Table 3 Differences between DXA, DLW and BIS (by Xitron and Tanita) to assess changes in body composition (fat mass, total body water and muscle mass), between baseline and after 12-week intervention (AB) and between baseline and 1 year later (AC) in overweight and obese initially lactating women postpartum

From: Body composition in overweight and obese women postpartum: bioimpedance methods validated by dual energy X-ray absorptiometry and doubly labeled water

  n mean±s.d. Pa LoA KCC rP Pb BA rP P3
FMAB DXA—BIS 60 0.9±2.6 0.01 −4.3–8.7 0.61 0.77 0.01 0.17 0.33
FMAB DXA—MFBIA 43 0.9±3.7 0.1 −6.5–8.3 0.49 0.65 0.01 0.20 0.20
FMAC DXA—BIS 50 0.1±2.8 0.80 −5.5–5.7 0.80 0.92 0.01 0.49 0.01
FMAC DXA—MFBIA 38 1.1±5.2 0.21 −9.3–11.5 0.54 0.69 0.01 0.10 0.53
TBWAB DLW-BIS 60 −0.7±1.7 0.01 −4.1–2.7 0.36 0.48 0.01 0.13 0.32
TBWAB DLW-MFBIA 43 −0.5±3.1 0.31 −6.7–5.7 0.14 0.18 0.19 0.66 0.01
SMMAB DXA—BIS 60 −0.2±1.2 0.22 −2.6–2.2 0.22 0.32 0.01 0.48 0.01
SMMAB DXA—MFBIA 43 −1.2±3.5 0.03 −8.2–5.8 0.19 0.19 0.09 0.78 0.01
SMMAC DXA—BIS 50 −0.3±1.0 0.03 −2.3–1.7 0.32 0.51 0.01 0.36 0.01
SMMAC DXA—MFBIA 38 −1.5±4.8 0.05 −11.1–8.1 0.14 0.07 0.22 0.85 0.01
  1. Abbreviations: BA, Bland–Altman regression for systematic bias expressed as rP; BIS, bioimpedance spectroscopy (Xitron 4200); BIS TBW, TBW by BIS with proprietary equations; BIS073, TBW calculated from a 73% hydration of fat-free mass; DLW, doubly labeled water; DXA, dual X-ray absorptiometry; FM, fat mass; KCC, Kendall's concordance correlation; MFBIA, multifrequency bioimpedance (Tanita MC180A); MFBIA073, TBW calculated from a 73% hydration of fat-free mass; SMM, skeletal muscle mass; rP, Pearson's correlation; TBW, total body water; TBW MFBIA=TBW by MFBIA by proprietary equations. P3=significance of regression for differences between reference method and secondary methods vs the mean of both methods.
  2. AB, differences in changes between baseline (A) and 12 weeks (B).
  3. AC, difference in changes between baseline (A) and 1 year (C).
  4. aPaired sample t-test; LOA, limits of agreement±2 s.d.
  5. bSignificance of KCC correlation.