Serum Adiponectin and Type 2 Diabetes: A 6-Year Follow-Up Cohort Study

BACKGROUND: Studies on factors which may predict the risk of diabetes are scarce. This prospective cohort study was conducted to determine the association between adiponectin and type 2 diabetes among Korean men and women. METHODS: A total of 42,845 participants who visited one of seven health examination centers located in Seoul and Gyeonggi province, Republic of Korea between 2004 and 2008 were included in this study. The incidence rates of diabetes were determined through December 2011. To evaluate the effects of adiponectin on type 2 diabetes, the Cox proportional hazard model was used. RESULTS: Of the 40,005 participants, 959 developed type 2 diabetes during a 6-year follow-up. After the adjustment for age, body mass index (BMI), and waist circumference, the risks for type 2 diabetes in participants with normoglycemia had a 1.70-fold (95% confidence interval [CI], 1.21 to 2.38) increase in men and a 1.83-fold (95% CI, 1.17 to 2.86) increase in women with the lowest tertile of adiponectin when compared to the highest tertile of adiponectin. For participants with impaired fasting glucose (IFG), the risk for type 2 diabetes had a 1.46-fold (95% CI, 1.17 to 1.83) increase in men and a 2.52-fold (95% CI, 1.57 to 4.06) increase in women with the lowest tertile of adiponectin. Except for female participants with normoglycemia, all the risks remained significant after the adjustment for fasting glucose and other confounding variables. Surprisingly, BMI and waist circumference were not predictors of type 2 diabetes in men or women with IFG after adjustment for fasting glucose and other confounders. CONCLUSION: A strong association between adiponectin and diabetes was observed. The use of adiponectin as a predictor of type 2 diabetes is considered to be useful.

Prediction of Colorectal Cancer Risk Using a Genetic Risk Score: The Korean Cancer Prevention Study-II (KCPS-II)

Colorectal cancer (CRC) is among the leading causes of cancer deaths and can be caused by environmental factors as well as genetic factors. Therefore, we developed a prediction model of CRC using genetic risk scores (GRS) and evaluated the effects of conventional risk factors, including family history of CRC, in combination with GRS on the risk of CRC in Koreans. This study included 187 cases (men, 133; women, 54) and 976 controls (men, 554; women, 422). GRS were calculated with most significantly associated single-nucleotide polymorphism with CRC through a genomewide association study. The area under the curve (AUC) increased by 0.5% to 5.2% when either counted or weighted GRS was added to a prediction model consisting of age alone (AUC 0.687 for men, 0.598 for women) or age and family history of CRC (AUC 0.692 for men, 0.603 for women) for both men and women. Furthermore, the risk of CRC significantly increased for individuals with a family history of CRC in the highest quartile of GRS when compared to subjects without a family history of CRC in the lowest quartile of GRS (counted GRS odds ratio [OR], 47.9; 95% confidence interval [CI], 4.9 to 471.8 for men; OR, 22.3; 95% CI, 1.4 to 344.2 for women) (weighted GRS OR, 35.9; 95% CI, 5.9 to 218.2 for men; OR, 18.1, 95% CI, 3.7 to 88.1 for women). Our findings suggest that in Koreans, especially in Korean men, GRS improve the prediction of CRC when considered in conjunction with age and family history of CRC.

Cigarette Smoking and Serum Bilirubin Subtypes in Healthy Korean Men: The Korea Medical Institute Study / 예방의학회지

OBJECTIVES: Cigarette smoking is a modifiable risk factor for cardiovascular disease. Bilirubin is a potent antioxidant and its concentration decreases in smokers. However, studies about the association between cigarette smoking and bilirubin are scarce and most are limited to total bilirubin. Additionally, bilirubin is highly related to hemoglobin. Therefore, this study evaluates the association between bilirubin subtypes and cigarette smoking in healthy Korean men independently of hemoglobin. METHODS: This study included 48 040 Korean men aged 30 to 87 years who visited the Korea Medical Institute for routine health examinations from January to December, 2007. The association of smoking with total, direct, and indirect bilirubin was assessed by logistic regression analysis taking into consideration differences in subjects and smoking characteristics. RESULTS: Current smokers had lower bilirubin concentrations than never-smokers and ex-smokers. Smoking amount and duration were inversely significantly associated with total, direct, and indirect bilirubin. In a multivariable adjusted model, compared to never-smokers, the odds ratios (ORs) and 95% confidence intervals (CIs) of current smokers with the highest number of pack-years were 1.7 (1.6 to 1.9) for total, 1.5 (1.4 to 1.6) for direct, and 1.7 (1.6 to 1.9) for indirect bilirubin. After further adjustment for hemoglobin, this association became stronger (OR [95% CI], 2.1 [1.9 to 2.2] for total; 1.9 [1.8 to 2.0] for direct; 2.0 [1.9 to 2.2] for indirect bilirubin). CONCLUSIONS: In this study, bilirubin subtypes are inversely associated with smoking status, smoking amount, and smoking duration in healthy Korean men independently of hemoglobin. Further studies are needed to investigate this association in healthy Korean women.

Linkage of Epidemiologic Evidence With the Clinical Aspects of Metabolic Syndrome

Metabolic syndrome (MetS) is characterized by a cluster of cardiovascular risk factors, such as hypertension, glucose intolerance, high triglycerides, and a low high density lipoprotein-cholesterol level. MetS is known to be associated with cardiovascular diseases. In order to diagnose MetS, definitions such as National Cholesterol Education Program Adult Treatment Panel III, American Heart Association/National Heart Lung and Blood Institute, International Diabetes Federation, World Health Organization, European Group for the Study of Insulin Resistance and American College of Endocrinology are widely used. However, using different criteria may lead to confusion regarding the diagnosis and treatment of patients with MetS in the primary care setting. Our objected was to review 3 aspects concerning MetS using the Metabolic Syndrome Research Initiatives study of 123892 healthy Koreans (1994-2001) that had a maximum follow-up of 12 years. The 3 aspects were reviewed by determination of the association of MetS with the development of atherosclerotic cardiovascular disease (ASCVD) and ischemic heart disease (IHD). Based on our findings, each metabolic factor associated with MetS was not weighted equally. The hazard ratio (HR) was higher in individuals with higher glucose compared with the HR in individuals with higher body mass index. Individuals with pre-MetS (having 1 or 2 metabolic factors) had 1.5-2.3 fold higher risk of developing ASCVD and IHD in both genders. In the presence of MetS, both singly and in combination, precede the development of ASCVD and IHD and individuals with pre-MetS must not be ignored as there is no apparent threshold in defining MetS. Furthermore, MetS may complement the Framingham Risk Score and can be used as the first line approach to treat the ASCVD or IHD.

Association between Alcohol Intake and Abdominal Obesity among the Korean Population / 한국역학회지

OBJECTIVES: Although abdominal obesity has been reported to be highly related with alcohol intake, the results are still inconclusive. Therefore, this study was conducted to explore the association between alcohol and abdominal obesity among the Korean population. METHODS: This study included 8,603 participants (men: 5,195, women: 3,408) aged 30 to 87 who visited the health promotion centers in Seoul for routine health examinations from April, 2006 to June, 2007. Abdominal obesity was defined as WC > or =90 cm for men and > or =85 cm for women in accordance with the Korean Society for the Study of Obesity. For ever drinkers, total alcohol consumption in grams was classified into four groups (group 1, non-drinkers; group 2, 1-10 g of alcohol per day; group 3, 11-20 g of alcohol per day; and group 4, over 20 g of alcohol per day). RESULTS: The mean age of the study population was 45.4 yr old (men) and 45.3 yr (women). The average waist circumference was 85.3 cm in men and 75.3 cm in women. A high alcohol intake was associated with high waist circumference in both genders. In multivariate analysis, the group of men and women drinkers consuming >20 g in a day had a large waist circumference compared with men and women non-drinkers. CONCLUSION: This study showed that a high alcohol intake was related to high waist circumference. Such association remained independently even after adjustment for smoking, which is strongly related to abdominal obesity.