Body mass index and mortality: a twelve-year prospective study in Korea

Human papillomavirus infection and cardiovascular mortality: a cohort study

BACKGROUND AND AIMS

High-risk human papillomavirus (HR-HPV) infection-a well-established risk factor for cervical cancer-has associations with cardiovascular disease (CVD). However, its relationship with CVD mortality remains uncertain. This study examined the associations between HR-HPV infection and CVD mortality.

METHODS

As part of a health examination, 163 250 CVD-free Korean women (mean age: 40.2 years) underwent HR-HPV screening and were tracked for up to 17 years (median: 8.6 years). National death records identified the CVD mortality cases. Hazard ratios (HRs) and 95% confidence intervals (CIs) for CVD mortality were estimated using Cox proportional hazard regression analyses.

RESULTS

During 1 380 953 person-years of follow-up, 134 CVD deaths occurred, with a mortality rate of 9.1 per 105 person-years for HR-HPV(-) women and 14.9 per 105 person-years for HR-HPV(+) women. After adjustment for traditional CVD risk factors and confounders, the HRs (95% CI) for atherosclerotic CVD (ASCVD), ischaemic heart disease (IHD), and stroke mortality in women with HR-HPV infection compared with those without infection were 3.91 (1.85-8.26), 3.74 (1.53-9.14), and 5.86 (0.86-40.11), respectively. The association between HR-HPV infection and ASCVD mortality was stronger in women with obesity than in those without (P for interaction = .006), with corresponding HRs (95% CI) of 4.81 (1.55-14.93) for obese women and 2.86 (1.04-7.88) for non-obese women.

CONCLUSIONS

In this cohort study of young and middle-aged Korean women, at low risks for CVD mortality, those with HR-HPV infection had higher death rates from CVD, specifically ASCVD and IHD, with a more pronounced trend in obese individuals.

Glycaemic status, insulin resistance, and risk of infection-related mortality: a cohort study

IMPORTANCE

The impact of non-diabetic hyperglycaemia and insulin resistance on infection-related mortality risk remains unknown.

OBJECTIVE

We investigated the association of glycaemic status and insulin resistance with infection-related mortality in individuals with and without diabetes.

DESIGN

Cohort study based on Kangbuk Samsung Health Study and national death records.

PARTICIPANTS

About 666 888 Korean adults who underwent fasting blood measurements including glucose, glycated haemoglobin (HbA1c), and insulin during health-screening examinations were followed for up to 15.8 years.

MAIN OUTCOME AND MEASURES

Infection-related mortality, therefore we used Cox proportional hazards regression analyses to estimate hazard ratios (HRs) and 95% CIs for infection-related mortality. Vital status and infection-related mortality were ascertained through national death records. Variable categories were created based on established cut-offs for glucose and HbA1c levels and homeostatic model assessment of insulin resistance (HOMA-IR) quintiles.

RESULTS

During a median follow-up of 8.3 years, 313 infectious disease deaths were dentified. The associations of glucose and HbA1c levels with infection-related mortality were J-shaped (P for quadratic trend<.05). The multivariable-adjusted HR (95% CIs) for infection-related mortality comparing glucose levels <5, 5.6-6.9, and ≥7.0 mmol/L to 5.0-5.5 mmol/L (the reference) were 2.31 (1.47-3.64), 1.65 (1.05-2.60), and 3.41 (1.66-7.00), respectively. Among individuals without diabetes, the multivariable-adjusted HR for infection-related mortality for insulin resistance (HOMA-IR ≥75th centile versus <75th centile) was 1.55 (1.04-2.32).

CONCLUSIONS AND RELEVANCE

Both low and high glycaemic levels and insulin resistance were independently associated with increased infection-related mortality risk, indicating a possible role of abnormal glucose metabolism in increased infection-related mortality.

Progranulin and Breast Cancer Mortality: 13-Year Follow-Up of a Cohort Study

Background

We have reported that serum progranulin (PGRN) levels are clinically significant in predicting recurrence in patients with HR-positive breast cancer. The aim of the present study was to examine whether PGRN levels might be associated with breast cancer mortality.

Methods

This was a cohort study of 695 newly diagnosed breast cancer patients who underwent curative surgery between 2001 and 2004. The relationship between breast cancer mortality and pre-operative serum PGRN levels in these patients with a median follow-up of 12.7 years was evaluated until May 2020.

Results

A total of 118 (17%) deaths were identified in the cohort. According to the HR status, (10, 15, and 20)-year overall survival (OS) rates were (91.4, 81.1, and 75.9) % for HR-positive patients, and (76.5, 74.2, and 69.8) % for HR-negative patients, respectively (p = 0.003). Higher levels of PGRN were significantly associated with poor OS in the HR-positive group (p for trend = 0.001). In particular, hazard ratios for PGRN quartiles suggested a dose-response relationship, with the highest quartile having the worst OS in the HR-positive group (highest vs lowest: 15-year OS, (68.3 vs 90.0) %; 20-year OS, (62.3 vs 84.8) %, even after adjusting for age, tumor stage, and metabolic confounders.

Conclusion

Pre-operative serum PGRN levels had clinical significance for predicting cancer mortality in breast cancer patients independent of tumor stage and metabolic parameters, especially in HR-positive tumors.

Isolated Hepatitis B Core Antibody Positivity and Long-Term Liver-Related Mortality in Korea: A Cohort Study

INTRODUCTION

Whether isolated hepatitis B core antibody (anti-HBc) positivity is a risk factor for long-term liver-related outcomes in hepatitis B virus (HBV)-endemic areas remains unclear. We aimed to investigate liver-related and liver cancer mortality of isolated anti-HBc positivity in Korean adults.

METHODS

A cohort study comprised 609,299 Korean adults who underwent hepatitis B serologic markers, as a part of health examination. Liver-related and liver cancer mortality were determined using the National Death Records.

RESULTS

During a median follow-up of 9.0 years (interquartile range, 5.5-13.7 years), 554 liver-related deaths were identified (liver-related mortality, 9.6 cases per 10 5 person-years). The prevalence of isolated anti-HBc positivity was 3.8% (n = 23,399) and was age-dependent. After adjustment for age, sex, and other confounders, hazard ratios (95% confidence interval) for liver-related mortality in isolated anti-HBc-positive and hepatitis B surface antigen-positive subjects compared with HBV-unexposed subjects were 1.69 (1.22-2.33) and 27.02 (21.45-34.04), respectively. These associations were pronounced in the analyses using liver cancer mortality as an outcome. Among isolated anti-HBc-positive patients, the risks of liver-related and liver cancer mortality were significantly higher in those with high fibrosis-4 scores compared with patients unexposed to HBV with the multivariable-adjusted hazard ratios (95% confidence interval) of 15.59 (9.21-26.37) and 72.66 (36.96-142.86), respectively.

DISCUSSION

In this cohort of Korean adults, isolated anti-HBc positivity was associated with an increased risk of liver-related and liver cancer mortality, especially when accompanied by a high fibrosis score. Isolated anti-HBc positivity may be an independent risk factor for liver-related outcomes, especially in high-endemic areas.

Liver fibrosis scores and risk of liver-related mortality in young adults with chronic hepatitis B: A cohort study

The predictive role of noninvasive liver fibrosis scores on liver-related mortality in patients with chronic hepatitis B below 40 years of age remains unclarified. We examined the association of liver fibrosis scores with liver-related mortality in young (<40 years) and older adults with hepatitis B virus (HBV) infection. A cohort study was performed in 21,360 HBsAg-positive Korean adults without liver cirrhosis or liver cancer at baseline who were followed up for up to 18 years. The liver fibrosis scores were determined using the fibrosis-4 score (FIB-4) and aspartate transaminase to platelet ratio index (APRI). Patients' vital status and cause of death were ascertained through the National Death Records. During a median follow-up of 10.2 years, 283 liver-related deaths were identified (liver-related mortality, 127.4/10⁵ person-years). The liver fibrosis scores were significantly associated with increased risks of liver-related mortality; this association did not differ by age group (<40 vs. ≥40 years). The multivariable-adjusted hazard ratios with 95% confidence intervals for liver-related mortality comparing intermediate and high to low FIB-4 scores were 4.23 (1.99-9.00), and 15.16 (5.18-44.38), respectively, among individuals under 40, and 4.46 (3.03-6.56) and 22.47 (15.11-33.41), respectively, among older individuals. These associations were similar in analyses using APRI. In this cohort of HBsAg-positive individuals, the liver fibrosis scores were associated with increased risks of liver-related mortality in young and older adults. The liver fibrosis scores have a role in predicting liver mortality, even in young adults with HBV.

Cigarette smoking and risk of infection-related mortality: A cohort study

BACKGROUND

Cigarette smoking is a leading cause of death worldwide and is associated with various diseases. However, studies addressing its impact on infection-related deaths are limited. This study examined the relationship between smoking and infection-related mortality.

METHODS

A cohort of 583,034 South Korean adults who underwent annual or biennial health examinations were followed-up for infection-related deaths using national records. Cox proportional hazards regression assessed hazard ratios (HRs) and 95% confidence intervals (CIs) for infection-related mortality.

RESULTS

The median follow-up was 9.1 years (maximum 18 years), and 335 infection-related deaths were identified. Current smoking, but not former smoking, was positively associated with an increased risk of infection-related mortality. After adjusting for possible confounders, the multivariable-adjusted HRs ( 95% CIs) for infection-related mortality comparing former and current smokers with never smokers were 0.94 (0.68-1.30) and 1.45 (1.05-2.02), respectively; and those for infection-related mortality by number of pack-years comparing 10-19.9 and ≥20 pack-years to <10 pack-years were 1.26 (0.81-1.96) and 1.47 (1.03-2.09), respectively, while those comparing 10-19 and ≥20 cigarettes/day to <10 cigarettes/day were 1.35 (0.86-2.11) and 1.54 (1.13-2.11), respectively (p for trend <0.05). Individuals with ≥20 pack-years had a 2.06 times greater risk of infection-related mortality when changes in smoking status and confounders during follow-up were updated in the analysis as time-varying covariates.

CONCLUSION

Current smoking status, intensity and pack-years were associated with an increased risk of infection-related death, with the highest risk of infection-related mortality found consistently in individuals with ≥20 pack-years.

IMPLICATIONS

In this large-scale cohort study of relatively young and middle-aged South Korean adults, current smoking, smoking intensity, and pack-years were associated with an increased risk of death due to infections; in particular, a significantly increased risk of infection-related mortality was consistently found in individuals with ≥20 pack-years. When appropriate, infection-related mortality should be included in smoking-attributable mortality burdens, and effective smoking control measures should be considered to improve infection-related mortality.

Low-level alcohol consumption and cancer mortality

The effect of light-to-moderate alcohol consumption on cancer risk remains controversial. We examined the association between low-level alcohol consumption and cancer mortality. A cohort study included 331,984 Korean adults free of cancer at baseline who underwent a comprehensive health checkup examination. Participants were categorized into never drinkers, former drinkers, and current drinkers who were further divided into light, moderate, heavy, and very heavy drinkers. Vital status and cancer-related deaths were ascertained through links to national death records. During 1,633,906 person-years of follow-up (median 5.3 years interquartile range 3.8–6.2), 374 cancer-related deaths were identified (cancer-cause mortality rate of 23 per 10⁵ person-years). When former and never drinkers were classified as non-drinkers, the light drinkers had a lowest risk of cancer mortality compared with non-drinkers and other current drinkers (J-shaped); however, with consideration of lifetime abstinence history, current drinking was positively associated with cancer mortality in a dose-dependent manner. When changes in alcohol drinking status and confounders during follow-up were updated as time-varying covariates and never drinkers were used as the reference, the multivariable-adjusted hazard ratios (HRs) (95% confidence intervals, CIs) for cancer mortality among current light, moderate, heavy, and very heavy drinkers were 1.58 (1.03–2.43), 2.28 (1.41–3.70), 2.34 (1.42–3.85), and 2.97 (1.80–4.90), respectively, and the highest risk of cancer mortality was observed in former drinkers, who had an HR (95% CI) of 3.86 (2.38–6.28). Alcohol consumption was significantly and positively associated with an increased risk of cancer mortality in a dose-dependent manner, beginning with light drinkers.

Visual acuity and risk of overall, injury-related, and cardiovascular mortality: the Kangbuk Samsung Health Study

AIMS 

The associations of visual impairment (VI) with cardio-metabolic risk factors have been reported but its association with cardiovascular mortality remains uncertain. Therefore, we evaluated the association of visual acuity (VA) with overall, injury-related, and cardiovascular mortality.

METHODS AND RESULTS

A cohort study was performed in 580 746 Korean adults (average age, 39.7 years) who were followed for a median of 8.1 years (maximum, 16 years). Presenting VA was measured by the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. Visual acuity in the better vision eye was categorized as normal vision (≥0.8), lowered vision (0.5-0.8), mild visual impairment (VI) (0.3-0.5), or moderate to severe VI (<0.3). Vital status and cause of death were ascertained through linkage to national death records. During 4 632 892.2 person-years of follow-up, 6585 overall deaths, 974 cardiovascular deaths, and 1163 injury-related deaths were identified. After adjustment for possible confounders, the multivariable-adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) for overall mortality among participants with lowered vision, minimal VI, and moderate to severe VI were 1.21 (1.13-1.29), 1.26 (1.15-1.37), and 1.54 (1.40-1.68), respectively, compared with those with normal vision. The corresponding HRs (95% CIs) for injury-related mortality were 1.12 (0.96-1.32), 0.98 (0.76-1.26), and 1.36 (1.04-1.79), respectively, and the corresponding HRs (95% CIs) for cardiovascular mortality were 1.32 (1.12-1.57), 1.43 (1.15-1.77), and 2.41 (1.94-2.99).

CONCLUSION 

In this large cohort of young and middle-aged individuals, VI was associated with increased risk of mortality especially due to cardiovascular disease.

Depressive symptoms and risk of liver-related mortality in individuals with hepatitis B virus infection: a cohort study

The impact of depression on the risk of liver-related mortality in individuals with hepatitis B virus (HBV) infection remains unclear. We examined the association between depression, HBV infection, and liver-related mortality. A total of 342,998 Korean adults who underwent health examinations were followed for up to 7.8 years. Depressive symptoms were defined as a Center for Epidemiologic Studies-Depression score ≥ 16. Cox proportional hazard models were used to estimate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs). During 1,836,508 person-years of follow-up, 74 liver-related deaths and 54 liver cancer deaths were identified (liver-related mortality rate of 4.0 per 10⁵ person-years and liver cancer mortality rate of 2.9 per 10⁵ person-years). Subjects with depressive symptoms had an increased risk of liver-related mortality with a corresponding multivariable aHR of 2.00 (95% CI 1.10–3.63) compared to those without depressive symptoms. This association was more evident in HBsAg-positive participants with a corresponding multivariable aHR of 4.22 (95% CI 1.81–9.88) than HBsAg-negative participants (P for interaction by HBsAg positivity = 0.036). A similar pattern was observed in relation to liver cancer mortality. In this large cohort, depressive symptoms were associated with an increased risk of liver-related mortality, with a stronger association in HBsAg-positive individuals.

Glycemic Status, Insulin Resistance, and Risk of Pancreatic Cancer Mortality in Individuals With and Without Diabetes

INTRODUCTION

The impact of glycemic status and insulin resistance on the risk of pancreatic cancer in the nondiabetic population remains uncertain. We aimed to examine the association of glycemic status and insulin resistance with pancreatic cancer mortality in individuals with and without diabetes.

METHODS

This is a cohort study of 572,021 Korean adults without cancer at baseline, who participated in repeat screening examinations which included fasting blood glucose, hemoglobin A1c, and insulin, and were followed for a median of 8.4 years (interquartile range, 5.3 -13.2 years). Vital status and pancreatic cancer mortality were ascertained through linkage to national death records.

RESULTS

During 5,211,294 person-years of follow-up, 260 deaths from pancreatic cancer were identified, with a mortality rate of 5.0 per 10 person-years. In the overall population, the risk of pancreatic cancer mortality increased with increasing levels of glucose and hemoglobin A1c in a dose-response manner, and this association was observed even in individuals without diabetes. In nondiabetic individuals without previously diagnosed or screen-detected diabetes, insulin resistance and hyperinsulinemia were positively associated with increased pancreatic cancer mortality. Specifically, the multivariable-adjusted hazard ratio (95% confidence intervals) for pancreatic cancer mortality comparing the homeostatic model assessment of insulin resistance ≥75th percentile to the <75th percentile was 1.49 (1.08-2.05), and the corresponding hazard ratio comparing the insulin ≥75th percentile to the <75th percentile was 1.43 (1.05-1.95). These associations remained significant when introducing changes in insulin resistance, hyperinsulinemia, and other confounders during follow-up as time-varying covariates.

DISCUSSION

Glycemic status, insulin resistance, and hyperinsulinemia, even in individuals without diabetes, were independently associated with an increased risk of pancreatic cancer mortality.

Abnormal and Euthyroid Ranges of Thyroid Hormones in Serum and Liver Cancer Mortality: A Cohort Study

BACKGROUND

This study aimed to evaluate the relationship of serum thyrotropin (TSH) and thyroid hormone concentration with liver cancer mortality.

METHODS

A cohort of 517,996 Korean adults, who did not have liver cancer at baseline and attended a health screening including free thyroxine (FT4) and TSH, were followed for up to 16 years. High and low TSH and FT4 were defined as those above the upper bound of reference interval and those below the lower bound of reference interval of their corresponding reference intervals, respectively. Mortality information was ascertained through National Death Records. The adjusted HR (aHR) with 95% confidence interval (CI) were estimated using a Cox proportional hazard model.

RESULTS

During a median follow-up of 8.1 years, 376 deaths from liver cancer were identified. Subjects with low FT4 levels were associated with an elevated risk of liver cancer mortality with a corresponding multivariable aHR 2.25 (95% CI: 1.62-3.12) compared with those with normal FT4 levels. Within the euthyroid range, there was also a dose-dependent inverse relationship between FT4 level and liver cancer mortality (P < 0.001). Levels of TSH and free T3 had no significant association with liver cancer mortality.

CONCLUSIONS

The risk of liver cancer mortality increased as FT4 level decreased, both within the normal and abnormal ranges of thyroid function.

IMPACT

Thyroid function within the abnormal and normal ranges might affect liver cancer mortality. Further study is warranted to elucidate the role of thyroid hormone in development of liver cancer including the underlying biological mechanism.

Non-invasive liver fibrosis scores are strongly associated with liver cancer mortality in general population without liver disease

BACKGROUND & AIMS

In a general population without known liver disease, we tested whether: (a) increased liver fibrosis scores (FIB-4 and APRI) are associated with liver cancer mortality and (b) the probability that a person with a higher score died of liver cancer.

METHODS

In a retrospective occupational cohort who underwent annual/biennial health examinations (between 2002 and 2015), subjects were excluded with known chronic liver disease. Based on their baseline FIB-4 and APRI scores, subjects were categorised in low-/intermediate-/high-risk groups for advanced liver fibrosis. Using Cox proportional hazards regression analyses adjusted hazard ratios (aHR) were estimated for liver cancer mortality, with the low-risk FIB-4/APRI group as the reference. Harrell's C statistics were also calculated.

RESULTS

In 200 479 participants, mean (SD) age was 36.4 (7.7) years. Median follow-up was 4.1 years (IQR 2.10-8.03) with 80 liver cancer deaths. High baseline FIB-4 or APRI scores occurred in 0.25% and 0.09% of subjects respectively. A high FIB-4 or APRI score was associated with a markedly increased risk of liver cancer mortality (aHRs 629.10 [95% CI 228.74-1730.20] and 80.42 [95% CI 34.37-188.18]) respectively. C statistics were FIB-4 = 0.841 (95% CI 0.735-0.946) and APRI = 0.933 (95% CI 0.864-0.999).

CONCLUSIONS

In a general population without known liver disease, high FIB-4 or high APRI (in keeping with a high probability of advanced fibrosis) occurred in 0.25% (FIB-4) and 0.09% (APRI) of subjects. Both scores were associated with a markedly increased risk of liver cancer mortality and FIB-4 and APRI models both strongly predicted liver cancer mortality.

Hearing Loss and Risk of Overall, Injury-Related, and Cardiovascular Mortality: The Kangbuk Samsung Health Study

Hearing loss (HL) has been related to cardiovascular risk factors as well as prevalence of cardiovascular disease itself. We evaluated the association of HL with overall, injury-related, and cardiovascular mortality. A cohort study included 580,798 Korean adults (mean age: 39.7) who attended a screening exam between 2002 and 2016 with a follow-up of up to 17 years. HL was defined as a pure-tone average of thresholds at 0.5, 1.0, and 2.0 kHz ≥25 dB (decibels) in the better ear and further categorized into mild (25–<40 dB) and moderate-to-severe (≥40 dB). Overall and cause-specific mortality was ascertained through linkage to national death records. During median follow-up of 8.4 years, 6581 overall deaths, 977 cardiovascular deaths, and 1161 injury-related deaths were identified. Compared to participants with normal hearing, multivariable-adjusted hazard ratios (HRs) with 95% confidence intervals (95% CIs) for overall mortality among participants with mild and moderate-to-severe HL were 1.13 (1.05–1.21) and 1.30 (1.16–1.46), respectively. Corresponding HRs (95% CIs) for cardiovascular mortality were 1.32 (1.10–1.58) and 1.53 (1.16–2.01), respectively, and corresponding HRs (95% CIs) for injury-related mortality were 1.03 (0.81–1.31) and 1.64 (1.13–2.36), respectively. In this large cohort, HL was positively and independently associated with overall, cardiovascular, and injury-related mortality. A significantly elevated risk of cardiovascular mortality started from mild HL.

Prostate-Specific Antigen Within the Reference Range, Subclinical Coronary Atherosclerosis, and Cardiovascular Mortality

RATIONALE

Although PSA (prostate-specific antigen)-a tumor marker for prostate cancer-has been reported to be associated with cardiovascular disease (CVD) risk factors, studies on the association of PSA with subclinical and clinical CVD remain limited.

OBJECTIVE

We examined the association of total serum PSA within the reference range with coronary artery calcium (CAC) score and CVD mortality.

METHODS AND RESULTS

A cross-sectional study was performed in 88 203 Korean men who underwent a health checkup exam including cardiac tomography estimation of CAC score. Logistic regression model was used to calculate odds ratios with 95% CIs for prevalent CAC. PSA levels were inversely associated with the presence of CAC. After adjusting for potential confounders, multivariable-adjusted odds ratio (95% CIs) for prevalent CAC comparing PSA quartiles 2, 3, and 4 to the first quartile were 0.96 (0.90-1.01), 0.88 (0.83-0.93), and 0.85 (0.80-0.90), respectively ( P for trend, <0.001). A cohort study was performed in 243 435 Korean men with a mean age of 39.3 years, PSA values of <4.0 ng/mL, and without known CVD or prostate disease who were followed up with for ≤14 years for CVD mortality (median, 7.3 years). CVD deaths were ascertained through linkage to national death records. Hazard ratios and 95% CIs for CVD mortality were estimated using Cox proportional hazards regression analyses. During 1 829 070.1 person-years of follow-up, 336 CVD deaths were identified. After adjustment for potential confounders, multivariable-adjusted hazard ratios (95% CIs) for CVD mortality comparing PSA quartiles 2, 3, and 4 to the lowest quartile were 0.90 (0.66-1.22), 0.79 (0.58-1.08), and 0.69 (0.51-0.93), respectively.

CONCLUSIONS

Serum total PSA levels within the reference range showed an inverse association with subclinical atherosclerosis and CVD mortality in young and middle-aged Korean men, indicating a possible role of PSA as a predictive marker for subclinical and clinical CVD.

Alcoholic and Nonalcoholic Fatty Liver Disease and Liver-Related Mortality: A Cohort Study

OBJECTIVES

We compared liver-related mortality by fibrosis severity between 2 types of fatty liver disease (FLD), nonalcoholic FLD (NAFLD) and alcoholic FLD (AFLD), in a large cohort of nonobese and obese individuals.

METHODS

A cohort study was performed with 437,828 Korean adults who were followed up for up to 14 years. Steatosis was diagnosed based on ultrasonography; fibrosis severity was determined by the fibrosis 4 (FIB-4) score. Vital status and liver-related deaths were ascertained through linkage to national death records.

RESULTS

The prevalence of NAFLD and AFLD was 20.9% and 4.0%, respectively. During 3,145,541.1 person-years of follow-up, 109 liver-related deaths were identified (incidence rate of 3.5 per 10 person-years). When changes in fatty liver status, FIB-4 scores, and confounders during follow-up were updated as time-varying covariates, compared with the reference (absence of both excessive alcohol use and FLD), the multivariable-adjusted hazard ratios with 95% confidence intervals for liver-related mortality among those with low, intermediate, and high FIB-4 scores were 0.43 (0.19-0.94), 2.74 (1.23-6.06), and 84.66 (39.05-183.54), respectively, among patients with NAFLD, whereas among patients with AFLD, the corresponding hazard ratios (95% confidence intervals) were 0.67 (0.20-2.25), 5.44 (2.19-13.49), and 59.73 (27.99-127.46), respectively. The associations were more evident in nonobese individuals than in obese individuals (P for interaction = 0.004).

DISCUSSION

In this large cohort of young and middle-aged individuals, NAFLD and AFLD with intermediate to high fibrosis scores were associated with an increased risk of liver-related mortality in a dose-dependent manner, especially among nonobese individuals.

Association between adult height, myocardial infarction, heart failure, stroke and death: a Korean nationwide population-based study

Background

The association between adult height and cardiovascular (CV) events and mortality has been suggested, albeit inconsistently. We sought to discover the comprehensive relationship between height, CV-related morbidity and all-cause death according to age.

Methods

We investigated the association between adult height and myocardial infarction (MI), heart failure (HF), stroke incidence and mortality in 16 528 128 Korean patients who underwent regular health check-ups (2005-08). Height was stratified by decile according to age (20-39 years, 40-59 years and ≥60 years) and gender.

Results

During a 9-year follow-up period, 590 346 participants died and 232 093 were admitted to hospital for MI, 201 411 for HF and 267 566 for stroke. An inverse relationship between height and MI, HF, stroke and all-cause death was observed in the overall cohort analysis. The association was unchanged after adjusting for CV risk and behavioural and adulthood socioeconomic factors. Both male and female sex showed an inverse relationship with height in adulthood, CV events and mortality. Adult height showed an inverse association in all CV events and mortality, especially in the older groups (≥40 years). In a subgroup analysis of body mass index, there was an inverse relationship between height, CV events and mortality in each group.

Conclusions

Shorter height in adulthood was strongly related to an increased risk of MI, HF, stroke and all-cause death. A suitable environment and appropriate nutrition early in life could influence adult height and eventually reduce the risk of CV events and mortality.

U-Shaped Association Between Serum Uric Acid Level and Risk of Mortality: A Cohort Study

OBJECTIVE

In addition to the controversy regarding the association of hyperuricemia with cardiovascular disease (CVD) mortality, few studies have examined the impact of a low uric acid level on mortality. We undertook the present study to evaluate the relationship between both low and high uric acid levels and the risk of all-cause and cause-specific mortality in a large sample of Korean adults over a full range of uric acid levels.

METHODS

A cohort study was performed in 375,163 South Korean men and women who underwent health check-ups from 2002 to 2012. Vital status and cause of death were ascertained from the national death records. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for mortality outcomes were estimated using Cox proportional hazards regression analysis.

RESULTS

During a total of 2,060,721.9 person-years of follow-up, 2,020 participants died, with 287 CVD deaths and 963 cancer deaths. Low and high uric acid levels were associated with increased all-cause, CVD, and cancer mortality. The multivariable-adjusted HRs for all-cause mortality in the lowest uric acid categories (<3.5 mg/dl for men and <2.5 mg/dl for women) compared with the sex-specific reference category were 1.58 (95% CI 1.18-2.10) and 1.80 (95% CI 1.10-2.93), respectively. Corresponding HRs in the highest uric acid categories (≥9.5 mg/dl for men and ≥8.5 mg/dl for women) were 2.39 (95% CI 1.57-3.66) and 3.77 (95% CI 1.17-12.17), respectively.

CONCLUSION

In this large cohort study of men and women, both low and high uric acid levels were predictive of increased mortality, supporting a U-shaped association between serum uric acid levels and adverse health outcomes.

Effects of Initial Body Mass Index and Weight Change on All-Cause Mortality: A 10-Year Cohort Study in Korea

We evaluated the effects of baseline body mass index (BMI) and its changes over 4 years on all-cause mortality in Korean population. We analyzed 351 735 participants whose BMI was measured in both 2002/2003 and 2006/2007. Mortality was assessed until 2013. Multivariate hazard ratios for all-cause mortality were estimated. Underweight and severe obesity with BMI >30 kg/m2 were significantly associated with higher mortality. Similarly, >5% decrease or >10% increase of BMI for 4 years was associated with the increased risk of death. Comparing the results between baseline BMI and BMI change, the BMI change showed more stable associations with mortality than the baseline BMI in subgroup analysis such as nonsmokers and healthy participants. This study suggests that BMI change could be a useful health indicator along with obesity level by BMI. In addition, maintaining a healthy weight is needed for longevity, but rapid weight change should be carefully monitored.

Body Mass Index and Mortality according to Gender in a Community-Dwelling Elderly Population: The 3-Year Follow-up Findings from the Living Profiles of Older People Surveys in Korea

Background

Body mass index is widely regarded as an important predictor of mortality. The purpose of this study was to investigate the relationship between body mass index and mortality and to compare community-dwelling elderly people in South Korea according to sex.

Methods

Data were collected from the 2008 and 2011 Living Profiles of Older People Surveys, which comprised 10,613 community-living South Korean men and women aged 65 years or older. The participants were stratified into five groups according to body mass index as defined by the World Health Organization guidelines. The sociodemographic characteristics of participants and mortality rates were compared across the body mass index groups.

Results

The highest survival rates were observed in men with a body mass index of 25.0–29.9 kg/m². A similar trend was observed in women, but it was not statistically significant. After adjusting for covariates, this association was also found in men across all BMI index groups, but not in women.

Conclusion

This study supports previous findings that overweight or mild obesity is associated with the lowest mortality and suggests that the current categories of obesity require revision. Furthermore, the absence of statistically significant findings in the female cohort suggests that body mass index is not a suitable predictor of mortality in women and that an alternative is required.

Gallstones and the Risk of Gallbladder Cancer Mortality: A Cohort Study

OBJECTIVES

Despite epidemiologic data, definitive evidence for the role of gallstones as a cause for gallbladder cancer is lacking. The goal of this study was to evaluate the association between gallstones, determined by ultrasound, and the risk of gallbladder cancer mortality in a large study of Korean men and women. In addition, the association between gallstones and cholecystectomy, and risk of hepatobiliary cancer mortality was investigated.

METHODS

A cohort study was performed for 396,720 South Korean men and women who underwent a health checkup from 2002 to 2012. Hazard ratios for mortality outcomes were estimated using Cox-proportional hazards regression analysis. Vital status and cause of death assignment were based on linkage to the National Death Index of death certificate records.

RESULTS

From a total of 2,158,906.2 person-years of follow-up (median follow-up of 5.4 years), we identified 224 deaths from hepatobiliary cancer, comprising 174 cases of liver/intrahepatic bile ducts cancer, 20 cases of gallbladder cancer, and 30 cases of biliary tract cancer. Gallstones were significantly associated with increased risk of hepatobiliary cancer mortality, especially liver/intrahepatic biliary cancer, and gallbladder cancer mortality. The multivariable-adjusted hazard ratios (95% confidence intervals) for hepatobiliary cancer, liver/intrahepatic biliary cancer, and gallbladder cancer mortality comparing subjects having gallstones with those without gallstone disease were 2.74 (1.83-4.10), 2.34 (1.45-3.77), and 7.35 (2.60-20.8), respectively. Cholecystectomy was not significantly associated with hepatobiliary cancer mortality.

CONCLUSIONS

In this large cohort study, gallstones were associated with increased risk of hepatobiliary cancer mortality, especially liver/intrahepatic cancer, and gallbladder cancer mortality independent of potential confounders. Future studies with longer follow-up periods that include data on incident cancer cases should provide a more comprehensive view of the role of gallstones in cancer development.

Association of Kidney Disease Measures with Cause-Specific Mortality: The Korean Heart Study

BACKGROUND

The link of low estimated glomerular filtration rate (eGFR) and high proteinuria to cardiovascular disease (CVD) mortality is well known. However, its link to mortality due to other causes is less clear.

METHODS

We studied 367,932 adults (20-93 years old) in the Korean Heart Study (baseline between 1996-2004 and follow-up until 2011) and assessed the associations of creatinine-based eGFR and dipstick proteinuria with mortality due to CVD (1,608 cases), cancer (4,035 cases), and other (non-CVD/non-cancer) causes (3,152 cases) after adjusting for potential confounders.

RESULTS

Although cancer was overall the most common cause of mortality, in participants with chronic kidney disease (CKD), non-CVD/non-cancer mortality accounted for approximately half of cause of death (47.0%for eGFR <60 ml/min/1.73 m2 and 54.3% for proteinuria ≥1+). Lower eGFR (<60 vs. ≥60 ml/min/1.73 m2) was significantly associated with mortality due to CVD (adjusted hazard ratio 1.49 [95% CI, 1.24-1.78]) and non-CVD/non-cancer causes (1.78 [1.54-2.05]). The risk of cancer mortality only reached significance at eGFR <45 ml/min/1.73 m2 when eGFR 45-59 ml/min/1.73 m2 was set as a reference (1.62 [1.10-2.39]). High proteinuria (dipstick ≥1+ vs. negative/trace) was consistently associated with mortality due to CVD (1.93 [1.66-2.25]), cancer (1.49 [1.32-1.68]), and other causes (2.19 [1.96-2.45]). Examining finer mortality causes, low eGFR and high proteinuria were commonly associated with mortality due to coronary heart disease, any infectious disease, diabetes, and renal failure. In addition, proteinuria was also related to death from stroke, cancers of stomach, liver, pancreas, and lung, myeloma, pneumonia, and viral hepatitis.

CONCLUSION

Low eGFR was associated with CVD and non-CVD/non-cancer mortality, whereas higher proteinuria was consistently related to mortality due to CVD, cancer, and other causes. These findings suggest the need for multidisciplinary prevention and management strategies in individuals with CKD, particularly when proteinuria is present.

Body mass index and mortality among Korean elderly in rural communities: Kangwha Cohort Study

Background

The relationship between body mass index (BMI) and mortality may differ by ethnicity, but its exact nature remains unclear among Koreans. The study aim was to prospectively examine the association between BMI and mortality in Korean.

Methods

6166 residents (2636 men; 3530 women) of rural communities (Kangwha County, Republic of Korea) aged 55 and above were followed up for deaths from 1985–2008. The multivariable-adjusted hazard ratios were calculated using the Cox proportional hazards model.

Results

During the 23.8 years of follow-up (an average of 12.5 years in men and 15.7 years in women), 2174 men and 2372 women died. Men with BMI of 21.0–27.4 and women with BMI of 20.0–27.4 had a minimal risk for all-cause mortality. A lower BMI as well as a higher BMI increased the hazard ratio of death. For example, multivariable-adjusted hazard ratios associated with BMI below 16, and with BMI of 27.5 and above, were 2.4 (95% CI = 1.6–3.5) and 1.5 (95% CI = 1.1–1.9) respectively, in men, compared to those with BMI of 23.0–24.9. This reverse J-curve association was maintained among never smokers, and among people with no known chronic diseases. Higher BMI increased vascular mortality, while lower BMI increased deaths from vascular diseases, cancers, and, especially, respiratory diseases. Except for cancers, these associations were generally weaker in women than in men.

Conclusions

A reverse J-curve association between BMI and all-cause mortality may exist. BMI of 21–27.4 (rather than the range suggested by WHO of 18.5–23 for Asians) may be considered a normal range with acceptable risk in Koreans aged 55 and above, and may be used as cut points for interventions. More concern should be given to people with BMI above and below a BMI range with acceptable risk. Further studies are needed to determine ethnicity-specific associations.

Low energy intake during the first week in an emergency intensive care unit is associated with reduced duration of mechanical ventilation in critically ill, underweight patients: a single-center retrospective chart review

BACKGROUND

Although nutrition support is essential in intensive care units, optimal energy intake remains unclear. Here, we assessed the influence of energy intake on outcomes of critically ill, underweight patients.

METHODS

A retrospective chart review was conducted in patients with body mass index (BMI) of <20.0 kg/m(2) in an emergency intensive care unit (EICU). Patients were categorized into 4 groups by initial Sequential Organ Failure Assessment score (I-SOFA) and average daily energy intake during the first week: group M-1, I-SOFA ≤8 and <16 kcal/kg/d; group M-2, I-SOFA ≤8 and ≥16 kcal/kg/d; group S-1, I-SOFA >8 and <16 kcal/kg/d; and group S-2, I-SOFA >8 and ≥16 kcal/kg/d.

RESULTS

The study included 51 patients with a median age of 69 years. No significant differences were noted in all-cause mortality and length of stay in the EICU and hospital between groups M-1 and M-2 or groups S-1 and S-2. The mechanical ventilation duration (MVD) was significantly shorter in group M-1 than M-2 (2.7 [1.0-5.7] vs 9.2 [4.2-17.4] days; P = .040) and in group S-1 than S-2 (3.1 [0.7-6.0] vs 8.8 [6.1-23.1] days; P = .006). The number of patients who underwent tracheostomy in hospital was significantly lower in group S-1 than in S-2 (20% vs 32%; P = .002). Multivariable analyses to adjust for confounders revealed that average energy intake during the first week in EICU was a significant factor independently associated with MVD but not with the requirement of tracheostomy.

CONCLUSION

Reduced energy intake during the first week in EICU was associated with a reduced MVD in clinically ill patients with BMI <20.0 kg/m(2).

A prospective study of arm circumference and risk of death in Bangladesh

BACKGROUND

Epidemiological studies have observed protective effects of mid-upper arm circumference (MUAC) against all-cause mortality mostly in Western populations. However, evidence on cause-specific mortality is limited.

METHODS

The sample included 19 575 adults from a population-based cohort study in rural Bangladesh, who were followed up for an average of 7.9 years for mortality. Cox proportional hazards regression was used to evaluate the effect of MUAC, as well as the joint effect of body mass index (BMI) and MUAC, on the risk of death from any cause, cancer and cardiovascular disease (CVD).

RESULTS

During 154 664 person-years of follow-up, 744 deaths including 312 deaths due to CVD and 125 deaths due to cancer were observed. There was a linear inverse relationship of MUAC with total and CVD mortality. Each 1-cm increase in MUAC was associated a reduced risk of death from any cause [hazard ratio (HR) = 0.85; 95% confidence interval (C), 0.81-0.89) and CVD (HR = 0.87; 95% CI, 0.80-0.94), after controlling for potential confounders. No apparent relationship between MUAC and the risk of death from cancer was observed. Among individuals with a low BMI (<18.5 kg/m(2)), a MUAC less than 24 cm was associated with increased risk for all-cause (HR = 1.81; 95% CI, 1.52-2.17) and CVD mortality (HR = 1.45; 95% CI, 1.11-1.91).

CONCLUSIONS

MUAC may play a critical role on all-cause and CVD mortality in lean Asians.

Update and validation of a national health risk appraisal tool in Korea

BACKGROUND

Health risk appraisal (HRA) is an effective tool for lifestyle modification. We updated a national HRA using Robbins' method and tested its validity for predicting mortality.

METHODS

We used various national statistical data (such as life tables and mortality rates) to construct a Geller-Gesner table and referred to well-designed cohort studies to calculate composite risks. We compiled an HRA age table from these data and calculated health age (HA). To test the validity of this HRA, we compared the difference in 8-year mortality among different chronological age and health age (CA-HA) categories and used age-adjusted, sex-specific Cox proportional hazard models to investigate the association between CA-HA and all-cause mortality.

RESULTS

There was a significant difference in mortality according to CA-HA category, and the Cox proportional hazard model showed that as CA-HA decreased from ≥2 to ≤-6, the cumulative survival rate was significantly decreased.

CONCLUSIONS

This HRA can be an effective tool for detecting people at risk and for motivating lifestyle modification in Korea.

The Korean Twin Registry — Methods, Current Stage, and Interim Results

The Korean Twin Registry is the first nationwide twin study in Korea. We compiled 154,783 twin pairs from existing nationwide data sources, mainly from address and national health insurance data. The coverage of this registry was almost complete for the twins born since 1970, but less complete as age increased, so that there were only 990 pairs who were born before 1930. The twins' health examination (N = 54,390 persons) and questionnaire (N = 44,546 persons) results were incorporated into the registry, yielding 12,894 and 9074 concordantly informative pairs. Morbidity and mortality outcomes have been followed up since 1990, for most diseases. For preliminary analysis of complex diseases, we selected ventricular septal defects (VSD) in young twins, stomach and colorectal cancers in adult twins. We identified 353 VSDs, 284 stomach cancers, and 116 colorectal cancers among twins. The prevalence rates of cancers, but not that of VSD, were lower in twins than those in population. The difference in the cancer prevalence was marked for twins born before 1926, implying some degree of selection. Like-sex (LS) twins showed familial recurrence risks (λLS) of 41.2 for VSD and 22.4 for colorectal cancers, and 1.74 for stomach cancers. For opposite-sex (OS) twins, we could estimate λOS of 19.8 for VSD only. These results were compatible with previous studies for VSD and colorectal cancers, but not for stomach cancers. Despite the strength in size, availability of health outcomes, and some lifestyle and basic laboratory data, we need accurate zygosity information to improve the validity of the results.

Trends in body mass index and associations with physical activity among career soldiers in South Korea

OBJECTIVE

This study was designed to describe the trends in body mass index (BMI) during 6 years (2002 - 2008) and to identify associations between these trends and the amount of physical activity of South Korean career soldiers.

METHOD

This study targeted the 40 993 (38 857 men and 2136 women) of the 58 657 career soldiers who had undergone four (2002, 2004, 2006, and 2008) biennial medical examinations conducted by the National Health Insurance Corporation; 17 664 soldiers with missing data on height, weight, and physical activity were excluded. A linear mixed-regression model was used to categorize changes in BMI due to age versus those due to amount of physical activity.

RESULTS

Career soldiers experienced significant increases in BMI compared with baseline data gathered in 2002. The increases in each age group were as follows: men aged 20-29: 1.16, men aged 30-39: 0.61, men aged 40-49: 0.05, women aged 20-29: 0.35, women aged 30-39: 0.30, women aged 40-49: 0.26, and women aged 50-59: 0.21. However, men aged 50 or older showed significant decreases (as high as 0.5) in BMI compared with baseline data obtained in 2002. They also experienced significant decreases in BMI compared with those who reported no physical activity. The differences between baseline and final BMIs were: 0.02 for men exercising 1-2 times per week, -0.07 for men exercising 3-4 times per week, -0.19 for men exercising 5-6 times per week, -0.21 for men exercising seven times per week, -0.05 for women exercising 1-2 times per week, -0.19 for women exercising 3-4 times per week, -0.30 for women exercising 5-6 times per week, and -0.30 for women exercising seven times per week.

CONCLUSIONS

Obesity in South Korean career soldiers increased markedly between 2002 and 2008, and our data showed that the amount of physical activity was inversely related to increases in BMI. Policies to prevent obesity are needed to reduce this trend.

Waist circumference as compared with body-mass index in predicting mortality from specific causes

BACKGROUND

Whether waist circumference provides clinically meaningful information not delivered by body-mass index regarding prediction of cause-specific death is uncertain.

METHODS

We prospectively examined waist circumference (WC) and body-mass index (BMI) in relation to cause-specific death in 225,712 U.S. women and men. Cox regression was used to estimate relative risks and 95% confidence intervals (CI). Statistical analyses were conducted using SAS version 9.1.

RESULTS

During follow-up from 1996 through 2005, we documented 20,977 deaths. Increased WC consistently predicted risk of death due to any cause as well as major causes of death, including deaths from cancer, cardiovascular disease, and non-cancer/non-cardiovascular diseases, independent of BMI, age, sex, race/ethnicity, smoking status, and alcohol intake. When WC and BMI were mutually adjusted in a model, WC was related to 1.37 fold increased risk of death from any cancer and 1.82 fold increase risk of death from cardiovascular disease, comparing the highest versus lowest WC categories. Importantly, WC, but not BMI showed statistically significant positive associations with deaths from lung cancer and chronic respiratory disease. Participants in the highest versus lowest WC category had a relative risk of death from lung cancer of 1.77 (95% CI, 1.41 to 2.23) and of death from chronic respiratory disease of 2.77 (95% CI, 1.95 to 3.95). In contrast, subjects in the highest versus lowest BMI category had a relative risk of death from lung cancer of 0.94 (95% CI, 0.75 to 1.17) and of death from chronic respiratory disease of 1.18 (95% CI, 0.89 to 1.56).

CONCLUSIONS

Increased abdominal fat measured by WC was related to a higher risk of deaths from major specific causes, including deaths from lung cancer and chronic respiratory disease, independent of BMI.

Is body mass index associated with pathological outcomes after radical prostatectomy in Korean men?

Study Type--Therapy (case series) Level of Evidence 4. What's known on the subject? and What does the study add? Today, controversies continue with regards to the potential impact of obesity or increased body mass index (BMI) on actual pathological features of prostate cancer and/or clinical outcome after radical prostatectomy (RP). Moreover, a paucity of relevant data exist in the literature regarding Asian or Korean men. For the first time to our knowledge, the study demonstrated that although higher BMI was significantly associated with extracapsular extension of tumour, BMI did not significantly enhance ability to preoperatively predict extracapsular extension of tumour and was not significantly associated with PSA outcome as well as other objective pathological outcomes in Korean men undergoing RP, who are generally leaner than Western counterparts.

OBJECTIVE

• To investigate the impact of increased body mass index (BMI) on pathological features after radical prostatectomy (RP) in Korean patients.

PATIENTS AND METHODS

• We reviewed the records of 1000 Korean patients who underwent RP for prostate cancer and assessed the differences in pathological outcomes and biochemical recurrence-free survival after RP according to BMI of subjects via univariate and multivariate analyses. • A multivariate logistics regression model, the performance of which was analysed from a receiver operator characteristics curve, was applied to assess the predictive capacity of variables shown to be significant predictors of adverse pathological outcome.

RESULTS

• Among our subjects, only 17 (1.7%) men had BMI ≥30 kg/m(2). After adjusting for various clinical variables, BMI (highest quartile vs others) was shown to be significantly associated with extracapsular extension of tumour (P= 0.014) and positive surgical margin (P= 0.019), but not with high pathological Gleason score (P= 0.912) and seminal vesicle invasion (P= 0.191). • Meanwhile, the addition of BMI to a multivariate model devised for preoperatively predicting extracapsular extension of tumour did not significantly increase predictive accuracy of the model (P= 0.319). On multivariate analysis, BMI was not shown to be a significant predictor of biochemical recurrence-free survival (P= 0.201).

CONCLUSION

• Although higher BMI was significantly associated with extracapsular extension of tumour, BMI did not significantly enhance the ability to preoperatively predict extracapsular extension of tumour and was not significantly associated with PSA outcome or with other objective pathological outcomes in Korean men undergoing RP, who are generally leaner than their western counterparts.

Socioeconomic disparities in behavioral risk factors and health outcomes by gender in the Republic of Korea

BACKGROUND

Few studies have examined socioeconomic disparities in health and behavioral risk factors by gender in Asian countries and in South Korea, specifically. We investigated the relationship between socioeconomic position (education, income, and occupation) and subjective and acute and chronic health outcomes and behavioral risk factors by gender, and compared results from 1998 and 2005, in the Republic of Korea.

METHODS

We examined data from a nationally representative stratified random sample of 4213 men and 4618 women from the 1998 Korea National Health and Nutrition Examination Survey, and 8289 men and 8827 women from the 2005 Korea National Health and Nutrition Examination Survey using General Linear Modeling and multiple logistic regression methods.

RESULTS

Controlling for behavioral risk factors (smoking, drinking, obesity, exercise, and sleep), those in lower socioeconomic positions had poorer health outcomes in both self-reported acute and chronic disease and subjective measures; differences were especially pronounced among women. A socioeconomic gradient for education and income was found for both men and women for morbidity and self-reported health status, but the gradient was more pronounced in women. In 1998, the odds ratios (ORs) of higher morbidity for illiterate vs. college educated females was 5.4:1 and 1.9:1 for females in the lowest income quintile vs. the highest. The OR for education decreased in 2005 to 2.9:1 and that for income quintiles remained the same at 1.9:1. The OR of lower self-reported health status for illiterate vs. college educated females was 2.9:1 and 1.6:1 for females in the lowest income quintile vs. the highest in 1998, and 3.3:1 and 2.3:1 in 2005.

CONCLUSIONS

Among Korean adults, men and women in lower socioeconomic position, as denoted by education, income, and somewhat less by occupation, experience significantly higher levels of morbidity and lower self-reported health status, even after controlling for standard behavioral risk factors. Disparities were more pronounced for women than for men. Efforts to reduce health disparities in South Korea require attention to the root causes of socioeconomic inequality and gender differences in the impact of socioeconomic position on health.

Increases in body mass index over a 7-year period and risk of cause-specific mortality in Korean men

BACKGROUND

The association between increased body mass index (BMI) and subsequent mortality remains unclear in Asians. This study investigated the associations between BMI increases and cause-specific mortality in middle-aged Korean men.

METHODS

We conducted a retrospective cohort study of 473 358 Korean men aged 30-64 years, who had undergone health examinations in both 1992 and 1998 and were followed up during 1998-2004. Cox proportional hazards for cause-specific 7-year mortality in relation to BMI changes after stratification of baseline BMI status were analysed.

RESULTS

Mortality from cardiovascular disease (CVD) was associated with BMI in both 1992 and 1998. Non-CVD mortality was inversely associated with BMI in both 1992 and 1998. We cross-classified participants into groups based on their baseline BMI levels and percent BMI changes during follow-up; men with the lowest BMI level at baseline (BMI in 1992 <21 kg/m(2)) and stable BMI during follow-up (percent change in BMI <5%) were included in the reference category. Compared with the reference group, CVD mortality was higher in initially obese men (BMI in 1992 > or =25 kg/m(2)) with any increase of BMI, and in initially lean men (BMI in 1992 <21 kg/m(2)) or initially overweight men (BMI in 1992 23-24.9 kg/m(2)) with BMI increases of > or =10%. BMI increases of 5.0-9.9% in men with baseline BMI <25 kg/m(2) and stable BMI in men with baseline BMI > or =21 kg/m(2) appeared to lower the risk for non-CVD or all-cause mortality, to below the levels seen in the reference group.

CONCLUSIONS

Among middle-aged Korean men, obesity or severe weight gain was detrimental to CVD mortality. An increase in BMI appeared to have a predictive value for CVD mortality, especially when used in combination with baseline BMI level. In contrast, moderate weight gain in non-obese men seemed to protect against non-CVD and all-cause mortality.

Survival in older men may benefit from being slightly overweight and centrally obese--a 5-year follow-up study in 4,000 older adults using DXA

BACKGROUND

Whether overweight in old age is hazardous remains controversial. Body mass index (BMI) overestimates adiposity and fails to measure central adiposity. We used dual-energy x-ray absorptiometry (DXA) to measure adiposity and hypothesized that overall adiposity, distribution of adiposity, and muscle mass might individually affect survival.

METHODS

We recruited 2000 men and 2000 women aged 65 years or older. Baseline BMI, waist-hip ratio (WHR), body fat index (BFI = total body fat/height square), relative truncal fat (RTF = trunk fat/total body fat), and body muscle mass index (BMMI = total body muscle mass/height square) were measured. Mortality was ascertained by death registry after 63.3 (median) months.

RESULTS

Two hundred and forty-two men and 78 women died. In men, mortality hazard ratio (HR) decreased consistently by 0.85 (p < .005), 0.86 (p < .005), and 0.86 (p < .005) per every quintile increase in BMI, BFI, and BMMI, respectively. A J-shaped relationship was observed in central adiposity (RTF and WHR) quintiles; the minimum values were at the 3rd WHR quintile (0.92-0.94) and 4th RTF quintile (mean WHR, 0.94). When RTF was tested with BFI, both high and low central adiposity were unfavorable while general adiposity became marginally insignificant (p = 0.062). When BFI and BMMI were tested together, increasing adiposity rather than muscle mass favored survival (BFI quintile, HR 0.97, p .015; BMMI quintile, HR 1.00, p .997).

CONCLUSIONS

Older men were resistive to hazards of overweight and adiposity; and mild-grade overweight, obesity, and even central obesity might be protective. This may bear significant implication on the recommended cutoff values for BMI and WHR in the older population.

Blood pressure has a greater impact on cardiovascular mortality than other components of metabolic syndrome in Koreans

OBJECTIVE

Limited information is currently available on the association of metabolic syndrome or individual components with risk of cardiovascular morbidity and mortality in diverse populations. Here, we investigate the relationship of metabolic syndrome and its individual components with cardiovascular mortality in Korean adults.

METHODS

Data were obtained from 57,237 patients (32,819 men and 24,418 women), aged 40-89 years, subjected to regular health examinations at the Health Promotion Center of Asan Medical Center, Seoul, Korea (1999-2001) and subsequently followed up for a median time of 5.6 years. The risk of cardiovascular mortality was analyzed in relation to metabolic syndrome and its individual components.

RESULTS

The risk of cardiovascular mortality attributable to elevated blood pressure was approximately 52% in men and 72% in women, respectively. Compared to subjects without metabolic syndrome, individuals with metabolic syndrome presented a relative risk (RR) of cardiovascular disease (CVD)-induced death of 1.75 (95% CI, 1.15-2.66). After mutual adjustment for the individual components of metabolic syndrome, elevated blood pressure was significantly associated with CVD death, with RR values of 2.08 (95% CI, 1.27-3.42) in men and 3.56 (95% CI, 1.55-8.19) in women.

CONCLUSION

In Koreans, metabolic syndrome increases the risk of CVD death, with the blood pressure component being the key predictor of mortality.

Body mass index and cardiovascular disease mortality in Japan: the Ohsaki Study

OBJECTIVE

Although there is a clear positive association between obesity and the incidence and severity of cardiovascular disease, the association between underweight and cardiovascular disease is unclear. The objective of this study was to examine the relation between body mass index (BMI) and cardiovascular disease in Japan, where the proportion of the population that is underweight is relatively high.

METHOD

A total of 43,916 Japanese adults (21,003 men and 22,913 women) aged 40 to 79 years who had no history of cancer, ischemic heart disease (IHD), or stroke participated in the baseline survey in 1994. Hazard ratios (HR) and their 95% confidence intervals (CIs) for death due to total cardiovascular disease, all strokes, ischemic stroke, hemorrhagic stroke, and IHD were calculated according to BMI by using Cox's proportional hazards regression models. The 22.5-24.9 kg/m(2) BMI category was used as the reference category in all analyses.

RESULTS

There were U-shaped associations between BMI and total cardiovascular disease, all stroke, hemorrhagic stroke, and IHD mortality, and a J-shaped association between BMI and ischemic stroke mortality. Participants with a BMI <18.5 kg/m(2) had a significantly increased risk of total cardiovascular disease, all stroke, hemorrhagic stroke, and IHD mortality, and the multivariate HR (95% CI) was 1.62 (1.19-2.19), 1.50 (1.02-2.21), 2.11 (1.07-4.17), 1.83 (1.11-3.01), respectively.

CONCLUSION

Underweight was substantially associated with hemorrhagic stroke and IHD mortality in Japan, while obesity was associated with increased risk of total cardiovascular disease mortality and mortality from individual cardiovascular diseases.

Changes in body weight predict CKD in healthy men

Several recent prospective studies have reported that obesity is associated with an increased risk for chronic kidney disease (CKD), but it is unknown whether weight gain increases the risk for CKD if one remains within the "normal" category of body mass index (BMI). We prospectively followed a cohort of 8792 healthy men who had no known risk factors for CKD and participated in a comprehensive health evaluation program at a large worksite. During 35,927 person-years of follow-up, 427 new incident cases of CKD (estimated GFR <64 ml/min per 1.73 m(2)) developed. Cox proportional hazards modeling revealed that in both the normal-weight and overweight groups, a U-shaped association between weight change categories and development of CKD was observed after adjustment for age, baseline GFR, baseline BMI, HDL, fasting blood glucose, uric acid, and exercise habits. The lowest risk for CKD was observed among those whose weight changed -0.25 to <0.25 kg/yr (P < 0.001 for quadratic term). Weight change as a time-dependent variable was significantly related to CKD incidence. These relationships remained significant even after further adjustment for Homeostasis Model Assessment of Insulin Resistance, high-sensitivity C-reactive protein, systolic BP, diastolic BP, metabolic syndrome, incident hypertension, or incident diabetes. In summary, increases in body weight are independently associated with an increased risk for CKD, even when the BMI remains within the normal range.

Association of body mass index with all-cause and cause-specific mortality: findings from a prospective cohort study in Mumbai (Bombay), India

BACKGROUND

The association between extremes of relative body weight and mortality has not been well characterized in developing countries. A prospective cohort study was conducted in Mumbai (India) to study the association of relative body weight, as estimated by body mass index [BMI = weight (kg)/height(2) (m(2))], with mortality.

METHODS

Using the voters' list as the selection frame, 148 173 men and women aged >/=35 years were recruited during 1991-97 in Mumbai city and were followed-up during 1997-2003.

RESULTS

During 774 129 person-years of follow-up, 13 261 deaths were observed. After adjusting for the potential confounders, increased mortality was observed in all under-weight categories [relative risk (RR) = 1.94 for BMI < 16.0 kg/m(2), 1.38 for BMI 16.0 to <17.0 and 1.24 for BMI 17.0 to <18.5 among women; the corresponding values for men were 2.24, 1.45 and 1.27, respectively] when compared with the rate in the normal weight category (BMI 18.5 to <25.0). Extremely thin (BMI < 16.0 kg/m(2)) cohort members were at highest risk for death due to tuberculosis (TB) (RR = 7.20 and 14.94 in women and men, respectively), cancer (RR = 1.87 and 2.44, respectively) and respiratory diseases (RR = 3.46 and 4.35, respectively). Subjects with above normal BMI had lower mortality risk than those with normal BMI values. Over-weight (BMI 25.0 to <30.0) women (RR = 0.89) and men (RR = 0.87) were at a lower risk; however, obese (BMI >/= 30.0) men <60 years of age had an increased mortality risk (RR = 1.22).

CONCLUSION

In Mumbai, under-weight was associated with an increased risk of pre-mature death. Despite the growing concerns regarding the gradual transition toward increasing rates of obesity, under-nutrition remains a major health problem in India. This study suggests the need for public health policies focusing on reducing under-nutrition.

Effects of age, time period, and birth cohort on the prevalence of diabetes and obesity in Korean men

OBJECTIVE

We examined changes in the prevalence of diabetes, obesity, and overweight in 412,881 Korean men in birth cohorts from 1933 to 1972 over 8 years from 1992 to 2000 and separately analyzed the effects of age, time period, and birth cohort.

RESEARCH DESIGN AND METHODS

The study included male employees of Korean government organizations and schools who were between 20 and 59 years of age in 1992. Diabetes was diagnosed on the basis of self-reports in 1992 or fasting blood glucose levels (>or=126 mg/ml, 7.0 mmol/l). The age-period-cohort model was used to estimate the effects of age, time period, and birth cohort.

RESULTS

In Korean male birth cohorts from 1933 to 1972, the age-specific prevalence of diabetes, obesity, and overweight in men aged 28-59 years increased annually by 0.41% (3.03 to 6.29%), 0.18% (0.70 to 2.16%), and 1.49% (23.48 to 35.41%), respectively, from 1992 to 2000. The relative change in diabetes was largest among the younger cohorts (>400% increase over 8 years) and corresponded to the change in obesity. Apart from the contribution of age, clear cohort and period effects were evident for diabetes, although the magnitude of the effect was slightly less than that for obesity.

CONCLUSIONS

Prevention of diabetes through the control of obesity, particularly in young men, clearly needs to be emphasized.

Body Mass Index and Mortality in Middle-Aged Korean Women

PURPOSE

We sought to evaluate the association between body mass index (BMI) and mortality in Korean women and to determine whether the association differs depending on menopausal status.

METHODS

A total of 338,320 Korean women ages 40 to 64 years categorized into seven groups by BMI level were prospectively followed for mortality from approximately 1994 to 2004.

RESULTS

Multivariable-adjusted analysis using Cox proportional hazards model showed a U-shaped association between BMI and all-cause deaths, with the lowest risk at BMI between approximately 25 and 26.9 kg/m2, even after excluding earlier deaths, which did not change when we did a stratified analysis according to menopausal status. A U-shaped association was observed between BMI and cancer death, and the risk associated with low BMI decreased significantly after excluding earlier cancer deaths. There was a J-shaped association between BMI and coronary heart disease (CHD) with a significantly increased risk at greater BMI (>26 kg/m2). Additional adjustment for possible biological effects of obesity (i.e., serum total cholesterol, glucose, and systolic blood pressure) changed the U-shaped association between BMI and all-causes mortality into an inverse shape and substantially reduced the size of risk for CHD death associated with high BMI level. In stratified analysis, the association between BMI and CHD was positive linear in women at premenopausal status, whereas it was U-shaped in women at postmenopausal status.

CONCLUSIONS

Obesity was associated with an increased risk of mortality in both premenopausal and postmenopausal Korean women, indicating that preventive strategies to control obesity are important even in population with a relatively low mean BMI level.

Measuring the burden of disease in Korea

This paper provides an overview of the Korean Burden of Disease (KBoD) study, which was the first such study to assess the national burden of disease using disability-adjusted life years (DALYs) in an advanced Asian country. The KBoD study generally followed the approach utilized in the original Global Burden of Disease study (GBD), with the exception of the disease classification and epidemiological data estimation methods used, and the relative weightings of disabilities. The results of the present study reveal that the burden of disease per 100,000 of the Korean population originates primarily from; cancer (1,525 Person Years, PYs), cardiovascular disease (1,492 PYs), digestive disease (1,140 PYs), diabetes mellitus (990 PYs), and certain neuro-psychiatric conditions (883 PYs). These results are largely consistent with those of developed countries, but also represent uniquely Korean characteristics.

Varying patterns of BMI increase in sex and birth cohorts of Korean adults

OBJECTIVE

The Korean population has recently experienced a rapid increase in obesity associated with lifestyle changes arising from economic growth. We examined trends in BMI by analyzing sex-specific birth cohorts using 3,400,727 measurements from 1,662,477 Korean adults.

RESEARCH METHODS AND PROCEDURES

Birth cohort data were collected from the employees of government organizations and schools and their dependents, 20 to 65 years of age, who participated in health examinations provided by the Korean National Health Insurance Corporation in 1992, 1996, and 2000.

RESULTS

The prevalence of obesity (BMI > or = 30 kg/m(2)) was 0.8% among men and 0.3% among women in 1992, but by 2000, it had increased 2.5-fold to 2.0% in men and 2.3-fold to 0.7% in women. Over the 8-year period, the mean BMI increased 0.8 kg/m(2) in men and 0.3 kg/m(2) in women. The rate of BMI increase over the 8 years varied markedly among the sex-specific birth cohorts, with the steepest slopes representing the youngest men (0.2 kg/m(2) per year).

DISCUSSION

National health promotion activities should target younger men to prevent an increase in obesity-related morbidity and mortality.

Body Mass Index and Risk of Hemorrhagic Stroke in Korean Adults: Case-control Study

OBJECTIVES

To evaluate the association between body mass index (BMI) and hemorrhagic stroke.

METHODS

A case-control study was conducted on 2,712 persons (904 cases, 904 hospital controls, and 904 community controls) participating in an Acute Brain Bleeding Analysis study from October 2002 to March 2004. Two controls for each case were matched according to age and gender. The information was obtained by trained interviewers using standardized questionnaire. A conditional logistic regression model was used to estimate the association between BMI and the frequency of having a hemorrhagic stroke.

RESULTS

Obese men (25.0 <or= BMI < 30.0 kg/m(2)) had an odds ratios (OR) of 1.39 (95% CI 1.03 to 1.87) a hemorrhagic stroke, compared to men with a normal BMI (18.5 to 24.9 kg/m(2)). Conversely, women with lower BMI had a higher risk of having hemorrhagic stroke. With respect to subtypes of hemorrhagic stroke, we observed about a three-fold increase in the risk of intracerebral hemorrhage (ICH) in the highly obese group. However, these trends were not significant in patients with subarachnoid hemorrhages.

CONCLUSIONS

Obesity was identified as one of the risk factors in hemorrhagic stroke, in particular ICH. Conversely, in women, a lean body weight increases the risk of hemorrhagic stroke. Consequently, managing one\s weight is essential to reduce the risks of hemorrhagic stroke.

Body mass index and all-cause mortality in a nationwide US cohort

OBJECTIVE

To investigate whether the nature of the relationship between body mass index (BMI (kg/m2)) and all-cause mortality is direct, J- or U-shaped, and whether this relationship changes as people age.

DESIGN

Prospective nationwide cohort study of US radiologic technologists (USRT).

SUBJECTS

Sixty-four thousand seven hundred and thirty-three female and 19 011 male certified radiation technologists.

METHODS

We prospectively followed participants from the USRT study who completed a mail survey in 1983-1989 through 2000. During an average of 14.7 years of follow-up or 1.23 million person-years, 2278 women and 1495 men died. Using Cox's proportional-hazards regression analyses, we analyzed the relationship between BMI and all-cause mortality by gender and by age group (<55 years; > or = 55 years). We also examined risk in never-smokers after the first 5 years of follow-up to limit bias owing to the confounding effects of smoking and illness-related weight loss on BMI and mortality.

RESULTS

Risks were generally J-shaped for both genders and age groups. When we excluded smokers and the first 5 year of follow-up, risks were substantially reduced in those with low BMIs. In never-smoking women under the age of 55 years (excluding the initial 5-year follow-up period), risk rose as BMI increased above 21.0 kg/m2, whereas in older women, risk increased beginning at a higher BMI (> or = 25.0 kg/m2). Among younger men who never smoked (excluding the initial 5-year follow-up period), risk began to rise above a BMI of 23.0 kg/m2, whereas in older men, risk did not begin to increase until exceeding a BMI of 30.0 kg/m2.

CONCLUSIONS

In younger/middle-aged, but not older, women and men, mortality risks appear directly related to BMI. The more complicated relationship between BMI and mortality in older subjects suggests the importance of assessing whether other markers of body composition better explain mortality risk in older adults.

Impact of overweight and obesity on medical care costs, all-cause mortality, and the risk of cancer in Japan

We conducted three prospective cohort studies that examined the association between body mass index (BMI) and health outcomes in Japan. Our studies found statistically significant relationships between excess body weight and increased medical costs, all-cause mortality, and risk of cancer incidence. There was a U-shaped association between BMI and mean total costs. The estimated excess costs attributable to overweight and obesity was 3.2% of the total costs. This 3.2% is within the range reported in studies in Western countries (0.7%-6.8%). We observed statistically significant elevations in mortality risk in obese (BMI> or = 30.0 kg/m(2)) women and lean (BMI<18.5 kg/m(2)) men and women. Our prospective cohort study found statistically significant relationships between excess weight and increased risk in women of all cancers. The population attributable fraction (PAF) of all incident cancers in this population that were attributable to overweight and obesity were 4.5% in women, which were within the range reported from Western populations, from 3.2% for US women to 8.8% for Spanish women. Our data suggests that excess body weight is a problem not only in Western countries but also in Japan.

Multiple metabolic risk factors and total and cardiovascular mortality in men with low prevalence of obesity

We investigated the association between the multiple metabolic risk factors and cardiovascular and overall mortality among Korean men, a population with a low prevalence of obesity. This prospective cohort study involved 682,597 Korean men, aged 30-69 years at baseline (1992), who were initially without cancer or debilitating diseases. Death due to ischemic heart disease (IHD), stroke, cardiovascular disease (CVD), and any cause among men relative to metabolic risk factors, including overweight, high blood pressure, high fasting glucose, and high total cholesterol was analyzed. There were 17,785 deaths during the 8.5-year follow-up, of which 874 were due to IHD, 1644 to stroke, and 3306 to CVD. As a function of the number of metabolic risk factors, the relative risk of death from CVD was 2.0 (1.7-2.2), 2.9 (2.5-3.3), 3.5 (3.0-4.1), and 5.0 (3.9-6.4) for 1, 2, 3, and 4 risk factors, respectively, whereas the relative risk of death from all causes was 1.3 (1.2-1.4), 1.5 (1.4-1.6), 1.6 (1.5-1.7), and 1.9 (1.6-2.2) for 1, 2, 3, and 4 risk factors, respectively. The relative risk of IHD, stroke, CVD and all-cause mortality increased linearly with the number of metabolic risk factors. Early identification and strict management of metabolic risk factors should be reinforced in Koreans, even though there is a low prevalence of obesity among this population.

Obesity has a greater impact on cardiovascular mortality in younger men than in older men among non-smoking Koreans

INTRODUCTION

We investigated the effects of age on the relationship between body mass index (BMI) and cardiovascular risk factors and cardiovascular mortality in non-smoking Korean men.

METHODS

We performed a prospective cohort study of 246,146 non-smoking Korean men aged 20-69 years at baseline (1992) who were initially without history of cancer or weight change. The associations between BMI and cardiovascular risk factors and mortality during an 9-year follow-up period (2000) were stratified by age group after adjustment for family history, alcohol consumption, exercise habits, and economic status.

RESULTS

Calculations of odds ratios (ORs) revealed that younger men (<40 years) with greater BMI (>or=28 kg/m2) were at greater risk of high blood pressure, high blood glucose, and high total cholesterol than older men. The ORs for cardiovascular risk factors associated with greater BMI declined linearly with age. The relative risks for mortality from stroke and from all cardiovascular diseases associated with greater BMI were also higher among younger men and declined linearly with age.

CONCLUSIONS

The cardiovascular risk factors and mortality associated with greater BMI were higher among younger than older non-smoking Korean men. These findings indicate that obesity has a greater impact among younger men with respect to premature cardiovascular related deaths.

Body mass index and incident ischemic heart disease in South Korean men and women

Asian populations have a higher body fat percentage for a given body mass index (BMI) than Caucasians. However, little information is available on the association of BMI with ischemic heart disease (IHD) incidence in Asians at low BMI levels. The authors prospectively evaluated the association of BMI (weight (kg)/height m2) with IHD incidence over 9 years of follow-up (1993-2001) among 133,740 South Korean adults (89,050 men, 44,690 women) who participated in the 1990 and 1992 examinations of the Korea Medical Insurance Corporation Study. Average BMI at baseline was 23.4 (standard deviation, 2.3) in men and 22.3 (standard deviation, 2.3) in women. After multivariate adjustment, there was a 14% (95% confidence interval: 12, 16) increased risk of incident IHD per unit of increase in BMI. This trend was also observed within the range considered normal by Western standards, and a BMI of 24-<25 was associated with an IHD hazard ratio of 2.01 (95% confidence interval: 1.32, 3.05) in comparison with a BMI of 18-<19. The association of BMI with IHD in this cohort of relatively young South Korean men and women was progressive over the range of BMI values, with no threshold of change in risk and no indication of a U-shaped relation at low BMI levels.