DXA-Derived Visceral Adipose Tissue (VAT) in Elderly: Percentiles of Reference for Gender and Association with Metabolic Outcomes

Association of body fat and muscle tissue parameters with fatty liver disease identified by ultrasound

AIMS

To examine the association between body fat and muscle parameters and FLD in individuals of Chinese descent.

METHODS

A total of 515 participants who underwent routine check-ups between November 2019 and August 2021 were reviewed. Based on ultrasound performance, the subjects were categorized into the non-FLD group and the FLD group. The prevalence of FLD in sex subgroups was analyzed using logistic regression to calculate the odds ratios (ORs) of body composition parameters with adjustment for confounders.

RESULTS

A total of 262 males and 253 females aged 20-84 years were reviewed. In both males and females, higher fat mass index (FMI) (OR: 1.989 for males vs. 1.389 for females), fat mass percent (FM%) (OR: 1.253 for males vs. 1.149 for females), visceral adipose tissue (VAT) (OR: 1.002 for males vs. 1.002 for females), and body mass index (BMI) (OR: 1.530 for males vs. 1.247 for females)were associated with increased ORs of FLD while higher lean mass percent (LM%) (OR: 0.839 for males vs. 0.856 for females)was associated with decreased ORs of FLD. Despite accounting for confounding factors, the associations remained present. Logistic regression of the quartiles of the indices showed associations with the prevalence of FLD. The trends still existed even after adjusting for confounders.

CONCLUSION

Independently of age, lipid profiles and other confounders, lower VAT, FM, FMI, FM% and BMI tended to be associated with a lower prevalence of FLD, while lower LM% trended to be associated with a higher prevalence of FLD in both sexes of the general population.

Equations for predicting DXA-measured visceral adipose tissue mass based on BMI or weight in adults

Background

Obesity, especially presenting with excessive amounts of visceral adipose tissue (VAT), is strongly associated with insulin resistance (IR), atherosclerosis, metabolic syndrome, and cardiovascular diseases (CVDs).

Aims

To construct a predication equation for estimating VAT mass using anthropometric parameters and validate the models with a validation group.

Methods

Five hundred fifteen subjects (366 for the derivation group and 149 for the validation group) were enrolled in the study. The anthropometric parameters, blood lipid profile, and VAT mass were accessed from medical records. Stepwise regression was applied to develop prediction models based on the dual X–ray absorptiometry (DXA)-measured VAT mass in the derivation group. Bland–Altman plots and correlation analysis were performed to validate the agreements in the validation group. The performance of the prediction equations was evaluated with the Hosmer–Lemeshow test and area under the curve (AUC).

Results

Model 1, which included age, sex, body mass index (BMI), triglyceride (TG), high-density lipoprotein (HDL), and the grade of hepatic steatosis, had a variance of 70%, and model 2, which included age, sex, weight, height, TG, HDL, and the grade of hepatic steatosis, had a variance of 74%. The VAT mass measured by DXA was correlated with age, sex, height, weight, BMI, TG, HDL, and grade of hepatic steatosis. In the validation group, the VAT mass calculated by the prediction equations was strongly correlated with the DXA–VAT mass (r = 0.870, r = 0.875, respectively). The AUC, sensitivity, and specificity of the two prediction equations were not significantly different (both P = 0.933).

Conclusion

The study suggests that prediction equations including age, sex, height, BMI, weight, TG, HDL, and the grade of hepatic steatosis could be useful tools for predicting VAT mass when DXA is not available.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-022-01652-8.

Current Applications and Selected Technical Details of Dual-Energy X-Ray Absorptiometry

The application of dual-energy X-ray absorptiometry (DXA) examinations in the assessment of bone mineral density (BMD) in the lumbar spine, hip, and forearm is the basic diagnostic method for recognition of osteoporosis. The constant development of DXA technique is due to the aging of societies and the increasing importance of osteoporosis as a public health problem. In order to assess the degree of bone demineralization in patients with hyperparathyroidism, forearm DXA examination is recommended. The vertebral fracture assessment (VFA) of the thoracic and lumbar spine, performed by a highly-skilled technician, is an interesting alternative to the X-ray examination. The DXA total body examination can be useful in the evaluation of fat redistribution among patients after bariatric surgery, in patients infected with HIV and receiving antiretroviral therapy, and in patients with metabolic diseases and suspected to have sarcopenia. The assessment of visceral adipose tissue (VAT) and detection of abdominal aortic calcifications may be useful in the prediction of cardiovascular events. The positive effect of anti-resorptive therapy may affect some parameters of DXA hip structure analysis (HSA). Long-term anti-resorptive therapy, especially with the use of bisphosphonates, may result in changes in the DXA image, which may herald atypical femur fractures (AFF). Reduction of the periprosthetic BMD in the DXA measurements can be used to estimate the likelihood of loosening the prosthesis and periprosthetic fractures. The present review aims to present current applications and selected technical details of DXA.

Proposed cut-off points for anthropometric and bioelectrical measures based on overweight and obesity criteria in Spanish institutionalised elderly people

The increasing prevalence of obesity among the institutionalised elderly population and its severe consequences on health requires an early and accurate diagnosis that can be easily achieved in any clinical setting. This study aimed to determine new cut-off values for anthropometric and bioelectrical impedance measures that are superior to body mass index criteria for overweight and obesity status in a sample of Spanish institutionalised elderly population. A total of 211 institutionalised older adults (132 women, aged 84.3±7.3 years; 79 men, aged 81.5±7.3 years) were enrolled in the current cross-sectional study. Anthropometric and bioelectrical impedance measures included the body mass index, waist circumference, gluteal circumference, waist-hip ratio, sagittal-abdominal diameter, trunk fat, and visceral-fat ratio. In women, the waist circumference, gluteal circumference, sagittal-abdominal diameter, trunk fat, and visceral-fat index presented strongly significant specificity and sensitivity (area under the curve [AUC], p<0.0001) and elevated discriminative values (receiver operating characteristic [ROC] curves: 0.827 to 0.867) for overweight and obesity status. In men, the waist-hip ratio, waist circumference, gluteal circumference, sagittal-abdominal diameter, trunk fat, and visceral-fat ratio were strongly significant AUC (p<0.0001), with moderate-to-high values (ROC curves: 0.757-0.871). In conclusion, our findings suggest that gluteal circumference, waist circumference, and sagittal-abdominal diameter in women and trunk fat, visceral-fat ratio, and waist circumference in men may represent more suitable cut-off values superior to body mass index criteria for overweight and obesity in the Spanish institutionalised elderly population.