Does exercise have a protective effect on cognitive function under hypoxia? A systematic review with meta-analysis

OBJECTIVE

This study aimed to examine (1) the independent effects of hypoxia on cognitive function and (2) the effects of exercise on cognition while under hypoxia.

METHODS

Design: Systematic review with meta-analysis.

DATA SOURCES

PubMed, Scopus, Web of Science, PsychInfo, and SPORTDiscus were searched. Eligibility criteria for selecting studies: randomized controlled trials and nonrandomized controlled studies that investigated the effects of chronic or acute exercise on cognition under hypoxia were considered (Aim 2), as were studies investigating the effects of hypoxia on cognition (Aim 1).

RESULTS

In total, 18 studies met our inclusionary criteria for the systematic review, and 12 studies were meta-analyzed. Exposure to hypoxia impaired attentional ability (standardized mean difference (SMD) = -0.4), executive function (SMD = -0.18), and memory function (SMD = -0.26), but not information processing (SMD = 0.27). Aggregated results indicated that performing exercise under a hypoxia setting had a significant effect on cognitive improvement (SMD = 0.3, 95% confidence interval: 0.14 - 0.45, I² = 54%, p < 0.001). Various characteristics (e.g., age, cognitive task type, exercise type, exercise intensity, training type, and hypoxia level) moderated the effects of hypoxia and exercise on cognitive function.

CONCLUSION

Exercise during exposure to hypoxia improves cognitive function. This association appears to be moderated by individual and exercise/hypoxia-related characteristics.

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.

Long-Term Particulate Matter Exposure and Incidence of Arrhythmias: A Cohort Study

Background Studies have shown that short-term exposure to air pollution is associated with cardiac arrhythmia hospitalization and mortality. However, the relationship between long-term particulate matter air pollution and arrhythmias is still unclear. We evaluate the prospective association between particulate matter (PM) air pollution and the risk of incident arrhythmia and its subtypes. Methods and Results Participants were drawn from a prospective cohort study of 178 780 men and women who attended regular health screening exams in Seoul and Suwon, South Korea, from 2002 to 2016. Exposure to PM with an aerodynamic diameter of ≤10 and ≤2.5 μm (PM₁₀ and PM_2.5, respectively) was estimated using a land-use regression model. The associations between long-term PM air pollution and arrhythmia were examined using pooled logistic regression models with time-varying exposure and covariables. In the fully adjusted model, the odds ratios (ORs) for any arrhythmia associated with a 10 μg/m³ increase in 12-, 36-, and 60-month PM₁₀ exposure were 1.15 (1.09, 1.21), 1.12 (1.06, 1.18), and 1.14 (1.08, 1.20), respectively. The ORs with a 10 μg/m³ increase in 12- and 36-month PM_2.5 exposure were 1.27 (1.15, 1.40) and 1.10 (0.99, 1.23). PM₁₀ was associated with increased risk of incident bradycardia and premature atrial contraction. PM_2.5 was associated with increased risk of incident bradycardia and right bundle-branch block. Conclusions In this large cohort study, long-term exposure to outdoor PM air pollution was associated with increased risk of arrhythmia. Our findings indicate that PM air pollution may be a contributor to cardiac arrhythmia in the general population.

Gut microbiota and metabolic health among overweight and obese individuals

Although obesity is associated with numerous diseases, the risks of disease may depend on metabolic health. Associations between the gut microbiota, obesity, and metabolic syndrome have been reported, but differences in microbiomes according to metabolic health in the obese population have not been explored in previous studies. Here, we investigated the composition of gut microbiota according to metabolic health status in obese and overweight subjects. A total of 747 overweight or obese adults were categorized by metabolic health status, and their fecal microbiota were profiled using 16S ribosomal RNA gene sequencing. We classified these adults into a metabolically healthy group (MH, N = 317) without any components of metabolic syndrome or a metabolically unhealthy group (MU, N = 430) defined as having at least one metabolic abnormality. The phylogenetic and non-phylogenetic alpha diversity for gut microbiota were lower in the MU group than the MH group, and there were significant differences in gut microbiota bacterial composition between the two groups. We found that the genus Oscillospira and the family Coriobacteriaceae were associated with good metabolic health in the overweight and obese populations. This is the first report to describe gut microbial diversity and composition in metabolically healthy and unhealthy overweight and obese individuals. Modulation of the gut microbiome may help prevent metabolic abnormalities in the obese population.

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.

Relationship Between Non-alcoholic Fatty Liver Disease and Decreased Bone Mineral Density: A Retrospective Cohort Study in Korea

Objectives

The aim of this retrospective cohort study was to investigate whether non-alcoholic fatty liver disease (NAFLD) was associated with incident bone mineral density (BMD) decrease.

Methods

This study included 4536 subjects with normal BMD at baseline. NAFLD was defined as the presence of fatty liver on abdominal ultrasonography without significant alcohol consumption or other causes. Decreased BMD was defined as a diagnosis of osteopenia, osteoporosis, or BMD below the expected range for the patient’s age based on dual-energy X-ray absorptiometry. Cox proportional hazards models were used to estimate the hazard ratio of incident BMD decrease in subjects with or without NAFLD. Subgroup analyses were conducted according to the relevant factors.

Results

Across 13 354 person-years of total follow-up, decreased BMD was observed in 606 subjects, corresponding to an incidence of 45.4 cases per 1000 person-years (median follow-up duration, 2.1 years). In the model adjusted for age and sex, the hazard ratio was 0.65 (95% confidence interval, 0.51 to 0.82), and statistical significance disappeared after adjustment for body mass index (BMI) and cardiometabolic factors. In the subgroup analyses, NAFLD was associated with a lower risk of incident BMD decrease in females even after adjustment for confounders. The direction of the effect of NAFLD on the risk of BMD decrease changed depending on BMI category and body fat percentage, although the impact was statistically insignificant.

Conclusions

NAFLD had a significant protective effect on BMD in females. However, the effects may vary depending on BMI category or body fat percentage.

Experimental effects of acute exercise on forgetting

Objective

Prior research has evaluated the effects of acute exercise on episodic memory function. These studies have, on occasion, demonstrated that acute exercise may enhance both short- and long-term memory. It is uncertain as to whether the acute exercise improvements in long-term memory are a result of acute exercise attenuating declines in long-term memory, or rather, are driven by the enhancement effects of acute exercise on short-term memory. The present empirical study evaluates whether the decline from short- to long-term is influenced by acute exercise. This relationship is plausible as exercise has been shown to activate neurophysiological pathways (e.g., RAC1) that are involved in the mechanisms of forgetting.

Methods

To evaluate the effects of acute exercise on forgetting, we used data from 12 of our laboratory's prior experiments (N = 538). Across these 12 experiments, acute exercise ranged from 10 to 15 mins in duration (moderate-to-vigorous intensity). Episodic memory was assessed from word-list or paragraph-based assessments. Short-term memory was assessed immediately after encoding, with long-term memory assessed approximately 20-min later. Forgetting was calculated as the difference in short- and long-term memory performance.

Results

Acute exercise (vs. seated control) was not associated with an attenuated forgetting effect (d = 0.10; 95% CI: -0.04, 0.25, P = 0.17). We observed no evidence of a significant moderation effect (Q = 6.16, df = 17, P = 0.17, I2 = 0.00) for any of the evaluated parameters, including study design, exercise intensity and delay period.

Conclusion

Across our 12 experimental studies, acute exercise was not associated with an attenuated forgetting effect. We discuss these implications for future research that evaluates the effects of acute exercise on long-term memory function.

Low Levels of Alcohol Consumption and Risk of Intestinal Metaplasia: A Cohort Study

BACKGROUND

The impact of alcohol drinking on gastric precancerous lesions remains unclear. We investigated the relationship of alcohol intake with risk of atrophic gastritis (AG) and intestinal metaplasia (IM).

METHODS

This study included 202,675 Korean adults free from AG and IM on their initial endoscopy who were followed with repeated endoscopic examinations. A parametric proportional hazards model was used to estimate the adjusted HR (aHR) with 95% confidence interval (CI) for incident AG and IM based on endoscopic diagnosis.

RESULTS

During a mean follow-up of 4.7 years, 64,853 incident AG cases and 4,536 IM cases were identified. Alcohol consumption including drinking frequency, quantity, and binge drinking were consistently associated with increased risk of both AG and IM in a dose-response manner. After adjustment for confounders, the multivariable aHRs (95% CIs) for incident IM comparing average alcohol intake of <10, 10-<20, 20-<40, and ≥40 g/day with lifetime abstainers were 1.27 (1.02-1.56), 1.34 (1.07-1.66), 1.50 (1.20-1.86), and 1.54 (1.23-1.93), respectively. Former drinkers were also at a higher risk for AG and IM compared with lifetime abstainers. These associations were consistently observed in never smokers and in time-dependent analyses.

CONCLUSIONS

In a large cohort of Korean individuals, alcohol intake even at low levels was independently associated with increased risk of developing endoscopic AG and IM, supporting a role of alcohol consumption in the pathogenesis of AG and IM, the precursor lesions of stomach cancer.

IMPACT

Alcohol consumption from low-level drinking may contribute to gastric carcinogenesis.

Proton pump inhibitor use is associated with hip fracture development: a nationwide population-based cohort study

BACKGROUND/AIMS

Effect of proton pump inhibitor (PPI) use on the risk of hip fracture is controversial. This study aimed to clarify the association between PPI use and hip fracture risk using a large cohort.

METHODS

This study recruited participants from the nationwide cohort (n = 1,025,340). After exclusion of participants who had hip fractures or were aged less than 40 years during the baseline period (2002 to 2004), 371,806 participants were followed to 2013. Participants prescribed PPIs for more than 90 days during baseline period were defined as users. Fracture cases were defined when participants were hospitalized with claims of a hip fracture.

RESULTS

During 4,159,343 person-years of follow-up, fractures developed more often in PPI users than in nonusers (relative risk [RR], 1.787; 95% confidence interval [CI], 1.260 to 2.534; p = 0.002). The results persisted after adjusting for age, sex, and many drugs relevant to osteoporosis or influential in bone health. Furthermore, fracture risk associated with PPI use increased with duration of use (p trend < 0.001). The fully adjusted RRs of hip fracture development were 1.350 (95% CI, 1.203 to 1.515) for 1- to 90-day users, 1.487 (95% CI, 0.957 to 2.311) for 91- to 180-day users, and 1.771 (95% CI, 0.931 to 3.368) for > 180-day users. The positive association between PPI use and fracture was also confirmed in a subgroup with health screening data where further adjustment for body mass index, smoking status, alcohol consumption, and physical activity was available (adjusted RR, 2.025; 95% CI, 1.151 to 3.564, p = 0.014).

CONCLUSION

PPI use is associated with hip fracture development.

Mammographic breast density, its changes, and breast cancer risk in premenopausal and postmenopausal women

BACKGROUND

The risk of breast cancer related to changes in breast density over time, including its regression and persistence, remains controversial. The authors investigated the relationship between breast density and its changes over time with the development of breast cancer in premenopausal and postmenopausal women.

METHODS

The current cohort study included 74,249 middle-aged Korean women (aged ≥35 years) who were free of breast cancer at baseline and who underwent repeated screening mammograms. Mammographic breast density was categorized according to the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS). A dense breast was defined as heterogeneously dense or extremely dense, and changes in dense breasts between baseline and subsequent follow-up were classified as none, developed, regressed, or persistent dense breast.

RESULTS

During a median follow-up of 6.1 years (interquartile range, 4.1-8.8 years), a total of 803 incident breast cancers were identified. Baseline breast density was found to be positively associated with incident breast cancer in a dose-response manner, and this association did not significantly differ by menopausal status. The multivariable-adjusted hazard ratios (HRs) for breast cancer comparing "heterogeneously dense" and "extremely dense" categories with the nondense category were 1.96 (95% confidence interval [95% CI], 1.40-2.75) and 2.86 (95% CI, 2.04-4.01), respectively. With respect to changes in dense breasts over time, multivariable-adjusted HRs for breast cancer comparing persistent dense breast with none were 2.37 (95% CI, 1.34-4.21) in premenopausal women and 3.61 (95% CI, 1.78-7.30) in postmenopausal women.

CONCLUSIONS

Both baseline dense breasts and their persistence over time were found to be strongly associated with an increased risk of incident breast cancer in premenopausal and postmenopausal women.

LAY SUMMARY

Both baseline breast density and its changes over time were found to be independently associated with the risk of breast cancer in both premenopausal and postmenopausal women. The risk of incident breast cancer increased in women with persistent dense breasts, whereas the breast cancer risk decreased as dense breasts regressed. The findings of the current study support that both dense breasts at baseline and their persistence over time are independent risk factors for developing breast cancer.

Association between reproductive lifespan and lung function among postmenopausal women

Correspondence to: Hye Yun Park, MD, PhD. Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, 06351, South Korea. Email: hyeyunpark@skku.edu; Juhee Cho, PhD. Department of Clinical Research Design and Evaluation, SAIHST, Sungkyunkwan University, 81 Irwon-ro, Gangnam-gu, Seoul, 06351, South Korea. Email: Jcho@skku.edu.

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.

Cluster Analysis of Inhalant Allergens in South Korea: A Computational Model of Allergic Sensitization

Objectives.

Sensitization to specific inhalant allergens is a major risk factor for the development of atopic diseases, which impose a major socioeconomic burden and significantly diminish quality of life. However, patterns of inhalant allergic sensitization have yet to be precisely described. Therefore, to enhance the understanding of aeroallergens, we performed a cluster analysis of inhalant allergic sensitization using a computational model.

Methods.

Skin prick data were collected from 7,504 individuals. A positive skin prick response was defined as an allergen-to-histamine wheal ratio ≥1. To identify the clustering of inhalant allergic sensitization, we performed computational analysis using the four-parameter unified-Richards model.

Results.

Hierarchical cluster analysis grouped inhalant allergens into three clusters based on the Davies-Bouldin index (0.528): cluster 1 (Dermatophagoides pteronyssinus and Dermatophagoides farinae), cluster 2 (mugwort, cockroach, oak, birch, cat, and dog), and cluster 3 (Alternaria tenus, ragweed, Candida albicans, Kentucky grass, and meadow grass). Computational modeling revealed that each allergen cluster had a different trajectory over the lifespan. Cluster 1 showed a high level (>50%) of sensitization at an early age (before 19 years), followed by a sharp decrease in sensitization. Cluster 2 showed a moderate level (10%–20%) of sensitization before 29 years of age, followed by a steady decrease in sensitization. However, cluster 3 revealed a low level (<10%) of sensitization at all ages.

Conclusion.

Computational modeling suggests that allergic sensitization consists of three clusters with distinct patterns at different ages. The results of this study will be helpful to allergists in managing patients with atopic diseases.

Sedentary Behavior and Obesity in Youth According to Meeting Physical Activity Guidelines: National Health and Nutrition Examination Survey 2003-2006

Background: The purpose of this study was to examine the association between sedentary time and obesity in youth according to meeting physical activity guidelines. Methods: A total of 1991 youth (10-17 years) from the 2003 to 2006 National Health and Nutrition Examination Survey were included in the analysis. Physical activity was categorized into two levels: (1) daily engagement in ≥60 minutes of moderate and vigorous physical activity (MVPA) and (2) <60 minutes per day of MVPA. Sedentary time was categorized into four levels using quartiles. BMI was categorized into two levels using sex-specific BMI for age percentiles from the CDC: (1) obese group: BMI ≥90 percentile and (2) nonobese group: BMI <90 percentile. Results: After adjusting for covariates, among those meeting physical activity guidelines, there was a statistically significant relationship between sedentary time and obesity for Q1 (sedentary time <383.5 min/day) vs. Q4 (sedentary time >523.5 min/day) [odds ratio (OR) = 0.14, 95% confidence interval (CI): 0.02-0.87] and Q2 (sedentary time = 383.5-451.83 min/day) vs. Q4 (sedentary time >523.5 min/day) (OR = 0.16, 95% CI: 0.03-0.99). Among youth not meeting physical activity guidelines, however, sedentary time was not associated with obesity [OR = 0.72 (Q1 vs. Q4), OR = 0.88 (Q2 vs. Q4), OR = 1.08 (Q3 vs. Q4)]. Conclusions: These results indicate that sedentary time is associated with obesity among those meeting physical activity guidelines. However, the relationship between sedentary time and obesity in a low physical activity group is not obvious. Therefore, to confirm the role of low-level physical activity on the relationship between sedentary time and health outcomes, further investigation is required.

Glycemic Status, Insulin Resistance, and the Risk of Nephrolithiasis: A Cohort Study

RATIONALE & OBJECTIVE

The effect of glycemic status on nephrolithiasis risk remains controversial. This study sought to examine the association of glycemic status and insulin resistance with incident nephrolithiasis.

STUDY DESIGN

A retrospective cohort study.

SETTING & PARTICIPANTS

278,628 Korean adults without nephrolithiasis who underwent a comprehensive health examination between 2011 and 2017.

EXPOSURES

Glucose level, glycated hemoglobin level, and Homeostasis Model Assessment of Insulin Resistance (HOMA-IR).

OUTCOME

Nephrolithiasis ascertained using abdominal ultrasound.

ANALYTICAL APPROACH

A parametric proportional hazard model was used to estimate adjusted HRs and 95% CIs. We explored prespecified potential sex differences in the association of glycemic status and incident nephrolithiasis.

RESULTS

During a median follow-up of 4.2 years, 6,904 participants developed nephrolithiasis. Associations between levels of glycemic status and incident nephrolithiasis were examined separately in men and women (P for interaction = 0.003). Among men, multivariable-adjusted HRs for incident nephrolithiasis comparing glucose levels of 90-99, 100-125, and ≥ 126 mg/dL were 1.10 (95% CI, 1.01-1.19), 1.11 (95% CI, 1.02-1.21), and 1.27 (95% CI, 1.10-1.46), respectively, while HRs for incident nephrolithiasis comparing glycated hemoglobin levels of 5.7%-5.9%, 6.0%-6.4%, and 6.5%-<5.7% were 1.03 (95% CI, 0.96-1.10), 1.18 (95% CI, 1.07-1.31), and 1.20 (95% CI, 1.06-1.37), respectively. The HR for incident nephrolithiasis comparing the highest HOMA-IR quintile to the lowest quintile was 1.18 (95% CI, 1.06-1.31). Among women, no apparent association was found between glycemic status and nephrolithiasis risk.

LIMITATIONS

Glucose tolerance testing and computed tomography assessment for nephrolithiasis were not available.

CONCLUSIONS

Higher glycemic values, even within the normoglycemic range, and HOMA-IR were positively associated with increased risk for nephrolithiasis, associations that were only observed among men. Insulin resistance and hyperglycemia may contribute to the development of nephrolithiasis, particularly among men.

Polygenic analysis of the effect of common and low-frequency genetic variants on serum uric acid levels in Korean individuals

Increased serum uric acid (SUA) levels cause gout and are associated with multiple diseases, including chronic kidney disease. Previous genome-wide association studies (GWAS) have identified more than 180 loci that contribute to SUA levels. Here, we investigated genetic determinants of SUA level in the Korean population. We conducted a GWAS for SUA in 6,881 Korean individuals, calculated polygenic risk scores (PRSs) for common variants, and validated the association of low-frequency variants and PRS with SUA levels in 3,194 individuals. We identified two low-frequency and six common independent variants associated with SUA. Despite the overall similar effect sizes of variants in Korean and European populations, the proportion of variance for SUA levels explained by the variants was greater in the Korean population. A rare, nonsense variant SLC22A12 p.W258X showed the most significant association with reduced SUA levels, and PRSs of common variants associated with SUA levels were significant in multiple Korean cohorts. Interestingly, an East Asian-specific missense variant (rs671) in ALDH2 displayed a significant association on chromosome 12 with the SUA level. Further genetic epidemiological studies on SUA are needed in ethnically diverse cohorts to investigate rare or low-frequency variants and determine the influence of genetic and environmental factors on SUA.

Decreased Vagal Activity and Deviation in Sympathetic Activity Precedes Development of Diabetes

OBJECTIVE

The objective of this study was to examine whether altered heart rate variability (HRV) could predict the risk of diabetes in Asians.

RESEARCH DESIGN AND METHODS

A cohort study was conducted in 54,075 adults without diabetes who underwent 3-min HRV measurement during health checkups between 2011 and 2014 at Kangbuk Samsung Hospital. We analyzed the time domain (SD of the normal-to-normal interval [SDNN] and root mean square differences of successive normal-to-normal intervals [RMSSD]) and the frequency domain (total power, normalized low-frequency power [LF], and normalized high-frequency power [HF] and LF/HF ratio). We compared the risk of diabetes until 2017 according to tertiles of heart rate and HRV variables, with tertile 1 serving as the reference group.

RESULTS

During 243,758.2 person-years, 1,369 subjects were diagnosed with diabetes. Both time and frequency domain variables were lower in the group with diabetes, with the exception of those with normalized LF and LF/HF ratio. In Cox analysis, as SDNN, RMSSD, and normalized HF tertiles increased, the risk of diabetes decreased (hazard ratios [95% CIs] of tertile 3: 0.81 [0.70-0.95], 0.76 [0.65-0.90], and 0.78 [0.67-0.91], respectively), whereas the risk of diabetes increased in the case of heart rate, normalized LF, and LF/HF ratio (hazard ratios [95% CIs] of tertile 3: 1.41 [1.21-1.65], 1.32 [1.13-1.53], and 1.31 [1.13-1.53), respectively) after adjusting for age, sex, BMI, smoking, drinking, systolic blood pressure, lipid level, CRP, and HOMA of insulin resistance.

CONCLUSIONS

Abnormal HRV, especially decreased vagal activity and deviation in sympathovagal imbalance to sympathetic activity, might precede incident diabetes.

Major Lipids, Apolipoproteins, and Alterations of Gut Microbiota

The gut microbiota has been linked to blood lipids. However, the relationship between the gut microbiome and other lipid markers like apolipoproteins A1 (apoA1) and B (apoB) as well as classical lipid markers in Asians remain unclear. Here, we examined the associations between gut microbial diversity and taxonomic compositions with both apolipoproteins and lipid markers in a large number of Korean patients. The fecal 16S rRNA gene sequencing data from 1141 subjects were analyzed and subjects were categorized into control group (G0) or abnormal group (G1) according to blood lipid measurements. The microbial diversity and several taxa of the gut microbiota were significantly associated with triglyceride, apoA1, and apoB levels, but not with total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol levels. The alpha diversity of the gut microbiota was inversely associated with high triglyceride level. Interestingly, G1 of apoA1 showed increased microbial richness and distinct microbial community compared with G0 of apoA1. A high abundance of Fusobacteria and low abundance of Oscillospira were found in the hypertriglyceridemia group. In this large-scale study, we identified associations of gut microbiota with apolipoproteins and classical lipid markers, indicating that the gut microbiota may be an important target for regulating blood lipids.

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.

Non-alcoholic fatty liver disease and the incidence of myocardial infarction: A cohort study

BACKGROUND AND AIM

Non-alcoholic fatty liver disease (NAFLD) is a multisystem disease associated with an increased risk of cardiovascular disease (CVD), diabetes, and chronic kidney disease. Indeed, CVD is the most common cause of death in NAFLD patients. This study aimed to evaluate the association between NAFLD and the risk of incident myocardial infarction.

METHODS

This is a retrospective cohort study involving 111 492 adults over 40 years old without history of CVD, liver disease, or cancer at baseline who participated in a regular health screening exam between 2003 and 2013. Fatty liver was diagnosed by ultrasonography.

RESULTS

During 725 706.9 person-years of follow-up, 183 participants developed myocardial infarction (incidence rate 0.3 cases per 1000 person-years). The age, sex, and year of visit-adjusted hazard ratio (HR) for incident myocardial infarction comparing participants with NAFLD with those without it was 2.14 (95% confidence interval 1.59, 2.89). This association remained significant in fully adjusted models (HR 1.54; 95% confidence interval 1.11, 2.14). Compared with participants without NAFLD, in participants with low NAFLD fibrosis score (NFS) (< -1.455) and with intermediate-to-high NFS (≥ -1.455), the fully adjusted HRs for incident myocardial infarction were 1.70 (1.22, 2.36) and 1.88 (1.24, 2.87), respectively.

CONCLUSION

In this large cohort study, NAFLD was associated with an increased incidence of myocardial infarction independently of established risk factors. In addition, this association was similar in participants with and without evidence of more advanced NAFLD as indicated by the NFS. NAFLD patients may need to be carefully monitored and managed early to prevent myocardial infarction.

Association between prostate-specific antigen and serum testosterone: A systematic review and meta-analysis

BACKGROUND

Serum testosterone assays are an important tool in the clinical evaluation of a number of endocrine disorders including male hypogonadism. However, serum testosterone has a limited role in real clinical use due to its inaccuracy. We aimed to assess the association between prostate-specific antigen (PSA) and testosterone as well as the effects of various types of testosterone replacement therapy (TRT) for PSA level.

METHODS

Two electronic databases were screened: PubMed (1966 through December 2018) and Cochrane Library (1993 through December 2018). The first strategy compared the overall increase in PSA following testosterone treatment compared with placebo. The second strategy analyzed the overall association between PSA and testosterone among the observational studies.

RESULTS

In the first strategy, 22 articles were included in the final analysis. In the second strategy, 18 studies were included. Testosterone replacement therapy (TRT) showed a significant change in PSA level compared to that in the placebo group (mean difference [MD]: 0.13, 95% CI: 0.01-0.25, P = .04). Compared to placebo, only intramuscular (IM) TRT shows a significant change in PSA level group (MD: 0.16, 95% CI: 0.01-0.30, P = .04), as neither the oral nor topical type showed a significant change in PSA. In the second strategy analysis, there was no overall correlation found between PSA and testosterone (z = 0.04, 95% CI: -0.04 to 0.12, P = .04; r = 0.039). However, in the subgroup of non-BPH (benign prostate hyperplasia), a significant correlation between PSA and testosterone (z = 0.07, 95% CI: 0.01-0.13, P = .009; r = 0.089) was found.

CONCLUSIONS

We found that TRT, particularly IM TRT, significantly changed the PSA level compared with the placebo group. Furthermore, there was a significant correlation between PSA and testosterone in patients with non-BPH. According to these findings, we suggest the possibility of PSA as a surrogate marker of testosterone.

[Impact of Sarcopenia on the Risk of Erosive Esophagitis]

Background/Aims

An association between obesity and erosive esophagitis has been reported, but the effects of sarcopenia and obesity on erosive esophagitis are unknown. This study examined the relationship between obesity, sarcopenia, sarcopenic obesity, and erosive esophagitis in a large population of asymptomatic men and women.

Methods

This study analyzed 32,762 subjects who underwent a comprehensive health check-up, which included upper gastrointestinal endoscopy, from August 2006 to December 2011 by a cross-sectional study. Sarcopenia was defined as a decrease in the appendicular skeletal muscle mass (ASM)/body weight value of two SD or more below the normal means for a younger reference group.

Results

The study was carried out on four groups according to obesity and sarcopenic status: normal, obesity, sarcopenic, and sarcopenic obese group. In a multivariable model, the risk of erosive esophagitis was higher in the obese (adjusted OR [aOR] 1.35, 95% CI 1.22-1.49), sarcopenic (aOR 2.12, 95% CI 1.40-3.19), and sarcopenic obese groups (aOR 1.54, 95% CI 1.27-1.87) than in the normal group. The risk of erosive esophagitis was higher in the sarcopenic and sarcopenic obese groups than the obese group; the ORs were 1.63 (95% CI 1.08-2.47) and 1.22 (95% CI 1.01-1.46), respectively. In dose-response analysis, increasing sarcopenia severity showed a positive and graded relationship with the overall, Los Angeles (LA)-B or higher grade, and LA-C erosive esophagitis.

Conclusions

This study suggests that sarcopenia is strongly and progressively associated with erosive esophagitis.

Visceral-to-Subcutaneous Abdominal Fat Ratio Is Associated with Nonalcoholic Fatty Liver Disease and Liver Fibrosis

BACKGROUND

We evaluated the association of visceral-to-subcutaneous fat ratio (VSR) with nonalcoholic fatty liver disease (NAFLD) and advanced fibrosis degree based on noninvasive serum fibrosis markers in the general population with NAFLD.

METHODS

This is a cross-sectional study, in 7,465 Korean adults who underwent health screening examinations. NAFLD was defined as fatty liver detected on ultrasonography, and visceral and subcutaneous abdominal fat was measured using computed tomography. We predicted fibrosis based on the fibrosis-4 (FIB-4) score and aspartate aminotransferase-to-platelet ratio index (APRI) and categorized the risk for advanced fibrosis as low, indeterminate, or high.

RESULTS

The multivariable-adjusted prevalence ratios for indeterminate to high risk of advanced fibrosis based on FIB-4, determined by comparing the second, third, and fourth quartiles with the first quartile of VSR, were 3.38 (95% confidence interval [CI], 0.64 to 17.97), 9.41 (95% CI, 1.97 to 45.01), and 19.34 (95% CI, 4.06 to 92.18), respectively. The multivariable-adjusted prevalence ratios for intermediate to high degree of fibrosis according to APRI also increased across VSR quartiles (5.04 [95% CI, 2.65 to 9.59], 7.51 [95% CI, 3.91 to 14.42], and 19.55 [95% CI, 9.97 to 38.34], respectively). High VSR was more strongly associated with the prevalence of NAFLD in nonobese subjects than in obese subjects, and the associations between VSR and intermediate to high probability of advanced fibrosis in NAFLD were stronger in obese subjects than in nonobese subjects.

CONCLUSION

High VSR values predicted increased NAFLD risk and advanced fibrosis risk with NAFLD, and the predictive value of VSR for indeterminate to high risk of advanced fibrosis was higher in obese subjects than in nonobese subjects.

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

Thyroid dysfunction is associated with the loss of bone density (osteoporosis). However, the connection between subclinical thyroid dysfunction and osteoporosis remains controversial. This study found no apparent association between subclinical hypothyroidism or subclinical hyperthyroidism and bone mineral density (BMD) in the lumbar spine and femur.

INTRODUCTION

The present study examined the relationship between subclinical thyroid dysfunction and BMD in healthy middle-aged adults.

METHODS

A total of 25,510 healthy Koreans with normal free thyroxine levels were enrolled from January 2011 to December 2016, and 91% of subjects visited only once. The average age of the 15,761 women was 45, and the average age of the 9749 men was 48. Levels of thyroid-stimulating hormone (TSH) and BMD were recorded in all subjects. BMD was measured using dual-energy X-ray absorptiometry.

RESULTS

No apparent association was found between subclinical thyroid dysfunction and BMD in the lumbar spine, femur-neck, and proximal femur sites compared with a euthyroid group. Age, body mass index (BMI), and postmenopausal status affected BMD in women, and only BMI affected BMD in men. Subclinical hypothyroidism was independently associated with a lower risk of osteoporosis (odds ratio 0.657, 95% confidence interval 0.464-0.930) in 4710 postmenopausal women.

CONCLUSIONS

No apparent association was found between subclinical hypothyroidism or subclinical hyperthyroidism defined on single TSH measurement and BMD at the lumbar spine and femur in a large cohort of middle-aged men and women. Subclinical hypothyroidism was independently associated with a lower risk of osteoporosis in postmenopausal women.

Low Levels of Alcohol Consumption, Obesity, and Development of Fatty Liver With and Without Evidence of Advanced Fibrosis

BACKGROUND AND AIMS

The effects of low-level alcohol consumption on fatty liver disease and the potential for effect modification by obesity is uncertain. We investigated associations among low-level alcohol consumption, obesity status, and the development of incident hepatic steatosis (HS), either with or without an increase in noninvasive liver fibrosis score category (from low to intermediate or high category).

APPROACH AND RESULTS

A total of 190,048 adults without HS and a low probability of fibrosis with alcohol consumption less than 30 g/day (men) and less than 20 g/day (women) were followed for up to 15.7 years. Alcohol categories of no, light, and moderate consumption were defined as 0, 1-9.9, and 10-29.9 g/day (10-19.9 g/day for women), respectively. HS was diagnosed by ultrasonography, and the probability of fibrosis was estimated using the fibrosis-4 index (FIB-4). Parametric proportional hazards models were used to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). A total of 43,466 participants developed HS, 2,983 of whom developed HS with an increase in FIB-4 index (to intermediate or high scores). Comparing light drinkers and moderate drinkers with nondrinkers, multivariable-adjusted HRs (95% CI) for incident HS were 0.93 (0.90-0.95) and 0.90 (0.87-0.92), respectively. In contrast, comparing light drinkers and moderate drinkers with nondrinkers, multivariable-adjusted HRs (95% CI) for developing HS plus intermediate/high FIB-4 were 1.15 (1.04-1.27) and 1.49 (1.33-1.66), respectively. The association between alcohol consumption categories and incident HS plus intermediate/high FIB-4 was observed in both nonobese and obese individuals, although the association was stronger in nonobese individuals (P for interaction by obesity = 0.017).

CONCLUSIONS

Light/moderate alcohol consumption has differential effects on the development of different stages of fatty liver disease, which is modified by the presence of obesity.

Weight Change and Development of Subclinical Carotid Atherosclerosis Among Metabolically Healthy Adults: A Cohort Study

BACKGROUND

The benefit of weight loss for reducing cardiovascular disease (CVD) risk in metabolically healthy obese people is unknown.

OBJECTIVES

We evaluated the association between weight change and incident subclinical carotid atherosclerosis (SCA) in metabolically healthy but overweight or obese subjects.

METHODS

Cohort study of 3117 metabolically healthy overweight or obese adults who did not have any metabolic syndrome components or insulin resistance at baseline. SCA was assessed using carotid artery ultrasonography. The study outcome was the development of incident SCA among participants free of the disease at baseline.

RESULTS

During 12 248 person-years of follow-up (median 3.42 years), 747 participants developed SCA. The proportions of participants with no reduction or increased weight, reduction in weight from 0.1% to 4.9%, and reduction in weight ≥ 5% during follow-up were 47.0%, 44.4%, and 8.6%, respectively. The fully-adjusted hazard ratios (HRs) for incident SCA in participants with a reduction in weight of 0.1% to 4.9% and ≥ 5% compared with those with no reduction or increased weight were 0.84 (95% CI, 0.72-0.98) and 0.66 (95% CI, 0.50-0.87), respectively.

CONCLUSIONS

In a large cohort study of metabolically healthy but overweight or obese adult men and women, weight reduction was associated with a lower incidence of SCA. Our findings suggest that metabolically healthy overweight or obese subjects may benefit from weight reduction in terms of CVD risk.

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.

Rasch calibration of the 25-item Connor-Davidson Resilience Scale

Rasch modeling was used to examine the 25-item Connor-Davidson Resilience Scale within adults (n = 410) in a weight management program. Rasch analysis assessed model-data fit, item difficulty and person's resilience level, an item-person map to evaluate relative distribution items and persons, and rating scale function. Four misfit items were identified and removed. Item difficulty ranged from 1.25 to 1.19 logits (higher logit values indicate more difficult items). Persons' resilience level had wide distribution (resilience = 2.27 ± 1.56 logits). Item difficulty levels did not adequately assess higher resilience levels. An improved inventory that measures a wider range of resilient behaviors would improve measurement quality.

Perceived stress and non-alcoholic fatty liver disease in apparently healthy men and women

Psychological stress may have adverse metabolic effects and induce unhealthy behaviors, but the role of stress in the development of non-alcoholic fatty liver disease (NAFLD) is largely unexplored. We investigated the association between perceived stress and the prevalence of NAFLD in a large sample of apparently healthy men and women. We performed a cross-sectional study of 171,321 adults who underwent health screening examination between 2011 and 2013 in one health screening center. Perceived stress was assessed using the short version of the Perceived Stress Inventory (PSI). NAFLD was assessed using ultrasonography in the absence of excessive alcohol use or any other identifiable cause of liver disease. The prevalence of NAFLD was 27.8%. In fully-adjusted multivariable models, the odds ratio (95% confidence intervals) for NAFLD comparing participants in the 5^th quintile of PSI score (≥23) with those in the lowest quintile (<12) was 1.17 (1.11, 1.22), with a moderately increased prevalence of NALFD across quintiles of PSI score. The positive association between PSI score and NAFLD was observed in all subgroups analyzed, although the association was stronger in men compared to women (p interaction <0.001), and in obese compared to non-obese (p interaction 0.005). In this large study of apparently healthy men and women, higher perceived stress was independently associated with an increased prevalence of NAFLD, supporting a possible relationship between perceived stress and NAFLD. Prospective study is needed to elucidate mediating mechanisms to warrant stress management to reduce NAFLD.

Alcoholic and Nonalcoholic Fatty Liver Disease and Incident Hospitalization for Liver and Cardiovascular Diseases

BACKGROUND & AIMS

We compared the associations of nonalcoholic fatty liver disease (NAFLD) and alcohol-associated fatty liver disease (AFLD) with risk of incident hospitalization for liver and cardiovascular diseases.

METHODS

We collected data from the Kangbuk Samsung Health Study on 218,030 men and women in Korea who underwent a health examination from 2011 through 2016. Fatty liver disease (FLD) was detected by ultrasound during the initial examination. The Fibrosis-4 index was used to identify individuals with liver fibrosis. Participants were followed up for as long as 5.9 years and data on hospitalizations for liver and cardiovascular diseases were collected.

RESULTS

The prevalence of NAFLD was 22.0% and the prevalence of AFLD was 6.4%. Over a median follow-up period of 4.2 years, we observed 51 and 1097 incident cases of liver disease- or cardiovascular disease-related hospitalizations, respectively. After adjustment for potential confounders, the multivariable-adjusted hazard ratios for liver disease-related hospitalization, comparing NAFLD and AFLD with the reference category (no excessive alcohol intake and no FLD), were 1.73 (95% CI, 0.76-3.96) and 5.00 (95% CI, 2.12-11.83), respectively. The corresponding hazard ratios for cardiovascular disease hospitalization were 1.20 (95% CI, 1.02-1.40) and 1.08 (95% CI, 0.86-1.34), respectively. Among participants with FLD, the risk of liver disease-related hospitalization increased with high Fibrosis-4 index scores, whereas the risk of incident cardiovascular disease did not.

CONCLUSIONS

In a large cohort study, we found an increased risk of liver disease-related hospitalizations for patients with NAFLD or AFLD, especially among those with Fibrosis-4 index scores. An increased risk of cardiovascular disease-associated hospitalization was observed in patients with NAFLD but not AFLD.

Systematic Review of the Proposed Associations between Physical Exercise and Creative Thinking

The objective of this study was to evaluate the association between physical exercise and creative thinking. A systematic review approach was employed by searching PubMed, Google Scholar and PsychInfo databases. Among the evaluated 13 studies, 92% indicated a beneficial relationship. However, 77% were vulnerable to moderate-high risk for methodological bias, suggesting adherence to standardized and controlled research initiatives should be promoted. There appears to be weak to modest support for acute, moderate-intensity exercise to benefit creativity. Exercise timing relative to creativity assessment protocols should be addressed and further detailed. Creativity scoring procedures must be refined, and an increased focus on the motivational components of exercise may help guide researchers in measuring creative thoughts and behavior. Broader concluding claims that creativity, in general, is improved or impaired by exercise, is as problematic as sweeping statements that exercise improves or impairs a measure as dynamic as intelligence. Scientific inquiries must specify precisely which outcome characteristics are changing in line with research interventions. This review identifies several fallible linkages between physical activity and creativity. Too few studies were conducted on strong methodological foundations, perpetuating the risk for undermining or inaccurately inflating the potential association between exercise and creative thinking behavior.

High-Risk Human Papillomavirus Infection and the Risk of Cardiovascular Disease in Korean Women

RATIONALE

Until now, no cohort studies have evaluated the relationship between high-risk human papillomavirus (HPV) infection and new-onset cardiovascular diseases (CVD).

OBJECTIVE

We investigated an association between high-risk HPV infection and the development of CVD.

METHODS AND RESULTS

We conducted a cohort study of 63 411 women aged 30 or older without CVD at baseline who underwent a high-risk HPV test and were followed annually or biennially from 2011 to 2016. CVD was ascertained through the linkage to the Health Insurance and Review Agency database. A Cox-proportional hazards regression model was used to estimate adjusted hazard ratios (HRs) with 95% CIs of incident CVD. The prevalence of high-risk HPV infection was 7.6%. During 261 598.9 person-years of follow-up, 1122 cases of new-onset CVD were identified (incidence rate of 4.3 per 10³ person-years). High-risk HPV infection was significantly associated with incident CVD. After adjustment for possible confounders, and high sensitivity C-reactive protein, a significant association between high-risk HPV infection and incident CVD was still observed, with a corresponding HR (95% CI) of 1.25 (1.03-1.52). This association was stronger among individuals with obesity and those with metabolic syndrome. Multivariable-adjusted HR (95% CI) for incident CVD comparing high-risk HPV-positive- to high-risk HPV-negative participants was 1.10 (0.87-1.39) in the nonobese, whereas corresponding HR (95% CI) was 1.73 (1.19-2.51) in those with obesity ( P for interaction by obesity=0.02). Similarly, multivariable-adjusted HR (95% CI) for incident CVD comparing high-risk HPV-positive- to high-risk HPV-negative participants was 1.09 (0.87-1.36) in those without metabolic syndrome and 1.99 (1.28-3.08) in those with MetS ( P for interaction=0.05).

CONCLUSION

In this large cohort, high-risk HPV infection was significantly associated with an increased risk of developing CVD, especially in obese individuals and those with MetS, indicating that high-risk HPV might affect CVD risk with possible effect modification by obesity and MetS.

Gender-specific cephalometric features related to obesity in sleep apnea patients: trilogy of soft palate-mandible-hyoid bone

Background

The aim of this study is to investigate the relationship between gender-specific and obesity-related airway anatomy in patients with obstructive sleep apnea (OSA) by using cephalometric analyses.

Methods

We retrospectively evaluated 206 patients with suspected OSA undergoing polysomnography and anthropometric measurements such as body mass index, neck circumference, and waist-hip ratio. We checked lateral cephalometry to measure tissue landmarks including angle from A point to nasion to B point (ANB), soft palate length (SPL), soft palate thickness (SPT), retropalatal space (RPS), retrolingual space (RLS), and mandibular plane to hyoid (MPH).

Results

Male with OSA showed significantly increased SPL (P = .006) compared with controls. SPL and MPH had significant correlation with apnea-hypopnea index (AHI) and central obesity. Female with OSA showed significantly increased ANB (P = .013) and SPT (P = .004) compared with controls. The receiver operating characteristic curves revealed that SPT in male and ANB and SPT in female were significant in model 1 (AHI ≥ 5) and model 2 (AHI ≥ 15). MPH was also significant for male in model 2.

Conclusion

Male and female with OSA had distinct anatomic features of the upper airway and different interactions among soft palate, mandible, and hyoid bone.

Mechanical stimulation of growth plate chondrocytes: Previous approaches and future directions

Growth plate cartilage resides near the ends of long bones and is the primary driver of skeletal growth. During growth, both intrinsically and extrinsically generated mechanical stresses act on chondrocytes in the growth plate. Although the role of mechanical stresses in promoting tissue growth and homeostasis has been strongly demonstrated in articular cartilage of the major skeletal joints, effects of stresses on growth plate cartilage and bone growth are not as well established. Here, we review the literature on mechanobiology in growth plate cartilage at macroscopic and microscopic scales, with particular emphasis on comparison of results obtained using different methodological approaches, as well as from whole animal and in vitro experiments. To answer these questions, macroscopic mechanical stimulators have been developed and applied to study mechanobiology of growth plate cartilage and chondrocytes. However, the previous approaches have tested a limited number of stress conditions, and the mechanobiology of a single chondrocyte has not been well studied due to limitations of the macroscopic mechanical stimulators. We explore how microfluidics devices can overcome these limitations and improve current understanding of growth plate chondrocyte mechanobiology. In particular, microfluidic devices can generate multiple stress conditions in a single platform and enable real-time monitoring of metabolism and cellular behavior using optical microscopy. Systematic characterization of the chondrocytes using microfluidics will enhance our understanding of how to use mechanical stresses to control the bone growth and the properties of tissue-engineered growth plate cartilage.

Observation of Electroweak Production of a Same-Sign W Boson Pair in Association with Two Jets in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector

This Letter presents the observation and measurement of electroweak production of a same-sign W boson pair in association with two jets using 36.1  fb^{-1} of proton-proton collision data recorded at a center-of-mass energy of sqrt[s]=13  TeV by the ATLAS detector at the Large Hadron Collider. The analysis is performed in the detector fiducial phase-space region, defined by the presence of two same-sign leptons, electron or muon, and at least two jets with a large invariant mass and rapidity difference. A total of 122 candidate events are observed for a background expectation of 69±7 events, corresponding to an observed signal significance of 6.5 standard deviations. The measured fiducial signal cross section is σ^{fid}=2.89_{-0.48}^{+0.51}(stat)_{-0.28}^{+0.29}(syst)  fb.

Contribution of SLC22A12 on hypouricemia and its clinical significance for screening purposes

Differentiating between inherited renal hypouricemia and transient hypouricemic status is challenging. Here, we aimed to describe the genetic background of hypouricemia patients using whole-exome sequencing (WES) and assess the feasibility for genetic diagnosis using two founder variants in primary screening. We selected all cases (N = 31) with extreme hypouricemia (<1.3 mg/dl) from a Korean urban cohort of 179,381 subjects without underlying conditions. WES and corresponding downstream analyses were performed for the discovery of rare causal variants for hypouricemia. Two known recessive variants within SLC22A12 (p.Trp258*, pArg90His) were identified in 24 out of 31 subjects (77.4%). In an independent cohort, we identified 50 individuals with hypouricemia and genotyped the p.Trp258* and p.Arg90His variants; 47 of the 50 (94%) hypouricemia cases were explained by only two mutations. Four novel coding variants in SLC22A12, p.Asn136Lys, p.Thr225Lys, p.Arg284Gln, and p.Glu429Lys, were additionally identified. In silico studies predict these as pathogenic variants. This is the first study to show the value of genetic diagnostic screening for hypouricemia in the clinical setting. Screening of just two ethnic-specific variants (p.Trp258* and p.Arg90His) identified 87.7% (71/81) of Korean patients with monogenic hypouricemia. Early genetic identification of constitutive hypouricemia may prevent acute kidney injury by avoidance of dehydration and excessive exercise.

Low Levels of Low-Density Lipoprotein Cholesterol and Mortality Outcomes in Non-Statin Users

We aimed to test the association between low-density lipoprotein cholesterol (LDL-C) and cardiovascular disease (CVD), cancer, and all-cause mortality in non-statin users. A total of 347,971 subjects in Kangbuk Samsung Health Study (KSHS.57.4% men, mean follow up: 5.64 ± 3.27 years) were tested. To validate these associations, we analyzed data from another cohort (Korean genome and epidemiology study, KoGES, 182,943 subjects). All subjects treated with any lipid-lowering therapy and who died during the first 3 years of follow up were excluded. Five groups were defined according to baseline LDL-C concentration (<70, 70–99, 100–129, 130–159, ≥160 mg/dL). A total of 2028 deaths occurred during follow-up in KSHS. The lowest LDL-C group (LDL < 70 mg/dL) had a higher risk of all-cause mortality (HR 1.95, 1.55–2.47), CVD mortality (HR 2.02, 1.11–3.64), and cancer mortality (HR 2.06, 1.46–2.90) compared to the reference group (LDL 120–139 mg/dL). In the validation cohort, 2338 deaths occurred during follow-up. The lowest LDL-C group (LDL < 70 mg/dL) had a higher risk of all-cause mortality (HR 1.81, 1.44–2.28) compared to the reference group. Low levels of LDL-C concentration are strongly and independently associated with increased risk of cancer, CVD, and all-cause mortality. These findings suggest that more attention is needed for subjects with no statin-induced decrease in LDL-C concentrations.

Metabolically healthy versus unhealthy obesity and risk of fibrosis progression in non-alcoholic fatty liver disease

BACKGROUND & AIMS

Little is known about the impact of metabolically healthy obesity on fibrosis progression in non-alcoholic fatty liver disease (NAFLD). We investigated the association of body mass index (BMI) category, body fat percentage and waist circumference with worsening of noninvasive fibrosis markers in metabolically healthy and unhealthy individuals with NAFLD.

METHODS

A cohort study was performed on 59 957 Korean adults with NAFLD (13 285 metabolically healthy and 46 672 metabolically unhealthy individuals) who were followed for a median of 7.7 years. Being metabolically healthy was defined as not having any metabolic syndrome component and having a homoeostasis model assessment of insulin resistance <2.5. Progression from low to intermediate or high probability of advanced fibrosis was assessed using the NAFLD fibrosis score (NFS).

RESULTS

During 339 253.1 person-years of follow-up, 9857 subjects with low NFS at baseline progressed to intermediate or high NFS. Among metabolically healthy individuals, the multivariable-adjusted HRs (95% CI) for NFS worsening comparing BMIs 23-24.9, 25-29.9 and ≥30 with a BMI of 18.5-22.9 kg/m² were 1.19 (1.00-1.42), 1.79 (1.52-2.10) and 3.52 (2.64-4.69), respectively, whereas the corresponding HRs (95% CI) in metabolically unhealthy individuals were 1.37 (1.24-1.52), 2.18 (1.99-2.39) and 4.26 (3.83-4.75). A similar trend was observed in the analyses using body fat and waist circumference.

CONCLUSION

In the large-scale cohort of young and middle-aged individuals with NAFLD, BMI was positively associated with worsening of noninvasive fibrosis marker regardless of metabolic health status. Excess adiposity per se, even without accompanying metabolic health status, may contribute to fibrosis progression in NAFLD.

Risk of chronic obstructive pulmonary disease in healthy individuals with high C-reactive protein levels by smoking status: a population-based cohort study in Korea

Purpose

Chronic obstructive pulmonary disease (COPD) is associated with systemic inflammation. We investigated whether elevated baseline serum C-reactive protein (CRP) levels in healthy individuals are associated with the risk of incident COPD by smoking status.

Patients and methods

This was a cohort study of 63,260 adult men and women who were older than 40 years, free of COPD at baseline, and underwent health screening from 2002 to 2016 with at least one follow-up visit through December 2016. We investigated the association between baseline high-sensitivity CRP (hsCRP) levels and incident COPD by smoking status, using flexible parametric proportional hazards models and pooled logistic regression analyses.

Results

The multivariable-adjusted hazard ratio (95% confidence interval) comparing participants in the 90th to those in the 10th percentile of hsCRP was 1.19 (1.08, 1.31). The corresponding hazard ratio in never, former, and current smokers were 1.07 (0.89, 1.29), 1.22 (1.05, 1.42), and 1.22 (1.05, 1.41), respectively. The association between hsCRP levels and incident COPD had a similar dose–response pattern in former and current smokers, but not in never smokers.

Conclusion

Higher baseline hsCRP is associated with an increased risk to develop COPD in ever smokers but not in never smokers.

Alcoholic and non-alcoholic fatty liver disease and associations with coronary artery calcification: evidence from the Kangbuk Samsung Health Study

OBJECTIVE

Recent evidence suggests that alcoholic fatty liver disease (AFLD) and non-alcoholic fatty liver disease (NAFLD) may differentially affect risk of cardiovascular mortality. To investigate whether early liver disease due to AFLD or NAFLD have similar or dissimilar effects on risk of early coronary artery atherosclerosis, we have investigated the associations between AFLD and NAFLD and coronary artery calcium (CAC).

DESIGN

A cross-sectional study was performed in 105 328 Korean adults who attended a health check-up programme. CAC score was assessed using CT, daily alcohol intake was recorded as grams/day and liver fat by ultrasound. Logistic regression model was used to calculate ORs with 95% CIs for prevalent CAC.

RESULTS

Both NAFLD and AFLD were positively associated with CAC score. After adjusting for potential confounders, multivariable-adjusted OR (95% CIs) for CAC >0 comparing NAFLD and AFLD to the reference (absence of both excessive alcohol use and fatty liver disease) were 1.10 (95% CI 1.05 to 1.16) and 1.20 (95% CI 1.11 to 1.30), respectively. In post hoc analysis, OR (95% CI) for detectable CAC comparing AFLD to NAFLD was 1.09 (95% CI 1.01 to 1.17). Associations of NAFLD and AFLD with CAC scores were similar in both non-obese and obese individuals without significant interaction by obesity (p for interaction=0.088). After adjusting for homeostasis model assessment of insulin resistance and high-sensitivity C reactive protein, the associations between fatty liver disease and CAC scores remained statistically significant.

CONCLUSION

In this large sample of young and middle-aged individuals, early liver disease due to NAFLD and AFLD were both significantly associated with the presence of coronary artery calcification.