Yeon Ji Lee

Mobile Phone Use and Risk of Tumors: A Meta-Analysis

PURPOSE Case-control studies have reported inconsistent findings regarding the association between mobile phone use and tumor risk. We investigated these associations using a meta-analysis. METHODS We searched MEDLINE (PubMed), EMBASE, and the Cochrane Library in August 2008. Two evaluators independently reviewed and selected articles based on predetermined selection criteria. RESULTS Of 465 articles meeting our initial criteria, 23 case-control studies, which involved 37,916 participants (12,344 patient cases and 25,572 controls), were included in the final analyses. Compared with never or rarely having used a mobile phone, the odds ratio for overall use was 0.98 for malignant and benign tumors (95% CI, 0.89 to 1.07) in a random-effects meta-analysis of all 23 studies. However, a significant positive association (harmful effect) was observed in a random-effects meta-analysis of eight studies using blinding, whereas a significant negative association (protective effect) was observed in a fixed-effects meta-analysis of 15 studies not using blinding. Mobile phone use of 10 years or longer was associated with a risk of tumors in 13 studies reporting this association (odds ratio = 1.18; 95% CI, 1.04 to 1.34). Further, these findings were also observed in the subgroup analyses by methodologic quality of study. Blinding and methodologic quality of study were strongly associated with the research group. CONCLUSION The current study found that there is possible evidence linking mobile phone use to an increased risk of tumors from a meta-analysis of low-biased case-control studies. Prospective cohort studies providing a higher level of evidence are needed.

Green tea consumption and risk of stomach cancer: A meta‐analysis of epidemiologic studies

This meta‐analysis investigated the quantitative association between the consumption of green tea and the risk of stomach cancer in epidemiologic studies using crude data and adjusted data. We searched MEDLINE, EMBASE and the Cochrane Review in August 2007. All the articles searched were independently reviewed and selected by 3 evaluators according to predetermined criteria. A total of 13 epidemiologic studies were included. When all the case–control and cohort studies were pooled, the relative risks (RR) of stomach cancer for the highest level of green tea consumption when compared with the lowest level of consumption were shown to be 1.10 (95% confidence interval (CI), 0.92–1.32) using the crude data and 0.82 (95% CI, 0.70–0.96) using the adjusted data. In the meta‐analyses of case–control studies, no significant association was seen between green tea consumption and stomach cancer using the crude data (RR, 0.79; 95% CI, 0.58–1.07), but green tea was shown to have a preventive effect on stomach cancer using the adjusted data (RR, 0.73; 95% CI, 0.64–0.83). In the meta‐analyses of the recent cohort studies, the highest green tea consumption was shown to significantly increase stomach cancer risk using the crude data (RR, 1.59; 95% CI, 1.16–2.18), but no significant association between them was seen when using the adjusted data (RR, 1.04; 95% CI, 0.93–1.17). Unlike the case–control studies, no preventive effect on stomach cancer was seen for the highest green tea consumption in the meta‐analysis of the recent cohort studies. Further clinical trials are needed.

Association between low SIRT1 expression in visceral and subcutaneous adipose tissues and metabolic abnormalities in women with obesity and type 2 diabetes

AIMS To assess the importance of adipose tissue sirtuin 1 (SIRT1) in the regulation of whole-body metabolism in humans with obesity and type 2 diabetes. METHODS In total, 19 non-diabetic obese women, 19 type 2 diabetic women undergoing gastric bypass surgery, and 27 normal-weight women undergoing gynecological surgery (total 65 women) were enrolled. Their anthropometric variables, abdominal fat distribution and metabolic parameters, serum adiponectin concentrations, and SIRT1 mRNA and protein and adiponectin mRNA expressions in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were measured. RESULTS SIRT1 mRNA levels in VAT and SAT were similar and these levels were suppressed in obese and type 2 diabetic women compared to normal-weight subjects. These decreases in SIRT1 expression were observed in both adipocytes and non-fat cells. There was a strong association between adipose tissue SIRT1 mRNA and protein levels. Adipose SIRT1 expression correlated inversely with HOMA-IR and other insulin resistance-related parameters. Adipose SIRT1 and adiponectin mRNA expression correlated very strongly and positively. SIRT1 mRNA level in VAT correlated inversely with visceral obesity whereas its expression in SAT correlated negatively with body mass index. CONCLUSIONS Adipose tissue SIRT1 may play a key role in the regulation of whole body metabolic homeostasis in humans. Downregulation of SIRT1 in VAT may contribute to the metabolic abnormalities that are associated with visceral obesity.

IL-34 is associated with obesity, chronic inflammation, and insulin resistance.

OBJECTIVES IL-34 is a recently identified alternative ligand for colony-stimulating factor-1 (CSF-1) receptor. IL-34 and CSF-1 are regulators of differentiation, proliferation, and survival in mononuclear phagocytes. Here, we investigated the IL-34 serum concentration and expression in human adipose tissues and any associations with insulin resistance. METHODS We recruited 19 nondiabetic obese women, 9 type 2 diabetic women, and 27 normal-weight women. Metabolic parameters, abdominal fat distribution, serum IL-34 concentration, and IL-34 mRNA expression were measured in abdominal sc adipose tissue (SAT) and visceral adipose tissue (VAT). In addition, the expression/secretion and putative effects of IL-34 were assessed in human differentiated adipocytes. Serum IL-34 concentration was measured before and 5 to 9 months after laparoscopic Roux-en-Y gastric bypass surgery was performed on the 20 obese patients. RESULTS Regardless of diabetes status, obese patients demonstrated significantly higher serum IL-34 concentrations than controls. Serum IL-34 was significantly and positively correlated with insulin resistance-related metabolic parameters. IL-34 mRNA was significantly higher in VAT than SAT. IL-34 was expressed in adipocytes as well as nonadipocytes, and expression was significantly higher during adipogenesis. In differentiated adipocytes, the expression/secretion of IL-34 was enhanced by TNFα and IL-1β. In addition, IL-34 augmented fat accumulation and inhibited the stimulatory effects of insulin on glucose transport. Moreover, serum IL-34 was significantly decreased after Roux-en-Y gastric bypass-induced weight loss. CONCLUSION The present study demonstrates, for the first time, that IL-34 is expressed in human adipose tissues and the circulating concentration is significantly elevated in obese patients. This suggests that IL-34 is associated with insulin resistance.

Patients taking medications for bipolar disorder are more prone to metabolic syndrome than Korea's general population

Despite growing concerns about the co-morbidity of metabolic syndrome (MetS) and bipolar disorder, few studies have been conducted on this topic in Asian populations. This study examined Korean patients with bipolar disorder to assess its co-morbidity with MetS and to compare the prevalence of MetS in patients with medication for bipolar disorder with that of healthy patients. We used cross-sectional data from the medical records of patients with bipolar disorder who presented to the psychiatric clinic in Seoul National University Hospital between June 2007 and June 2008. The control group, matched for age and gender, was randomly drawn from visitors to the Health Promotion Center at the same hospital during the same period. We compared the prevalence of MetS between these two groups with independent sample t-tests and chi-squared tests. We also calculated the indirectly standardized prevalence ratio (ISPR) with a standardization that used the Fourth Korean National Health and Nutrition Examination Survey (KNHNES, 2007). The prevalence of MetS in patients who took medication for bipolar disorder (N=152) was 27.0%, 25.0% and 25.7%, based on the definitions of the American Heart Association and the National Heart, Lung and Blood Institutes adaptation of the Adult Treatment Panel III (AHA), the National Cholesterol Education Program for Adult Treatment Panel III (ATPIII) and the International Diabetes Federation (IDF), respectively. The present study determined that the prevalence of MetS was significantly higher in patients with bipolar disorder than in the control group; the odds ratios (OR) (95% CI) were 2.44 (1.35-4.40), 2.48 (1.34-4.59) and 2.57 (1.40-4.74), based on the definition of the AHA, ATPIII and IDF, respectively. The ISPR (95% CI) was 1.48 (1.02-1.93), 1.54 (1.05-2.03) and 1.98 (1.36-2.60), respectively. Patients with medications for bipolar disorder showed a significantly higher prevalence of increased waist circumference, elevated triglycerides, and reduced HDL-cholesterol than the control group. The prevalence of MetS in patients taking medication for bipolar disorder was higher than that in the general population. Obesity and dyslipidemia were particularly prevalent in patients with bipolar disorder.

Alcohol consumption and higher incidence of impaired fasting glucose or type 2 diabetes in obese Korean men

It is inconclusive whether moderate alcohol consumption reduces the diabetes risk. We observed the development of impaired fasting glucose or type 2 diabetes according to the amount of alcohol intake and body mass index. The annual health evaluation data of 2,500 male workers from 2002 to 2006 were reviewed retrospectively deleting personal identification code. The information contained sex, age, medical history, smoking status, alcohol consumption, participating regular exercise, anthropometric, and biochemistry measurement. Impaired fasting glucose or diabetes was determined when fasting plasma glucose was > or =100mg/dL. Thousand seven hundred seven subjects were eligible after excluding medical history of diabetes or fasting glucose > or =100mg/dL at baseline. The relative risks of its development in group of taking 1-14, 15-29, and > or =30.0g ethanol were 0.842 (95% confidence interval [CI], 0.603-1.176), 1.068 (95% CI, 0.736-1.551), and 1.019 (95% CI, 0.662-1.568) within normal weight group, 1.164 (95% CI, 0.795-1.705), 1.421 (95% CI, 0.947-2.133), and 1.604 (95% CI, 1.031-2.495) within overweight group, and 1.498 (95% CI, 1.042-2.153), 1.634 (95% CI, 1.091-2.447), and 1.563 (95% CI, 1.019-2.396) within obese group each after adjusting age, family history of diabetes, smoking, exercise, serum fasting glucose, aspartate aminotransferase, and gamma-glutamyltransferase with nondrinkers as a reference group. Not only high alcohol consumption but also moderate drinking was related with higher incidence of impaired fasting glucose or diabetes in obese Korean men.

Influence of gastrectomy for stomach cancer on type 2 diabetes mellitus for patients with a body mass index less than 30 kg/m2

Purpose The impressive effect of LRYGBP on mildly obese patients (30 kg/m2 < BMI < 35 kg/m2) with T2DM raises the argument for lowering the threshold for surgical intervention to non-obesity (BMI < 30 kg/m2). The goal of this study was to evaluate the effect of gastrectomy on non-obese patients with T2DM and what preoperative clinical factors are associated with postoperative long term improvement. Methods In this retrospective review, we analyzed the change in diabetic status in 75 patients with gastric cancer undergoing three different gastrectomies in a single institution from June 1996 to September 2009. Pre- and postoperative fasting blood glucose, serum hemoglobin A1c and diabetic medication requirements were compared. The demographic data and other biochemical markers were also collected. Results At an average follow-up of 35.0 ± 25.9 months, we collected the data of 75 patients and evaluated the change of diabetes status. There was no resolution of diabetes in Billroth-I (B-I) group, and 45.2% of patients improved whereas the resolution rate of Billroth-II (B-II) and RY group was 22.2% and 23.5% and 85.2% and 88.2%, respectively. The improvement rate of diabetes mellitus (DM) status was 7.46 times higher in B-II than in B-I patients. The method of reconstruction is the most powerful factor and severity and duration of diabetes showed significant clinical factors for the improvement of the disease after surgery. Conclusion According to these results, foregut-bypass procedure may improve the type 2 DM better than can be explained by the effect of weight loss only. Diabetes remission is significantly higher in those with duration of diabetes less than 5 years.

Effectiveness of Proactive Quitline Service and Predictors of Successful Smoking Cessation : Findings from a Preliminary Study of Quitline Service for Smoking Cessation in Korea

This study was to evaluate the effectiveness of the first proactive Quitline service for smoking cessation in Korea and determine the predictors of successful smoking cessation. Smoking participants were voluntarily recruited from 18 community health centers. The participants were proactively counseled for smoking cessation via 7 sessions conducted for 30 days from November 1, 2005 to January 31, 2006. Of the 649 smoking participants, 522 completed 30 days at the end of the study and were included in the final analysis. The continuous abstinence rate at 30 days of follow-up was found to be 38.3% (200/522), in the intention-to-treat analysis. Compared with non-quitters, quitters were mostly male, smoked <20 cigarettes/day, had started smoking at the age of ≥20 yr, and were less dependent on nicotine. Based on the stepwise multiple logistic regression analysis, the significant predictors of successful smoking cessation were determined to be male sex, low cigarette consumption, and older age at smoking initiation. We investigated the short-term effectiveness of the Quitline service and determined the predictors of successful smoking cessation.

Roux-en-Y Gastric Bypass vs. Sleeve Gastrectomy vs. Gastric Banding: The First Multicenter Retrospective Comparative Cohort Study in Obese Korean Patients

Purpose Bariatric surgery is relatively new in Korea, and studies comparing different bariatric procedures in Koreans are lacking. This study aimed to compare the clinical outcomes of laparoscopic adjustable gastric banding (LAGB), Roux-en-Y gastric bypass (RYGB), and sleeve gastrectomy (SG) for treating morbidly obese Korean adults. Materials and Methods In this multicenter retrospective cohort study, we reviewed the medical records of 261 obese patients who underwent different bariatric procedures. Clinical outcomes were measured in terms of weight loss and resolution of comorbidities, such as diabetes, hypertension, and dyslipidemia. Safety profiles for the procedures were also evaluated. Results In terms of weight loss, the three procedures showed similar results at 18 months (weight loss in 52.1% for SG, 61.0% for LAGB, and 69.2% for RYGB). Remission of diabetes, hypertension, and dyslipidemia was more frequent in patients who underwent RYGB (65.9%, 63.6%, and 100% of patients, respectively). Safety profiles were similar among groups. Early complications occurred in 26 patients (9.9%) and late complications in 32 (12.3%). In the LAGB group, five bands (6.9%) were removed. Among all patients, one death (1/261=0.38%) occurred in the RYGB group due to aspiration pneumonia. Conclusion The three bariatric procedures were comparable in regards to weight-loss outcomes; nevertheless, RYGB showed a higher rate of comorbidity resolution. Bariatric surgery is effective and relatively safe; however, due to complications, some bands had to be removed in the LAGB group and a relatively high rate of reoperations was observed in the RYGB group.

Fibronectin Gene Expression in Human Adipose Tissue and Its Associations with Obesity-Related Genes and Metabolic Parameters

BackgroundLimited data are available on the in vivo expression of fibronectin, one of the main extracellular matrix components. We investigated the expression of fibronectin in abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) and the associations of leptin, adiponectin, and vaspin gene expression with metabolic parameters in obese women.MethodsWe recruited female subjects undergoing bariatric surgery for obesity (n = 24) and patients undergoing benign gynecological surgery as the control group (n = 23). We measured anthropometric variables, abdominal fat distribution, metabolic parameters, serum concentrations of leptin, adiponectin, and vaspin, and depot-specific mRNA expression of fibronectin, leptin, adiponectin, and vaspin.ResultsFibronectin expression in both VAT and SAT was significantly lower in the obese group than in the control group. Fibronectin expression in both VAT and SAT were negatively correlated with body mass index or waist circumference, with higher prominence in VAT. In multiple regression analysis, fibronectin expression in both VAT and SAT was negatively correlated with serum leptin concentration. Fibronectin expression in VAT was negatively correlated with leptin expression in VAT. Additionally, fibronectin expression in SAT was negatively correlated with leptin expression in SAT and positively correlated with adiponectin expression in VAT and SAT.ConclusionsWe found significant negative associations between depot-specific fibronectin expression in human adipose tissue and obesity indices and obesity-related biomarkers. Our results suggest that fibronectin expression may contribute to obesity and metabolic dysregulation in humans.