Fat distribution and mortality: the AGES-Reykjavik Study

Molecular and pathophysiological relationship between obesity and chronic inflammation in the manifestation of metabolic dysfunctions and their inflammation‑mediating treatment options (Review)

Obesity reaches up to epidemic proportions globally and increases the risk for a wide spectrum of co‑morbidities, including type‑2 diabetes mellitus (T2DM), hypertension, dyslipidemia, cardiovascular diseases, non‑alcoholic fatty liver disease, kidney diseases, respiratory disorders, sleep apnea, musculoskeletal disorders and osteoarthritis, subfertility, psychosocial problems and certain types of cancers. The underlying inflammatory mechanisms interconnecting obesity with metabolic dysfunction are not completely understood. Increased adiposity promotes pro‑inflammatory polarization of macrophages toward the M1 phenotype, in adipose tissue (AT), with subsequent increased production of pro‑inflammatory cytokines and adipokines, inducing therefore an overall, systemic, low‑grade inflammation, which contributes to metabolic syndrome (MetS), insulin resistance (IR) and T2DM. Targeting inflammatory mediators could be alternative therapies to treat obesity, but their safety and efficacy remains to be studied further and confirmed in future clinical trials. The present review highlights the molecular and pathophysiological mechanisms by which the chronic low‑grade inflammation in AT and the production of reactive oxygen species lead to MetS, IR and T2DM. In addition, focus is given on the role of anti‑inflammatory agents, in the resolution of chronic inflammation, through the blockade of chemotactic factors, such as monocytes chemotractant protein‑1, and/or the blockade of pro‑inflammatory mediators, such as IL‑1β, TNF‑α, visfatin, and plasminogen activator inhibitor‑1, and/or the increased synthesis of adipokines, such as adiponectin and apelin, in obesity‑associated metabolic dysfunction.

Effects of various exercise types on visceral adipose tissue in individuals with overweight and obesity: A systematic review and network meta-analysis of 84 randomized controlled trials

The purpose of this systematic review and network meta-analysis (NMA) of randomized controlled trials (RCTs) was to investigate the effects of various exercise categories on visceral adipose tissue (VAT) and other anthropometric variables in individuals with overweight and obesity. A total of 84 RCTs (4836 patients) were included. Aerobic exercise (AE) of at least moderate intensity, resistance training (RT), AE combined with RT (AE + RT), and high-intensity interval training (HIIT) were beneficial for reducing VAT. A subgroup analysis showed that RT improves VAT in males and those with BF% < 40% but not in females and those with body fat percentage (BF%) ≥ 40%. AE, RT, AE + RT, and HIIT significantly improved weight (except RT), total body fat (TBF), body mass index (BMI), waist circumference (WC), and subcutaneous adipose tissue (SAT). Surface under the cumulative ranking curve (SUCRA) probability ranking showed that AE with vigorous intensity and HIIT have the highest probability of being the best exercise intervention for improving VAT, weight, TBF, BMI, WC, and SAT. These findings suggest that regular exercise can improve VAT in individuals with overweight and obesity. AE of vigorous intensity and HIIT may be the best exercise treatment, and RT is the least effective intervention.

Abdominal adipose tissue distribution assessed by computed tomography and mortality in hospitalised patients with COVID-19: a retrospective longitudinal cohort study

BACKGROUND

Visceral adiposity has been associated with an increased risk of critical illness in COVID-19 patients. However, if it also associates to a poor survival is still not well established. The aim of the study was to assess the relationship between abdominal fat distribution and COVID-19 mortality.

METHODS

In this six-month longitudinal cohort study, abdominal visceral (VAT) and subcutaneous adipose tissues (SAT) were measured by computed tomography in a cohort of 174 patients admitted to the emergency department with a diagnosis of COVID-19, during the first wave of pandemic. The primary exposure and outcome measures were VAT and SAT at hospital admission, and death at 30 and 180 days, respectively.

RESULTS

Overall survival was not different according to VAT (p = 0.94), SAT (p = 0.32) and VAT/SAT ratio (p = 0.64). However, patients in the lowest SAT quartile (thickness ≤ 11.25 mm) had a significantly reduced survival compared to those with thicker SAT (77 vs. 94% at day 30; 74 vs. 91% at day 180, p = 0.01). Similarly, a thinner SAT was associated with lower survival in Intensive Care Unit (ICU) admitted patients, independently of sex or age (p = 0.02). The VAT/SAT ratio showed a non-linear increased risk of ICU admission, which plateaued out and tended for inversion at values greater than 1.9 (p = 0.001), although was not associated with increased mortality rate.

CONCLUSIONS

In our cohort, visceral adiposity did not increase mortality in patients with COVID-19, but low SAT may be associated with poor survival.

Age-adjusted visceral adiposity index (VAI) is superior to VAI for predicting mortality among US adults: an analysis of the NHANES 2011-2014

BACKGROUND

The association of visceral adiposity with mortality in older adults is conflicting. Whether age influences the predicting ability of visceral adiposity (VAI) for mortality remains unknown. This study uncovered the relationship between age-adjusted visceral adiposity index and mortality through the data of NHANES 2011-2014.

METHODS

This study obtained data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. The age-adjusted visceral adiposity index (AVAI) scores were expressed as quartiles. Receiver operating characteristics (ROC) curve analysis was also applied to compare the predictive ability for mortality. Multivariate weighted Cox regression models were constructed to explore the association between AVAI and mortality. Kaplan-Meier survival curves were conducted for survival analyses. Smooth curve fittings and two-piecewise linear models were applied to explore the relationships between AVAI and mortality.

RESULTS

This study recruited 4281 subjects aged ≥ 18 years from the NHANES 2011-2014. The AUCs of AVAI were 0.82 (0.79, 0.86) and 0.89 (0.85, 0.92) for predicting all-cause mortality and cardiovascular mortality, which were superior to BMI, WC and VAI (all p < 0.05). AVAI is still an independent predictor for mortality adjusted for confounders. The associations of AVAI with all-cause and cardiovascular mortalities were dose-responsive, with higher AVAI scores indicating higher mortality risks.

CONCLUSION

Age significantly improves the ability of VAI for predicting all-cause and cardiovascular mortality. Age-adjusted VAI is independently associated with mortality risk, and thus could be considered a reliable parameter for assessing mortality risk.

The effects of sex hormones on the size of intestinal lipoproteins

Larger intestinal lipoproteins are more likely to be retained longer in the intestinal wall, allowing more time for their fat to be hydrolyzed and subsequently taken up by the abdominal viscera. Since men generally accumulate more abdominal visceral fat than women, we sought to determine if males produce larger intestinal lipoproteins compared to females. Using the conscious lymph fistula mouse model, we discovered that the male mice indeed produced larger intestinal lipoproteins than the female mice when they were intraduodenally infused with lipid emulsion. We then employed our differentiated Caco-2 cell model with semipermeable membrane system to determine the effects of sex hormones on the size of intestinal lipoproteins. Lipoprotein size was quantitatively measured by calculating the ratio of triglycerides (TG)/Apolipoprotein B (ApoB) and by analyzing their transmission electron micrographs. Our studies showed that while there was no dose-dependent effect of estrogen and progesterone, testosterone significantly increased the size of lipoproteins. When these hormones were combined to resemble the physiological concentrations observed in males and the different ovarian cycle phases in premenopausal females, both the male and luteal groups had significantly larger lipoproteins than the ovulatory group; and the male group also had significantly larger lipoproteins than the follicular group. The ovulatory group secreted a significantly lower amount of TG than the male and luteal groups. ApoB was comparable among all these groups. These findings support our hypothesis that, through their testosterone effects, males are more likely to produce larger intestinal lipoproteins. Larger lipoproteins tend to remain longer in the intestinal wall and may facilitate fat uptake preferentially by the abdominal viscera. Our studies may partly explain why men are more prone to accumulating abdominal visceral fat, which is an independent predictor of mortality.

Central mechanisms in sympathetic nervous dysregulation in obesity

Cardiovascular and metabolic complications associated with excess adiposity are linked to chronic activation of the sympathetic nervous system, resulting in a high risk of mortality among obese individuals. Obesity-related positive energy balance underlies the progression of hypertension, end-organ damage, and insulin resistance, driven by increased sympathetic tone throughout the body. It is, therefore, important to understand the central network that drives and maintains sustained activation of the sympathetic nervous system in the obese state. Experimental and clinical studies have identified structural changes and altered dynamics in both grey and white matter regions in obesity. Aberrant activation in certain brain regions has been associated with altered reward circuitry and metabolic pathways including leptin and insulin signaling along with adiposity-driven systemic and central inflammation. The impact of these pathways on the brain via overactivity of the sympathetic nervous system has gained interest in the past decade. Primarily, the brainstem, hypothalamus, amygdala, hippocampus, and cortical structures including the insular, orbitofrontal, temporal, cingulate, and prefrontal cortices have been identified in this context. Although the central network involving these structures is much more intricate, this review highlights recent evidence identifying these regions in sympathetic overactivity in obesity.

Obesity and lifespan, a complex tango

Obesity and aging share comorbidities, phenotypes, and deleterious effects on health that are associated with chronic diseases. However, distinct features set them apart, with underlying biology that should be explored and exploited, especially given the demographic shifts and the obesity epidemic that the world is facing.

Adipose Tissue Metabolism in Response to Food Intake

The quality and quantity of the food we consume have a major impact on our general health and longevity [...].

Thigh-hip ratio is significantly associated with all-cause mortality among Japanese community-dwelling men

Anthropometric evaluation is a simple yet essential indicator of muscle and fat mass when studying life prognosis in aging. This study aimed to investigate the contributions of anthropometric measurements, independent of body mass index, to measures of all-cause mortality. We examined data for 1,704 participants from the 2014 Nomura Cohort Study who attended follow-ups for the subsequent eight years (follow-up rate: 93.0%). Of these, 765 were male (aged 69 ± 11 years) and 939 were female (aged 69 ± 9 years). The Japanese Basic Resident Registry provided data on adjusted relative hazards for all-cause mortality. The data were subjected to a Cox regression analysis, wherein the time variable was age and the risk factors were gender, age, anthropometric index, smoking habits, drinking habits, exercise habits, cardiovascular history, hypertension, lipid levels, diabetes, renal function, and serum uric acid. Of the total number of participants, 158 (9.3%) were confirmed to have died, and of these, 92 were male (12.0% of all male participants) and 66 were female (7.0% of all female participants). The multivariable Cox regression analysis revealed that a smaller thigh-hip ratio predicted eight-year all-cause mortality in male participants, but only baseline body mass index was associated with all-cause mortality in female participants. Thigh-hip ratio is a useful predictor of death in Japanese community-dwelling men.

Concurrence of hyperinsulinemia and hyperuricemia significantly augmented all-cause mortality

BACKGROUND AND AIMS

Hyperinsulinemia and hyperuricemia are known to increase the risk of mortality due to certain complications, such as Type 2 Diabetes and cardiovascular disease. However, despite their common comorbidities, their combined effect has not been evaluated. The study's aim was to evaluate the combine effect of hyperinsulinemia and hyperuricemia on all-cause mortality.

METHODS AND RESULTS

NHANES datasets (cycles 2003-2018) were examined. Differences between groups were evaluated using Rao-Scott Chi-square and General Linear Model for categorical and continuous data, respectively. Hazard Ratios (HR) were calculated using Cox regression with 95% confidence intervals (95%CI). There was significant difference (p < 0.05) in the mortality rate between the control group (2.3 ± 0.2%), the hyperinsulinemia only group (3.1 ± 0.3%), the hyperuricemia only group (4.0 ± 0.8%), and both conditions (5.1 ± 0.8%). Individually, when compared to the control group, there was a significant increase in mortality risk for hyperinsulinemia (HR: 1.50, 95%CI: 1.12-2.01, p = 0.007) and hyperuricemia (HR: 1.80, 95%CI:1.18-2.75, p = 0.006). However, when both conditions were present, there appeared an additive effect in the mortality risk (HR: 2.32, 95%CI: 1.66-3.25, p < 0.001). When stratified by BMI class, only normal weight participants presented with a significant risk (HR: 7.00, 95%CI: 2.50-20.30, p < 0.001). Also, when stratified by age, only participants older than 40 years presented a risk (HR: 2.22, 95%CI: 1.56-3.16, p < 0.001).

CONCLUSION

Alone, hyperuricemia and hyperinsulinemia significantly increased the mortality rate; however, the combined presence of both pathologies was associated with a significantly augmented mortality rate. Normal weight participant or that were >40 years old had a greater risk for mortality.

Crossover point and maximal fat oxidation training effects on blood lipid metabolism in young overweight women: a pilot study

Purpose: To determine the effects of weight reduction schemes using the exercise intensities corresponding to maximal fat oxidation (FATmax) and crossover point (COP). The effects of different intervention protocols on blood lipid metabolism were compared to explore how fat can be consumed and used more efficiently and provide a theoretical basis for weight loss through exercise. Methods: This study included 30 young overweight women randomly divided into the COP, FATmax, and control groups. Participants in the COP and FATmax groups exercised for 45 min four times a week for 8 weeks after the individual treadmill exercise test. The control group did not perform any exercise. Results: After 8 weeks of training, participants in the COP group significantly decreased weight (2.6 ± 3.3 kg), body mass index (0.91 ± 1.26 kg/m²), body fat percentage (1.21% ± 1.50%), and fat mass (1.90 ± 2.30 kg) (p < 0.05). They also had significantly decreased hip circumference (4.8 ± 3.3 cm), serum apolipoprotein B (ApoB) levels (15.48 ± 14.19 mg/dL), and ApoB/apolipoprotein AI (ApoAI) ratios (0.47 ± 0.37) (p < 0.01). However, their serum ApoAI levels were significantly increased (14.18 ± 10.24 mg/dL; p < 0.01). Participants in the FATmax group had significantly decreased hip circumference (2.4 ± 2.0 cm), serum ApoB levels (14.49 ± 11.00 mg/dL), and ApoB/ApoAI ratios (0.59 ± 0.30) (p < 0.01) but significantly increased serum ApoAI levels (29.53 ± 13.29 mg/dL; p < 0.01). No significant changes in physiological indexes were observed in participants in the control group. Conclusion: Personalised exercise intervention positively affected central obesity, effectively improving blood lipid metabolism and fat oxidation, reducing cardiovascular disease risk in young overweight women. COP training improved weight and body composition better than the FATmax exercise, while the latter provided greater improvements in serum ApoAI levels.

From Beneath the Skin to the Airway Wall: Understanding the Pathological Role of Adipose Tissue in Comorbid Asthma-Obesity

This article provides a contemporary report on the role of adipose tissue in respiratory dysfunction. Adipose tissue is distributed throughout the body, accumulating beneath the skin (subcutaneous), around organs (visceral), and importantly in the context of respiratory disease, has recently been shown to accumulate within the airway wall: "airway-associated adipose tissue." Excessive adipose tissue deposition compromises respiratory function and increases the severity of diseases such as asthma. The mechanisms of respiratory impairment are inflammatory, structural, and mechanical in nature, vary depending on the anatomical site of deposition and adipose tissue subtype, and likely contribute to different phenotypes of comorbid asthma-obesity. An understanding of adipose tissue-driven pathophysiology provides an opportunity for diagnostic advancement and patient-specific treatment. As an exemplar, the potential impact of airway-associated adipose tissue is highlighted, and how this may change the management of a patient with asthma who is also obese. © 2023 American Physiological Society. Compr Physiol 13:4321-4353, 2023.

Association between Vitamin B and Obesity in Middle-Aged and Older Chinese Adults

OBJECTIVE

Previous studies have found that obese people have lower levels of vitamin B, but most have focused on obesity as defined by body mass index (BMI), and its relationship with other types of obesity is unclear. The aim of this study was to explore the relationship between vitamin B levels and obesity assessed by different definitions among Chinese middle-aged and older community-dwelling adults.

METHODS

This cross-sectional study included 887 participants aged 45 years and older (45-82 years). The concentrations of vitamin B (B₁, B₂, B₆, and B₉) were measured by robotic dry blood spot extraction systems in combination with liquid chromatography-tandem mass spectrometry. BMI, body fat percentage (BF%), visceral fat area (VFA), and waist circumference (WC) were used to diagnose obesity. VFA and BF% were assessed by bioelectrical impedance analysis. The logistic regression model was used to assess the associations between vitamin B levels and the odds of obesity.

RESULTS

The average age of all participants was 60.77 (SD 6.33) years. The prevalence of obesity varied from 8.6% to 52.4% depending on different diagnostic criteria. After adjusting for covariates, a negative correlation was observed between vitamin B₁ level and obesity according to the criteria of WC, VFA, and BF%, and the adjusted odds ratio (OR) was 0.47, 0.52, and 0.46, respectively. When using WC and BF% to define obesity, higher quartiles of vitamin B₂ were negatively associated with the odds of obesity (OR: 0.62 and 0.62, respectively). Vitamin B₆ was inversely associated with VFA-defined and BF%-defined obesity (OR: 0.64 and 0.64, respectively). When using VFA and BF% to define obesity, a negative correlation was observed in vitamin B₉ (OR: 0.61 and 0.67, respectively).

CONCLUSIONS

Vitamin B (B₁, B₂, B₆, and B₉) level was negatively related to obesity (defined by WC, VFA, or BF%) in Chinese middle-aged and older adults.

Intestinal Calcium Absorption Decreases After Laparoscopic Sleeve Gastrectomy Despite Optimization of Vitamin D Status

CONTEXT

Laparoscopic sleeve gastrectomy (LSG), now the most commonly performed bariatric operation, is a highly effective treatment for obesity. While Roux-en-Y gastric bypass is known to impair intestinal fractional calcium absorption (FCA) and negatively affect bone metabolism, LSG's effects on calcium homeostasis and bone health have not been well characterized.

OBJECTIVE

We determined the effect of LSG on FCA, while maintaining robust 25-hydroxyvitamin D (25OHD) levels and recommended calcium intake.

DESIGN, SETTING, PARTICIPANTS

Prospective pre-post observational cohort study of 35 women and men with severe obesity undergoing LSG.

MAIN OUTCOMES

FCA was measured preoperatively and 6 months postoperatively with a gold-standard dual stable isotope method. Other measures included calciotropic hormones, bone turnover markers, and bone mineral density (BMD) by dual-energy X-ray absorptiometry and quantitative computed tomography.

RESULTS

Mean ± SD FCA decreased from 31.4 ± 15.4% preoperatively to 16.1 ± 12.3% postoperatively (P < 0.01), while median (interquartile range) 25OHD levels were 39 (32-46) ng/mL and 36 (30-46) ng/mL, respectively. Concurrently, median 1,25-dihydroxyvitamin D level increased from 60 (50-82) pg/mL to 86 (72-107) pg/mL (P < 0.01), without significant changes in parathyroid hormone or 24-hour urinary calcium levels. Bone turnover marker levels increased substantially, and areal BMD decreased at the proximal femur. Those with lower postoperative FCA had greater areal BMD loss at the total hip (ρ = 0.45, P < 0.01).

CONCLUSIONS

FCA decreases after LSG, with a concurrent rise in bone turnover marker levels and decline in BMD, despite robust 25OHD levels and with recommended calcium intake. Decline in FCA could contribute to negative skeletal effects following LSG.

Sex is a major effect modifier between body composition and mortality in patients with cirrhosis assessed for liver transplantation

BACKGROUND AND AIMS

Body composition predicts mortality in patients with cirrhosis. The impact of sex on this association is unknown. We investigated the impact of sex on this association in patients with cirrhosis assessed for liver transplantation.

METHODS

This single-centre retrospective cohort study included adults assessed for liver transplantation. Nutritional status was assessed using the Royal Free Hospital-Global Assessment (RFH-GA). Body composition at the third lumbar vertebrae was determined. SarcopeniaSMI was defined as Skeletal Muscle Index <50 cm2 /m2 in males and <39 cm2 /m2 in females. SarcopeniaPMI was defined as the sex-specific 25th percentile of the Psoas Muscle Index. Patients were assessed for the occurrence of liver transplantation and death. Analyses were stratified by sex.

RESULTS

The cohort comprised 628 patients, including 199 females and 429 males. Both groups were similar in terms of baseline liver disease severity by Model for End-stage Liver Disease (MELD) (p = .98) and nutritional status (p = .24). SarcopeniaSMI was present in 41% of males compared to 27% of females (p < .001). In the male cohort, when adjusted for age and MELD, sarcopeniaPMI (aHR 1.74, 95% CI 1.08-2.80) and RFH-GA (aHR 1.40, 95% CI 1.03-1.90) remained independent predictors of mortality. Adipose tissue had no impact on outcomes in males. In female patients, adipose tissue (TATI or VATI depending on the multivariable model) was independently associated with mortality, whereas sarcopenia and malnutrition were not.

CONCLUSIONS

This study demonstrates that male patients were susceptible to low muscle mass, whereas female patients were not. Future research in this patient population should minimize sex-related bias and present data for both groups separately.

Effect of High-Intensity Interval Training Combined with Blood Flow Restriction at Different Phases on Abdominal Visceral Fat among Obese Adults: A Randomized Controlled Trial

BACKGROUND

High-intensity interval training (HIIT) and blood flow restriction (BFR) represent a critical nonpharmacological strategy to reduce the excess deposition of visceral fat, as well as relevant complications, among obese populations. Applying BFR at diverse phases may have different effects. Therefore, the exercise program of this study combined HIIT with BFR, so as to explore the effect of BFR on abdominal visceral fat area and its mechanism in different periods of HIIT. The aim is to provide a more effective exercise prescription for obese people who want to reduce visceral fat quickly.

METHODS

This study was a randomized controlled trial involving 72 obese adults. One week before intervention, both regional and whole-body fat masses, abdominal subcutaneous and visceral fat areas, variables of blood metabolism, and VO_2max were recorded. Additionally, subjects with a matched fat percentage were randomized as a no-training control (C), HIIT (H), HIIT with BFR during interval (I), and HIIT with BFR during exercise (E) groups for 24 sessions within a 12-week period, using a cycle ergometer. During session one, this study recorded blood lactate, specific serum lipolytic hormones, rating of perceived exertion (RPE), and exercise heart rate (HR) and compared them among three groups. The baseline tests were repeated at 1 week after intervention.

RESULTS

There was no significant statistical difference in the indicators of each group at baseline (p > 0.05). The improvement of trunk fat mass and fat percentage of the I and E groups markedly increased relative to the H group (p < 0.05). Meanwhile, the I group had improved android fat mass and whole-body fat mass relative to group H (p < 0.05). Those exercise groups had markedly improved indices compared with the C group (p < 0.05). Additionally, the reduction in the I group had remarkably superior abdominal visceral fat areas (AVFA) to the H and E groups (p < 0.05). Immediately and 30 min following exercise, the E and I groups had remarkably increased growth hormone (GH) compared with the H group (p < 0.05). After exercise, the I group showed markedly increased epinephrine (EPI) compared with the H group (p < 0.05). The LA level in the I group evidently increased relative to the E group (p < 0.05), while that in the E group evidently increased compared with the H group (p < 0.05).

CONCLUSION

Compared with HIIT alone, HIIT with BFR can better improve the body-fat level and glucose metabolism. HIIT with BFR in the interval phase better reduces the abdominal visceral-fat level than in the exercise phase, which may be due to the increase in lipolytic hormone level caused by the higher physiological load.

Associations of eating speed with fat distribution and body shape vary in different age groups and obesity status

Background

Eating speed has been reported to be associated with energy intake, body weight, waist circumference (WC), and total body fat. However, no study has explored the association between eating speed and body fat distribution, especially its difference among different age or body mass index (BMI) groups.

Methods

4770 participants aged 18–80 years were recruited from the baseline survey of the Lanxi Cohort Study. They were categorized into three groups according to meal duration. Linear regression analyses were performed among all participants and separately by age group and obesity status to evaluate the associations of WC and total and regional fat mass percentages (FM%) with eating speed.

Results

After adjusting for confounding factors, eating slowly was significantly related to lower WC, lower total, trunk, and android FM%, lower android-to-gynoid fat mass ratio, and higher leg and gynoid FM%. After stratification by age or obesity status, the associations were especially prominent among participants aged 18–44 years or those with BMI < 24 kg/m². No significant trends were found for participants aged 65–80 years or those who were overweight/obese.

Conclusions

Eating slowly is closely related with better fat distribution among Chinese adults, especially for those aged 18–44 years and those with BMI < 24 kg/m². If confirmed prospectively, it might be a potential efficient approach to improve fat distribution.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12986-022-00698-w.

Sex-different changes of body composition in aging: a systemic review

OBJECTIVE

Aging causes changes in body composition, in which differences in the distribution and amount of fat and muscle tissue affect the development of various diseases according to sex. We conducted a systemic review of the literature and examined the relationship between body composition differences and related health conditions or diseases in older men and women.

METHODS

Three different electronic databases (MEDLINE, Web of Science, and Embase) were used to find articles from 2000 until March 2022. Information on the study design characteristics, setting, measure of body composition, and health outcomes was extracted.

RESULTS

A total of 217 articles were retrieved, and 28 studies met the inclusion criteria. The included studies showed that older men have larger skeletal muscle mass (sMM) than women, while older women have larger fat mass (FM) than men. sMM has a favorable effect on physical performance, bone density, metabolism, cognitive function, and mortality in both men and women; however, the effects of sMM in women are less significant and even negligible compared to those in men. FM is significantly unfavorable for physical performance in women but sometimes favorable or unfavorable for glucose level and cognitive and lung function according to location. FM in men is usually less important for function, bone density, glucose level, and cognitive function than in women.

CONCLUSION

Changes in muscle and fat distribution according to aging and their correlation with health outcomes differ according to sex. Muscle mass may not always be favorable, and fat mass may not always be unfavorable in older adults.

Lymphatics in Cardiovascular Physiology

The lymphatic vessels play an essential role in maintaining immune and fluid homeostasis and in the transport of dietary lipids. The discovery of lymphatic endothelial cell-specific markers facilitated the visualization and mechanistic analysis of lymphatic vessels over the past two decades. As a result, lymphatic vessels have emerged as a crucial player in the pathogenesis of several cardiovascular diseases, as demonstrated by worsened disease progression caused by perturbations to lymphatic function. In this review, we discuss the major findings on the role of lymphatic vessels in cardiovascular diseases such as hypertension, obesity, atherosclerosis, myocardial infarction, and heart failure.

Adipose Tissue Aging and Metabolic Disorder, and the Impact of Nutritional Interventions

Adipose tissue is the largest and most active endocrine organ, involved in regulating energy balance, glucose and lipid homeostasis and immune function. Adipose tissue aging processes are associated with brown adipose tissue whitening, white adipose tissue redistribution and ectopic deposition, resulting in an increase in age-related inflammatory factors, which then trigger a variety of metabolic syndromes, including diabetes and hyperlipidemia. Metabolic syndrome, in turn, is associated with increased inflammatory factors, all-cause mortality and cognitive impairment. There is a growing interest in the role of nutritional interventions in adipose tissue aging. Nowadays, research has confirmed that nutritional interventions, involving caloric restriction and the use of vitamins, resveratrol and other active substances, are effective in managing adipose tissue aging’s adverse effects, such as obesity. In this review we summarized age-related physiological characteristics of adipose tissue, and focused on what nutritional interventions can do in improving the retrogradation and how they do this.

Body fat and risk of all-cause mortality: a systematic review and dose-response meta-analysis of prospective cohort studies

BACKGROUND/OBJECTIVES

We aimed to evaluate the relationships between body fat percentage (BF%), fat mass (FM), fat mass index (FMI) and visceral (VAT) and subcutaneous adipose tissue (SAT) with risk of all-cause mortality.

METHODS

We did a systematic search in PubMed, Scopus, and Web of Science to June 2021. We selected prospective cohorts of the relationship between body fat with risk of all-cause mortality in the general population. We applied random-effects models to calculate the relative risks (RRs) and 95%CIs.

RESULTS

A total of 35 prospective cohort studies with 923,295 participants and 68,389 deaths were identified. The HRs of all-cause mortality for a 10% increment in BF were 1.11 (95%CI: 1.02, 1.20; I² = 93%, n = 11) in the general adult populations, and 0.92 (95%CI: 0.79, 1.06; I² = 76%, n = 7) in adults older than 60 years. The HRs were 1.06 (95%CI: 1.01, 1.12; I² = 86%, n = 10) for a 5 kg increment in FM, 1.11 (95%CI: 1.06, 1.16; I² = 79%, n = 7) for a 2 kg/m² increment in FMI, and 1.17 (95%CI: 1.03, 1.33; I² = 72%, n = 8) and 0.81 (0.66, 0.99; I² = 59%, n = 6) for a 1-SD increment in VAT and SAT, respectively. There was a J shaped association between BF% and FM and all-cause mortality risk, with the lowest risk at BF% of 25% and FM of 20 kg. In subgroup analyses, although there was little evidence of between-subgroup heterogeneity, the observed positive associations were more pronounced in studies which had a longer duration, excluded participants with prevalent cardiovascular disease and cancer at baseline, with adjustment for smoking or restricted to never smokers, and less pronounced in studies which adjusted for potential intermediates, suggesting an impact of reverse causation, confounding and over-adjustment in some of the studies.

CONCLUSIONS

Higher body fat content was related to a higher risk of mortality in a J shaped manner. Any future studies should further assess the impact of reverse causation and residual confounding on these associations.

REGISTRATION

PROSPERO (CRD42021240743).

The role of the androgen receptor in the pathogenesis of obesity and its utility as a target for obesity treatments

Obesity is associated with hypothalamic-pituitary-testicular axis dysregulation in males. Here, we summarize recent evidence derived from clinical trials and studies in preclinical animal models regarding the role of androgen receptor (AR) signaling in the pathophysiology of males with obesity. We also discuss therapeutic strategies targeting the AR for the treatment of obesity and their limitations and provide insight into the future research necessary to advance this field.

Intermuscular adipose tissue in Type 2 diabetes mellitus: Non-invasive quantitative imaging and clinical implications

Intermuscular adipose tissue (IMAT) is an ectopic fat depot found beneath the fascia and within the muscles. IMAT modulates muscle insulin sensitivity and triggers local and systemic chronic low-grade inflammation by producing cytokines and chemokines, which underlie the pathogenesis of Type 2 diabetes mellitus (T2DM). Imaging techniques have been increasingly used to non-invasively quantify IMAT in patients with diabetes in research and healthcare settings. In this study, we systematically reviewed the cell of origin and definition of IMAT, and the use of quantitative and functional imaging technology pertinent to the etiology, risk factors, lifestyle modification, and therapeutic treatment of diabetes. The purpose of this article is to provide important insight into the current understanding of IMAT and future prospects of targeting IMAT for T2DM control.

Morbidity and mortality in PCOS: A prospective follow-up up to a mean age above 80 years

OBJECTIVE

Despite the clear evidence of increased cardiovascular disease (CVD) risk factors, the long-term effect on CVD and mortality is still uncertain in women with PCOS, especially in the elderly. Studies in elderly women with PCOS are lacking. The objective was to study morbidity/mortality in PCOS women compared with a reference group up to a mean age above 80 years.

STUDY DESIGN

A well-defined cohort of women with PCOS, examined in 1987 and 2008, was re-examined 32 years later in 2019 (age range 72-91 years), in parallel with an age-matched reference group. For deceased women register data was used, for women alive interviews were done, and medical records studied. Blood pressure and blood tests were analyzed. Morbidity and mortality data was available in 35/36 women with PCOS, and in 99/118 women in the reference group.

RESULTS

At mean age 81 years there was no difference in all-cause mortality (HR 1.1, ns), CVD-related mortality (HR 1.7, ns), all CVD (HR 1.2, ns), hypertension (HR 1.8, ns), type 2 diabetes (HR 1.7, ns), in levels of blood lipids, glucose, insulin or thyroid hormones. Comparing baseline data from the deceased and living women with PCOS, no differences were found regarding age, menopausal age, BMI, HOMA-IR, FAI, total testosterone or SHBG. However, deceased women with PCOS had a higher WHR (0.87 vs. 0.80; p-value < 0.01) at baseline.

CONCLUSIONS

No evidence of increased all-cause mortality or CVD was found in women with PCOS. The elevated testosterone levels and CVD risk profile in PCOS present during perimenopause do not seem to be associated with increased CVD morbidity/mortality risk later in life.

Subcutaneous and visceral fat assessment by DXA and MRI in older adults and children

OBJECTIVE

Given the importance of body fat distribution in chronic disease development, feasible methods to assess body fat are essential. This study compared dual-energy x-ray absorptiometry (DXA) in measuring visceral and subcutaneous adipose tissue (VAT and SAT) with magnetic resonance imaging (MRI).

METHODS

VAT and SAT were assessed using similar DXA and MRI protocols among 1,795 elderly participants of the Adiposity Phenotype Study (APS) and 309 children/adolescents in Shape Up! Kids (SKids). Spearman correlations, Bland-Altman plots, and coefficients of determination (R2 ) assessed agreement between DXA and MRI measures.

RESULTS

DXA overestimated SAT values in APS (315 vs. 229 cm2 ) and SKids (212 vs. 161 cm2 ), whereas DXA underestimated VAT measures (141 vs. 167 cm2 ) in adults only. The correlations between DXA and MRI values were stronger for SAT than VAT (APS: r = 0.92 vs. 0.88; SKids: 0.90 vs. 0.74). Bland-Altman plots confirmed better agreement for SAT than VAT despite differences by sex, ethnicity, and weight status with respective R2 values for SAT and VAT of 0.88 and 0.84 (APS) and 0.81 and 0.69 (SKids).

CONCLUSION

These findings indicate that SAT by DXA reflects MRI measures in children and older adults, whereas agreement for VAT is weaker for individuals with low VAT levels.

Prevalence of cardiovascular disease risk factors in Chinese patients with type 2 diabetes mellitus, 2013-2018

OBJECTIVE

Coronary heart disease (CHD) is the most common cause of death in patients with type 2 diabetes (T2DM). We aim to estimate the prevalence of CHD and cardiovascular risk factors in Chinese patients with T2DM.

METHODS

A total of 66,536 inpatients with diabetes treated from 2013 to 2018 were investigated, and demographic and clinical data were collected from 30,693 patients with T2DM. Age-standardized prevalence of CHD was calculated on the basis of data from the Chinese population census in 2010. Logistic regression analysis was used to analyze the risk factors.

RESULTS

The crude prevalence of CHD was estimated to be 23.5% and a standardized prevalence was 13.9% (16.0% in men and 11.9% in women). More than half of patients with CHD have four or more of the five traditional risk factors, much higher than the 38.96% of patients without CHD (p < .01). Multivariate regression analysis showed that diabetes duration, hypertension, smoking, underweight, overweight, obesity and hypoglycaemia were significantly associated with increased risk of CHD (all p < .05). The odds ratio of CHD in patients with three, four or five defined CHD risk factors (i.e. diabetes, hypertension, dyslipidaemia, overweight or obese, and smoking) were 2.35 (95% CI 1.81-3.04), 2.96 (95% CI 2.28-3.85) or 5.29 (95% CI 4.04-6.93), compared with diabetes patients without any other risk factors.

CONCLUSIONS

The prevalence of CHD was rather high in Chinese T2DM inpatients, and the aggregation of CHD risk factors was severe. Thus, hierarchical CHD prevention strategies based on risk factors are necessary.

Obesity history, physical exam, laboratory, body composition, and energy expenditure: An Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) 2022

Background

This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) on History, Physical Exam, Body Composition and Energy Expenditure is intended to provide clinicians an overview of the clinical and diagnostic evaluation of patients with pre-obesity/obesity.

Methods

The scientific information for this CPS is based upon published scientific citations, clinical perspectives of OMA authors, and peer review by the Obesity Medicine Association leadership.

Results

This CPS outlines important components of medical, dietary, and physical activity history as well as physical exams, with a focus on specific aspects unique to managing patients with pre-obesity or obesity. Patients with pre-obesity/obesity benefit from the same preventive care and general laboratory testing as those without an increase in body fat. In addition, patients with pre-obesity/obesity may benefit from adiposity-specific diagnostic testing - both generally and individually - according to patient presentation and clinical judgment. Body composition testing, such as dual energy x-ray absorptiometry, bioelectrical impedance, and other measures, each have their own advantages and disadvantages. Some patients in clinical research, and perhaps even clinical practice, may benefit from an assessment of energy expenditure. This can be achieved by several methods including direct calorimetry, indirect calorimetry, doubly labeled water, or estimated by equations. Finally, a unifying theme regarding the etiology of pre-obesity/obesity and effectiveness of treatments of obesity centers on the role of biologic and behavior efficiencies and inefficiencies, with efficiencies more often associated with increases in fat mass and inefficiencies more often associated with decreases in fat mass.

Conclusion

The Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) on History, Physical Exam, Body Composition and Energy Expenditure is one of a series of OMA CPSs designed to assist clinicians in the care of patients with the disease of pre-obesity/obesity.

Two Blautia Species Associated with Visceral Fat Accumulation: A One-Year Longitudinal Study

Simple Summary

Intestinal microflora has been associated with obesity. While cardiovascular disorders are more strongly associated with visceral fat than the body mass index (BMI), the link between visceral fat area (VFA) and intestinal microflora has been little studied. In this study, we investigated the association between intestinal microflora and VFA and BMI using a longitudinal study (N = 767). We found that the intestinal microflora composition is significantly associated with VFA or BMI; however, the associated gut microbes differ. Furthermore, two gut species—Blautia hansenii and Blautia producta—were significantly and negatively associated with VFA accumulation.

Abstract

Intestinal microflora has been associated with obesity. While visceral fat is more strongly associated with cardiovascular disorder, a complication linked to obesity, than the body mass index (BMI), the association between intestinal microflora and obesity (as defined in terms of BMI) has been studied widely. However, the link between visceral fat area (VFA) and intestinal microflora has been little studied. In this study, we investigate the association between intestinal microflora and VFA and BMI using a longitudinal study on Japanese subjects with different VFA statuses (N = 767). Principal component analysis of the changes in intestinal microflora composition over the one-year study period revealed the different associations between intestinal microflora and VFA and BMI. As determined by 16S rRNA amplicon sequencing, changes in the abundance ratio of two microbial genera—Blautia and Flavonifractor—were significantly associated with VFA changes and changes in the abundance ratio of four different microbial genera were significantly associated with BMI changes, suggesting that the associated intestinal microbes are different. Furthermore, as determined by metagenomic shotgun sequences, changes in the abundance ratios of two Blautia species—Blautia hansenii and Blautia producta—were significantly and negatively associated with VFA changes. Our findings might be used to develop a new treatment for visceral fat.

Apolipoprotein ε4 modifies obesity-related atrophy in the hippocampal formation of cognitively healthy adults

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Age-related inverted U-shaped curve of hippocampal myelin/neurite packing.

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Reduced hippocampal myelin/neurite packing and size/complexity in obesity.

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APOE modifies the effects of obesity on hippocampal size/complexity.

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Age-related slowing of spatial navigation but no risk effects on cognition.

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CA/DG predict episodic memory and subiculum predicts spatial navigation performance.

Characterizing age- and risk-related hippocampal vulnerabilities may inform about the neural underpinnings of cognitive decline. We studied the impact of three risk-factors, Apolipoprotein (APOE)-ε4, a family history of dementia, and central obesity, on the CA1, CA2/3, dentate gyrus and subiculum of 158 cognitively healthy adults (38-71 years). Subfields were labelled with the Automatic Segmentation of Hippocampal Subfields and FreeSurfer (version 6) protocols. Volumetric and microstructural measurements from quantitative magnetization transfer and Neurite Orientation Density and Dispersion Imaging were extracted for each subfield and reduced to three principal components capturing apparent myelin/neurite packing, size/complexity, and metabolism. Aging was associated with an inverse U-shaped curve on myelin/neurite packing and affected all subfields. Obesity led to reductions in myelin/neurite packing and size/complexity regardless of APOE and family history of dementia status. However, amongst individuals with a healthy Waist-Hip-Ratio, APOE ε4 carriers showed lower size/complexity than non-carriers. Segmentation protocol type did not affect this risk pattern. These findings reveal interactive effects between APOE and central obesity on the hippocampal formation of cognitively healthy adults.

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.

The Optimal Axial Anatomical Site for a Single-Slice Area to Quantify the Total Volume of Visceral Adipose Tissue in Quantitative CT

PURPOSE

Determine the association between cross-sectional visceral adipose tissue (VAT) area of different anatomic locations and total abdominopelvic VAT volume; identify the optimal measurement site in a single-slice to quantify the total VAT volume.

METHOD

Participants who underwent non-contrast abdominal scan by quantitative CT (QCT) were enrolled from May 2021 to October 2021. The VAT area (cm²) at different anatomic sites as upper-pole, lower-pole, and hilum of the kidney, intervertebral disc of L2/L3 and L5/S1, and umbilical level were measured on QCT PRO BMD workstation (Mindways QCT PRO workstation). The total VAT volume (cm³) from the upper pole of kidney to the L5/S1 intervertebral disc of the pelvis (abdominopelvic region) was obtained by using Siemens Healthineers Syngo via Frontier cardiac risk assessment. Regression models were used to identify the optimal single-slice in different gender for estimating VAT volume. Statistical significance was established at P < 0.05.

RESULTS

Total of 311 Chinese participants including 179 men [age, 55.1 ± 14.9 years; body mass index (BMI), 24.2 ± 3.2 kg/m²; total VAT volume, 2482.6 ± 1276.5 mL] and 132 women [age, 54.3 ± 14.9; BMI, 23.5 ± 2.9; total VAT volume, 1761.5 ± 876.4]. Pearson's correlation analysis revealed a strong association between the VAT area and total abdominopelvic VAT volume at the hilum of the kidney in both men (r=0.938, P<0.001) and women (r=0.916, P<0.001). Adjust for covariates including age, BMI, and waist circumference make a relatively small effect on predicting the total VAT volume.

CONCLUSIONS

Measurement of cross-sectional areas at the hilum of the kidney in both genders showed a strongest relation to TVAT volume. Our results may provide an identifiable and valuable axial landmark for measuring visceral adipose tissue in clinical practice.

Association between waist-hip ratio and subclinical myocardial injury in the general population: Insights from the NHANES

BACKGROUND

Although studies have shown that higher waist-hip ratio (WHR) is closely related to higher risk of metabolism-related diseases, the relationship between WHR and subclinical myocardial injury (SC-MI) is unknown. This study was to evaluate the effect of WHR on SC-MI in the general population free from cardiovascular disease.

METHODS

The cross-sectional study included 6253 participants without cardiovascular disease (CVD) from the third National Health and Nutrition Examination Survey (NHANES III) for further analysis. Restricted cubic spline, multivariable logistic regression models and subgroup analyses were performed to assess the association between WHR and SC-MI.

RESULTS

The multivariate logistic regression showed that after adjusting for potential confounding factors, participants in the higher quartiles had higher risk of developing SC-MI than those in the first quartile of WHR [Q3, OR (95% CI): 1.523 (1.159, 2.000), P = 0.002; Q4, OR (95% CI): 1.719 (1.279, 2.311), P < 0.001], and this relationship was robust among the participants aged ≥ 50 years, with hypertension and without diabetes. Every 0.1 unit increase in WHR, as a continuous variable, increased the risk of SC-MI by more than 20% [OR (95% CI): 1.233 (1.092, 1.392), P = 0.001]. And restricted cubic spline analysis showed that there was a linear positive correlation between WHR and the risk of SC-MI.

CONCLUSIONS

WHR may be an independent risk factor for SC-MI in the general population free from CVD.

FSH Level and Changes in Bone Mass and Body Composition in Older Women and Men

CONTEXT

FSH may have independent actions on bone remodeling and body fat regulation. Cross-sectionally, we have shown that serum FSH is associated with bone mineral density (BMD) and body fat in older postmenopausal women, but it remains unknown whether FSH predicts bone and fat changes.

OBJECTIVE

We examined whether baseline FSH level is associated with subsequent bone loss or body composition changes in older adults.

SETTING, DESIGN, PARTICIPANTS

We studied 162 women and 158 men (mean age 82 ± 4 years) from the Age, Gene/Environment Susceptibility (AGES)-Bone Marrow Adiposity cohort, a substudy of the AGES-Reykjavik Study of community-dwelling older adults. Skeletal health and body composition were characterized at baseline and 3 years later.

MAIN OUTCOMES

Annualized change in BMD and body composition by dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT). Models were adjusted for serum estradiol and testosterone levels.

RESULTS

There was no evidence for an association between baseline FSH level and change in BMD or body composition by DXA or QCT. For femoral neck areal BMD, adjusted mean difference (95% CI) per SD increase in FSH was 1.3 (-0.7 to 3.3) mg/cm2/y in women, and -0.2 (-2.6 to 2.2) mg/cm2/y in men. For visceral fat, adjusted mean difference (95% CI) per SD increase in FSH was 1.80 (-0.03 to 3.62) cm2/y in women, and -0.33 (-3.73 to 3.06) cm2/y in men.

CONCLUSIONS

Although cross-sectional studies and studies in perimenopausal women have demonstrated associations between FSH and BMD and body composition, in older adults, FSH level is not associated with bone mass or body composition changes.

Association between Visceral Fat and Brain Structural Changes or Cognitive Function

Visceral fat accumulation is an independent risk factor for cardiovascular disease and mortality. Visceral fat is a causal risk factor for hypertension and type 2 diabetes, which was reported as one of the risk factors for dementia. Visceral fat areas (VFA) might be clinically important to prevent dementia; however, the association between VFA and cognitive function in the elderly remains unknown. We aimed to evaluate the association between brain structural abnormalities using magnetic resonance imaging (MRI) and VFA, and the association between cognitive function and VFA, in the elderly. A total of 2364 healthy individuals were enrolled, and we excluded those diagnosed with dementia. Participants were divided into a high-VFA and a low-VFA group based on median VFA. The high-VFA group had significantly lower cognitive function than the low-VFA group (p = 0.025), after adjustment for related factors using a linear regression model. Regarding brain structure in MRI, VFA remained significantly associated with white matter lesions (odds ratio (OR), 1.90; 95% confidence interval (1.33-2.70); adjusted p < 0.001) and perivascular space (OR, 1.28; 95% confidence interval (1.02-1.61); adjusted p = 0.033). Further follow-up studies are needed, but reducing visceral fat might be important, not only to prevent cardiovascular disease but also to prevent dementia.

Biomarker-based visceral adiposity score and incident type 2 diabetes in the multiethnic cohort

PURPOSE

Visceral adipose tissue (VAT) may be more important than subcutaneous fat in type 2 diabetes (T2D) etiology. We examined a VAT score developed in reference to MRI measurement of VAT in the Multiethnic Cohort (MEC) as a risk factor for incident T2D.

METHODS

Two nested case-control studies of cancer allowed calculation of the VAT score based on anthropometric measures and 8 biomarkers among 2,556 participants without T2D. Incident cases were identified from Medicare linkages and self-reports after blood draws in 2001-2006. Cox regression with age as time metric was applied to estimate the association of the VAT score with T2D.

RESULTS

During 10.1 ± 2.4 years, 355 incident T2D cases were identified. VAT scores were higher in T2D cases than among those without disease (5.06±0.43 vs. 4.95±0.41; P<0.0001) and significantly associated with T2D (HR = 2.70; 95%CI 1.60, 4.58 per unit) with similar values in men (HR = 2.99; 95%CI 1.03, 8.73) and women (HR = 2.61; 95%CI 1.39, 4.91). A significant association was observed in all five ethnic groups but only statistically significant among Japanese Americans (HR = 6.24; 95%CI 2.34, 16.68).

CONCLUSION

These findings support that VAT as estimated by a biomarker-based score predicts T2D incidence beyond BMI in particular among older adults of Japanese ancestry.

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 exercise intervention dosage on reducing visceral adipose tissue: a systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Visceral adipose tissue (VAT) are deleterious fat deposits in the human body and can be effectively reduced by exercise intervention. Despite well-established exercise prescriptions are available, the effective dosage of exercise for reducing VAT requires verification.

OBJECTIVES

The aims of this systematic review and meta-analysis were to determine the most effective exercise dosage (modality, intensity, duration, and amount) for decreasing VAT.

METHODS

Nine databases (EMBASE, Medline, Cochrane Central Register of Controlled Trial, PubMed, CINAHL, Scopus, Web of Science, Airiti Library, and PerioPath) were systematically searched for randomized controlled trials that objectively assessed VAT. The arms of included studies covered with different exercise modalities and dosage. Relevant databases were searched through February 2020.

RESULTS

Of the 34 studies (n = 1962) included in systematic review, 32 (n = 1900) were pooled for pairwise or network meta-analysis. The results indicated that high-intensity interval training (SMD -0.39, 95% CI -0.60 to -0.18) and aerobic exercise (SMD -0.26, 95% CI -0.38 to -0.13) of at least moderate intensity were beneficial for reducing VAT. By contrast, resistance exercise, aerobic exercise combined with resistance exercise, and sprint interval training had no significant effects. No difference in VAT reduction was observed between exercising more or less than 150 min per week. Meta-regression revealed that the effect of VAT reduction was not significantly influenced by an increase in the duration of or amount of exercise in an exercise program. The effective dosage of exercise for reducing VAT was three times per week for 12 to 16 weeks, while duration per session for aerobic exercise was 30-60 min, and either less than 30 min or 30-60 min of high-intensity interval training accomplished sufficient energy expenditure to impact VAT.

CONCLUSIONS

These results can inform exercise prescriptions given to the general population for improving health by reducing VAT.

Quantitative Analysis of Adipose Depots by Using Chest CT and Associations with All-Cause Mortality in Chronic Obstructive Pulmonary Disease: Longitudinal Analysis from MESArthritis Ancillary Study

Background Obesity and sarcopenia are associated with mortality in chronic obstructive pulmonary disease (COPD). Routine chest CT examinations may allow assessment of obesity and sarcopenia by soft-tissue markers for predicting risks of mortality. Purpose To investigate associations between soft-tissue markers subcutaneous adipose tissue (SAT), intermuscular adipose tissue (IMAT), and pectoralis muscle (PM) index from chest CT with mortality in participants with COPD. Materials and Methods In this secondary analysis of a prospectively enrolled cohort from the Multi-Ethnic Study of Atherosclerosis, participants with available chest CT in 2010-2012 were included. CT examinations were analyzed to determine SAT, IMAT (within PM), and PM areas. The spirometry evaluations were used to establish COPD diagnosis. Mortality data were extracted from the National Death Index (April 2010 to December 2017). The correlations of the soft-tissue markers with fat mass index were studied. The associations of these markers and risks of mortality in participants with COPD were assessed by using Cox proportional-hazard models adjusted for confounders. Results Among 2994 participants who were included (mean age, 69 years ± 9 [standard deviation]; 1551 women), 265 had COPD (9%; mean age, 72 years ± 9; 162 men) and 49 participants with COPD (18%) died during follow-up. The SAT, IMAT, and PM areas had moderate-to-excellent reliabilities (intraclass correlation coefficient, 0.88-0.99). In the 2994 participants, the SAT (ρ = 0.80; 95% CI: 0.78, 0.81; P < .001) and IMAT indexes (ρ = 0.37; 95% CI: 0.34, 0.41; P < .001) were correlated with fat mass index. Those with COPD and higher SAT index had lower risks of mortality (hazard ratio, 0.2; 95% CI: 0.1, 0.4; P < .001, per doubling), whereas a higher IMAT index was associated with a higher risk of mortality (hazard ratio, 1.4; 95% CI: 1.0, 1.9; P = .04, per doubling). Conclusion Soft-tissue markers were reliably obtained by using chest CT performed for lung assessment. In participants with chronic obstructive pulmonary disease, a high intermuscular adipose tissue index was associated with a higher risk of mortality than was a high subcutaneous adipose tissue index. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Sverzellati and Cademartiri in this issue.

Serum FSH Is Associated With BMD, Bone Marrow Adiposity, and Body Composition in the AGES-Reykjavik Study of Older Adults

CONTEXT

Follicle-stimulating hormone (FSH) concentrations increase during the perimenopausal transition and remain high after menopause. Loss of bone mineral density (BMD) and gain of bone marrow adiposity (BMA) and body fat mass also occur during this time. In mice, blocking the action of FSH increases bone mass and decreases fat mass.

OBJECTIVE

To investigate the associations between endogenous FSH levels and BMD, BMA, and body composition in older adults, independent of estradiol and testosterone levels.

DESIGN, SETTING, AND PARTICIPANTS

Older adults from the AGES-Reykjavik Study, an observational cohort study.

MAIN OUTCOME MEASURES

Areal BMD, total body fat, and lean mass were measured with dual-energy x-ray absorptiometry. Lumbar vertebral BMA was measured by 1H-magnetic resonance spectroscopy. Volumetric BMD and visceral and subcutaneous adipose tissue (VAT, SAT) areas were measured with quantitative computed tomography. The least squares means procedure was used to determine sex hormone-adjusted associations between quartiles of serum FSH and BMD, BMA, and body composition.

RESULTS

In women (N = 238, mean age 81 years), those in the highest FSH quartile, compared with the lowest quartile, had lower adjusted mean spine integral BMD (-8.6%), lower spine compressive strength index (-34.8%), higher BMA (+8.4%), lower weight (-8.4%), lower VAT (-17.6%), lower lean mass (-6.1%), and lower fat mass (-11.9%) (all P < 0.05). In men, FSH level was not associated with any outcome.

CONCLUSIONS

Older postmenopausal women with higher FSH levels have higher BMA, but lower BMD and lower fat and lean mass, independent of estradiol and testosterone levels. Longitudinal studies are needed to better understand the underlying mechanisms.

Fat-to-muscle Ratio: A New Indicator for Coronary Artery Disease in Healthy Adults

Background: Coronary artery disease (CAD) is an important issue in public health. Previous studies have shown that the ratio of fat to muscle mass is a significant predictor of metabolic disease, and it is known to be associated with atherosclerosis. In this study, we evaluated the association between the fat-to-muscle ratio (FMR) and CAD in healthy adults. Methods: A total of 617 participants without diabetes mellitus, hypertension, known CAD, or stroke who visited the Health Promotion Center from 2009 to 2018 were included in this study. Computed tomography imaging and bioelectrical impedance analysis were used to ascertain the coronary artery calcium (CAC) score, degree of CAD, and FMR. Results: Univariate logistic regression analysis showed that old age, male sex, smoking history, creatinine, aspartate aminotransferase, gamma-glutamyl transferase, uric acid, total cholesterol, and low-density lipoprotein cholesterol were significantly associated with CAC. After adjusting for potential confounding covariates, the presence of CAC was independently associated with FMR (OR, 1.014; 95% CI, 1.002-1.026; p = 0.019. The association was maintained even after adjusting for body mass index and waist circumference (odds ratio, 1.019; 95% confidence interval, 1.004 -1.034; P = 0.012). Conclusion: In this study, a high FMR was significantly associated with CAC. A large-scale prospective study on the association with FMR and cardiovascular diseases is necessary to confirm this relationship.

Abdominal Wall Thickness is a Predictor for Surgical Site Infections in Patients Undergoing Colorectal Operations

BACKGROUND

Surgical site infections (SSIs) are an established complication following colorectal operations, with rates up to 30% reported in the literature. Obesity is a known risk factor for SSI; however, body mass index (BMI), body fat percentage, waist-hip ratio, or abdominal circumference are imperfect measures. The purpose of our study was to determine whether abdominal wall thickness (AWT) is predictive of SSI.

METHODS

We queried our American College of Surgeons National Surgical Quality Improvement Project (ACS-NSQIP) database for patients (age ≥18 years) undergoing a colectomy at the University of Kentucky (UK) from January 1, 2013 to December 31, 2018. The exclusion criteria included patients with open abdomens or the lack of preoperative computed tomography (CT) within 3 months of their operation. AWT was measured at the level of the anterior superior iliac spine (ASIS) on abdominal CT. SSI was defined by superficial SSI, deep SSI, and wound dehiscence.

RESULTS

Of 1261 patients enrolled, 52.2% were female, with an average age of 57.4 years. More patients had laparoscopic operations (51%), and the median length of stay was 7 days. Our study demonstrated an SSI rate of 9.4% and a 30-day readmission rate of 11%. The overall mean AWT was 2.6 cm (range .1-13.1), and patients with the highest AWT quintile were more likely to develop an SSI than the lowest quintile (12% vs. 5%). After controlling for risk factors and confounders, the odds of an SSI were 3.6 times higher for patients with the highest AWT than patients with the lowest AWT.

CONCLUSIONS

Among colorectal surgery patients, AWT is an independent risk factor predictive for SSI.

Exercise training-induced visceral fat loss in obese women: The role of training intensity and modality

Visceral fat loss in response to four-cycle ergometer training regimens with explicit differences in exercise intensity and modality was compared. Fifty-nine obese young women (body fat percentage ≥ 30%) were randomized to a 12-week intervention consisting of either all-out sprint interval training (SIT_all-out , n = 11); supramaximal SIT (SIT₁₂₀ , 120% V ˙ O_2peak , n = 12); high-intensity interval training (HIIT₉₀ , 90% V ˙ O_2peak , n = 12), moderate-intensity continuous training (MICT, 60% V ˙ O_2peak , n = 11), or no training (CON, n = 13). The total work done per training session in SIT₁₂₀ , HIIT₉₀ , and MICT was confined to 200 kJ, while it was deliberately lower in SIT_all-out . The abdominal visceral fat area (AVFA) was measured through computed tomography scans. The whole-body and regional fat mass were assessed through dual-energy X-ray absorptiometry. Pre-, post-, and 3-hour post-exercise serum growth hormone (GH), and epinephrine (EPI) were measured during selected training sessions. Following the intervention, similar reductions in whole-body and regional fat mass were found in all intervention groups, while the reductions in AVFA resulting from SIT_all-out , SIT₁₂₀ , and HIIT₉₀ (>15 cm² ) were greater in comparison with MICT (<3.5 cm² , P < .05). The AVFA reductions among the SITs and HIIT groups were similar, and it was concomitant with the similar exercise-induced releases of serum GH and EPI. CON variables were unchanged. These findings suggest that visceral fat loss induced by interval training at or above 90% V ˙ O_2peak appeared unresponsive to the change in training intensity. Nonetheless, SIT_all-out is still the most time-efficient strategy among the four exercise-training regimes for controlling visceral obesity.

The independent role of deprivation in abdominal obesity beyond income poverty. A population-based household survey in Chinese adults

BACKGROUND

Individual-level deprivation takes into account the non-monetary aspects of poverty that neither income poverty nor socio-economic factors could fully capture; however, it has rarely been considered in existing studies on social inequality in obesity. Therefore, we examined the associations of deprivation, beyond income poverty, with both general and abdominal obesity.

METHODS

A territory-wide two-stage stratified random sample of 2282 community-dwelling Hong Kong adults was surveyed via face-to-face household interviews between 2014 and 2015. Deprivation was assessed by a Deprivation Index specific to the Hong Kong population. General obesity was defined as body mass index (BMI) ≥ 25 kg/m2, while abdominal obesity was defined as waist circumference (WC) ≥ 90 cm/80 cm for male/female. Multivariable binary logistic regressions were performed.

RESULTS

Deprivation was independently associated with abdominal obesity (odds ratios (OR) = 1.68; 95% confidence intervals (CI): 1.27-2.22); however, no significant association was found with general obesity (OR=1.03; CI: 0.77-1.38). After additional adjustment for BMI, deprivation remained strongly associated with abdominal obesity (OR=2.00; CI: 1.41-2.83); and after further adjustment for WC, deprivation had a marginal inverse association with general obesity (OR=0.72; CI: 0.51-1.01).

CONCLUSIONS

Deprivation is an important risk factor of abdominal obesity and plays a critical role in capturing the preferential abdominal fat deposition beyond income poverty.

Association of infra-patellar fat pad size with age and body weight in children and adolescents

BACKGROUND

The infra-patellar fat pad (IPFP) represents a potential mediator between obesity, low grade inflammation, and knee osteoarthritis via endocrine pathways. Yet, not only in adults, but also in childhood obesity negatively impacts knee structures.

OBJECTIVE

The current study therefore investigated the sex-specific growth of the IPFP with age and body weight in healthy children and adolescents.

MATERIALS AND METHODS

Thirty young healthy subjects (60% girls; age 4-17 years, body weight 14-90 kg in girls and 29-105 kg in boys; BMI 12.2-32.4 kg/m²) without magnetic resonance imaging (MRI) knee pathology were studied. The IPFP volume was determined from sagittal T-1 weighted and proton-density spectral attenuated inversion recovery MRIs. The primary analysis focused on the sex-specific IPFP volume/body weight ratio as dependent, and age as independent variable, using linear regression models. A secondary analytic focus was the slope of the age-dependence of IPFP volume, without normalization to body weight.

RESULTS

There was no statistically significant association of the IPFP volume/body weight ratio with age in girls (p = 0.57) or boys (p = 0.31), the R² of ranging from -0.32 to 0.14. The ratio was greater in boys (0.54 ± 0.10 cm³/kg) than in girls (0.45 ± 0.07 cm³/kg) (p < 0.01). The IPFP volume increased by approx. 2 cm³ per annum in both girls and boys, without any indication of a non-linear relationship.

CONCLUSION

Our findings reveal that the ratio of the IPFP volume and body weight remains constant between age 4 and 17 in both normal weight girls and boys, and that the IPFP volume increases linearly with age throughout this period.

Association between abdominal fat distribution and coronary plaque instability in patients with acute coronary syndrome

BACKGROUND AND AIMS

This study aimed to assess possible association of detailed abdominal fat profiles with coronary plaque characteristics in patients with acute coronary syndrome (ACS).

METHODS AND RESULTS

In 60 patients with ACS, culprit arteries were evaluated at 1-mm intervals (length analyzed: 66 ± 28 mm) by grayscale and integrated backscatter intravascular ultrasound (IB-IVUS) before percutaneous coronary intervention. Standard IVUS indexes (as a volume index: volume/length), plaque components (as percent tissue volume) and fibrous cap thickness (FCT) were assessed by IB-IVUS. Plain abdominal computed tomography was performed to evaluate subcutaneous adipose tissue (SAT) area, visceral adipose tissue (VAT) area, and VAT/SAT ratio. While SAT area only correlated with vessel volume (r = 0.27, p = 0.04), VAT area correlated positively with vessel (r = 0.30, p = 0.02) and plaque (r = 0.33, p = 0.01) volumes and negatively with FCT (r = -0.26, p = 0.049), but not with percent plaque volume and plaque tissue components. In contrast, higher VAT/SAT ratio significantly correlated with higher percent lipid (r = 0.34, p = 0.008) and lower percent fibrous (r = -0.34, p = 0.007) volumes with a trend toward larger percent plaque volume (r = 0.19, p = 0.15), as well as thinner FCT (r = -0.53, p < 0.0001). In the multiple regression analysis, higher VAT/SAT ratio was independently associated with higher percent lipid with lower percent fibrous volumes (p = 0.03 for both) and thinner fibrous cap thickness (p = 0.0001).

CONCLUSION

Coronary plaque vulnerability, defined as increased lipid content with thinner fibrous cap thickness, appears to be more related to abnormal abdominal fat distribution, or so-called hidden obesity, compared with visceral or subcutaneous fat amount alone in patients with ACS.

Body Fat Changes and Liver Safety in Obese and Overweight Women Supplemented with Conjugated Linoleic Acid: A 12-Week Randomised, Double-Blind, Placebo-Controlled Trial

Preliminary evidence suggests that conjugated linoleic acid (CLA) may reduce body weight and affect body composition. The present study assessed the effect of CLA supplementation on body fat composition in overweight and obese women, while also evaluating the liver safety of CLA use. Seventy-four obese or overweight women were randomly assigned to receive 3 g/day CLA or placebo for 12 weeks. Body composition (dual-energy X-ray absorptiometry) and liver function (¹³C-methacetin breath test and serum liver enzymes) were assessed before and after the trial. Patients receiving CLA experienced a significant reduction of total body fat expressed as mass (p = 0.0007) and percentage (p = 0.0006), android adipose tissue (p = 0.0002), gynoid adipose tissue (p = 0.0028), and visceral adipose tissue (p = 4.2 × 10⁻⁹) as well as a significant increase in lean body mass to height (p = 6.1 × 10⁻¹¹) when compared to those receiving a placebo. The maximum momentary 13C recovery changes and end-point values were significantly higher in the CLA group when compared to the placebo group (p = 0.0385 and p = 0.0076, respectively). There were no significant changes in alanine aminotransferase, asparagine aminotransferase, and gamma-glutamyl transpeptidase activities between the groups. In conclusion, CLA supplementation was well tolerated and safe for the liver, which shows beneficial effects on fat composition in overweight and obese women.

Neck circumference is associated with adipose tissue content in thigh skeletal muscle in overweight and obese premenopausal women

Neck circumference (NC) has been proposed as a simple and practical tool, independently associated with cardiometabolic risk factors. However, the association of NC with inter-muscular adipose tissue (IMAT) is still to be determined. We aimed to examine the association of NC with thigh IMAT, and visceral adipose tissue (VAT) measured with computed tomography (CT) in overweight/obese women. 142 premenopausal overweight and obese Caucasian women participated in this cross-sectional study. NC was measured with an inextensible metallic tape above the thyroid cartilage according to International Society for Advancement of Kinanthropometry protocol. Thigh IMAT and VAT volumes were measured with a single cross-sectional CT. Regarding the covariates, fat mass (FM) was assessed with dual-energy x-ray absorptiometry and physical activity was objectively measured with accelerometry. NC was positively associated with thigh IMAT and VAT volumes (standardized β coefficient: β = 0.45, P-value = ≤0.001, β = 0.60, P = ≤ 0.001; respectively), which persisted after adjusting for age, height, overall FM or moderate-to-vigorous physical activity. Our findings show that NC is associated with thigh IMAT volume in overweight and obese premenopausal Caucasian women, regardless of the amount of lower-body fatness. These results suggest underscoring the relevance of NC as a marker of adipose tissue content in thigh skeletal muscle.

Reference values of body composition parameters and visceral adipose tissue (VAT) by DXA in adults aged 18-81 years-results from the LEAD cohort

Background

Increasing attention has been drawn on the assessment of body composition phenotypes, since the distribution of soft tissue influences cardio-metabolic risk. Dual-energy X-ray absorptiometry (DXA) is a validated technique to assess body composition. European reference values from population-based cohorts are rare.

Aims

To provide age- and sex-related reference values of body composition parameters and visceral adipose tissue (VAT) mass, and for lean mass index (LMI) with regard to fat mass index (FMI) quantities and BMI categories.

Methods

GE-Lunar Prodigy DXA scans of 10.894 participants, aged 18–81 years, recruited from 2011 to 2019 by the Austrian LEAD study, a population-based cohort study, have been used to construct reference curves using the LMS method. Parameters assessed are FMI, LMI, appendicular LMI, fat mass ratios android/gynoid and trunk/limbs, and VAT.

Results

All lean mass and fat mass parameters indicating central fat accumulation were higher in men, whereas other fat mass indices were higher in women. LMI differed between each FMI subgroup (low vs. normal, low vs. high, normal vs. high), and BMI category in all ages and LMI increased with FMI and BMI classes. VAT mass was higher in men compared with women and increased across all age groups within both sexes.

Conclusion

The present study provides age- and sex-related reference values for European adults aged 18–81 years for body composition parameters and VAT mass for Lunar Prodigy DXA. In addition, this study reports LMI reference values with regard to fat mass quantities, showing a positive association with increasing FMI percentiles and BMI categories.