Kelly et al. 2009 (NHANES DXA)
About this reference
Kelly et al. used DXA scans from NHANES 1999-2004 to fit LMS (lambda-mu-sigma) reference curves for lean mass, appendicular lean mass, fat mass, regional fat distribution and bone mineral, separately for non-Hispanic White, non-Hispanic Black and Mexican American adults; the paper's Table 1 lists 13,145 adults aged 20 and over across the three groups. The paper reports each curve as three parameters at five-year age points, median (M), population standard deviation (sigma) and skewness (L), rather than as percentile tables. FitnessNorms used its White-reference curves for lean mass index, appendicular lean mass index, fat mass index and the trunk fat ratios until October 2026. Since October 2026 the body-composition pages use an all-adult derivation from the same NHANES scans instead (NHANES 1999-2004 DXA); this paper is cited as a comparison and for its fat mass index classification ranges.
Known limitations
- US population only; values may differ from European or other Western populations in body composition
- Curves are fitted separately by ethnic group (White, Black, Mexican American); there is no pooled all-adult curve
- Cross-sectional design reflects population averages, not individual trajectories over time
- NHANES excludes institutionalised individuals (nursing homes, prisons)
- The paper publishes LMS parameters at single ages (20, 25, ... 85), not percentile tables
- Kelly et al. note that body composition results are technology- and calibration-dependent and vary widely between instruments; the NHANES scanners used the Schoeller calibration
- The lean mass values Kelly et al. fitted behave as if they include bone mineral content