Endocrine Abstracts

Up-to-date dual-energy X-ray absorptiometry (DXA) offers an insight into body composition (fat and lean mass) in different body regions.

Objectives: To measure the regional fat and lean mass in women of different age and to describe age-related changes.

Material and Methods: One hundred and twenty women referred for DXA participated in the whole body (WB) study – age range was 20–75 yrs. They were subdivided in three age groups: 20–44 (20 premenopausal women), 45–59 (80 postmenopausal women), and 60–75 (20 women). WB DXA was performed on a Hologic QDR 4500 A bone densitometer (Hologic Inc., Bedford MA) and software version 8.26:3. Total body and regional BMC, fat and lean mass were measured. Regional analysis included arms and legs (as the sum of both left and right), as well as trunk. Descriptive and regression analyses with age as independent variable were performed on an IBM SPSS Statistics 19.0 for Windows platform. The data were first analyzed as a whole and then separately for the different age groups.

Results: Comparing the 45–59 versus the 20–44 aged subgroups fat and lean mass showed a parallel decrease, while in the older subgroup (60–75 yrs) the decrease of fat was greater than that of lean mass. The percentage of fat mass was lowest in the oldest subgroup. Comparing the 45–59 versus the 20–44 aged subgroups fat and lean mass showed a parallel decrease in the legs, but fat showed a greater decrease than lean in the arms and trunk. Best fitting regression models with age as independent and WB lean and fat mass as dependent variables are shown.

Conclusion: Aging has a more pronounced effect on fat than lean mass. The reduction of both body compartments is different according to the region studied. This type of data could be useful in the study of sarcopenia.