Brown adipose tissue is associated with healthier body fat distribution and metabolic benefits independent of regional adiposity

Figures

• 

  Figure 1. Flowchart of study participant selection Shown is an outline of screening, enrollment, 1:1 propensity score matching, and derivation of the analysis cohort from all individuals age 18 and above who received a 18F-FDG PET/CT scan in 2016.

• 

  Figure 2. Illustration of 18F-FDG PET/CT measurements and WAT distribution (A) Schematic of WAT quantification on transverse CT slides at the L3/L4 level and detection and quantification of BAT by 18F-FDG PET. (B) Scatterplot depicting the correlation between BMI and VAT and SAT areas. Solid lines represent fitted curves derived from second-order polynomial equations, and shaded areas are 95% CIs. Correlation was assessed by calculating Spearman’s rank correlation coefficient. Fitted curves are shown up to a BMI of 50 kg/m2, and individual data points are depicted for 1,701 individuals. (C) Scatterplot depicting the correlation between BMI and SAT:VAT ratio. The solid line represents the fitted curve derived from second-order polynomial equations, and shaded areas are 95% CIs. Correlation was assessed by calculating Spearman’s rank correlation coefficient. The fitted curve is shown up to a BMI of 50 kg/m2, and individual data points are depicted for 1,701 individuals. (D) Scatterplot depicting the relative distribution of SAT:VAT ratio in our cohort. The solid blue line represents the fitted curve derived from second-order polynomial equations. The fitted curve is shown up to a SAT:VAT…

• 

  Figure 3. BAT status and activity are associated with body fat distribution (A) Distribution of BMI by BAT status. Lines represent the 10th percentile, median, and 90th percentile. The p value was calculated based on a Mann-Whitney U test. (B) Distribution of waist circumference on CT by BAT status. Lines represent the 10th percentile, median, and 90th percentile. The p value was calculated based on a Mann-Whitney U test. (C) Distribution of SAT:VAT ratio by BAT status. Lines represent the 10th percentile, median, and 90th percentile. The p value was calculated based on a Mann-Whitney U test. The depicted data show measurements for 1,662 individuals. (D) Best fit curves representing the relationship between BMI and SAT area (solid lines) or VAT area (dashed lines), stratified by BAT status, were calculated using linear regression analysis. The shaded areas represent the 95% CIs. The p values were calculated for assessing statistically significant differences between the slopes of these two lines. Best fit curves are shown up to a BMI of 40 kg/m2. (E) Best fit curves representing the relationship between BMI and SAT:VAT ratio, stratified by BAT status, were calculated using linear…

• 

  Figure 4. BAT is associated with improved metabolic parameters independent of SAT:VAT ratio (A–D) Boxplots of glucose (A), WBCs (B), triglycerides (C), and HDL (D), stratified by BAT status. Boxes represent the 25th percentile, median, and 75th percentile, and whiskers illustrate the 10th and 90th percentiles. All p values were calculated based on a Mann-Whitney U test. The data depicted in (A) show measurements for 1,683 individuals, in (B) for 1,221 individuals, in (C) for 249 individuals, and in (D) for 209 individuals. (E–H) Association between SAT:VAT ratio and levels of glucose (E), WBCs (F), triglycerides (G), or HDL (H), stratified by BAT status. Best fit curves were calculated using linear regression. The shaded areas represent the 95% CIs. Best fit curves were derived for (A) from measurements of 1,683 individuals, in (B) of 1,221 individuals, in (C) of 249 individuals, and in (D) of 209 individuals and are shown up to a SAT:VAT ratio of 7.8. (I–L) Multivariable linear regression analysis adjusted for age, gender, BMI, SAT:VAT ratio, and BAT as predictors of levels of glucose (I), WBCs (J), triglycerides (K), or HDL (L) as outcome.

• 

  Figure 5. BAT is associated with improved markers of hepatic steatosis and T2DM (A) Illustration of liver density (HU) measurement as a surrogate for fatty liver disease. (B) Association of liver density based on HU measurements and SAT:VAT ratio. β-Estimate and p value were calculated using linear regression analysis. The best fit curve was derived from measurements of 1,298 individuals and is shown up to a SAT:VAT ratio of 7.8. (C) Boxplot of mean liver HUs stratified by BAT status. Boxes represent the 25th percentile, median, and 75th percentile, and whiskers illustrate the 10th and 90th percentiles. The p value is calculated based on a Mann-Whitney U test. The depicted data show measurements for 1,298 individuals. (D) Best fit curves of mean liver HUs across SAT:VAT ratios, stratified by BAT status, were calculated using linear regression analysis, and shaded areas depict 95% CIs. The best fit curves were derived from measurements of 1,298 individuals and are shown up to a SAT:VAT ratio of 7.8. (E) Prevalence of T2DM stratified by BAT status. Data are shown for 1,702 individuals. (F) Best fit curve of the probability of T2DM across SAT:VAT ratios was calculated using logistic…