Lean body mass and risk of incident atrial fibrillation in post-menopausal women

Exploring the association between regional fat distribution and atrial fibrillation risks: a comprehensive cohort study

Background

The contribution of total fat mass and regional fat distribution to the risk of AF has rarely been studied.

Methods

This prospective cohort study(N=494,063) evaluated the association of total fat mass measured by fat percentage (FP) and regional fat measured by arm fat percentage (AFP), trunk fat percentage (TFP), and leg fat percentage (LFP) with incident AF. A subgroup (N = 25,581) underwent MRI, which allowed us to further assess whether visceral adipose tissue (VAT) and abdominal subcutaneous adipose tissue (ASAT) of the trunk fat exert different effects on AF incidence.

Results

Over, a median 12.9 ± 1.86 years of follow-up, 29,658 participants (cumulative rate: 6.0%) developed AF. Each 1-standard deviation (SD) increase in LFP was associated with a 16% lower risk of AF (HR: 0.84, 95% CI: 0.82, 0.85). The association between FP and AF was weaker than that between LFP and AF (HR: 0.90, 95% CI: 0.89, 0.92). AFP and TFP only had a marginal association with a lower incidence of AF. Both the VAT and ASAT showed a U-shaped relationship with incident AF.

Conclusions

Fat mass, mainly leg fat mass, was associated with a lower risk of AF. ASAT did not exert protective effects.

Nutritional Status and Sleep Quality Are Associated with Atrial Fibrillation in Patients with Obstructive Sleep Apnea: Results from Tokyo Sleep Heart Study

The prevalence of obstructive sleep apnea (OSA) in patients with atrial fibrillation (AF) has been observed to be much higher than in control participants without AF. Limited data exist regarding the prevalence of AF in patients with OSA. The clinical characteristics, nutritional status, and sleep parameters associated with AF in patients with OSA remain unclear. In this study, we aimed to determine the prevalence and factors associated with AF in patients with OSA from a large Japanese sleep cohort (Tokyo Sleep Heart Study). This was a single-center explorative cross-sectional study. Between November 2004 and June 2018, we consecutively recruited 2569 patients with OSA who underwent an overnight full polysomnography at our hospital. They were assessed using a 12-lead ECG and echocardiography. The clinical characteristics, sleep parameters, and medical history were also determined. Of the OSA patients, 169 (6.6%) had AF. Compared with the non-AF patients, OSA patients with AF were older and male, and they had higher prevalence of a history of alcohol consumption, hypertension, chronic kidney disease, and undernutrition, as well as a reduced ejection fraction. With regard to the sleep study parameters, OSA patients with AF had reduced slow-wave sleep and sleep efficiency, as well as higher periodic limb movements. There were no significant differences in the apnea-hypopnea index or hypoxia index between the two groups. The logistic regression analysis demonstrated that age (OR = 4.020; 95% CI: 1.895-8.527; p < 0.001), a history of alcohol consumption (OR = 2.718; 95% CI: 1.461-5.057; p = 0.002), a high CONUT score (OR = 2.129; 95% CI: 1.077-4.209; p = 0.030), and reduced slow-wave sleep (OR = 5.361; 95% CI: 1.505-19.104; p = 0.010) were factors significantly related to AF. The prevalence of AF in patients with OSA was 6.6%. Age, a history of alcohol consumption, undernutrition, and reduced sleep quality were independent risk factors for the presence of AF in patients with OSA, regardless of the severity of OSA.

Causal association between basal metabolic rate and risk of cardiovascular diseases: a univariable and multivariable Mendelian randomization study

Basal metabolic rate (BMR) is associated with cardiovascular health; however, the causal relationship between BMR and the risk of cardiovascular diseases (CVDs) remains unclear. This study aimed to investigate the potential causal relationship of BMR on common CVDs including aortic aneurysm (AA), atrial fibrillation and flutter (AFF), calcific aortic valvular stenosis (CAVS), heart failure (HF), and myocardial infarction (MI) by Mendelian randomization (MR). The univariable MR analysis using inverse variance weighted (IVW) model as the primary analysis method revealed that genetically predicted higher BMR causally increased the risk of AA [IVW odds ratio (OR) = 1.34, 95% confidence interval CI  1.09-1.65, p = 0.00527], AFF (IVW OR = 1.87, 95% CI  1.65-2.12, p = 1.697 × E-22), and HF (IVW OR = 1.35, 95% CI  1.20-1.51, p = 2.364 × E-07), while causally decreasing the risk of MI (IVW OR = 0.83, 95% CI  0.73-0.93, p = 0.00255). In the multivariable MR analysis, which controlled for common cardiovascular risk factors, direct effects of BMR on an increased risk of AA and AFF, as well as a decreased risk of MI, but an attenuated causal effect on HF, were observed. In conclusion, the current MR study provides evidence for a causal relationship between BMR and the risk of AA, AFF, HF, and MI.

Multiple anthropometric measures and proarrhythmic 12-lead ECG indices: A mendelian randomization study

BACKGROUND

Observational studies suggest that electrocardiogram (ECG) indices might be influenced by obesity and other anthropometric measures, though it is difficult to infer causal relationships based on observational data due to risk of residual confounding. We utilized mendelian randomization (MR) to explore causal relevance of multiple anthropometric measures on P-wave duration (PWD), PR interval, QRS duration, and corrected QT interval (QTc).

METHODS AND FINDINGS

Uncorrelated (r2 < 0.001) genome-wide significant (p < 5 × 10-8) single nucleotide polymorphisms (SNPs) were extracted from genome-wide association studies (GWAS) on body mass index (BMI, n = 806,834), waist:hip ratio adjusted for BMI (aWHR, n = 697,734), height (n = 709,594), weight (n = 360,116), fat mass (n = 354,224), and fat-free mass (n = 354,808). Genetic association estimates for the outcomes were extracted from GWAS on PR interval and QRS duration (n = 180,574), PWD (n = 44,456), and QTc (n = 84,630). Data source GWAS studies were performed between 2018 and 2022 in predominantly European ancestry individuals. Inverse-variance weighted MR was used for primary analysis; weighted median MR and MR-Egger were used as sensitivity analyses. Higher genetically predicted BMI was associated with longer PWD (β 5.58; 95%CI [3.66,7.50]; p = < 0.001), as was higher fat mass (β 6.62; 95%CI [4.63,8.62]; p < 0.001), fat-free mass (β 9.16; 95%CI [6.85,11.47]; p < 0.001) height (β 4.23; 95%CI [3.16, 5.31]; p < 0.001), and weight (β 8.08; 95%CI [6.19,9.96]; p < 0.001). Finally, genetically predicted BMI was associated with longer QTc (β 3.53; 95%CI [2.63,4.43]; p < 0.001), driven by both fat mass (β 3.65; 95%CI [2.73,4.57]; p < 0.001) and fat-free mass (β 2.08; 95%CI [0.85,3.31]; p = 0.001). Additionally, genetically predicted height (β 0.98; 95%CI [0.46,1.50]; p < 0.001), weight (β 3.45; 95%CI [2.54,4.36]; p < 0.001), and aWHR (β 1.92; 95%CI [0.87,2.97]; p = < 0.001) were all associated with longer QTc. The key limitation is that due to insufficient power, we were not able to explore whether a single anthropometric measure is the primary driver of the associations observed.

CONCLUSIONS

The results of this study support a causal role of BMI on multiple ECG indices that have previously been associated with atrial and ventricular arrhythmic risk. Importantly, the results identify a role of both fat mass, fat-free mass, and height in this association.

Height Explains Sex Difference in Atrial Fibrillation Risk: Copenhagen General Population Study

OBJECTIVE

To test the hypothesis that the increased risk of atrial fibrillation (AF) in men compared with women is explained by height.

METHODS

From the Copenhagen General Population Study, we included 106,207 individuals (47,153 men and 59,054 women) from 20 to 100 years of age, without a prior diagnosis of AF, examined between November 25, 2003, and April 28, 2015. The main outcome was AF incidence from national hospital registers until April 2018. The association of risk factors with AF incidence was assessed by cause-specific Cox proportional hazards regression and Fine-Gray subdistribution hazards regression analysis.

RESULTS

During a maximum of 14.4 years of follow-up (median, 8.9 years), incident AF was observed in 3449 men and 2772 women with 845 (95% CI, 815 to 875) and 514 (95% CI, 494 to 535) events per 100,000 person-years, respectively. The age-adjusted hazard of incident AF was 63% (95% CI, 55% to 72%) higher in men compared with women. Risk factors for AF were generally similar in men and women, except men were taller than women (179 cm vs 166 cm, respectively; P<.001). When controlling for height, the difference in hazard of incident AF between sexes disappeared. For population attributable risk of AF, height was the most important risk factor investigated and explained 21% and 19% of the risk of incident AF in men and women, respectively.

CONCLUSION

A 63% higher risk of incident AF in men compared with women is explained by differences in height.

Evaluation of the association between circulating IL-1β and other inflammatory cytokines and incident atrial fibrillation in a cohort of postmenopausal women

BACKGROUND

Inflammatory cytokines play a role in atrial fibrillation (AF). Interleukin (IL)-1β, which is targeted in the treatment of ischemic heart disease, has not been well-studied in relation to AF.

METHODS

Postmenopausal women from the Women's Health Initiative were included. Cox proportional hazards regression models were used to evaluate the association between log-transformed baseline cytokine levels and future AF incidence. Models were adjusted for body mass index, age, race, education, hypertension, diabetes, hyperlipidemia, current smoking, and history of coronary heart disease, congestive heart failure, or peripheral artery disease.

RESULTS

Of 16,729 women, 3,943 developed AF over an average of 8.5 years. Racial and ethnic groups included White (77.4%), Black/African-American (16.1%), Asian (2.7%), American Indian/Alaska Native (1.0%), and Hispanic (5.5%). Baseline IL-1β log continuous levels were not significantly associated with incident AF (HR 0.86 per 1 log [pg/mL] increase, P= .24), similar to those of other inflammatory cytokines, IL-7, IL-8, IL-10, IGF-1, and TNF-α. There were significant associations between C-reactive protein (CRP) and IL-6 with incident AF.

CONCLUSIONS

In this large cohort of postmenopausal women, there was no significant association between IL-1β and incident AF, although downstream effectors, CRP and IL-6, were associated with incident AF.

Independent Relevance of Different Measures of Adiposity for Carotid Intima-Media Thickness in 40 000 Adults in UK Biobank

Background Uncertainty persists about carotid intima-media thickness (CIMT) as a marker of subclinical atherosclerosis and the independent relevance of different measures of adiposity for CIMT. We assessed the independent relevance of general adiposity (body mass index), central adiposity (waist circumference), and body composition (fat mass index and fat-free mass index) with CIMT among adults in the United Kingdom. Methods and Results Multivariable linear regression of cross-sectional analyses of UK Biobank assessed the mean percentage difference in CIMT associated with equivalent differences in adiposity measures. To assess independent associations, body mass index and waist circumference were mutually adjusted, as were fat mass index and fat-free mass index. Among 39 367 participants (mean [SD] age 64 [8] years, 52% female, 97% White), median (interquartile range) CIMT was 0.65 (0.14) mm in women and 0.69 (0.18) mm in men. All adiposity measures were linearly and positively associated with CIMT after adjusting for confounders. Fat-free mass index was most strongly associated with CIMT after adjustment for fat mass index (% difference in CIMT: 1.23 [95% CI 0.93-1.53] women; 3.44 [3.01-3.86] men), while associations of fat mass index were attenuated after adjustment for fat-free mass index (0.28 [-0.02, 0.58] women; -0.59 [-0.99, -0.18] men). After mutual adjustment, body mass index remained positively associated with CIMT, but waist circumference was completely attenuated. Conclusions Fat-free mass index was the adiposity measure most strongly associated with CIMT, suggesting that CIMT may reflect vascular compensatory remodeling rather than atherosclerosis. Hence, screening for subclinical atherosclerosis should evaluate carotid plaques in addition to CIMT.

Epidemiology and modifiable risk factors for atrial fibrillation

The global prevalence of atrial fibrillation (AF) has increased substantially over the past three decades and is currently approximately 60 million cases. Incident AF and its clinical consequences are largely the result of risk factors that can be modified by lifestyle changes. In this Review, we provide evidence that the lifetime risk of AF is modified not only by sex and race but also through the clinical risk factor and comorbidity burden of individual patients. We begin by summarizing the epidemiology of AF, focusing on non-modifiable and modifiable risk factors, as well as targets and strategies for the primary prevention of AF. Furthermore, we evaluate the role of modifiable risk factors in the secondary prevention of AF as well as the potential effects of risk factor interventions on the frequency and severity of subsequent AF episodes. We end the Review by proposing strategies that require evaluation as well as global policy changes that are needed for the prevention of incident AF and the management of recurrent episodes in patients already affected by AF.

Imaging-based body fat depots and new-onset atrial fibrillation in general population: a prospective cohort study

BACKGROUND

Obesity is a well-established risk factor for atrial fibrillation (AF). Whether body fat depots differentially associate with AF development remains unknown.

METHODS

In the prospective population-based Rotterdam Study, body composition was assessed using dual-energy X-ray absorptiometry (DXA) and liver and epicardial fat using computed tomography (CT). A body composition score was constructed by adding tertile scores of each fat depot. Principal component analysis was conducted to identify potential body fat distribution patterns. Cox proportional hazards regression was used to calculate hazard ratios and 95% confidence intervals (HR; 95% CI) per 1-standard deviation increase in corresponding fat depots to enable comparisons.

RESULTS

Over a median follow-up of 9.6 and 8.6 years, 395 (11.4%) and 172 (8.0%) AF cases were ascertained in the DXA and the CT analyses, respectively. After adjustments for cardiovascular risk factors, absolute fat mass (HR; 95% CI 1.33; 1.05-1.68), gynoid fat mass (HR; 95% CI 1.36; 1.12-1.65), epicardial fat mass (HR; 95% CI 1.27; 1.09-1.48), and android-to-gynoid fat ratio (HR; 95% CI 0.81; 0.70-0.94) were independently associated with new-onset AF. After further adjustment for lean mass, associations between fat mass (HR; 95% CI 1.17; 1.04-1.32), gynoid fat mass (HR; 95% CI 1.21; 1.08-1.37), and android-to-gynoid fat ratio (HR; 95% CI 0.84; 0.72-0.97) remained statistically significant. Larger body fat score was associated with a higher AF risk (HR; 95% CI 1.10; 1.02-1.20). Borderline significant association was found between a subcutaneous fat predominant pattern with AF onset (HR; 95% CI 1.21; 0.98-1.49).

CONCLUSIONS

Various body fat depots were associated with new-onset AF. Total fat mass and gynoid fat mass were independently associated with AF after adjustment for body size. The inverse association between android-to-gynoid fat ratio with AF presents a novel finding. A significant dose-response relationship between body fat accumulation and AF was observed. Our results underscore the predominant role of subcutaneous fat on AF development among a middle-aged and elderly population. Associations betw2een body fat depots, fat distribution and new-onset atrial fibrillation.

ABBREVIATIONS

AF, atrial fibrillation.

Contributions of the Women's Health Initiative to Cardiovascular Research: JACC State-of-the-Art Review

The WHI (Women's Health Initiative) enrolled 161,808 racially and ethnically diverse postmenopausal women, ages 50-79 years, from 1993 to 1998 at 40 clinical centers across the United States. In its clinical trial component, WHI evaluated 3 randomized interventions (menopausal hormone therapy; diet modification; and calcium/vitamin D supplementation) for the primary prevention of major chronic diseases, including cardiovascular disease, in older women. In the WHI observational study, numerous clinical, behavioral, and social factors have been evaluated as predictors of incident chronic disease and mortality. Although the original interventions have been completed, the WHI data and biomarker resources continue to be leveraged and expanded through ancillary studies to yield novel insights regarding cardiovascular disease prevention and healthy aging in women.

Exercise Effects On Cardiovascular Disease: From Basic Aspects To Clinical Evidence

Cardiovascular (CV) disease (CVD) remains the leading cause of major morbidity and CVD- and all-cause mortality in most of the world. It is now clear that regular physical activity (PA) and exercise training (ET) induces a wide range of direct and indirect physiologic adaptations and pleiotropic benefits for human general and CV health. Generally, higher levels of PA, ET, and cardiorespiratory fitness (CRF) are correlated with reduced risk of CVD, including myocardial infarction, CVD-related death, and all-cause mortality. Although exact details regarding the ideal doses of ET, including resistance and, especially, aerobic ET, as well as the potential adverse effects of extreme levels of ET, continue to be investigated, there is no question that most of the world's population have insufficient levels of PA/ET, and many also have lower than ideal levels of CRF. Therefore, assessment and promotion of PA, ET, and efforts to improve levels of CRF should be integrated into all health professionals' practices worldwide. In this state-of-the-art review, we discuss the exercise effects on many areas related to CVD, from basic aspects to clinical practice.

Caution, "normal" BMI: health risks associated with potentially masked individual underweight-EPMA Position Paper 2021

An increasing interest in a healthy lifestyle raises questions about optimal body weight. Evidently, it should be clearly discriminated between the standardised "normal" body weight and individually optimal weight. To this end, the basic principle of personalised medicine "one size does not fit all" has to be applied. Contextually, "normal" but e.g. borderline body mass index might be optimal for one person but apparently suboptimal for another one strongly depending on the individual genetic predisposition, geographic origin, cultural and nutritional habits and relevant lifestyle parameters-all included into comprehensive individual patient profile. Even if only slightly deviant, both overweight and underweight are acknowledged risk factors for a shifted metabolism which, if being not optimised, may strongly contribute to the development and progression of severe pathologies. Development of innovative screening programmes is essential to promote population health by application of health risks assessment, individualised patient profiling and multi-parametric analysis, further used for cost-effective targeted prevention and treatments tailored to the person. The following healthcare areas are considered to be potentially strongly benefiting from the above proposed measures: suboptimal health conditions, sports medicine, stress overload and associated complications, planned pregnancies, periodontal health and dentistry, sleep medicine, eye health and disorders, inflammatory disorders, healing and pain management, metabolic disorders, cardiovascular disease, cancers, psychiatric and neurologic disorders, stroke of known and unknown aetiology, improved individual and population outcomes under pandemic conditions such as COVID-19. In a long-term way, a significantly improved healthcare economy is one of benefits of the proposed paradigm shift from reactive to Predictive, Preventive and Personalised Medicine (PPPM/3PM). A tight collaboration between all stakeholders including scientific community, healthcare givers, patient organisations, policy-makers and educators is essential for the smooth implementation of 3PM concepts in daily practice.

Genetically predicted body composition in relation to cardiometabolic traits: a Mendelian randomization study

Fat mass and fat-free mass are found to be associated with different health outcomes in observational studies, but the underlying causality remains unclear. We aimed to investigate the causal relationships between body composition and cardiometabolic traits using a two-sample Mendelian randomization (MR) approach. Independent genetic variants associated with body fat mass, fat-free mass, and fat percentage in UK Biobank population were used as genetic instrumental variables, and their causal effects on circulatory diseases, type 2 diabetes, glycemic traits, and lipid fractions were estimated from large-scale genome-wide association studies (GWAS) in European populations. Univariable, multivariable, and bidirectional MR analyses were performed. Genetically predicted high fat mass and fat percentage significantly increased risks of most cardiometabolic diseases, and high fat-free mass had protective effects on most cardiometabolic diseases after accounting for fat mass. Fat mass, fat-free mass, and fat percentage were all positively associated with higher risks of atrial fibrillation and flutter, varicose veins, and deep vein thrombosis and pulmonary embolism. High fat mass increased fasting glucose, homeostasis model assessment-insulin resistance (HOMA-IR), triglycerides, decreased high-density lipoprotein cholesterol, and high fat-free mass reduced HOMA-IR, triglycerides, and low-density lipoprotein cholesterol. Genetically predicted fat-free mass was bidirectionally negatively associated with 2-h glucose and total cholesterol. The findings may be helpful in risk stratification and tailoring management of body composition in patients with different cardiometabolic statuses.

Life course socioeconomic position and body composition in adulthood: a systematic review and narrative synthesis

INTRODUCTION

Multiple systematic reviews have investigated the relation between socioeconomic position (SEP) and body mass index (BMI) throughout the life course. However, BMI does not capture quantity and distribution of fat and muscle, which are better indicators of obesity than BMI, and have been independently linked to adverse health outcomes. Less is known about the relation between SEP and body composition, and the literature has not been reviewed. We therefore systematically reviewed the literature on the association between life course SEP and body composition in adulthood.

METHODS

A protocol was registered on PROSPERO (CRD42019119937), and the review followed PRISMA guidelines. An electronic search of three databases (MEDLINE, Embase Classic + Embase and SPORTDiscus) was conducted. Original studies in the English language were included that examine the association between any recognised measure of SEP at any age and body composition (fat mass, fat-free mass, ratio and distribution) in adulthood, measured using a direct technique, i.e., not an anthropometric measure. A narrative synthesis was conducted.

RESULTS

A total of 47 papers were included in the final review, none were from low-income countries (LICs). Greater advantage in childhood and adulthood was associated with lower fat levels in high-income countries (HICs). Associations in the opposite direction were found exclusively in middle-income countries (MICs). No studies in MICs reported associations for childhood SEP. For measures of lean mass, the majority of papers reported no association, or greater advantage in adulthood associated with higher lean mass, with little variation between HICs and MICs. Associations in HICs are more often observed in women than men.

CONCLUSION

The results indicate that fat measures follow similar patterns to those seen for BMI, and that women in HICs are more likely to experience inequalities in both fat and lean measures. Further research in LICs and MICs is needed.

The epidemiology of atrial fibrillation in Chinese postmenopausal women and its association with age of menopause

OBJECTIVES

To investigate the epidemiology of atrial fibrillation (AF) in postmenopausal women and to evaluate the association between age of menopause and AF.

STUDY DESIGN

A total of 9117 postmenopausal women were selected from a cross-sectional study conducted among the general population of north-east China from September 2017 and March 2019.

MAIN OUTCOME MEASURES

AF was diagnosed according to self-reported medical history of AF and/or current ECG findings. The epidemiology of AF including prevalence, awareness, use of anticoagulants and cardiovascular risk factors in postmenopausal women were carefully assessed. The association between age of menopause and AF was evaluated by stepwise logistic regression.

RESULTS

The prevalence of AF was up to 1.1 % (95 % CI, 0.9 %-1.3 %) in postmenopausal women, but the awareness of it was 61.2 %. The proportion of AF patients requiring treatment with an oral anticoagulant (OAC) was as high as 87.8 % according to CHA₂DS₂-VASc score, while only 5.8 % of them received it. The prevalence of cardiovascular risks factors was high among postmenopausal women with AF, but awareness, treatment and control of these comorbidities were unacceptably low. Compared with the women with premature menopause (< 45 years), participants reporting onset of menopause at 50-54 years had a significantly lower risk of AF (OR 0.49, 95 % CI 0.27-0.91).

CONCLUSIONS

The widespread use of OAC and the control of cardiovascular risk factors in postmenopausal women with AF was of great significance in preventing AF-related stroke. The history of premature menopause provided a reliable opportunity for primary prevention of AF.

Grip Strength and Demographic Variables Estimate Appendicular Muscle Mass Better Than Bioelectrical Impedance in Taiwanese Older Persons

OBJECTIVES

This study aimed to develop an equation model combining physical fitness and anthropometric parameters and compare its results with those of bioelectrical impedance analysis (BIA)-measured lean mass (LM) using dual-energy X-ray absorptiometry (DXA)-measured appendicular muscle mass (AMM) as reference.

DESIGN

Observational analysis.

SETTING AND PARTICIPANTS

Healthy community-dwelling older subjects.

METHODS

A total of 1020 participants were randomly allocated to the development group (development group, n = 510) or the cross-validation group (validation group, n = 510). Body composition was measured using both DXA and BIA, and physical fitness parameters, including grip strength, timed stepping test, sit-to-stand test, flexibility, and walking speed were also assessed. A prediction equation model of AMM by stepwise linear regression analysis that included or excluded 1 independent variable at each step, based on the P value of significance (P < .05), was developed.

RESULTS

Using weight, sex, height, and handgrip strength as independent variables, the equation AMM = -9.833 + 0.397 × weight (kg) + 4.433 × sex + 0.121 × height (cm) + 0.061 × handgrip strength (kg) best predicts DXA-measured AMM (adjusted R² = 0.914, SEE = 2.062, P < .001). The predicted AMM was more highly correlated with DXA-measured AMM than the commonly used BIA-measured LM (R²= 0.9158 and 0.8427, respectively, both P < .001). Using DXA-measured AMM as reference, the Bland-Altman plot showed mean differences of -0.03 kg and -0.12 kg, with limits of agreement of -3.98 to 3.92 kg and -5.97 to 5.73 kg for the predicted AMM and BIA-measured AMM, respectively.

CONCLUSIONS AND IMPLICATIONS

The proposed equation offers a practical alternative method for estimating AMM that is less facility-dependent and more easy to use and affordable than instrumental studies.

Associations of body composition with incident dementia in older adults: Cardiovascular Health Study-Cognition Study

INTRODUCTION

A body of literature reported associations between late-life general adiposity measures (eg, body mass index) and dementia. Little is known about the association of late-life body composition with dementia risk.

METHODS

We determined this association among cognitively normal participants from the Cardiovascular Health Study- Cognition Study. Body composition was assessed by dual-energy x-ray absorptiometry in 1994-1995. Dementia was ascertained at annual follow-up from 1998-1999 to 2013. Associations of body composition with incident dementia were assessed by the Fine-Gray model.

RESULT

Among 344 participants (mean age 78, 62.2% women), body composition was significantly different between men and women, despite similar body mass indexes (BMIs). Increased dementia risk was significantly associated with lower lean mass in men and marginally with low appendicular lean mass in women.

DISCUSSION

Decreased lean mass was an indicator of increased dementia risk in older adults. Studies should test whether preventing lean mass loss in older adults reduces dementia risk.

Atrial fibrillation is associated with lean body mass in postmenopausal women

This study investigated the association between body composition and risk of atrial fibrillation (AF) in postmenopausal women. In a retrospective analysis we assessed data from 5704 postmenopausal women (age 70.7 ± 6.5 yrs.) who in 1999–2001 participated in The Prospective Epidemiological Risk Factor study with body composition assessed by dual-energy X-ray absorptiometry. Outcomes were obtained from Danish Health Registries and body composition association to risk of AF was evaluated by univariable and multivariable Cox Hazard regression. 850 women developed AF after baseline. High lean body mass was associated with increased risk of AF in multivariable analyses, adjusting for body mass index (BMI), height or weight (adjusted for: BMI, hazard ratio (HR) 1.49, 95% Confidence Interval (1.22–1.80); height, HR 1.27 (1.03–1.56); weight, 1.33 (1.06–1.65)). Height and weight were associated with increased risk of AF in multivariable analyses adjusting for body composition measures. When adjusting for total lean mass, only height remained statistically significant (HR 1.34 (1.09–1.64)). In a cohort of elderly Caucasian women, high lean body mass, height and weight were associated with increased risk of AF and the variables remained significant after adjusting for age and other known risk factors of AF.

No time to weight: obesity through life and AF risk

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Association Between Regional Adipose Tissue Distribution and Risk of Heart Failure Among Blacks

BACKGROUND

Obesity is highly prevalent among blacks and is associated with a greater risk of heart failure (HF). However, the contribution of regional adiposity depots such as visceral adipose tissue (VAT) and abdominal subcutaneous adipose tissue toward risk of HF in blacks is unknown.

METHODS AND RESULTS

We included 2602 participants (mean age: 59 years, 35% men) from the Jackson Heart Study without prevalent HF who underwent computed tomography quantification of VAT and subcutaneous adipose tissue during the second visit (2005-2009). The associations between different adiposity measures and HF were evaluated using adjusted Cox models. There were 122 incident HF events over a median follow-up of 7.1 years. Higher amounts of VAT were associated with greater risk of HF in age- and sex-adjusted analyses (hazard ratio [95% CI] per 1-SD higher VAT: 1.29 [1.09-1.52]). This association was attenuated and not significant after additional adjustment for traditional HF risk factors and body mass index. Overall obesity, represented by body mass index, was associated with higher risk of HF independent of risk factors and VAT (hazard ratio [95% CI] per 1-kg/m² higher body mass index: 1.06 [1.02-1.11]). Subcutaneous adipose tissue was not associated with risk of HF in adjusted analyses.

CONCLUSIONS

In a community-dwelling black population, higher amounts of overall and visceral adiposity are associated with higher risk of HF. The association between VAT and HF risk in blacks may reflect differences in traditional HF risk factor burden. Future studies are needed to confirm this observation and clarify the independent role of different measures of adiposity on HF outcomes.

Body composition and atrial fibrillation: a Mendelian randomization study

AIMS

Increases in fat-free mass and fat mass have been associated with higher risk of atrial fibrillation (AF) in observational studies. It is not known whether these associations reflect independent causal processes. Our aim was to evaluate independent causal roles of fat-free mass and fat mass on AF.

METHODS AND RESULTS

We conducted a large observational study to estimate the associations between fat-free mass and fat mass on incident AF in the UK Biobank (N = 487 404, N events = 10 365). Genome-wide association analysis was performed to obtain genetic instruments for Mendelian randomization (MR). We evaluated the causal effects of fat-free mass and fat mass on AF with two-sample method by using genetic associations from AFGen consortium as outcome. Finally, we evaluated independent causal effects of fat-free mass and fat mass with multivariate MR. Both fat-free mass and fat mass had observational associations with incident AF [hazard ratio (HR) = 1.77, 95% confidence interval (CI) 1.72-1.83; HR = 1.40, 95% CI 1.37-1.43 per standard deviation increase in fat-free and fat mass, respectively]. The causal effects using the inverse-variance weighted method were 1.55 (95% CI 1.38-1.75) for fat-free mass and 1.30 (95% CI 1.17-1.45) for fat mass. Weighted median, Egger regression, and penalized methods showed similar estimates. The multivariate MR analysis suggested that the causal effects of fat-free and fat mass were independent of each other (causal risk ratios: 1.37, 95% CI 1.06-1.75; 1.28, 95% CI 1.03-1.58).

CONCLUSION

Genetically programmed increases in fat-free mass and fat mass independently cause an increased risk of AF.

Established and novel risk factors for atrial fibrillation in women compared with men

BACKGROUND

Atrial fibrillation (AF) is a stronger risk factor for cardiovascular disease in women than men. We assessed whether there are sex differences in the effects of 43 established and novel risk factors and the risk of incident AF.

METHODS

Data were used from the Scottish Heart Health Extended Cohort, a prospective cohort study with over 20 years of follow-up for AF incidence. Cox regression models were used to obtain the adjusted sex-specific HRs and 95% CIs, and the women-to-men ratio of HRs (RHRs), of incident AF associated with personal characteristics, smoking, physical measurements, diabetes mellitus, lipid, inflammatory, cardiac, and diet- and renal-related markers.

RESULTS

Overall, 15 737 participants (52% women) were included. There were sex differences in the relationship between a 1 SD increase in body mass index (BMI), NT-pro-BNP, uric acid, and cystatin-C and the risk of AF. The HRs were 1.17 (95% CI 1.08 to 1.27) in women and 1.36 (95% CI 1.24 to 1.49) in men for BMI (RHR 0.86, 95% CI 0.77 to 0.97); 1.84 (95% CI 1.62 to 2.09) in women and 1.54 (95% CI 1.40 to 1.68) in men for NT-pro-BNP (RHR 1.22, 95% CI1.05 to 1.42); 1.27 (95% CI 1.14 to 1.41) in women and 1.10 (95% CI 1.00 to 1.20) in men for uric acid (RHR 1.17, 95% CI 1.01 to 1.35); and 1.22 (95% CI 1.13 to 1.32) in women and 1.07 (95% CI 0.96 to 1.18) in men for cystatin-C (RHR 1.16, 95% CI 1.05 to1.27).

CONCLUSION

Higher BMI is a stronger risk factor for AF in men whereas elevated NT-pro-BNP, uric acid and cystatin-C were more strongly associated with the risk of AF in women.

Visceral Adipose Tissue Accumulation and Residual Cardiovascular Risk

PURPOSE OF THE REVIEW

Low-grade systemic inflammation increases residual cardiovascular risk. The pathogenesis of low-grade systemic inflammation is not well understood.

RECENT FINDINGS

Visceral adipose tissue accumulates when the subcutaneous adipose tissue can no longer store excess nutrients. Visceral adipose tissue inflammation initially facilitates storage of nutrients but with time become maladaptive and responsible for low-grade systemic inflammation. Control of low-grade systemic inflammation requires reversal of visceral adipose tissue accumulation with intense and sustained aerobic exercise or bariatric surgery. Alternatively, pharmacologic inhibition of the inflammatory signaling pathway may be considered. Reversal visceral adipose tissue accumulation lowers residual cardiovascular risk.

Height, Weight, and Aerobic Fitness Level in Relation to the Risk of Atrial Fibrillation

Tall stature and obesity have been associated with a higher risk of atrial fibrillation (AF), but there have been conflicting reports of the effects of aerobic fitness. We conducted a national cohort study to examine interactions between height or weight and level of aerobic fitness among 1,547,478 Swedish military conscripts during 1969-1997 (97%-98% of all 18-year-old men) in relation to AF identified from nationwide inpatient and outpatient diagnoses through 2012 (maximal age, 62 years). Increased height, weight, and aerobic fitness level (but not muscular strength) at age 18 years were all associated with a higher AF risk in adulthood. Positive additive and multiplicative interactions were found between height or weight and aerobic fitness level (for the highest tertiles of height and aerobic fitness level vs. the lowest, relative excess risk = 0.51, 95% confidence interval (CI): 0.40, 0.62; ratio of hazard ratios = 1.50, 95% CI: 1.34, 1.65). High aerobic fitness levels were associated with higher risk among men who were at least 186 cm (6 feet, 1 inch) tall but were protective among shorter men. Men with the combination of tall stature and high aerobic fitness level had the highest risk (for the highest tertiles vs. the lowest, adjusted hazard ratio = 1.70, 95% CI: 1.61, 1.80). These findings suggest important interactions between body size and aerobic fitness level in relation to AF and may help identify high-risk subgroups.

Lean Body Mass Is the Predominant Anthropometric Risk Factor for Atrial Fibrillation

BACKGROUND

Obesity is repeatedly emphasized as a risk factor for atrial fibrillation or flutter (AF). However, the underlying evidence may be questioned, as the obvious correlations between various anthropometric measures hamper identification of the characteristics that are biologically driving AF risk, and recent studies suggest that fat carries limited or no independent risk of AF.

OBJECTIVES

This study sought to assess mutually adjusted associations among AF risk and height, weight, body mass index, hip and waist circumference, waist-to-hip ratio, and bioelectrical impedance-derived measures of fat mass, lean body mass, and fat percentage.

METHODS

Anthropometric measures and self-reported life-style information were collected from 1993 to 1997 in a population-based cohort including 55,273 persons age 50 to 64 years who were followed in Danish registers until June 2013.

RESULTS

During a median of 17 years of follow-up, 3,868 persons developed AF. Adjusted hazard ratios per population SD difference (HRs) showed highly statistically significant, positive associations for all 9 anthropometric measures (HRs ranging from 1.08 [95% confidence interval (CI): 1.05 to 1.12] for waist-to-hip ratio to 1.37 [95% CI: 1.33 to 1.42] for lean body mass). Pairwise mutual adjustment of the 9 measures left the association for lean body mass virtually unchanged (lowest HR: 1.33 [95% CI: 1.28 to 1.39] when adjusting for height), whereas no other association remained substantial when adjusted for lean body mass (highest HR: 1.05 [95% CI: 1.01 to 1.10] for height).

CONCLUSIONS

Lean body mass was the predominant anthropometric risk factor for AF, whereas no association was observed for either of the obesity-related anthropometric measures after adjustment for lean body mass.

Impact of Body Mass Index on the Prognosis of Japanese Patients With Non-Valvular Atrial Fibrillation

Obesity is a risk factor for atrial fibrillation (AF); however, obesity is associated with lower mortality in patients with established AF, a phenomenon known as the obesity paradox. Previous studies reported inconsistent results regarding effects of body weight on risk of cardiogenic embolism in patients with AF. To determine relation between body mass index (BMI) and prognosis among Japanese patients with nonvalvular AF (NVAF), a post hoc analysis was conducted using observational data in the J-RHYTHM Registry. Subjects were categorized as underweight (BMI <18.5), normal (18.5 to 24.9), overweight (25.0 to 29.9), or obese (≥30 kg/m(2)). End points included thromboembolism, major hemorrhaging, all-cause mortality, and cardiovascular mortality. Of the 7,406 patients with NVAF, 6,379 patients (70 ± 10 years old; BMI, 23.6 ± 3.9 kg/m(2)) having baseline BMI data constituted the study group. During the 2-year follow-up period, 111 patients had thromboembolism, 124 experienced major hemorrhage, and 159 died. Multivariate analysis with the Cox proportional hazards model showed that none of the BMI categories were independent predictors of thromboembolism. However, being underweight was an independent predictor of all-cause mortality (hazard ratio [HR] 2.45; 95% confidence interval [CI] 1.62 to 3.69; p <0.001) and cardiovascular mortality (HR 3.00, 95% CI 1.52 to 5.91, p = 0.001) when normal weight was used as the reference. Additionally, being overweight was a predictor of lower all-cause mortality (HR 0.60, 95% CI 0.37 to 0.95, p = 0.029). In conclusion, being underweight is associated with higher risks of all-cause and cardiovascular mortality compared with having a normal weight. Being overweight or obese is not associated with increased mortality among Japanese patients with NVAF.