5% in 2002 to 20.9% in 2013 among women. However, severe obesity (BMI ≥ 30.0 kg/m2) was rapidly increased and the prevalence in 2013 (4.2%) was almost doubled the prevalence in 2002 (2.5%). We observed a steep rise of severe obesity as well as potentially right shifting of the obese category.

Eating alone and metabolic syndrome: A population-based Korean National Health and Nutrition Examination Survey 2013–2014

Eating alone has been an emerging social concern in modern life. However, there is little research on the association between eating alone and Metabolic syndrome (MetS). We aimed to assess the association between eating alone and the MetS and to identify whether sociodemographic factors modify this association. This study included 7725 adults (≥19 years) who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) 2013-2014. Multivariable logistic regression analysis was used for assessing the association of eating alone (none, 1 time/day, and ≥2 times/day) with MetS. The percentages of subjects with MetS were 30.4% in men and 24.2% in women. 20.8% of men and 29.2% of women ate alone ≥2 times/day. Individuals who ate alone 2 or more times per day showed higher frequency of living alone, having no spouse, skip meals, and less eating out (p<0.05). Women with eating alone ≥2 times/day had a crude OR of 1.29 (95% CI:1.08-1.53, p-trend=0.001) for MetS compared with women without eating alone. However, this association was no longer significant after adjustments for confounding factors. Eating alone ≥2 times/day was significantly associated with increase abdominal obesity (OR, 95% CI:1.45, 1.10-1.91, p-trend=0.039) and MetS (1.64, 1.28-2.10, p-trend=0.004) in men. Eating alone was associated with a higher likelihood of having a MetS in men without spouse as compared with those with spouse (OR for men without spouse 3.02, 95% CI:1.50-6.11 and OR for men with spouse 1.48, 95% CI:1.22-1.7, p-interaction=0.027). Our results indicate that eating alone may be a potential risk factor for MetS.