Is epidural fat associated with body habitus?
OBJECTIVE
To evaluate, in the spine, the relationship between the amount of epidural fat to body weight, height, body mass index (BMI), presence of obesity, depth of posterior subcutaneous fat, as well as gender and age.


METHODS
At 1.5 T, 101 random patients were analyzed. In the lumbar spine, we calculated the depth of the anterior and posterior epidural fat, as well as posterior subcutaneous fat, separately at the L3-4, L4-5, and L5-S1 levels. Obtained via questionnaire was patient's age, gender, body weight, height, with a calculated BMI (body weight/height, kg/m). Statistical analysis was performed to assess the correlation between epidural and subcutaneous fat with age and gender, weight, height, BMI, and presence of obesity (BMI > 27.5 kg/m).


RESULTS
There were 66 men and 45 women, age ranged 14-83 years old (mean 43). The weight range was 47.6-135.4 (mean 79.5 kg); height range was 124.5-208.3 (mean 169.7 cm); BMI range was 16.9-42.8 (mean 27.8). Female gender correlated only with subcutaneous fat depth (sum, r=-0.31, P=0.002). Younger patients had more anterior epidural fat (sum, r=-0.22, P=0.024) but not posterior epidural fat (sum, r=0.01, P=0.954) or subcutaneous fat (sum, r=0.09, P=0.0357). Weight correlated with posterior epidural fat (sum, r=0.21, P=0.037) and subcutaneous fat (sum, r=0.51, P <0.0001). Height showed correlation negatively with posterior subcutaneous fat thickness (sum, r=-0.25, P=0.014), but had no significant correlation with epidural fat. BMI showed a correlation with posterior subcutaneous fat (r=0.71, P <0.0001 for sum). Somewhat unexpectedly, BMI had no correlation with either posterior (r=0.12, P=0.221 for sum) or anterior epidural fat (r=0.11, P=0.271 for sum), and most importantly the presence of obesity was associated only with subcutaneous fat (P <0.0001), but not with any specific or summated epidural fat measurement (P=0.0801-0.7692).


CONCLUSIONS
Weight but not body habitus is associated with specific, usually posterior, patterns of epidural fat deposition. Overall obesity is unrelated to epidural fat.
Wu
Hung Ta H
HT
Department of Radiology, Taipei Veterans General Hospital, National Yang Ming University, Taipei, Taiwan.
Schweitzer
Mark E
ME
Parker
Laurence
L
D000273:Adipose Tissue / Q000033:anatomy & histology*; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001824:Body Constitution; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D004824:Epidural Space; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000473:pathology; D011446:Prospective Studies; D012737:Sex Factors; D012867:Skin / Q000033:anatomy & histology; D012885:Skinfold Thickness; D013131:Spine / Q000033:anatomy & histology*