Waist circumference and risk of breast cancer in Korean women: A nationwide cohort study.

Although postmenopausal breast cancer (BC) risk has been linked to adiposity, associations between adiposity and premenopausal BC remain unclear. To address this question, we investigated the association of BC risk with measures of adiposity, including body mass index (BMI) and waist circumference (WC), in a large cohort of Asian women. We used a nationwide cohort of adult Korean women selected from the National Health Insurance Corporation database merged with national health examination data from 2009 to 2015. A total of 11,227,948 women were tracked to retrospectively identify incident cases of BC. Our analysis used Cox proportional hazards models to calculate hazard ratios and assess the association of BC risk with BMI and/or WC in both pre- and postmenopausal women. BMI and WC were robustly associated with increased risk for postmenopausal BC (ptrend <0.001 for both BMI and WC) but not with premenopausal BC. Association between WC and premenopausal BC was only statistically significant when considering BMI (ptrend =0.044). In contrast, postmenopausal BC was negatively associated with WC when considering BMI (ptrend =0.011). In premenopausal women, WC may predict increased BC risk when considering BMI. However, in postmenopausal women, WC is not superior to BMI as an indicator of BC risk.

Waist circumference and risk of 23 site-specific cancers: a population-based cohort study of Korean adults.

BACKGROUND: Large waist circumference (WC) is a risk factor for several site-specific cancers, but a large-scale systematic investigation across all common cancers adjusted for potential confounders has not been conducted. This study aimed to evaluate the possible links between WC and common cancers. METHODS: We prospectively examined the association between WC and the risk of cancers in a 7-year cohort study of nearly 22.9 million Korean adults. Using the claims database merged with the national health check-up data, we fitted proportional hazard models to investigate associations between WC and 23 of the most common cancers, with adjustment for potential confounders, including body mass index (BMI). We also evaluated the modification of BMI on the relationships between WC and the incidence of cancer. RESULTS: A total of 769,871 cancer cases were identified. WC was positively associated with 18 of 23 cancers, and the effects varied substantially by site in each sex. The modification of BMI on the WC-cancer association also varied across the cancer site; in most cases it mitigated the association. For cancers of the oral cavity, larynx, oesophagus, lung, and premenopausal breast, the BMI adjustment reversed the association toward being positive (all Ptrend < 0.001). CONCLUSIONS: Central obesity, independent of general obesity, was associated with the risk of several cancers. The heterogeneity in the mediating effects of BMI suggests that different mechanisms are associated with different cancer sites. Based upon these findings, active strategies to monitor and prevent central obesity should be implemented.

Effect of Influenza Vaccination on Risk of Stroke: A Systematic Review and Meta-Analysis.

BACKGROUND: Despite the presence of a strong association between influenza infection and stroke, whether influenza vaccination reduces the risk of stroke is yet a matter of controversy. We conducted a meta-analysis to determine whether influenza vaccination protects against stroke. METHODS: We searched PubMed, EMBASE, and the Cochrane Library from database inception date to November 18, 2016, without language restrictions, to identify studies investigating the effect of influenza vaccination on subsequent risk of stroke. We conducted a meta-analysis to quantify the risk of stroke in overall and subgroup analyses and calculated a pooled OR for developing stroke with a 95% CI. Publication bias was assessed by Begg's rank correlation test. RESULTS: Eleven studies fulfilled our inclusion criteria. In a random-effects model, vaccinated individuals had a decreased risk of stroke compared with unvaccinated individuals (OR 0.82; 95% CI 0.75-0.91; p < 0.001). The relationship between influenza vaccination and stroke risk remained robust in subgroup analyses. The significant effect of influenza vaccination was associated with ascertainment of vaccination status and stage of prevention. CONCLUSION: Vaccination against influenza is associated with a lower risk of stroke. Well-designed prospective studies are needed to provide stronger evidence of the protective effect of influenza vaccination against stroke.

Association between blood lead levels and blood pressures in a non-smoking healthy Korean population.

OBJECTIVE: The Korea National Health and Nutrition Examination Survey (KNHANES) has been performed every 3 years in Korea to help prevent cardiovascular mortality in the general population. Previous studies showed an association between blood lead levels and cardiovascular mortality. In order to assess the relationship between blood lead concentration and blood pressure in the healthy general population, we investigated whether blood lead levels were related to blood pressure in a non-smoking healthy population without any known medical diseases in the 2013 KNHANES. METHODS: 896 (mean age 40.55±13.83 years; body mass index 23.06±3.33 kg/m2) subjects who had no known diseases were included among 8018 subjects. Exclusion criteria were: hypertension, diabetes, hyperlipidaemia, cerebrovascular events, renal insufficiency, liver cirrhosis, thyroid dysfunction, any cardiovascular or renal disease, and any malignancy. Blood pressures were measured three times by sphygmomanometers, 5 min apart. Blood pressures were then expressed as the average between the second and third values. Height, weight, waist circumferences and blood pressure, as well as total cholesterol, high density lipoprotein cholesterol, triglycerides, low density lipoprotein cholesterol, aspartate aminotransferase (AST), alanine aminotransferase (ALT), white blood cell count and blood lead levels were measured. In addition, dietary components were analysed by 24 hour recall. RESULTS: The association between log blood lead levels and systolic/diastolic pressure was stronger after it was controlled for age, sex, education, body mass index (BMI), waist circumference and fasting plasma glucose (FPG) (p=0.048, 0.002). Furthermore, the association between log blood lead levels and systolic pressure (p=0.048) and diastolic pressure (p=0.002) was more evident when controlled for age, sex, education, BMI, waist circumference, FPG, AST and ALT. CONCLUSIONS: Blood lead levels are significant determinants of systolic and diastolic blood pressure in a healthy Korean population, irrespective of sociodemographic factors and metabolic derangements.

Fatty Liver Change in Korean Adults in a Systematic Social Distancing System Amid the COVID-19 Pandemic: A Multicenter Analysis.

In response to the COVID-19 pandemic, the Korean government implemented policies including the systematic social distancing (SSD) system which started on 28 June 2020. The present study investigated the development and aggravation of fatty liver measured using ultrasonography during the transition period (from pre-SSD to SSD) compared to the fatty liver changes during the pre-SSD period. Changes in fatty liver and liver enzymes were assessed in different groups stratified by alcohol consumption. Our retrospective cohort analysis included 5668 participants who underwent health checkups at 13 university hospitals during the SSD period and two or more checkups before the SSD period. Fatty liver developed and aggravated more in the transition period (13.6% development and 12.0% aggravation) than in the pre-SSD period (10.8% development and 10.1% aggravation) in the alcohol consumption group. This finding was more prominent in women than in men. Abnormal alanine transaminase levels were more often developed in the transition period than in the pre-SSD period, especially in men (11.1% vs. 8.6% in each period). In conclusion, the SSD system may contribute to fatty liver changes in individuals who regularly consume alcohol. Further research of the post-pandemic period is needed to assess long-term changes in fatty liver disease.

COVID-19 and related social distancing measures induce significant metabolic complications without prominent weight gain in Korean adults.

Background: This study using multi-center health examination data from Korean adults was conducted to confirm changes in weight, and their related cardiometabolic parameters, before and after strengthening of social distancing regulations. Methods: A retrospective cohort study was conducted using health check-up data from 13 university hospitals. The study period was from January 2018 to July 2020. To examine the effect of systematic social distancing measures, participants who underwent a health check-up (Visit 3) between July 2020 and July 2021 (during full scale social distancing), and had undergone two previous health check-ups (Visits 1 and 2) between January 2018 and June 2020 (before social distancing), were selected. In total, data from 7,875 participants were analyzed. Linear mixed-effect models were used to calculate estimates of anthropometric indices and metabolic markers measured on Visits 2 and 3, compared with measurements from Visit 1. Results: There were no significant differences in body weight, body mass index, waist circumference, and body composition on Visit 3 than on Visits 1 and 2. However, the odds of metabolic syndrome and its components, including hypertension, high glucose, diabetes, hypercholesterolemia, hypertriglyceridemia, hyper-non-high-density lipoprotein cholesterolemia, and dyslipidemia were significantly higher on Visit 3 than on Visits 1 and 2. The increase in metabolic complications was marked, particularly in relatively young adults who visited health check-up centers located in the capital area. Conclusion: Metabolic syndrome and its components were significantly worse after high level social distancing, although there were no significant increases in anthropometric indices and body fat levels. Healthcare providers need to prevent and manage worsening of metabolic parameters in subpopulations prone to be more sedentary and eat unhealthy food during the COVID-19 pandemic and associated social distancing measures.

Association between handgrip strength and cardiovascular risk factors among Korean adolescents.

Background It remains unclear whether muscle strength, which reduces cardiovascular (CV) risk in adults, is associated with similar protection in Asian adolescents. This study investigated the association between handgrip strength and CV health in a large Korean sample of school-age adolescents. Methods We performed a cross-sectional analysis of adolescents aged 10-18 years (n=4,018) from the Korean National Health and Nutrition Survey between 2014 and 2017. Handgrip strength was measured using a dynamometer. CV risk factors include waist circumference, blood pressure, fasting glucose or hemoglobin A1c, and lipid levels. Logistic regression models were applied with adjustment for potential confounders. Results The mean age of participants was 14.0 years, and 53.6% were boys. Mean handgrip strength was 30.4 kg for boys and 22.0 kg for girls. Boys more frequently had high systolic blood pressure and impaired fasting glucose, whereas girls more frequently had low high-density lipoprotein cholesterol. Multivariate logistic regression analysis revealed that in boys only, handgrip strength was negatively associated with central obesity and hypertriglyceridemia and positively associated with higher systolic blood pressure. Conclusion Handgrip strength is independently associated with some CV risk factors only in boys.

Cryolipolysis-induced abdominal fat change: Split-body trials.

Cryolipolysis has been considered as a noninvasive alternative to surgical procedures for reducing subcutaneous fat without affecting the surrounding tissues. However, no clinical trial has investigated changes in the abdominal fat tissue by 12 weeks after cryolipolysis. Therefore, in this split-body trial, we explored whether a single session of unilateral cryolipolysis could change visceral and subcutaneous adipose tissue over a period of 12 weeks. We compared the cross-sectional areas of the abdominal adipose tissue of 15 subjects (9 women; 38.3 [10.8] years) by computed tomography before and at 12 weeks after a single treatment of cryolipolysis to the left abdomen and used the right abdomen as untreated control. In addition, we measured participants' waist circumference, percentage of body fat (by bioelectrical impedance analysis) at baseline and at 6- and 12-weeks post-treatment. Single unilateral cryolipolysis tended to reduce the cross-sectional areas of visceral adipose tissue, by 8.4 cm2 (9.9%), the waist circumferences, and the percent body fat, by 2.8 cm2 (0.6%), overall. The cross-sectional area of visceral adipose tissues on the treated side significantly decreased, by 6.8 cm2 (15.6%; P = 0.003), and that of the untreated side tended to decrease by 1.2 cm2 (3.6%). Thus, a single unilateral session of noninvasive selective cryolipolysis can be considered as a safe and effective treatment for reduction of visceral adipose tissue over a period of 12 weeks, which should result in metabolic improvement.

Association between shift work and suicidal ideation: data from the Korea National Health and Nutrition Examination Survey (2008-2016).

Objective Studies on the relationship between shift work and suicidal ideation are scarce. This study aimed to investigate the impact of shift work on suicidal ideation using a nationwide representative sample from the Korean working population. Methods The association between shift work and suicidal ideation was determined using data in 17 756 Korean workers over 19 years of age with fixed work schedules. These data were collected from the nationwide cross-sectional Korean National Health and Nutrition Examination Survey (2008-2016). The odds ratios (OR) and 95% confidence intervals (CI) for suicidal ideation were calculated by sex and age using multiple logistic regression models. Results Approximately 14% of included participants were classified as shift workers. Among male workers, evening and night shift workers had a significantly increased risk of suicidal ideation compared to day workers after adjusting for demographics, lifestyle factors, comorbidities, number of work hours, and occupational type (OR 1.89, 95% CI 1.25-2.88 for evening-fixed workers and OR 1.38, 95% CI 1.03-1.86) for night-fixed workers]. Age-stratified analyses indicated that shift workers were more likely to report suicidal ideation than day workers in young and middle-aged groups. Conclusion Evening and night shift work is associated with higher suicidal ideation among male workers.

Corrigendum: 2018 Korean Society for the Study of Obesity Guideline for the Management of Obesity in Korea.

[This corrects the article on p. 40 in vol. 28, PMID: 31089578.].

2018 Korean Society for the Study of Obesity Guideline for the Management of Obesity in Korea.

Obesity increases the risks of diabetes, hypertension, and cardiovascular diseases, ultimately contributing to mortality. Korean Society for the Study of Obesity (KSSO) was established to improve the management of obesity through research and education; to that end, the Committee of Clinical Practice Guidelines of KSSO reviews systemic evidence using expert panels to develop clinical guidelines. The clinical practice guidelines for obesity were revised in 2018 using National Health Insurance Service Health checkup data from 2006 to 2015. Following these guidelines, we added a category, class III obesity, which includes individuals with body mass index (BMI) ≥35 kg/m2. Agreeing with the International Federation for the Surgery of Obesity and Metabolic Disorders, Asian Pacific Chapter consensus, we determined that bariatric surgery is indicated for Korean patients with BMI ≥35 kg/m2 and for Korean patients with BMI ≥30 kg/m2 who have comorbidities. The new guidelines focus on guiding clinicians and patients to manage obesity more effectively. Our recommendations and treatment algorithms can serve as a guide for the evaluation, prevention, and management of overweight and obesity.

Does Weight Gain Associated with Thiazolidinedione Use Negatively Affect Cardiometabolic Health?

Thiazolidinediones (TZDs) are oral anti-diabetic drugs that are peroxisome proliferator-activated receptor gamma (PPARγ) agonists and act as insulin sensitizers. The clinical efficacy and durability of the currently available TZDs in improving glycemic control are well established. However, TZDs cause weight gain, which has been thought to be a class effect of TZDs. TZD-associated weight gain may result mainly from increased fat mass and fluid retention and may be in part congruent to the mechanism of action of TZD. Increases in fat mass are almost exclusively limited to subcutaneous fat, while there are no effects or even decreases in visceral fat. Insulin resistance and cardiovascular risk associated with fat accumulation (obesity) depend on body fat distribution, with visceral fat associated with insulin resistance and a greater degree of risk than subcutaneous fat. Therefore, despite TZD-associated weight gain, TZDs are less likely to confer an increased risk of insulin resistance and cardiovascular complications. As patients with diabetes are younger and/or more obese in Korea, TZDs may be a cost-effective treatment option, offering a unique insulin-sensitizing action and good durability for the long-term management of type 2 diabetes.

Conduction, Evaluation, and Future Considerations for an Obesity Educator Training Program in Korea.

To reduce the prevalence of obesity and provide information on evidence-based obesity treatments, the Education Committee of the Korean Society for the Study of Obesity (KSSO) has developed and launched the first Obesity Educator Training Program (OETP). After the course, we analyzed the results of a survey from 110 participants, comprising medical doctors (n=58), nutrition specialists (n=19), exercise specialists (n=14), and students (n=6). Approximately half of the participants were recruited through the Internet (48%), followed by academic leaflets, such as conference posters (21%); the reasons for participation were to learn about evidence-based treatments for obesity (47%), to receive up-to-date knowledge on obesity treatments (39%), to obtain basic information on obesity (10%), and others (4%). More than half of the participants found the date, lecture time, process, and theme of the OETP favorable. The participants indicated that there should be an in-depth course, sharing of the presented files with attendees, a longer lecture time, and a broader OETP that includes other specialties such as nursing. To improve the OETP, the educational committee of the KSSO must develop an in-depth OETP that will reflect these participant's feedback.

Effects on weight reduction and safety of short-term phentermine administration in Korean obese people.

The phentermine, an appetite suppressant, has been widely applied in Korea since 2004. However, there have been relatively few reports about the efficacy and the safety of phentermine in Korea. The aim of this study is to verify the effect of phentermine on weight reduction and the safety in Korean patients. This randomized, double-blind, placebo- controlled study had been performed between February and July, 2005, in Seoul on 68 relatively healthy obese adults whose body mass index was 25 kg/m2 or greater. They received phentermine-HCl 37.5 mg or placebo once daily with behavioral therapy for obesity. The primary endpoints were the changes of body weight and waist circumference from the baseline in the intention-to-treat population. Mean decrease of both body weight and waist circumference in phentermine-treated subjects were significantly greater than that of placebo group (weight: -6.7 +/- 2.5 kg, p < 0.001; waist circumference: -6.2 +/- 3.5 cm, p < 0.001). Significant number of subjects in phentermine group accomplished weight reduction of 5% or greater from the baseline and 10% or more (p < 0.001). There were no significant differences in systolic and diastolic blood pressure between the groups (p = 0.122 for systolic BP; p = 0.219 for diastolic BP). Dry mouth and insomnia were the only statistically significant adverse events that occurred more frequently in phentermine group. Most side effects of phentermine were mild to moderate in intensity. Short-term phentermine administration induced significant weight reduction and reduction of waist circumference without clinically problematic adverse events on relatively healthy Korean obese people.

2014 clinical practice guidelines for overweight and obesity in Korea.

The dramatic increase in the prevalence of obesity and its accompanying comorbidities are major health concerns in Korea. Obesity is defined as a body mass index ≥25 kg/m² in Korea. Current estimates are that 32.8% of adults are obese: 36.1% of men and 29.7% of women. The prevalence of being overweight and obese in national surveys is increasing steadily. Early detection and the proper management of obesity are urgently needed. Weight loss of 5% to 10% is the standard goal. In obese patients, control of cardiovascular risk factors deserves the same emphasis as weight-loss therapy. Since obesity is multifactorial, proper care of obesity requires a coordinated multidisciplinary treatment team, as a single intervention is unlikely to modify the incidence or natural history of obesity.

Serum ferritin is linked with aortic stiffness in apparently healthy Korean women.

BACKGROUND: There has been strong recent interest in the association between serum ferritin concentrations and increased risk of cardiovascular events. Surplus nutrition and convenience-seeking behavior has contributed to emergence of an increasingly obese population, with a concurrent increase in the prevalence of cardiovascular diseases. To date, few studies have specifically examined the association between serum ferritin and aortic stiffness in healthy populations, thus we investigated the association between serum ferritin and aortic stiffness according to sex and obesity in healthy subjects. METHODS AND RESULTS: From a register of 196 healthy subjects (146 males, 50 females) 23 to 76 years of age, we measured BMI, serum ferritin, blood pressures, metabolic variables, and brachial ankle pulse wave velocity (baPWV). The average baPWV, serum ferritin and the sociodemographic prevalence (smoking, alcohol, and exercise) were higher in men than women. There was a positive association between serum ferritin and baPWV (R = 0.02) in total subjects after adjusting for age, sex, and blood pressures. The association between serum ferritin and baPWV (R = 0.099) in women was positive, yet negative in men (R = -0.007). The average baPWV and serum ferritin were highest in obese men, on the other hand lowest in nonobese women among 4 groups according to sex and obesity. CONCLUSIONS: In conclusion, there was a stronger association between serum ferritin and PWV in healthy Korean women than men. Our finding suggests that cardiovascular risk factor monitoring through baPWV should be considered for even apparently healthy Korean women.