Anthropometry of leg lean volume: Application to nutrition in systemic disorders

Abstract

Depletion of leg lean mass has been progressively recognised as an important clinical outcome in disease populations, being related to early disability, impaired health-related quality of life, and even mortality. Estimation of leg lean volumes (LLV) from circumferences and skinfold thicknesses, in particular, have long been used as these techniques are inexpensive and widelyavailable in clinical settings. The truncated cones method proposed by Jones and Pearson (1967) might be particularly useful for clinical populations in which loss of leg lean mass is common, usually as part of the cachexia syndrome (e.g., chronic heart failure, chronic obstructive pulmonary disease (COPD), chronic renal failure, liver failure, sepsis, rheumatoid arthritis, AIDS and cancer). The method divides the leg into six segments which are assumed to represent truncated cones. Summation of the volume of each cone, determined from the circumferences and the height of each individual cone, gives an estimate of total LV. By subtracting the skinfold thicknesses from the circumferences, a lean volume of each cone can be derived, thereby providing an estimate of LLV. Despite its obvious advantages compared to more sophisticated and costier approaches, the method is time-consuming, needs careful standardization and a trained observer. Moreover, it is technically difficult to be performed in bed-bound patients, being influenced by oedema and obesity. More importantly, however, skinfold thickness measurements are obtained only at few selected locations and it is assumed that they are invariant across the lower limbs and not influenced by gender-specific patterns of fat tissue deposition. Notwithstanding these limitations, there is limited evidence that the method might be highly sensitive to indicate depletion of metabolic active tissue and its functional consequences in specific clinical populations, such as those with chronic obstructive pulmonary disease (COPD). Additional studies are warranted to extrapolate these findings for other disease populations with different levels of nutritional impairment.