Effect of regional fat loss assessed by DXA on insulin resistance and dyslipidaemia in obese women

Abstract

Objective. To investigate the impact of reduction in total fat mass (FM) and regional FMs on indices of insulin resistance and dyslipidaemia in obese women (BMI > 30 kg/m²) after a 1-year weight loss (WL) program; and, secondly, to investigate the potential predictive effect of baseline insulin resistance on reduction in total and regional FMs. Material and methods. In 35 women with > 4kg weight loss, body composition by DXA (dual X-ray absorptiometry), fasting insulin, C-Peptide, insulin resistance (HOMA-IR), insulin sensitivity (QUICKI), metabolic clearance rate (MCRestOGTT) and serum lipids were assessed. Results. Mean WL was 9.6%; trunk and leg FM were reduced proportionally (14.9–14.7%). Improvement in HOMA-IR was 34.7%, insulin 30.7%, QUICKI 8.6% and MCRest OGTT 74%. The reduction in total, trunk and leg FM were similarly correlated with improvement in indices of insulin resistance (p < 0.001–0.05) and also with initial HOMA-IR (p = 0.000–0.02). In linear regressions improvement in HOMA-IR was similarly related with these FMs (p = 0.008), and initial HOMA predicted loss of trunk FM (p = 0.01). In multivariate analysis improvement in HOMA-IR was explained by loss of total FM (R² = 0.20, p = 0.004); improvement of QUICKI by loss of leg FM (R² = 0.33, p < 0.001). Conclusion. Loss of leg FM and trunk FM had similar importance for the improvement in insulin resistance. Baseline HOMA-IR predicted the potential for reduction in trunk FM.

Key Words::

• Weight loss
• body composition
• trunk fat mass
• leg fat mass
• insulin resistance

Acknowledgements

The authors are very thankful to Elisabeth Rambøl, RN, Sian Thomas, Lill Johannnessen, May Grenmark (DXA technicians) for their contribution to the study. The study has received financial support from the Norwegian Research Council.

Contribution of authors

Gunnar Aasen was the main investigator. Johan Halse was advisor and had overall responsibility for the project. Hans Fagertun was the statistical consultant. All authors participated in the result evaluation and the writing and editing of the manuscript.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.