Central Obesity and Visceral Adipose Tissue Are Not Associated With Incident Atherosclerotic Cardiovascular Disease Events in Older Men

Evaluating the visceral adiposity inflammatory index for enhanced stroke risk assessment

Stroke is a leading cause of global morbidity and mortality, with risk factors like visceral adiposity and inflammation playing significant roles. This study introduces the Visceral Adiposity Inflammatory Index (VAII), combining the Visceral Adiposity Index (VAI) and high-sensitivity C-reactive protein (CRP), to better predict stroke risk. Analyzing data from 8415 participants in the China Health and Retirement Longitudinal Study over 9 years, the study found that higher VAII levels were strongly associated with increased stroke incidence, with a hazard ratio of 1.91 for the highest quartile. VAII outperformed VAI and CRP alone in predictive accuracy, enhancing traditional risk models as shown by improved Net Reclassification Index and Integrated Discrimination Improvement Index. Furthermore, blood pressure and the triglyceride-glucose index were identified as mediators in the VAII-stroke relationship. These findings underscore VAII as a promising tool for stroke risk assessment, suggesting that public health interventions targeting VAII reduction could help mitigate stroke risk.

Visceral fat and its dynamic changes are associated with incident stroke: evidence from the China Health and Retirement Longitudinal Study

BACKGROUND AND AIMS

Central obesity demonstrated an association with stroke, while the association between visceral fat accumulation and stroke required further investigation. We aimed to evaluate the association of Chinese visceral adiposity index (CVAI) and its dynamic change patterns with stroke risk.

METHODS AND RESULTS

A total of 9052 individuals from a nationally representative cohort were included. The main outcome was a self-reported physician's diagnosis of stroke. Multivariable Cox and logistic regression models were employed to evaluate the association of the exposure with stroke. The shape of the association was explored using restricted cubic splines. The mean age of the study population was 60.0 ± 9.5 years, and the median follow-up period was 7 years. A linear dose-response association between baseline CVAI and stroke risk was observed. Compared with the lowest CVAI quartile, those in the second, third, and fourth quartiles had 1.62, 1.72, and 2.08 times higher risk, respectively. Additionally, each standard deviation increase in CVAI induced 23 % increased risk of stroke. Among the five CVAI change patterns, the low-stable pattern carried a greatest protective effect against stroke (OR = 0.35, 95 % CI: 0.21-0.58); the decreasing pattern exhibited greater risk reduction compared to the moderate and the increasing patterns (with reference to the persistent-high pattern). In terms of identifying high-risk individuals of stroke, CVAI outperformed other obesity indices.

CONCLUSION

Higher baseline CVAI and a persistent-high pattern were associated with increased risk of incident stroke. Maintaining a low level of CVAI or reducing it may have potential benefits for stroke prevention.

Age-specific and sex-specific associations of visceral adipose tissue with metabolic health status and cardiovascular disease risk

BACKGROUND

Visceral adipose tissue (VAT) is known to play a role in the development of metabolic and cardiovascular disease (CVD). However, the age- and sex-specific associations between VAT and these diseases remain unclear.

METHODS

In this cross-sectional study, 1,150 participants (39.5% women; mean age 61.5 years) underwent VAT measurement using dual abdominal bioelectrical impedance analysis (BIA). The four age groups that the participants were divided into were 18-44, 45-59, 60-74, and ≥ 75 years. The relationships between VAT and cardiometabolic outcomes were analyzed by age and sex using multivariable logistic regression.

RESULTS

Significant associations between VAT and metabolic health status were observed in middle-aged (45-59 years; OR = 1.41, 95% CI: 1.04-1.92) and elderly adults (60-74 years; OR = 1.45, 95% CI: 1.10-1.92). VAT demonstrated age-dependent relationships with cardiovascular risk factors, with the strongest associations found in the 60-74 years group for hypertension (OR: 1.55, 95% CI: 1.22-1.98) and low high-density lipoprotein cholesterol (OR: 1.66, 95% CI: 1.33-2.08). Notably, the VAT-CVD association was most pronounced in elderly women (60-74 years; OR: 1.86, 95% CI: 1.14-3.11), while no significant associations were observed in men across all age groups.

CONCLUSIONS

The impact of VAT on metabolic and cardiovascular disease risk varies by age and sex, with particularly strong associations observed in elderly women. This highlights the need for tailored prevention and treatment strategies.

Coexistence of high visceral fat area and sarcopenia is associated with atherosclerotic markers in old-old patients with diabetes: A cross-sectional study

AIMS/INTRODUCTION

To investigate whether sarcopenic obesity is associated with the progression of atherosclerotic lesions in older patients with diabetes and to identify the obesity components of sarcopenic obesity that best reflect atherosclerosis.

MATERIALS AND METHODS

In 118 inpatients aged ≥75 years with diabetes mellitus, sarcopenia defined as a low skeletal muscle mass and low grip strength was assessed, and sarcopenia coexisting with a high body-fat percentage or visceral fat area was defined as sarcopenic obesity. Correlations between the obesity components and atherosclerotic markers, including the carotid intima-media thickness, were analyzed; the intima-media thickness was analyzed in four groups with and without obesity and sarcopenia, and a multiple linear regression analysis adjusted for covariates was conducted to investigate whether sarcopenic obesity was independently associated with the intima-media thickness.

RESULTS

The visceral fat area and intima-media thickness showed positive correlations in the overall patients (P = 0.032) and the sarcopenia (P = 0.016) group but showed no associations in participants without sarcopenia. The intima-media thickness in the group showing sarcopenia with a high visceral fat area was significantly higher than that in the control group (P = 0.012). Sarcopenic obesity defined by a high body-fat percentage and high visceral fat area was independently associated with the intima-media thickness even after adjusting for age, sex, and atherogenic risk factors. However, sarcopenic obesity defined by a high visceral fat area was more strongly associated with the intima-media thickness (β = 0.384, P = 0.002) than that defined by the high body-fat percentage (β = 0.237, P = 0.068).

CONCLUSIONS

Sarcopenic obesity, especially that defined by visceral fat accumulation, reflected the risk of atherosclerotic lesion progression in older patients with diabetes.

Central Lean Mass Distribution and the Risks of All-Cause and Cause-Specific Mortality in 40,283 UK Biobank Participants

INTRODUCTION

The purpose of this study was to investigate the association of central lean mass distribution with the risk of mortality.

METHODS

This cohort study included 40,283 UK Biobank participants. Cox proportional hazards regression models were used to estimate the association of central lean mass distribution, i.e., trunk-to-leg lean mass ratio, assessed by dual-energy X-ray absorptiometry, with the risk of mortality.

RESULTS

The median age of the participants was 65 years, and 52% were women. During a median follow-up of 4.18 years, 674 participants died, of whom 366 were due to cancer and 126 were due to cardiovascular causes. Compared with the lowest tertile of a trunk-to-leg lean mass ratio, the multivariable-adjusted (age, sex, ethnicity, lifestyle, comorbidities, body mass index, and appendicular muscle mass index) hazards ratios of the highest tertile of trunk-to-leg lean mass ratio were 1.55 (95% CI: 1.23-1.94), 1.69 (95% CI: 1.26-2.26), and 1.14 (95% CI: 0.72-1.80) for all-cause, cancer, and cardiovascular mortality, respectively. Neutrophil-to-lymphocyte ratio mediated 9.3% (95% CI: 3.3%-40.4%) of the association of trunk-to-leg lean mass ratio with all-cause mortality. There was evidence for additive interactions of trunk-to-leg lean mass ratio with older age and poor diet quality for all-cause mortality.

CONCLUSION

Trunk-to-leg lean mass ratio, assessed by dual-energy X-ray absorptiometry, was positively associated with the risks of all-cause and cancer mortality, independent of general obesity and central obesity, in UK middle-aged and older adults. Central lean mass distribution may interact synergistically with aging and poor diet quality to further increase the risk of death.

Predicted visceral adiposity index in relation to risk of coronary heart disease and all-cause mortality: insights from NHANES

Background and aims

The Visceral Adiposity Index (VAI) is a straightforward and gender-specific marker that combines anthropometric measurements with lipid profiles. The objective of this study was to evaluate the relationship between VAI and coronary heart disease (CHD).

Methods and results

The study examined data collected from adults during the NHANES 1999-2018 cycle. The analyses were weighted, and multivariable logistic regression models were employed to investigate the association between VAI and CHD. Additionally, subgroup analyses stratified by age were conducted. To evaluate the impact of VAI levels on survival outcomes, the study utilized the Kaplan-Meier method and performed the log-rank test to evaluate the survival outcome of participants with different VAI levels. The study findings revealed a significant association between VAI and CHD, indicating a non-linear relationship where an increase in VAI was associated with an elevated risk of CHD. High levels of VAI were linked to an increased prevalence of CHD (Q4 vs Q1, OR 1.50, 95% CI 1.12-2.01, P=0.01). Additionally, higher levels of VAI were associated with a poorer overall prognosis in terms of survival outcomes. There were no statistically significant differences in survival outcomes among the population with CHD.

Conclusion

The results of this study highlighted a significant association between VAI and CHD, with a non-linear relationship observed. High VAI levels were associated with an increased risk of CHD and poor survival outcomes, emphasizing the importance of understanding and managing this risk factor, particularly in older age groups.

Association between Chinese visceral adiposity index and risk of stroke incidence in middle-aged and elderly Chinese population: evidence from a large national cohort study

BACKGROUND

Abdominal obesity has long been considered as a crucial risk factor of stroke. Chinese visceral adiposity index (CVAI), a novel surrogate indicator of abdominal obesity, has been confirmed as a better predictor for coronary heart disease than other indicators in Asian population. However, the data on the relationship of CVAI with stroke is limited. The objective of our study is evaluating the relationship between CVAI and stroke incidence.

METHODS

In the present study, we enrolled 7242 middle-aged and elderly residents from the China Health and Retirement Longitudinal Study (CHARLS) and placed them into groups according to quartile of CVAI. The outcome of interest was stroke. Kaplan-Meier curves were used to estimate the cumulative incidences of stroke. Cox regression analyses and multivariable-adjusted restricted cubic spline (RCS) curves were performed to evaluate the relationship between CVAI and incident stroke. Multiple sensitivity analyses and subgroups analyses were performed to test the robustness of the findings.

RESULTS

During a median 84 months of follow-up, 612 (8.45%) participants experienced incident stroke, and the incidences of stroke for participants in quartiles (Q) 1-4 of CVAI were 4.42%, 7.29%, 9.06% and 13.04%, respectively. In the fully adjusted model, per 1.0-SD increment in CVAI has a significant increased risk of incident stroke: hazard ratio (HR) [95% confidence interval (CI)] was 1.17 (1.07-1.28); compared with participants in Q1 of CVAI, the HRs (95% CI) of incident stroke among those in Q2-4 were 1.47 (1.10-1.95), 1.62 (1.22-2.15), and 1.70 (1.28-2.27), respectively. Subgroups analyses suggested the positive association was significant in male participants, without diabetes, hypertension and heart disease. The findings were robust in all the sensitivity analyses. Additional, RCS curves showed a significant dose-response relationship of CVAI with risk of incident stroke (P for non-linear trend = 0.319).

CONCLUSION

Increased CVAI is significantly associated with higher risk of stroke incidence, especially in male individuals, without hypertension, diabetes and heart disease. The findings suggest that baseline CVAI is a reliable and effective biomarker for risk stratification of stroke, which has far-reaching significance for primary prevention of stroke and public health.

Distribution of lean mass and mortality risk in patients with type 2 diabetes

AIMS

The aim of the study is to evaluate the association of distribution of lean mass with the risk of all-cause mortality among patients with type 2 diabetes.

METHODS

The present cohort study included 2 335 patients with type 2 diabetes. Lean mass was assessed by dual energy X-ray absorptiometry. Cox proportional hazards regressions were used to estimate the association of lean mass distribution on the risk of mortality.

RESULTS

The average age of the patients was 58 years at baseline and 51.4% of patients were women. During a median follow-up of 4.31 years, 128 patients died. The multivariable-adjusted hazards ratios for all-cause mortality were 1.00, 1.63 (0.89-2.99), and 2.68(1.51-4.76) across the tertiles of android-to-gynoid lean mass ratio (P for trend < 0.001), respectively. The positive association of android-to-gynoid lean mass ratio with the risk of all-cause mortality was present among patients of different ages, body mass index ≥ 24 kg/m², hemoglobin A1c ≥ 7.0%, nonsmokers, men, patients using insulin, and patients with diabetes durations of more than 10 years.

CONCLUSIONS

Higher android-to-gynoid lean mass ratio, assessed by dual energy X-ray absorptiometry, was significantly associated with increased risk of all-cause mortality among patients with type 2 diabetes.

Abdominal Visceral Adipose Tissue and All-Cause Mortality: A Systematic Review

Introduction

Increased abdominal visceral adipose tissue (VAT) implies an adverse cardio-metabolic profile. We examined the association of abdominal VAT parameters and all-cause mortality risk.

Methods

We systematically searched four databases. We performed citations/articles screening, data abstraction, and quality assessment in duplicate and independently (CRD42020205021).

Results

We included 12 cohorts, the majority used computed tomography to assess abdominal VAT area. Six cohorts with a mean age ≤ 65 years, examining all-cause mortality risk per increment in VAT area (cm2) or volume (cm3), showed a 11-98% relative risk increase with higher VAT parameters. However, the association lost significance after adjusting for glycemic indices, body mass index, or other fat parameters. In 4 cohorts with a mean age >65 years, the findings on mortality were inconsistent. Conversely, in two cohorts (mean age 73-77 years), a higher VAT density, was inversely proportional to VAT area, and implied a higher mortality risk.

Conclusion

A high abdominal VAT area seems to be associated with increased all-cause mortality in individuals ≤ 65 years, possibly mediated by metabolic complications, and not through an independent effect. This relationship is weaker and may reverse in older individuals, most likely secondary to confounding bias and reverse causality. An individual participant data meta-analysis is needed to confirm our findings, and to define an abdominal VAT area cutoff implying increased mortality risk.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=205021, identifier CRD42020205021.

Effect of visceral adipose tissue mass on coronary artery disease and heart failure: A Mendelian randomization study

OBJECTIVES

Obesity is associated with coronary artery disease (CAD) and its risk factors in observational studies. This two-sample Mendelian randomization (MR) study investigated the effect of visceral adipose tissue (VAT) mass on coronary artery disease (CAD), myocardial infarction (MI) and heart failure (HF).

METHODS

Genetic variants (220 SNPs, P < 5 × 10^-8) associated with VAT mass were obtained from a genome-wide association study (GWAS) in the UK Biobank. Genetic associations with CAD outcomes including CAD and myocardial infarction (MI) were obtained from the CARDIoGRAMplusC4D 1000 Genomes-based GWAS (including up to 60,801 cases and 123,504 controls) and data on patients with HF were obtained from the HERMES Consortium (47,309 cases and 930,014 controls). The effects of VAT mass on CAD outcomes and HF were estimated using the inverse variance weighted (IVW) method. Sensitivity analysis and multi-variable MR were used to examine the stability of the IVW results.

RESULTS

Our results showed that genetically predicted higher VAT mass was associated with increased risk of CAD (odds ratio [OR] 1.57, 95% confidence interval [CI], 1.44-1.71; P = 7.62 × 10^-24), MI (OR 1.63, 95% CI: 1.48-1.79; P = 3.76 × 10^-24) and HF (OR 1.71, 95% CI: 1.60-1.83; P = 1.72 × 10^-53). These findings remained significant in the sensitivity analysis and multi-variable MR.

CONCLUSION

This MR study suggests that genetic determinants of VAT mass are causally associated with CAD, MI and HF.

Sarcopenia is associated with cardiovascular risk in men with COPD, independent of adiposity

Background

Sarcopenia is a well-established risk factor for atherosclerotic cardiovascular disease (ASCVD), but its relationship with chronic obstructive pulmonary disease (COPD) has not been fully determined. This study is aimed to investigate the association between sarcopenia and risk for ASCVD in patients with COPD, independent of central obesity and fat mass.

Methods

Data regarding 704 men with COPD (mean age: 63.4 years) were extracted from the 2008 to 2011 Korean National Health and Nutrition Examination Surveys. Sarcopenia index and fat mass were assessed using dual-energy X-ray absorptiometry. Sarcopenia was defined according to the presence of sarcopenia index values < 1 standard deviation from the cutoff (0.774) among the study participants. ASCVD risk was evaluated using American College of Cardiology/American Heart Association guidelines. High probability of ASCVD was defined as ASCVD risk > 20%.

Results

The quartile-stratified sarcopenia index was negatively associated with ASCVD risk (P < 0.001). ASCVD risk and prevalence of high ASCVD risk were significantly greater in sarcopenic participants than in non-sarcopenic participants, regardless of central obesity and fat mass (all P < 0.001). Multivariate regression analyses demonstrated an independent association between sarcopenia and ASCVD risk (estimated ± standard error = 3.63 ± 0.77%, P < 0.001) and high ASCVD risk (odds ratio [OR] = 2.32, 95% confidence interval [CI] 1.05–5.15, P = 0.039). Furthermore, sarcopenia was an independent factor for high ASCVD risk in participants with moderate to very severe airflow limitation (OR = 2.97, 95% CI 1.06–8.36, P < 0.001).

Conclusions

Sarcopenia was significantly associated with an increased risk for ASCVD in men with COPD, independent of central obesity and fat mass. High ASCVD risk was significantly associated with sarcopenia, particularly in participants with moderate to very severe airflow limitation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02109-3.

Association between visceral adiposity index and incident stroke: Data from the China Health and Retirement Longitudinal Study

BACKGROUND AND AIMS

Visceral adiposity index (VAI), an indicator of visceral fat, is associated with metabolic health and arterial stiffness. However, studies correlating VAI and stroke are limited. This study aimed to explore the association between VAI and incident stroke in the Chinese population.

METHODS AND RESULTS

We retrospectively analysed the data of 9127 individuals enrolled in the China Health and Retirement Longitudinal Study. The first survey of the study was conducted during 2011-2012 and the individuals were followed up until Survey 4 (2017-2018). Multivariable-adjusted Cox regression models were used to evaluate the association between VAI and stroke. The mean age of the study population was 59.3 ± 9.5 years and 4938 (54.1%) participants were women. During the median follow-up of 5.2 [1.0-7.0] years, 833 (9.1%) participants developed stroke, and the cumulative incidence of stroke increased with increasing quartiles of VAI (8.6%, 8.7%, 9.2%, and 10.0%). Compared to those in the first quartile of VAI, individuals in the fourth quartile had an increased risk of stroke (adjusted hazard ratio, 1.45; 95% CI, 1.15-1.75). The results were stable in several sensitivity analyses.

CONCLUSION

Our findings suggest a positive association between VAI and incident stroke in the Chinese population.

Association of visceral adiposity index with incident nephropathy and retinopathy: a cohort study in the diabetic population

Background

The association between visceral adiposity index (VAI) and diabetic complications has been reported in cross-sectional studies, while the effect of VAI on complication development remains unclear. This study aims to evaluate the longitudinal association of VAI and Chinese VAI (CVAI) with the incidence of diabetic nephropathy and retinopathy using a Chinese cohort.

Methods

A total of 8 948 participants with type 2 diabetes from Beijing Health Management Cohort were enrolled during 2013–2014, and followed until December 31, 2019. Nephropathy was confirmed by urine albumin/creatinine ratio and estimated glomerular filtration rate; retinopathy was diagnosed using fundus photograph.

Results

The mean (SD) age was 53.35 (14.66) years, and 6 154 (68.8%) were men. During a median follow-up of 4.82 years, 467 participants developed nephropathy and 90 participants developed retinopathy. One-SD increase in VAI and CVAI levels were significantly associated with an increased risk of nephropathy, and the adjusted hazard ratios (HR) were 1.127 (95% CI 1.050–1.210) and 1.165 (95% CI 1.003–1.353), respectively. On contrary, VAI and CVAI level were not associated with retinopathy after adjusting confounding factors.

Conclusion

VAI and CVAI are independently associated with the development of nephropathy, but not retinopathy in Chinese adults with diabetes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01464-1.

Comparison of novel visceral obesity indexes with traditional obesity measurements in predicting of metabolically unhealthy nonobese phenotype in hemodialysis patients

BACKGROUND

Normal-weight maintenance hemodialysis (MHD) patients with abdominal obesity exhibited a more proatherogenic profile than overweight and obesity patients with abdominal obesity, highlighting the importance of early identification of metabolically unhealthy nonobese (MUNO) in this population. Visceral fat accumulation plays a crucial role in the development of MUNO. Lipid accumulation product (LAP), visceral adiposity index (VAI) have been proved as reliable visceral obesity markers. The Chinese visceral adiposity index (CVAI) and a body shape index (ABSI) are newly discovered indexes of visceral obesity and have been reported to be associated with multiple metabolic disorders. There are limited studies investigating the associations between different visceral obesity indices and risk of MUNO, especially in hemodialysis patients. Moreover, no general agreement has been reached to date regarding which of these obesity indices performs best in identifying MUNO. We aimed to investigate the prevalence of MUNO in MHD patients and compare the associations between different adiposity indices (CVAI, ABSI,VAI, LAP, body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHtR)) with MUNO risk in this population.

METHODS

We conducted a multi-center cross-sectional study in Guizhou Province, Southwest China. 1302 nonobese adult MHD patients were included in our study. MUNO was defined as being nonobese and having the presence of > = 2 components of metabolic syndrome (MetS). Nonobese was defined as BMI less than 25 kg/m². VAI, LAP, CVAI, ABSI, BMI, WC and WHtR were calculated. Logistic regression analyses and receiver operator curve (ROC) analyses were performed. Results 65.6% participants were metabolically unhealthy. The ROC curve analysis demonstrated that of the seven obesity indices tested, the VAI (AUC 0.84 for women and 0.79 for men) followed by LAP (AUC 0.78 for women and 0.72 for men) had the highest diagnostic accuracy for MUNO phenotype while ABSI exhibited the lowest AUC value for identifying MUNO phenotype CONCLUSIONS: Metabolically unhealthy is highly prevalent in nonobese MHD patients. VAI and LAP outperformed CVAI in discriminating MUNO in MHD patients. Though ABSI could be a weak predictor of MUNO, it is not better than WHtR, WC and BMI.

Longitudinal Changes in Adiposity and Lower Urinary Tract Symptoms Among Older Men

BACKGROUND

Adiposity increases risk for male lower urinary tract symptoms (LUTS), although longitudinal studies have produced conflicting results. No prior studies have evaluated longitudinal associations of changes in adiposity with concurrent LUTS severity among older men.

METHODS

We used repeated adiposity measurements from dual-energy x-ray absorptiometry (DXA), body mass index (BMI), and American Urological Association Symptom Index (AUASI) measured at four study visits over a 9-year period among 5949 men enrolled in the Osteoporotic Fractures in Men (MrOS) study. Linear mixed effect models adjusted for age, health-related behaviors, and comorbidities were created to evaluate the association between baseline and change in visceral adipose tissue (VAT) area, total fat mass, and BMI with change in LUTS severity measured by the AUASI.

RESULTS

A non-linear association was observed between baseline VAT area and change in AUASI: men in baseline VAT tertile (T) 2 had a lower annual increase in AUASI score compared to men in T1 and T3 (T2 versus T1: β=-0.07; 95% CI -0.12, -0.03; P= 0.008; T3 versus T1: NS) but differences were small. No significant associations were observed between change in VAT area and change in AUASI score. Neither baseline tertiles nor change in total fat mass or BMI were associated with change in AUASI score.

CONCLUSIONS

Changes in VAT area, total fat mass, and BMI were not associated with change in LUTS severity in this cohort. Thus, despite other health benefits, interventions targeting adiposity alone are unlikely to be effective for preventing or treating LUTS among older men.

Associations of Visceral Adipose Tissue and Skeletal Muscle Density With Incident Stroke, Myocardial Infarction, and All-Cause Mortality in Community-Dwelling 70-Year-Old Individuals: A Prospective Cohort Study

Background Aging leads to increased visceral adipose tissue (VAT) and reduced skeletal muscle density. To which extent these are associated with the risk of stroke, myocardial infarction (MI), and all-cause mortality in older adults is unknown. Methods and Results A total of 3294 70-year-old individuals (49.6% women) underwent a health examination in Umeå, Sweden, during 2012 to 2018. VAT and muscle density were measured using dual-energy x-ray absorptiometry and peripheral quantitative computed tomography. Cases of stroke, MI, and all-cause mortality were collected through national registers. Cox regressions were used to calculate hazard ratios (HRs) and 95% CIs per SD greater VAT and per SD lower muscle density. During a mean follow-up of 3.6 years, there were 108 cases of stroke or MI, and 97 deaths. Greater VAT (adjusted HR [aHR], 1.56; 95% CI, 1.09-2.22), but not lower muscle density (aHR, 1.14; 95% CI, 0.97-1.34), was associated with increased risk of stroke or MI. Neither VAT (aHR, 0.95; 95% CI, 0.65-1.41) nor muscle density (aHR, 1.11; 95% CI, 0.92-1.34) was associated with all-cause mortality. The association of VAT with stroke or MI was only significant in men (aHR, 1.86; 95% CI, 1.19-2.91) but not women (aHR, 0.60; 95% CI, 0.25-1.42) (Pinteraction=0.038). Conclusions With the limitation of being an observational study, these findings suggest that VAT is an important obesity-related predictor of cardiovascular risk in 70-year-old men, and by implication, that decreasing VAT may potentially reduce their risk of cardiovascular disease.

Effect of genetic liability to visceral adiposity on stroke and its subtypes: A Mendelian randomization study

BACKGROUND

Observational studies have found an association between visceral adiposity and stroke.

AIMS

The purpose of this study was to investigate the role and genetic effect of visceral adipose tissue accumulation on stroke and its subtypes.

METHODS

In this two-sample Mendelian randomization study, genetic variants (221 single nucleotide polymorphisms; P < 5 × 10^-8) using as instrumental variables for Mendelian randomization analysis was obtained from a genome-wide association study of visceral adipose tissue. The outcome datasets for stroke and its subtypes were obtained from the MEGASTROKE consortium (up to 67,162 cases and 453,702 controls). Mendelian randomization standard analysis (inverse variance weighted method) was conducted to investigate the effect of genetic liability to visceral adiposity on stroke and its subtypes. Sensitivity analyses (Mendelian randomization-Egger, weighted median, Mendelian randomization-pleiotropy residual sum and outlier) were also utilized to assess horizontal pleiotropy and remove outliers. Multi-variable Mendelian randomization analysis was employed to adjust potential confounders.

RESULTS

In the standard Mendelian randomization analysis, genetically determined visceral adiposity (per 1 SD) was significantly associated with a higher risk of stroke (odds ratio (OR) 1.30; 95% confidence interval (CI) 1.21-1.41, P = 1.48× 10^-11), ischemic stroke (OR 1.30; 95% CI 1.20-1.41, P = 4.01 × 10^-10) and large artery stroke (OR 1.49; 95% CI 1.22-1.83, P = 1.16 × 10^-4). The significant association was also found in sensitivity analysis and multi-variable Mendelian randomization analysis.

CONCLUSIONS

Genetic liability to visceral adiposity was significantly associated with an increased risk of stroke, ischemic stroke, and large artery stroke. The effect of genetic susceptibility to visceral adiposity on the stroke warrants further investigation.

Precision and Effects of a Small Meal on DXA-Derived Visceral Adipose Tissue, Appendicular Lean Mass, and Other Body Composition Estimates In Nonobese Elderly Men

BACKGROUND

Information on precision errors and the least significant change (LSC) of dual energy X-ray absorptiometry (DXA)-derived body composition estimates is scarce, particularly for the appendicular lean mass (ALM) and appendicular lean mass index (ALMI). Overnight fasting is recommended for body composition measurements but has not been well tolerated by some elderly patients. This study aimed to establish precision errors and LSC values of body composition estimates in all regions-including visceral adipose tissue (VAT) and ALM-and the ALMI to assess the effect of a small meal on body composition and to estimate the changes it incurred.

METHODOLOGY

Our institutional review board approved the study protocol. Altogether, 36 non-obese men aged ≥60 years, having given written informed consent, underwent body composition assessment after fasting overnight except for water. They underwent DXA scans three times, each time with repositioning (to simulate the clinical setting), the last after consuming a standardized meal (210-250 g and 200 cc of water).

RESULTS

Precision errors and LSC values of DXA-derived body composition estimates in these elderly men tended to be higher than those in reports on younger subjects. Coefficients of variation (CVs (%)) of total bone mass (Tb.BMC) and total lean mass (Tb.LM) were <1%, whereas those of total fat mass (Tb.FM) and total %fat mass (Tb.%FM) were <2%, with LSCs of 45.8 g, 706.52 g, 731.4 g, and 1.15%, respectively. The CVs (LSC) of VAT, ALM, and ALMI were 8.9% (150.65 g), 0.93% (501 g), and 0.94% (0.19), respectively. After meal consumption, the mean changes in Tb.FM, Tb.BMC, and Tb.LM were -100, -8.2, and 440 g, respectively.

CONCLUSIONS

Effects of a small meal on most parameters were trivial, including those for VAT, ALM, and ALMI, where changes were not statistically significant. None exceeded the LSC of ALM and ALMI, suggesting that a small meal is allowable before these measurements.

Added values of DXA-derived visceral adipose tissue to discriminate cardiometabolic risks in pre-pubertal children

BACKGROUND

The new generation of dual energy X-ray absorptiometry (DXA) scanners provide visceral adipose tissue (VAT) estimates by applying different algorithms to the conventional DXA-derived fat parameters such as total fat, trunk fat and android fat for the same image data.

OBJECTIVE

This cross-sectional study aimed to investigate whether VAT estimates from Hologic scanners are better predictors of VAT than conventional DXA parameters in pre-pubertal children, and to explore the discrimination ability of these VAT methods for cardiometabolic risks.

METHODS

Healthy pre-pubertal children aged 7-10 years were recruited for basic anthropometric, DXA and magnetic resonance imaging (MRI) measurements. Laboratory tests included lipid profile, glycaemic tests and blood pressure.

RESULTS

All VAT methods had acceptable to excellent performance for the diagnosis of dyslipidaemia (area under the curve [AUC] = 0.753-0.837) and hypertensive risk (AUC = 0.710-0.821) in boys, but suboptimal performance for these risks in girls, except for VAT by MRI in the diagnosis of dyslipidaemia. In both sexes, all VAT methods had no or poor discrimination ability for diabetes risk.

CONCLUSIONS

DXA-derived VAT estimates are very highly correlated with standard methods but has equivalent discrimination abilities compared to the existing DXA-derived fat estimates.

The association between obesity indices and obstructive sleep apnea is modified by age in a sex-specific manner

BACKGROUND

The beneficial effects of weight reduction on obstructive sleep apnea (OSA) are highly variable. Whether or not the variability is associated with the effects of age and sex remains unclear. This study examined this issue with large cross-sectional data.

METHOD

Anthropometric measurements, polysomnographic variables, biochemical indicators, and medical history were collected for each participant. Multivariable linear regression with interaction terms was used to estimate the modification effect of age on the associations between OSA severity (assessed by apnea-hypopnea index, AHI) with obesity indices (body mass index, BMI; neck circumference, NC; waist circumference, WC; waist-to-hip ratio, WHR) in a sex-specific manner, and vice versa. To facilitate interpretation of the results, participants were further classified into six subpopulations according to both sex and age, and population-specific beta-coefficients were calculated and compared.

RESULTS

A total of 5756 adults (4600 men) with suspected OSA were included in the study. BMI, NC, WC, and WHR were all positively correlated with AHI after adjusting for potential confounders in all populations. In men, these associations were much stronger and more significant in younger than older individuals (P for interaction < 0.001). For example, a 10% increase in BMI was independently associated with a 32% increase in AHI for men < 40 years old, whereas the corresponding increases were 21% and 17% for men 40-60 and > 60 years old, respectively. By contrast, no modification effect of age was observed in women (P for interaction > 0.05). A 10% increase in BMI was associated with 26%, 27%, and 24% increases in AHI for women < 40, 40-60, and > 60 years old, respectively.

CONCLUSIONS

Age modifies the associations between obesity indices and OSA severity in a sex-specific manner. These findings may broaden the understanding of age- and sex-related heterogeneities in the pathogenic role of obesity in OSA, and may be beneficial for individualized risk evaluation and treatment management for patients with OSA.

Comparison of single-slice CT and DXA-derived measures of central adiposity in South African women

BACKGROUND

Visceral adipose tissue (VAT) accumulation is a known risk factor for cardiometabolic diseases. Efficient imaging modalities are necessary to quantify VAT. The study assessed the agreement between dual-energy x-ray absorptiometry (DXA) and single-slice computed tomography (CT) for abdominal fat quantification in mixed-ancestry South African women, and determined if this differed by body mass index (BMI) categories.

METHODS

VAT and abdominal subcutaneous adipose tissue (SAT) were measured using single-slice CT and DXA in 132 women aged 55 (45-64) years. Participants were categorised as normal weight (BMI < 25 kg/m²), overweight (BMI: 25-29.9 kg/m²) and obese (BMI ≥ 30 kg/m²). Pearson correlation coefficients and Bland-Altman analysis were used to determine agreement between the two measurements.

RESULTS

Two thirds of the participants were obese. DXA and CT-derived measurements of abdominal VAT and SAT were significantly correlated in the overall sample (r = 0.872 and r = 0.966, both p < 0.001, respectively) and within BMI categories. DXA overestimated VAT and SAT in the overall sample and across BMI categories. In the overall sample, the mean difference (DXA-CT estimates) was 75.3 cm² (95% CI: 68.8-81.8 cm², p ≤ 0.0001) for VAT and 54.7 cm² (47.1-62.3 cm², p ≤ 0.0001) for SAT. Within increasing BMI categories, the variance between the two modalities was fixed for VAT (p = 0.359 for obese), whereas the variance for SAT was heteroscedastic (p ≤ 0.0001).

CONCLUSIONS

DXA overestimated VAT and abdominal SAT in a sample of middle-aged mixed-ancestry South African women. VAT variance was fixed in the obesity category, an indication that DXA may be valid in measuring VAT in obese people.