Endocrine Abstracts

The prevalence of obesity markedly increased in the last 2 decades. This have asserted researchers’ attention to the role of adipose tissue throughout the pathophysiology process of a number of diseases. Fatness, namely abdominal fat, is a risk for insulin resistance, type 2 diabetes mellitus (T2DM), and cardiovascular disease. Physical activity is recommended as one of treatment options for individuals with T2DM. This study aimed to determine the relationship between insulin sensitivity measured by HOMA-IR/QUICKI and: total body fat [measured by dual energy X-ray absorptiometry (DXA)], waist circumference, daily physical activity behavior [measured by the ActiGraph accelerometer]; daily total energy expenditure (TEE) and activity energy expenditure (AEE) [measured by doubly labelled water (DLW)]. Following the collection of fasting baseline blood samples and anthropometric evaluation, 43 obese men (39.38 ± 8.44 years of age) were advised to remain sedentary and not initiating any exercise programme during a period of four weeks of weight-stable diet (an energy balance diet were prescribed for all participants). The participants of this study were part of weight stabilization period from a big weight loss intervention study [Queensland University of Technology (QUT) in Brisbane, Australia]. During this 4-week period measurements of AEE, resting metabolic rate (RMR) and physical activity levels (PALs) were recorded at week-4 and baseline. Participants were instructed to wear the accelerometer GT1 Min the first visit (week-4) and TEE was tracked over a period of time of 14 days. This study showed that obesity (BMIs ranging from 30 to 45 kg/m² and body fat with mean of 39.2 ± 5.3%) is a good predictor of insulin resistance (HOMA-IR = 4.69±2.63 and QUICKI = 0.31 ± 0.02). The participants had markedly increased cardiovascular risk, with a mean waist circumference of 110.1 ± 8.3 cm. Physical activity was positive correlated at moderate intensity (min/day) with fasting plasma glucose (r = .397, P < .006). The linear regression showed that moderate-intensity physical activity behaviour explained 15% of variation of fasting plasma glucose. The limitations of this study are the capability of GT1M to only capture activities on a flat surface. Another limitation of this study is the inability of energy expenditure measurements from the DLW method to capture aspects of activity such as mode or intensity, which may be more important for stimulating the physiological training adaptations. In conclusion, daily physical activity seems to be a bigger determinant of insulin sensitivity than total daily expenditure.