BACKGROUND: Unlike patterns observed in the general population, obesity is associated with better survival among hemodialysis patients, which could be explained by reverse causation or illness-related weight loss. However, the time-varying effect of body mass index (BMI) on hemodialysis survival has not been investigated. Therefore, this study investigated the time-varying effect of BMI on mortality after starting hemodialysis. METHODS: In the present study, we examined Korean Society of Nephrology data from 16,069 adult patients who started hemodialysis during or after the year 2000. Complete survival data were obtained from Statistics Korea. Survival analysis was performed using Cox regression and a non-proportional hazard fractional polynomial model. RESULTS: During the median follow-up of 8.6 years, 9,272 patients (57.7%) died. Compared to individuals with normal BMI (18.5–24.9 kg/m²), the underweight group (< 18.5 kg/m²) had a higer mortality hazard ratio (HR, 1.292; 95% confidence interval [CI], 1.203–1.387; P < 0.001) and the overweight group (25.0–29.9 kg/m²) had a lower mortality HR (0.904; 95% CI, 0.829–0.985; P = 0.022). The underweight group had increasing HRs during the first 3 to 7 years after starting hemodialysis, which varied according to age group. The young obese group (< 40 years old) had a U-shaped temporal trend in their mortality HRs, which reflected increased mortality after 7 years. CONCLUSION: The obese hemodialysis group had better survival during the early post-dialysis period, although the beneficial effect of obesity disappeared 7 years after starting hemodialysis. The young obese group also had an increased mortality HR after 7 years.
Adult ; Body Mass Index ; Follow-Up Studies ; Humans ; Korea ; Models, Statistical ; Mortality ; Nephrology ; Obesity ; Overweight ; Renal Dialysis ; Thinness ; Weight Loss

BACKGROUND: Underweight is associated with increased mortality, relative to the normal weight category. The importance of managing underweight patients has not yet been recognized seriously in South Korea, and little information is available on the prevalence of underweight and its associated risk factors. This study aims to investigate changes in the prevalence of underweight by gender and age and analyze its trend.METHODS: Data were obtained from individuals aged >20 years, from the Korean National Health and Nutrition Examination Survey between 1995 and 2015. The subjects of this study included 134,613 adults (male, 61,152; female, 73,461). The prevalence of underweight was determined as defined by the Asia-Pacific Perspective, and socioeconomic factors associated with a predisposition to underweight were analyzed using the chi-squared test and multiple logistic regression analysis.RESULTS: Among Korean adults, the age-adjusted prevalence of underweight (body mass index < 18.5 kg/m²) was 3.1% in men and 6.3% in women. Overall, a U-shaped relationship was established between the prevalence of underweight by gender and age. There was no significant difference in socioeconomic factors related to the prevalence of underweight in men and women in their twenties. The prevalence of underweight in women aged 20–59 years showed an increasing trend (P for trends < 0.05).CONCLUSION: In individuals aged 20–29 years, the prevalence of being underweight was higher in women than in men. Recently, there has been an increasing trend in the prevalence of underweight young women of reproductive age. This requires national public health attention.
Adult ; Body Mass Index ; Female ; Humans ; Korea ; Life Style ; Logistic Models ; Male ; Mortality ; Nutrition Surveys ; Prevalence ; Public Health ; Risk Factors ; Social Class ; Socioeconomic Factors ; Thinness

BACKGROUND: Obesity is related to several comorbidities and mortality, but its relationship with acute kidney injury (AKI) and long-term mortality remain undetermined in patients undergoing coronary artery bypass grafting. METHODS: Data from 3,018 patients (age ≥ 18 years) who underwent coronary artery bypass graft surgery from two tertiary referral centers were retrospectively reviewed between 2004 and 2015. Obesity was defined using the body mass index, according to the World Health Organization's recommendation. The odds and hazard ratios in post-surgical, AKI, and all-cause mortality were calculated after adjustment for multiple covariates. Patients were followed for 90 ± 40.9 months (maximum: 13 years). RESULTS: Among the cohort, 37.4%, 2.4%, 21.1%, 35.1%, and 4.0% of patients were classified as normal weight, underweight, overweight-at-risk, obese I, and obese II, respectively. Post-surgical AKI developed in 799 patients (26.5%). Patients in the obese groups (overweight-at-risk to obese II) had a higher risk of AKI than did those in the normal-weight group. During the follow-up period, 787 patients (26.1%) died. Underweight patients had a higher risk of mortality than did normal-weight patients, whereas overweight-at-risk, obese I, and obese II patients showed better survival rates. CONCLUSION: After coronary artery bypass graft surgery, obese patients encountered a high risk of AKI, and underweight patients exhibited a low chance of survival. Awareness of both obese and underweight statuses should be raised in these patients.
Acute Kidney Injury* ; Body Mass Index ; Cohort Studies ; Comorbidity ; Coronary Artery Bypass* ; Coronary Vessels* ; Follow-Up Studies ; Global Health ; Humans ; Mortality* ; Obesity* ; Retrospective Studies ; Survival Rate ; Tertiary Care Centers ; Thinness ; Transplants

BACKGROUND: Liver transplantation (LT) is a complicated procedure with a high incidence of postoperative acute kidney injury (AKI). Previous studies indicate that even transient or mild post-LT AKI can result in critical conditions, including prolonged stays in hospitals and intensive care units and increased morbidity and mortality. The aim of this study was to investigate the association between body mass index (BMI) and occurrence of AKI in LT recipients. METHODS: Medical data from 203 patients who received LT surgery from January 2010 to August 2016 in a single university hospital setting were retrospectively collected and analyzed. Patients were classified as either underweight (BMI <20 kg/m²) or normal weight (20 ≤ BMI < 30 kg/m²). Demographic data, anesthetic methods, complications, and perioperative laboratory test values of each patient were assessed. Propensity analyses and logistic regression were performed to evaluate the association between BMI and post-LT AKI. RESULTS: There was no significant difference in occurrence of post-LT AKI between underweight and normal weight patients. The underweight patient group had significantly longer hospital stay compared with the normal weight patient group (P = 0.023). CONCLUSIONS: BMI classification was neither a positive nor negative predictor of postoperative AKI occurrence. However, patients with lower BMI had significantly longer hospital stay compared with their counterparts. Although our study was limited by its retrospective design, our observations suggest that lower BMI might play a role in post-LT AKI.
Acute Kidney Injury* ; Body Mass Index* ; Classification ; Humans ; Incidence ; Intensive Care Units ; Length of Stay ; Liver Transplantation* ; Liver* ; Logistic Models ; Mortality ; Retrospective Studies* ; Thinness

BACKGROUND: Liver transplantation (LT) is a complicated procedure with a high incidence of postoperative acute kidney injury (AKI). Previous studies indicate that even transient or mild post-LT AKI can result in critical conditions, including prolonged stays in hospitals and intensive care units and increased morbidity and mortality. The aim of this study was to investigate the association between body mass index (BMI) and occurrence of AKI in LT recipients. METHODS: Medical data from 203 patients who received LT surgery from January 2010 to August 2016 in a single university hospital setting were retrospectively collected and analyzed. Patients were classified as either underweight (BMI <20 kg/m²) or normal weight (20 ≤ BMI < 30 kg/m²). Demographic data, anesthetic methods, complications, and perioperative laboratory test values of each patient were assessed. Propensity analyses and logistic regression were performed to evaluate the association between BMI and post-LT AKI. RESULTS: There was no significant difference in occurrence of post-LT AKI between underweight and normal weight patients. The underweight patient group had significantly longer hospital stay compared with the normal weight patient group (P = 0.023). CONCLUSIONS: BMI classification was neither a positive nor negative predictor of postoperative AKI occurrence. However, patients with lower BMI had significantly longer hospital stay compared with their counterparts. Although our study was limited by its retrospective design, our observations suggest that lower BMI might play a role in post-LT AKI.
Acute Kidney Injury ; Body Mass Index ; Classification ; Humans ; Incidence ; Intensive Care Units ; Length of Stay ; Liver Transplantation ; Liver ; Logistic Models ; Mortality ; Retrospective Studies ; Thinness

Osteoporosis is a major health problem that can lead to mortality. This study was conducted to estimate the prevalence of osteopenia and osteoporosis separately and to assess the risk factors associated with osteopenia/osteoporosis in Korean men aged 50 years and over. A total of 1,136 subjects were analyzed among the participants of the Korea National Health and Nutrition Examination Survey (KNHANES) 2010~2011 by using SPSS statistics complex samples (windows ver. 23.0). The prevalence rates of osteopenia and osteoporosis were 46.3% and 7.3%, respectively, and the mean ages of both osteopenia and osteoporosis risk groups were significantly higher than that of the normal group. The mean values for lifetime tallest height and bone mineral density in whole body, total femur, femoral neck, and lumbar spine were significantly lower in the risk group (osteopenia/osteoporosis) than in the normal group, whereas the mean values for height, body weight, BMI, waist circumference, alkaline phosphatase, parathyroid hormone, fasting blood glucose, total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglycerides of the two groups showed no significant differences. The intakes of energy and carbohydrates were significantly higher in the risk group than in the normal group. The results of multiple logistic regression showed that being underweight and having hypercholesterolemia were significantly related with the prevalence of osteopenia/osteoporosis, whereas health habits such as smoking and exercise, chronic diseases such as obesity and hypertension, and nutrient intakes were not. These findings suggest the need for further studies to examine osteopenia/osteoporosis risk factors and outcomes specificly focused on Korean men.
Alkaline Phosphatase ; Blood Glucose ; Body Height ; Bone Density ; Bone Diseases, Metabolic ; Carbohydrates ; Cholesterol ; Chronic Disease ; Fasting ; Femur ; Femur Neck ; Humans ; Hypercholesterolemia ; Hypertension ; Korea* ; Logistic Models ; Male ; Mortality ; Nutrition Surveys* ; Obesity ; Osteoporosis ; Parathyroid Hormone ; Prevalence* ; Risk Factors* ; Smoke ; Smoking ; Spine ; Thinness ; Triglycerides ; Waist Circumference

The prognostic impact of body mass index (BMI) in patients with upper tract urothelial carcinoma (UTUC) is an ongoing debate. Our study aimed to investigate the prognostic role of BMI in patients treated with radical nephroureterectomy (RNU) for UTUC from a multi-institutional Korean collaboration. We retrospectively reviewed data from 440 patients who underwent RNU for UTUC at four institutions in Korea. To avoid biasing the survival estimates, patients who had previous or concomitant muscle-invasive bladder tumors were excluded. BMI was categorized into approximate quartiles with the lowest quartile assigned to the reference group. Kaplan-Meier and multivariate Cox regression analyses were performed to assess the influence of BMI on survival. The lower quartile BMI group showed significantly increased overall mortality (OM) and cancer specific mortality (CSM) compared to the 25%-50% quartiles and upper quartile BMI groups. Kaplan-Meier estimates showed similar results. Based on multivariate Cox regression analysis, preoperative BMI as a continuous variable was an independent predictor for OM and CSM. In conclusion, preoperative underweight patients with UTUC in Korea survive less after RNU. Preoperative BMI may provide additional prognostic information to establish risk factors.
Aged ; Asian Continental Ancestry Group ; Body Mass Index ; Carcinoma, Transitional Cell/*mortality ; Cystectomy/*mortality ; Female ; Humans ; Kidney Pelvis/surgery ; Male ; Nephrectomy/*mortality ; Republic of Korea ; Retrospective Studies ; Thinness/*mortality ; Ureter/surgery ; Urinary Bladder/surgery ; Urologic Neoplasms/*mortality/pathology/*surgery ; Urothelium/pathology/*surgery

OBJECTIVES: With a gradual decline in maternal mortality in recent years in Iran, this study was conducted to identify the remaining risk factors for maternal death. METHODS: This 8-year nested case-control study was conducted in Hamadan Province, in the west of Iran, from April 2006 to March 2014. It included 185 women (37 cases and 148 controls). All maternal deaths that occurred during the study period were considered cases. For every case, four women with a live birth were selected as controls from the same area and date. Conditional logistic regression analysis was performed and the odds ratio (OR) and its 95% confidence interval (CI) were obtained for each risk factor. RESULTS: The majority of cases were aged 20-34 years, died in hospital, and lived in urban areas. The most common causes of death were bleeding, systemic disease, infection, and pre-eclampsia. The OR estimate of maternal death was 8.48 (95% CI=1.26-56.99) for advanced maternal age (> or =35 years); 2.10 (95% CI=0.07-65.43) for underweight and 10.99 (95% CI=1.65-73.22) for overweight or obese women compared to those with normal weight; 1.56 (95% CI=1.08-2.25) for every unit increase in gravidity compared to those with one gravidity; 1.73 (95% CI=0.34-8.88) for preterm labors compared to term labors; and 17.54 (95% CI= 2.71-113.42) for women with systemic diseases. CONCLUSIONS: According to our results, advanced maternal age, abnormal body mass index, multiple gravidity, preterm labor, and systemic disease were the main risk factors for maternal death. However, more evidence based on large cohort studies in different settings is required to confirm our results.
Body Mass Index ; Case-Control Studies* ; Cause of Death ; Cohort Studies ; Female ; Gravidity ; Hemorrhage ; Humans ; Iran* ; Live Birth ; Logistic Models ; Maternal Age ; Maternal Death ; Maternal Mortality* ; Obstetric Labor, Premature ; Odds Ratio ; Overweight ; Pre-Eclampsia ; Pregnancy ; Risk Factors* ; Thinness

BACKGROUND: Underweight is associated with increased risk of mortality and morbidity. It is reported that the prevalence of underweight is increasing among Korean young women. However, there have been few studies on sociodemographic factors related to being underweight. This study was conducted to elucidate the sociodemographic characteristics of Korean underweight adults. METHODS: This study is a cross-sectional study of 7,776 adults aged 25 to 69 years using data from the Korea National Health and Nutrition Examination Survey, 2007-2010. Study subjects were composed of underweight and normal-weight adults excluding overweight adults. Body mass index was calculated from measured height and weight. Health behaviors such as smoking, drinking, and physical activity were surveyed through self-administered questionnaires, and socioeconomic status, marital status, and history of morbidity were surveyed through face-to-face interviews. RESULTS: Women had a higher frequency of underweight (10.4% vs. 7.0%, P < 0.001) than men. Among men, current smoking (odds ratio [OR], 1.62) and past history of cancer (OR, 2.55) were independently related to underweight. Among women, young age (OR, 2.06), former smoking (OR, 1.69), and being unmarried (OR, 1.56) were identified as independently related factors of underweight. In addition, among both men and women, alcohol drinking (men OR, 0.57; women OR, 0.77) and past history of chronic diseases (men OR, 0.55; women OR, 0.43) were independently related to a lower frequency of underweight. CONCLUSION: We showed that various sociodemographic factors were associated with underweight. It was ascertained that there were differences in the sociodemographic factors related to underweight between Korean men and women.
Adult* ; Alcohol Drinking ; Body Mass Index ; Chronic Disease ; Cross-Sectional Studies ; Demography ; Drinking ; Female ; Health Behavior ; Humans ; Korea* ; Male ; Marital Status ; Mortality ; Motor Activity ; Nutrition Surveys* ; Overweight ; Prevalence ; Single Person ; Smoke ; Smoking ; Social Class ; Sociology ; Thinness* ; Surveys and Questionnaires

BACKGROUND: The aim of this study was to investigate the association between body mass index (BMI) and survival in patients with severe sepsis or septic shock. METHODS: We analyzed the sepsis registry of patients presenting to the emergency department (ED) of a tertiary urban hospital and meeting the criteria for severe sepsis or septic shock from August 2008 to March 2012. We categorized patients into the underweight group (BMI < 18.5 kg/m2), the normal weight group (18.5 < or = BMI < 25 kg/m2) and the obese group (BMI > or = 25 kg/m2). Then, we analyzed the registry to evaluate the relation between obesity and in-hospital mortality. RESULTS: A total of 770 adult patients with severe sepsis and septic shock were analyzed. In-hospital mortality rate of the underweight group (n = 86), the normal weight group (n = 489) and the obese group (n = 195) was 22.1%, 15.3% and 16.4%, respectively. In a multivariate regression analysis, the underweight group had a significant association with in-hospital mortality compared with the normal weight group (odds ratio [OR], 1.12; 95% confidence interval [CI], 0.68-1.87; p = 0.028). The obese group showed no significant difference in mortality (OR, 2.04; 95% CI, 1.08-3.86; p = 0.65). CONCLUSIONS: The underweight patients showed significantly higher mortality than the normal weight patients with severe sepsis and septic shock.
Adult ; Body Mass Index* ; Emergencies ; Hospital Mortality ; Hospitals, Urban ; Humans ; Mortality ; Obesity ; Sepsis* ; Shock, Septic* ; Thinness