Age‐associated changes of resting energy expenditure, body composition and fat distribution in Chinese Han males

Age‐related alterations in whole body composition, particularly, reduced fat free mass (FFM) and increased fat mass (FM), lead to a progressive decline in resting energy expenditure (REE). Similarly, regional body composition and fat distribution changes with age might also contribute to an overall lower REE. This study investigated the influence of age on REE, regional body composition and fat distribution, including subcutaneous fat (SF) and visceral fat (VF), in a Chinese Han population as well as their contributions to age‐related changes in REE. One hundred and two males aged 31–83 years old underwent dual‐energy X‐ray absorptiometry (DXA) which measured whole body and regional FM and FFM. SF and VF were measured by magnetic resonance imaging (MRI) and REE by indirect calorimetry. Age was significantly negatively correlated with REE (r = −0.37), total FFM (r = −0.25), upper limbs FFM (r = −0.32), lower limbs FFM (r = −0.34) and showed positive association with trunk FFM (β=0.926). FM, SF and VF decreased in older age groups after an initial rise up to 55–65 years. REE correlated positively to FM, FFM, SF, VF and showed significant association with age (β = −0.254) independent of age‐associated changes in body composition. The regional alterations in body composition with age were explained by changes in trunk FFM (β = 0.926). Age‐related decline in REE were not solely due to alterations in FM and FFM. Therefore, the changes in regional body composition, fat distribution and REE which occur during aging could be explained by disparities in race, ethnicity, diet, physical activity, and lower specific metabolic rates of FFM components.