Subclinical thyroid dysfunction, bone mineral density, and osteoporosis in a middle-aged Korean population.

Thyroid dysfunction is associated with the loss of bone density (osteoporosis). However, the connection between subclinical thyroid dysfunction and osteoporosis remains controversial. This study found no apparent association between subclinical hypothyroidism or subclinical hyperthyroidism and bone mineral density (BMD) in the lumbar spine and femur. INTRODUCTION: The present study examined the relationship between subclinical thyroid dysfunction and BMD in healthy middle-aged adults. METHODS: A total of 25,510 healthy Koreans with normal free thyroxine levels were enrolled from January 2011 to December 2016, and 91% of subjects visited only once. The average age of the 15,761 women was 45, and the average age of the 9749 men was 48. Levels of thyroid-stimulating hormone (TSH) and BMD were recorded in all subjects. BMD was measured using dual-energy X-ray absorptiometry. RESULTS: No apparent association was found between subclinical thyroid dysfunction and BMD in the lumbar spine, femur-neck, and proximal femur sites compared with a euthyroid group. Age, body mass index (BMI), and postmenopausal status affected BMD in women, and only BMI affected BMD in men. Subclinical hypothyroidism was independently associated with a lower risk of osteoporosis (odds ratio 0.657, 95% confidence interval 0.464-0.930) in 4710 postmenopausal women. CONCLUSIONS: No apparent association was found between subclinical hypothyroidism or subclinical hyperthyroidism defined on single TSH measurement and BMD at the lumbar spine and femur in a large cohort of middle-aged men and women. Subclinical hypothyroidism was independently associated with a lower risk of osteoporosis in postmenopausal women.

Relationships between serum total bilirubin levels and metabolic syndrome in Korean adults.

BACKGROUND AND AIMS: Metabolic syndrome (MS) is associated with insulin resistance in all parts of its natural history, which is accompanied by oxidative stress. Bilirubin is a potent endogenous antioxidant and cytoprotectant. The current study was performed to identify the major predictors of the total bilirubin level and to assess the relationships between the total bilirubin levels and MS in Korean adults. METHODS AND RESULTS: This is a cross-sectional study involving 12342 adults aged 20 years and over who visited a Health Promotion Center. Physical examinations and laboratory tests including total and direct bilirubin levels were performed. MS was defined based on the modified NCEP-ATP III definition and the determinations of the Korean Society for the Study of Obesity. The results showed that hemoglobin had the strongest influence on the total bilirubin levels after adjusting for age, gender, and all other variables. The high-bilirubin group (≥15.4 µmol/L in males and ≥12.1 µmol/L in females) was associated with significantly decreased odds of MS compared to the low-bilirubin group (OR 0.74 [95% CI 0.64-0.86]). High levels of bilirubin also were negatively associated with abdominal obesity and hypertriglyceridemia. The total bilirubin levels decreased with an increase in the number of MS components after adjustment for all covariates. CONCLUSION: Within the physiological range, the serum total bilirubin level was negatively associated with the MS in subjects without overt metabolic or cardiovascular diseases. This may be partially due to the negative association between the total bilirubin level and abdominal obesity and hypertriglyceridemia.

Impact of BMI on the incidence of metabolic abnormalities in metabolically healthy men.

OBJECTIVES: Although the existence of metabolically healthy obese (MHO) individuals has been recognized, little is known regarding metabolic health status in these subjects over time. Thus, we evaluated longitudinal changes in metabolic parameters among MHO subjects compared with metabolically healthy, normal-weight (MHNW) subjects. METHODS: A cohort study was performed on 2599 Korean men, 30-59 years of age, with no evidence of fatty liver disease on ultrasound and no traits of metabolic syndrome at baseline. BMI was categorized based on criteria for Asian population. Study participants were followed annually or biennially between 2002 and 2009. At each visit, the fatty liver on ultrasound was assessed and metabolic abnormalities were measured. Parametric Cox models and a pooled logistic regression models were used to evaluate the relationships of BMI with incident metabolic abnormalities. RESULTS: During 9647.1 person-years of follow-up, 1673 participants developed metabolic abnormalities. After adjusting for age, smoking, alcohol intake and exercise, higher baseline BMI categories predicted increased incidences of metabolic abnormalities in a dose-response manner. The hazard ratios (95% confidence intervals) for hypertriglyceridemia, prediabetes, pre-hypertension, low high-density lipoprotein-cholesterol, fatty liver, elevated high sensitivity-C reactive protein, elevated homeostasis model assessment of insulin resistance, any metabolic abnormality and metabolic syndrome among the MHO subjects compared with the MHNW subjects were 1.51 (1.23-1.85), 1.43 (1.19-1.72), 1.79 (1.45-2.22), 1.80 (1.30-2.49), 2.69 (2.19-3.31), 1.39 (1.16-1.67), 2.90 (2.31-3.62), 1.68 (1.45-1.93) and 1.84(1.02-3.30), respectively. CONCLUSION: In this study, MHO individuals showed higher incidences of metabolic abnormalities compared with MHNW individuals. This suggests that initially MHO individuals undergo adverse metabolic changes associated with obesity over time.

Risk factors associated with high glycated hemoglobin levels (≥5.7%) in Korean adults with normal fasting glucose.

BACKGROUND: Early detection of high risk for Type 2 diabetes (T2DM) and early diagnosis of T2DM are fundamental for the prevention of diabetes and associated complications. AIM: To identify the major predictors of high glycated hemoglobin (HbA(1C)) levels in people with normal fasting glucose levels. SUBJECTS AND METHODS: This was a cross-sectional study involving 8035 adults aged ≥20 yr. Multivariate logistic regression analyses were performed to estimate the odds ratios (OR) of clinical risk factors for high HbA(1C) (≥5.7%) in the subjects with normal fasting glucose levels (<100 mg/dl). RESULTS: Except for fasting glucose levels, age, and total cholesterol levels were significantly associated with HbA(1C) levels. After adjustment for gender, fasting glucose, and behavioral factors, OR for high HbA(1C) levels for age (≥40 yr old) and high total cholesterol levels (≥200 mg/dl) were 2.27 (95% CI: 2.01-2.56) and 1.76 (95% CI: 1.56-1.97), respectively. Each OR was higher than that of metabolic syndrome (MS) (OR=1.59, 95% CI: 1.34- 1.87). Coexistence of both factors had a higher OR (OR=2.40, 95% CI: 2.11-2.72) for high HbA(1C) levels when compared to each factor alone. CONCLUSIONS: HbA(1C) was significantly associated with fasting glucose, age, and total cholesterol levels. In subjects with normal fasting glucose levels, age of over 40 yr or high total cholesterol levels (≥200 mg/dl) is more predictive of high HbA(1C) levels than MS. These findings suggest that both factors might be better predictors than MS for the screening of pre-diabetes or diabetes in clinical practice.

Gender and age differences in the impact of overweight on obesity-related quality of life among Korean adults.

OBJECTIVE: To investigate gender and age difference in impact of overweight on health-related quality of life (HRQOL) among Korean adults. METHODS: Cross-sectional obesity-related quality of life (QOL) scores were measured by a Korean obesity-related QOL scale (KOQOL) from 448 Korean adults aged 20-80 years. A body mass index (BMI) was categorized with normal-weight as BMI < 23 kg/m(2), overweight as BMI ≥ 23 kg/m(2) based on the alternative cutoff points for Asians. Each gender was respectively stratified by median age, 45 years for men and 50 years for women, to examine the obesity-related QOL by age groups. RESULTS: Women had a poorer obesity-related QOL compared to men (p < 0.001). In the younger age group, overweight women had a poorer obesity-related QOL compared with normal-weight women (p < 0.001), however normal-weight and overweight men showed no difference in obesity-related QOL. In the older age group, overweight men showed better QOL on the domains of work-related and psychosocial health than those for normal-weight men, but overweight women still suffered from work-related and routine life QOL. CONCLUSIONS: This study showed the impact of overweight on obesity-related QOL was different for gender and age group. We should consider the results to manage weight in overweight persons.

Metabolic syndrome and quality of life (QOL) using generalised and obesity-specific QOL scales.

OBJECTIVES: We investigated the association between metabolic syndrome (MS) and health-related quality of life (HRQOL) assessed using generalised and obesity-specific QOL instruments. METHODS: We recruited 456 outpatients [age: 19-81 years, body mass index (BMI): 16.3-36.7 kg/m2] in the primary care division from 12 general hospitals in Korea. HRQOL was measured using EuroQol comprising the health states descriptive system (EQ-5D) and visual analogue scale (EQ-VAS) as a general instrument. The Korean Obesity-related QOL scale (KOQOL) composed of six domains was used as a disease-specific QOL instrument. MS was defined on the basis of International Diabetes Federation (IDF) criteria with Korean-specific waist circumference cutoffs (men: 90 cm, women: 85 cm). RESULTS: Subjects with MS displayed significantly higher impairment of EQ-5D and KOQOL. Binary logistic regression analysis of MS patients with controls for age, gender, smoking, alcohol, exercise, education, income, marital status and medication history disclosed odds ratio (OR) values of 2.13 (1.33-3.41) for impaired total KOQOL, 2.07 (1.31-3.27) for impaired physical health, 1.63 (1.03-2.60) for impaired work-related health, 2.42 (1.45-4.04) for impaired routine life, 2.08 (1.27-3.40) for impaired sexual life and 2.56 (1.59-4.11) for diet distress. Among the EQ-5D dimensions, only pain/discomfort displayed a significantly increased OR of 1.60 (1.01-2.56) in MS group. CONCLUSIONS: Subjects with MS displayed a significantly impaired HRQOL compared with those without MS. MS and HRQOL were more strongly associated in obesity-specific QOL than in generalised QOL.

Lack of management of cardiovascular risk factors in type 2 diabetic patients.

Effective management of diabetic patients includes comprehensive control for not only blood sugar, but also other cardiovascular risk factors. We assessed whether haemoglobin A1c (A1C) concentrations, blood pressure, low density lipoprotein (LDL) cholesterol levels and microalbuminuria were regularly measured in 281 patients with type 2 diabetes who received care for over 1 year in the Department of Family Medicine located in an urban area of Korea. Subsequently, in patients with A1C > 7%; blood pressure >130/80 mmHg; LDL cholesterol levels >100 mg/dl; or microalbuminuria, we evaluated the status of management for those cardiovascular risk factors. Physicians were most likely to measure A1C levels (98.6%), but less likely to measure microalbuminuria (56.2%), LDL cholesterol (73.7%), or blood pressure (74.4%). Patients whose A1C levels were above the goal (78.2%) were likely to receive optimal therapy. In contrast, only 21.1% of patients with uncontrolled blood pressure and 5.3% of patients with LDL cholesterol levels above the target range received optimal management. Of the 36 patients with microalbuminuria or overt proteinuria, 66.7% took angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. Measurement of parameters indicating cardiovascular risk factors in type 2 diabetic patients was not optimal, particularly regular measurements for microalbuminuria and for controlling LDL-cholesterol and blood pressure. These findings indicate a need for greater education of comprehensive cardiovascular management in type 2 diabetic patients and their physicians.