Association of epicardial fat thickness with the severity of obstructive sleep apnea in obese patients.
BACKGROUND
The correlation between obesity and severity of obstructive sleep apnea (OSA) is controversial. Although fat excess is a predisposing factor for the development of OSA, it has not been determined whether fat distribution rather than obesity per se is associated with OSA severity. Epicardial fat thickness (EFT) is an independent index of visceral adiposity and cardiometabolic risk. We investigated the relation between fat distribution and cardiometabolic risk factors, including EFT and common carotid intima-media thickness (cIMT), with the severity of OSA in obese patients.


METHODS
One hundred and fifteen obese patients (56 males, 59 females) with polysomnographic evidence of OSA (≥ 5 apnea/hypopnea events per hour) of various degrees, without significant differences in grade of obesity as defined by body mass index (BMI), were evaluated. The following parameters were measured: BMI, body composition by dual energy X-ray absorptiometry, EFT, right ventricular end-diastolic diameter (RVEDD) and cIMT by ultrasound, and parameters of metabolic syndrome (waist circumference, arterial blood pressure, fasting glucose, HDL-cholesterol and triglycerides).


RESULTS
EFT, RVEDD, cIMT and trunk/leg fat mass ratio showed a positive correlation with OSA severity in univariate analysis (r=0.536, p<0.001; r=0.480, p<0.001; r=0.345, p<0.001; r=0.330, p<0.001, respectively). However, multiple linear regression analysis showed that EFT was the most significant independent correlate of the severity of OSA (R(2)=0.376, p=0.022).


CONCLUSIONS
The present study suggests that, in obese patients, EFT may be included among the clinical parameters associating with OSA severity. The association of EFT with OSA, both cardiovascular risk factors, is independent of obesity as defined by classical measures.
Department of Experimental Medicine, Section of Medical Physiopathology and Endocrinology, Sapienza University of Rome, Rome, Italy.
Stefania
S
Mariani
Daniela
D
Fiore
Giuseppe
G
Barbaro
Sabrina
S
Basciani
Maurizio
M
Saponara
Enzo
E
D'Arcangelo
Salvatore
S
Ulisse
Costanzo
C
Moretti
Andrea
A
Fabbri
Lucio
L
Gnessi
D015502:Absorptiometry, Photon / Q000379:methods; D000273:Adipose Tissue / Q000000981:diagnostic imaging* / Q000503:physiopathology; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000503:physiopathology; D010496:Pericardium / Q000000981:diagnostic imaging* / Q000503:physiopathology; D017286:Polysomnography / Q000379:methods; D012307:Risk Factors; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000503:physiopathology