Dual energy X-ray absorptiometry spine scans to determine abdominal fat in postmenopausal women

Effect of high-intensity interval training on cardiovascular disease risk factors and body composition in psoriatic arthritis: a randomised controlled trial

Background

Psoriatic arthritis (PsA) is associated with an accumulation of cardiovascular disease (CVD) risk factors. The aim of this study was to evaluate the effect of high-intensity interval training (HIIT) on CVD risk factors in patients with PsA.

Methods

We randomly assigned 61 patients with PsA (41 women and 20 men) to an intervention group performing HIIT for 11 weeks or a control group who were instructed to not change their physical exercise habits. Outcomes were assessed at 3 and 9  months with measures on maximal oxygen uptake (VO_2max), fat percentage and Body Mass Index (BMI). We used linear mixed models to calculate mean difference with 95% CI between the groups according to the intention-to-treat principle.

Results

At 3  months, the HIIT group had a 3.72  mL/kg/min (95%  CI 2.38 to 5.06) higher VO_2max and a 1.28 (95% CI −2.51 to −0.05) lower truncal fat percentage than controls. There was also some evidence that the HIIT group had lower total fat percentage (−0.80; 95%  CI −1.71 to 0.10) and slightly lower BMI (−0.31; 95%  CI −0.78 to 0.17) than the control group. At 9  months, the HIIT group had still a higher VO_2max (3.08; 95%  CI 1.63 to 4.53) than the control group, whereas the difference in other factors were small.

Conclusion

In patients with PsA, 3  months with HIIT was associated with a substantial increase in VO_2max and a reduction in truncal fat percentage compared with controls. The beneficial effect on VO_2max was also sustained through 9  months.

Trial registration number

NCT02995460.

Use of iDXA spine scans to evaluate total and visceral abdominal fat

OBJECTIVES

Abdominal fat may be a better predictor than body mass index (BMI) for risk of metabolically-related diseases, such as diabetes, cardiovascular disease, and some cancers. We sought to validate the percent fat reported on dual energy X-ray absorptiometry (DXA) regional spine scans (spine fat fraction, SFF) against abdominal fat obtained from total body scans using the iDXA machine (General Electric, Madison, WI), as previously done on the Prodigy model.

METHODS

Total body scans and regional spine scans were completed on the same day (N = 50). In alignment with the Prodigy-based study, the following regions of interest (ROI) were assessed from total body scans and compared to the SFF from regional spine scans: total abdominal fat at (1) lumbar vertebrae L2-L4 and (2) L2-Iliac Crest (L2-IC); (3) total trunk fat; and (4) visceral fat in the android region. Separate linear regression models were used to predict each total body scan ROI from SFF; models were validated by bootstrapping.

RESULTS

The sample was 84% female, a mean age of 38.5 ± 17.4 years, and mean BMI of 23.0 ± 3.8 kg/m² . The SFF, adjusted for BMI, predicted L2-L4 and L2-IC total abdominal fat (%; Adj. R² : 0.90) and total trunk fat (%; Adj. R² : 0.88) well; visceral fat (%) adjusted R² was 0.83. Linear regression models adjusted for additional participant characteristics resulted in similar adjusted R² values.

CONCLUSIONS

This replication of the strong correlation between SFF and abdominal fat measures on the iDXA in a new population confirms the previous Prodigy model findings and improves generalizability.