Correlation of principal component analysis (PCA) factors with the residual
amount of energy expenditure (EE) measurements and the relative amount of annual
weight change (%Δwt/yr). Twenty-four hour EE was adjusted for
age, sex, fat mass (FM), fat-free mass (FFM), and physical activity. Sleeping
metabolic rate (SMR) adjustments included age, sex, FM, and FFM. Sex and age
were used as covariates for %Δwt/yr. Correlations of
sphingomyelin factor 1 (SM-factor 1) with the residual amount of SMR and
%Δwt/yr are shown in A and B, respectively. Correlations of
sphingomyelin factor 2 (SM-factor 2) with the residual amount of SMR and
%Δwt/yr are shown in C and D, respectively. Correlations of
ceramide factor (C-factor) with the residual amount of 24h-EE and
%Δwt/yr are shown in E and F, respectively. Pearson’s
correlation and P-value are reported. Sensitivity analysis
excluded the study volunteer who lost approximately 6% body weight per
year: This nominally affected the P-value for the association
of SM-factor 1 with %Δwt/yr (r = 0.53,
P = 0.08). Given the lack of association between
weight change per year and initial weight (r = −0.34,
P = 0.20), we performed the analysis using weight
change per year (kg/yr) only, yielding similar results for principal
components.