Activated brown adipose tissue and its relationship to adiposity and metabolic markers: an exploratory study

Figures & data

Table 1. Participant characteristics

Characteristic	N(%)
Race
Asian	6 (24%)
Black/African American	4 (16%)
White	15 (60%)
Ethnicity
Hispanic/Latino	4 (16%)
Non Hispanic/Latino	21 (84%)
	Mean (SD)	Range (min-max)
Age (years)	21.1 (1.8)	18 – 24
Weight (kg)	80.5 (17.4)	56.5–118.9
BMI (kg/m^2)	25.2 (4.8)	19.4–35.9
	Median (25th, 75th percentile)
Waist circumference (cm)*	82.5 (78.4, 99.5)	70 – 120
Body fat (%)*	21.2 (14.7, 27.5)	9.4–40.2
	Mean (SD)
Glucose (mg/dL)	85.6 (6.0)	77 – 104
Insulin (uU/mL)	9.5 (5.6)	3.4–27.5
HbA1c (%)	5.3 (0.2)	4.9–5.7
HDL (mg/dL)	49.4 (14.8)	32 – 99
LDL (mg/dL)	86.9 (23.6)	53 – 136
Triglycerides (mg/dL)	74.9 (29.3)	34 – 129
Total cholesterol (mg/dL)	149.6 (28.6)	109 – 205
	Median (25th, 75th percentile)
FGF21 (pg/mL)*	77.7 (43.2, 120.1)	11.0–204.7
Leptin (ng/mL)*	2.9 (1.2, 7.3)	0.4–42.2

Data not normally distributed, median presented rather than mean.

Table 2. Brown adipose tissue (BAT) characteristics on PET/CT imaging

Variable	Mean (SD)	min, max
SUVmean (g/mL)	3.56 (1.93)	0, 7.94
SUVmax (g/mL)	10.52 (7.31)	0, 27
	Median (25th, 75th percentile)
Total BAT activity (KBq)	362.9 (93.7, 1045.2)	0, 3904.3
BAT volume (mL)	37.6 (10.6, 86.7)	0, 178.2

*Data not normally distributed, median presented rather than mean.

Table 3. Correlations between SUV_mean, SUV_max, total BAT activity, BAT volume and measures of adiposity, and metabolic markers

Characteristic	SUVmean r (p-value)^†	SUVmax r (p-value)^†	Total BAT activity r (p-value)^‡	BAT volume r (p-value)^‡
Age	0.08 (0.69)	−0.03 (0.88)	−0.03 (0.90)	−0.03 (0.90)
BMI	−0.22 (0.30)	−0.18 (0.38)	−0.10 (0.63)	−0.13 (0.53)
FMI	−0.19 (0.38)	−0.13 (0.53)	0.02 (0.92)	0.01 (0.97)
Waist Circumference	−0.15 (0.46)	−0.10 (0.64)	−0.05 (0.80)	−0.08 (0.71)
Glucose	−0.30 (0.14)	−0.38 (0.06)	−0.40 (0.05)	−0.40 (0.048)
HbA1c	−0.04 (0.85)	−0.09 (0.68)	−0.09 (0.68)	−0.10 (0.64)
Insulin	0.01 (0.96)	0.05 (0.80)	0.07 (0.76)	0.05 (0.81)
HOMA2-IR	0.00 (0.99)	0.04 (0.84)	0.07 (0.73)	0.06 (0.79)
Leptin	−0.33 (0.12)	−0.26 (0.22)	−0.04 (0.85)	−0.08 (0.71)
Adiponectin	0.09 (0.67)	0.11 (0.58)	0.24 (0.25)	0.21 (0.32)
FGF21	0.35 (0.09)	0.51 (0.01)	0.31 (0.14)	0.29 (0.17)
IL-6	0.34 (0.09)	0.37 (0.07)	−0.17 (0.42)	−0.11 (0.59)
TSH	0.09 (0.67)	0.05 (0.80)	0.13 (0.54)	0.15 (0.48)
fT4	0.06 (0.77)	−0.13 (0.54)	−0.13 (0.55)	−0.11 (0.61)

†Pearson correlations.

‡Spearman’s rank correlations.

Figure 1. Correlation between BAT characteristics on PET/CT imaging and fasting glucose

Figure 2. Correlation between SUV_max and FGF21