Center for Cohort Studies

Total, South Korea

Center for Cohort Studies

Total, South Korea

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Zhang Y.,Welch Center for Prevention | Kim B.-K.,Center for Cohort Studies | Chang Y.,Welch Center for Prevention | Chang Y.,Center for Cohort Studies | And 11 more authors.
Arteriosclerosis, Thrombosis, and Vascular Biology | Year: 2014

OBJECTIVE - Overt and subclinical hypothyroidism are risk factors for atherosclerosis. It is unclear whether thyroid hormone levels within the normal range are also associated with atherosclerosis measured by coronary artery calcium (CAC). APPROACH AND RESULTS - We conducted a cross-sectional study of 41 403 apparently healthy young and middle-aged men and women with normal thyroid hormone levels. Free thyroxin, free triiodothyronine, and thyroid-stimulating hormone levels were measured by electrochemiluminescent immunoassay. CAC score was measured by multidetector computed tomography. The multivariable adjusted CAC ratios comparing the highest versus the lowest quartile of thyroid hormones were 0.74 (95% confidence interval, 0.60-0.91; P for trend <0.001) for free thyroxin, 0.81 (0.66-1.00; P for trend=0.05) for free triiodothyronine, and 0.78 (0.64-0.95; P for trend=0.01) for thyroid-stimulating hormone. Similarly, the odds ratios for detectable CAC (CAC >0) comparing the highest versus the lowest quartiles of thyroid hormones were 0.87 (0.79-0.96; P for linear trend <0.001) for free thyroxin, 0.90 (0.82-0.99; P for linear trend=0.02) for free triiodothyronine, and 0.91 (0.83-1.00; P for linear trend=0.03) for thyroid-stimulating hormone. CONCLUSIONS - In a large cohort of apparently healthy young and middle-aged euthyroid men and women, low-normal free thyroxin and thyroid-stimulating hormone were associated with a higher prevalence of subclinical coronary artery disease and with a greater degree of coronary calcification. © 2014 American Heart Association, Inc.


PubMed | University of Ulsan, Sungkyunkwan University, Center for Cohort Studies, MRC Integrative Epidemiology Unit and Seoul National University
Type: | Journal: International journal of epidemiology | Year: 2017

We examined whether alcohol flushing could be used as an instrumental variable (IV) and investigated the effect of alcohol consumption on coronary calcification using alcohol flushing status as an IV.We analysed cross-sectional data from 24681 Korean adults (20696 men and 3985 women) who had been administered a questionnaire assessing alcohol consumption and alcohol flushing, as well as a coronary artery calcium (CAC) measurement. The associations of alcohol flushing status with potential confounders and alcohol consumption were examined. We employed two-stage predictor substitution methodology for the IV analysis.The prevalence of alcohol flushing did not differ depending on gender, education, household income, cigarette smoking or physical activity. Balanced levels of confounders were observed between alcohol flushers and non-flushers. Alcohol flushing was closely related to alcohol consumption and levels of liver enzymes. In men, a doubling in alcohol consumption was associated with increased odds of coronary calcification in both the IV analysis [odds ratio (OR) of CAC scores of 1 or over = 1.11; 95% confidence interval (CI) = 1.03-1.20) and the multivariable regression analysis (OR=1.04; 95% CI=1.01-1.07). For cardiovascular risk factors, the IV analysis showed a positive association between alcohol consumption and blood pressure and high-density lipoprotein-cholesterol.Alcohol flushing can be used as an IV in studies evaluating the health impact of alcohol consumption, especially in East Asian countries. Through such an analysis, we found that increased alcohol consumption was associated with an increased risk of subclinical coronary atherosclerosis.


Yun K.E.,Center for Cohort Studies | Chang Y.,Center for Cohort Studies | Chang Y.,Sungkyunkwan University | Jung H.-S.,Center for Cohort Studies | And 9 more authors.
Cancer Research | Year: 2013

Metabolically healthy obese (MHO) states exist that seem to be protected from cardiovascular risks. Although obesity is a risk factor for colorectal adenoma (CRA), there has yet to be any study of the risks of CRA in MHO individuals. In this study, we compared CRA prevalence in MHO individuals versus metabolically healthy individuals who were normal in weight. This cross-sectional study involved 18,085 Korean adults (39.1±6.7 years) who had a health checkup including a colonoscopy. High-risk CRA was defined as any adenoma over 1 cm, 3 or more adenomas, adenoma with a villous component, or high-grade dysplasia. Multinomial logistic regression models were used to measure the associations between body mass index (BMI) and the risk of low-risk and highrisk CRA. Low-risk and high-risk CRA were present in 9.3% and 1.4% of the study population, respectively. After adjusting for age, sex, smoking, drinking, exercise, family history of colorectal cancer, education, and use of analgesic and aspirin, compared with normal healthy individuals, the prevalence of low-risk and high-risk CRA was increased inMHOindividuals [OR=1.44; 95% confidence interval (CI), 1.23-1.69 and OR=1.62; 95% CI, 1.09- 2.41, respectively]. In fully adjusted models, the prevalence of low-risk and high-risk CRA was associated with increasing categories of BMI in a dose-response manner (P for trend < 0.001 and 0.01, respectively). Thus, excess body weight, even in the absence of a metabolic unhealthy state, was found to be positively associated with increased presence of CRAs. © 2013 American Association for Cancer Research.

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