Comparison between DXA and MRI for the Visceral Fat Assessment in Athletes

A Brief Review of the Literature for Published Dual-Energy X-Ray Absorptiometry Protocols for Athletes

CONTEXT

Dual-energy x-ray absorptiometry (DXA) is widely known for its utility in diagnosing a patient with osteopenia or osteoporosis; however, its utility in evaluation of body composition and potential athletic performance was previously routinely overlooked. In recent years, athletic programs have begun employing this equipment during athlete screening. However, it is currently unknown how athletic programs are utilizing this information to guide an athlete's training and health.

OBJECTIVE

To explore the literature to identify what is known regarding sports performance and athlete health based on body composition recordings.

DATA SOURCES

PubMed and Google Scholar databases were searched for this brief review.

STUDY SELECTION

A focus was placed on articles within the past 10 years that discussed DXA protocols within athletic populations; 14 articles were included in this brief literature review.

STUDY DESIGN

Brief literature review.

LEVEL OF EVIDENCE

Level 5.

DATA EXTRACTION

One member of the research team searched the literature and retrieved articles with the purpose of analyzing and/or explaining DXA imaging in body composition analysis of active persons (primarily athletes).

RESULTS

Quality assurance scans with a phantom calibration block as well as athlete prescreening condition and activity standardization was routinely recommended. However, only 1 study reported a specific DXA protocol for athletes, and only 1 study described guidelines for how to report DXA results in athletic populations, suggesting it is plausible yet difficult due to the small changes detectable.

CONCLUSION

Due to the limited literature as well as a lack of reference values for specific athletic populations, the authors of this review recommend using the current Nana et al (Int J Sport Nutr Exerc Metab 2015;25:198-215) DXA protocol for performing DXA scans in the athletic population as well as current Hind et al (J Clin Densitom 2018;21:429-443) guidelines for distributing the information.

Subscapular skinfold thickness, not other anthropometric and dual-energy X-ray absorptiometry-measured adiposity, is positively associated with the presence of age-related macular degeneration: a cross-sectional study from National Health and Nutrition Examination Survey 2005-2006

OBJECTIVE

Current literature reveals an association between anthropometric measures of adiposity (AnthM) and age-related macular degeneration (AMD), but few have explored the disease association with imaging methods. This study aimed to explore the relationship between AMD status and dual-energy X-ray absorptiometry measures (DEXAMs) among a representative sample of the US population, and compare the association with AnthM.

METHOD

Using a representative sample in the National Health and Nutrition Examination Study 2005-2006 (n=1632), DEXAMs across the whole body and waist (ie, android), and relative fat distributions (eg, percentage fat, android-to-total body ratio) were analysed between no AMD (baseline) and any AMD. Bivariate analyses across AMD status were similarly performed for AnthM (ie, body mass index, waist circumference and skinfold thicknesses) and potential confounders (ie, demographics and health-related variables). Significant adiposity measures were analysed using logistic regression, adjusting for confounders.

RESULTS

The participants in the sample were aged 40-69 years, were majority female (52%) and mainly Caucasian (76.5%). Bivariate analysis revealed having any AMD had positive significant associations with android-to-total fat ratio and subscapular skinfold thickness (SSFT). Other AnthM and DEXAMs were not significant. After adjusting age, gender and prescription of cholesterol-lowering medicine, only SSFT remained significantly associated.

CONCLUSION

SSFT represents an independent risk factor for AMD presence compared with other AnthM and DEXAMs. SSFT is an established method of measuring fat under the skin (ie, subcutaneous fat). Hence, subcutaneous fat may be more relevant in explaining the adiposity-AMD link due to physiological properties specific to the tissue. Limitations include the restricted age range and low numbers of participants with late AMD.

Exploring the correlation of skin temperature and body composition in athletes undergoing exhaustive physical exercise

During strenuous exercise, skin temperature (Tsk) plays an essential role in thermoregulatory processes. As indicated in the literature, its response might be influenced by body composition, among other factors. Hence, the objectives of this investigation were to determine whether there is a correlation between selected body components, specifically fat tissue and muscle tissue, and Tsk during graded exercise and recovery in athletes, and to identify which body component exhibits the strongest correlation with Tsk. Participants were grouped according to their aerobic capacity (VO2max/kg). A significant main effect was observed for the test stages (p < .001, η2 = 0.71), with Tsk decreasing from the start of the exercise, significantly decreasing at 12 km/h-1 (p < .001), and then increasing after exercise, especially within the first 5 min of recovery. Weak and non-significant effect for group/stage interaction was detected (p = .374, η2 = 0.03). A significant negative correlation was found between Tsk and both total tissue fat [%] (-0.51 < r < -0.63, p < .001) and lower limb tissue fat [%] (-0.50 < r < -0.71, p < .001) across all test stages. The correlation between Tsk and BMI was inconsistent, appearing only during the first stage of exercise and throughout recovery. No correlation was observed between Tsk and skeletal muscle mass, appendicular lean soft tissue, or relative skeletal muscle index. Endurance running to exhaustion leads to a progressive decrease in the Tsk of the lower extremity, followed by rewarming during recovery. The observed inverse correlation between adipose tissue and Tsk, along with the distinct temperature trends in groups with varying levels of fat tissue, could imply that the skin and subcutaneous tissue complex may play a more intricate role in thermal energy exchange beyond its insulating function. This implies a multifaceted involvement of these tissues in thermoregulation.

The Impact of Obesity on Inflammatory Bowel Disease

Obesity is prevalent in the inflammatory bowel disease (IBD) population, particularly in newly developed countries where both IBD and obesity in the general population are on the rise. The role of obesity in the pathogenesis of IBD was entertained but results from available studies are conflicting. It does, however, appear to negatively influence disease course whilst impacting on our medical and surgical therapies. The pro-inflammatory profile of the visceral adipose tissue might play a role in the pathogenesis and course of Crohn's Disease (CD). Interestingly, isolating the mesentery from the surgical anastomosis using a KONO-S technique significantly decreases anastomotic recurrence rate. Anti-obesity therapy is not widely used in IBD but was suggested as an adjunctive therapy in those patients. In this review, we aimed to highlight the epidemiology of obesity in IBD and to describe its influence on disease course and outcomes.

Body Composition Predictors of Complicated Crohn's Disease

BACKGROUND

High visceral adipose tissue (VAT) and creeping fat (CrF) in Crohn's disease (CD) have been widely recognized. The VAT to subcutaneous adipose tissue (SAT) ratio and sarcopenia have been associated with CD complications. Studies regarding the influence of body composition predictors on CD complications assessed with magnetic resonance enterography (MRE) are scarce.

AIM

The aim of this study was to assess body composition parameters and CrF in opportunistic MRE as predictors of complicated CD.

METHODS

This was a retrospective study of 114 patients with inflammatory (n = 54) and complicated (n = 60) CD. The semiautomated assessment of body composition and the qualitative evaluation of CrF were performed.

RESULTS

Body composition parameters did not differ between both groups regarding the body mass index (p = 0.50), total adipose tissue index (TATI) (p = 0.14), subcutaneous adipose tissue index (SATI) (p = 0.17), visceral adipose tissue index (VATI) (p = 0.33), VAT/SAT ratio (p = 0.77), intramuscular adipose tissue (p = 0.64), skeletal muscle index (p = 0.22), and sarcopenia (p = 0.50). 47 strictures, 18 fistulae, and seven abscesses were identified. Fistulae were more likely to occur in patients with CrF (odds ratio [OR] 5.07, 95% confidence interval [CI] 1.76-14.56; p=<0.001) and high VAT/SAT ratio (OR: 3.82, 95% CI 1.34-10.85; p = 0.01).

CONCLUSION

Body composition measurements in CD patients displayed no statistically significant difference between the groups of inflammatory and complicated disease. Nonetheless, CD patients stratified in the group of high VAT/SAT ratio and the presence of CrF should be recognized as risk groups for the occurrence of fistulae.