Relative sarcopenia and mortality and the modifying effects of chronic kidney disease and adiposity

Abstract Background Conventional definitions of sarcopenia based on lean mass may fail to capture low lean mass relative to higher fat mass, that is, relative sarcopenia. The objective of this study is to determine the associations of sarcopenia and relative sarcopenia with mortality independent of co‐morbidities, and whether chronic kidney disease (CKD) and adiposity alter these associations. Methods Dual energy X‐ray absorptiometry‐derived appendicular lean mass index (ALMI, kg/m2) and fat mass index (FMI, kg/m2) were assessed in 14 850 National Health and Nutrition Examination Survey participants from 1999 to 2006 and were linked to death certificate data in the National Death Index with follow‐up through 2011. Sarcopenia was defined using sex‐specific and race/ethnicity‐specific standard deviation scores compared with young adults (T‐scores) as an ALMI T‐score