Association of Abdominal Circumference, Body Mass Index, and Inflammation in Kidney Transplant Recipients

Objective: Increased abdominal circumference is a marker of obesity, and it is associated with increased mortality in renal transplant recipients. Recent findings suggest that increased visceral fat deposition is a modifier of inflammation. However, little is known about the association of inflammation with abdominal circumference in kidney transplant recipients.

Design: Cross-sectional.

Subject: We collected sociodemographic and clinical parameters, medical and transplant history, and laboratory data from 985 prevalent kidney transplant recipients. Abdominal circumference, body mass index (BMI), and inflammatory markers were measured at baseline. Associations of inflammatory markers with abdominal circumference and BMI were examined in unadjusted and adjusted regression models.

Results: Mean ± standard deviation age was a 51 ± 13 years, 57% were men, and 21% were diabetics. Patients with abdominal circumference above the median had higher BMI and were older (mean ± standard deviation: 23.9 ± 3.6 vs. 30.1 ± 3.9 kg/m(2), P < .001; and 48 ± 14 vs. 54 ± 11 years, P < .001). Furthermore, patients with higher abdominal circumference had higher inflammatory parameters: median (interquartile range) C-reactive protein (mg/L): 2.3 (3.9) versus 4.1 (6.2), P < .001; and IL-6 (pg/mL): 1.9 (2.2) versus 2.3 (2.4), P < .001. In multivariable-adjusted linear regression models, higher abdominal circumference showed significant linear associations with inflammatory markers (standardized regression coefficients (β) of abdominal circumference for lnCRP: βabdominal circumference = 0.29, P < .001; and for lnIL-6: βabdominal circumference = 0.09, P = .018). Moreover, in multivariable-adjusted linear regression models, higher BMI showed significant linear associations with inflammatory markers (standardized regression coefficients (β) of BMI for lnCRP: βBMI = 0.24, P < .001; and for white blood cells: βBMI = 0.07, P = .041).

Conclusions: Abdominal circumference and BMI are independently associated with inflammatory markers in prevalent kidney transplant recipients.