Comparison of estimates of body fat content in childhood-onset systemic lupus erythematosus

Abstract

Objective

We aimed to compare estimates of body fat content with respect to their ability to predict the percentage of body fat, confirmed by dual-energy X-ray absorptiometry scans in childhood-onset systemic lupus erythematosus.

Methods

We included 64 consecutive childhood-onset systemic lupus erythematosus patients and 64 healthy age and sex-matched controls in a cross-sectional study. Anthropometric data, body mass index and body adiposity index were calculated for all subjects. Childhood-onset systemic lupus erythematosus patients were further assessed for clinical and laboratory childhood-onset systemic lupus erythematosus manifestations and fat mass, lean mass and percentage of body fat evaluated by dual-energy X-ray absorptiometry.

Results

Elevated waist/hip ratio was observed in childhood-onset systemic lupus erythematosus patients when compared to controls (p < 0.001). We did not find differences between body mass index and body adiposity index classification in childhood-onset systemic lupus erythematosus patients and controls. Using dual-energy X-ray absorptiometry as gold standard we observed that all indirect estimates of body fat were correlated with whole body fat mass. We observed a correlation between height and cumulative corticosteroid dose adjusted by weight (r = 0.429, p = 0.005) in childhood-onset systemic lupus erythematosus. On whole body analysis we observed a correlation between lean mass and ACR Damage Index scores (r = −0.395; p = 0.019); percentage of body fat and adjusted Systemic Lupus Erythematosus Disease Activity Index (r = 0.402; p = 0.008), disease duration (r = −0.370; p = 0.012). On trunk analysis we observed a correlation between lean mass and ACR Damage Index (r = −0.319; p = 0.042); percentage of body fat with adjusted Systemic Lupus Erythematosus Disease Activity Index (r = 0.402; p = 0.005), disease duration (r = −0.408; p = 0.005).

Conclusions

This is the first study analyzing body adiposity index in childhood-onset systemic lupus erythematosus patients. We observed that all indirect estimates of body fat were correlated with whole body fat mass. This study shows that we should not replace body mass index by body adiposity index to evaluating fat levels in childhood-onset systemic lupus erythematosus. In consideration of the importance of overweight classification in cardiovascular diseases, any direct estimates of body fat can be used in an attempt to improve the prognosis of patients.

Note

We believe that we have presented evidence of body adiposity index accuracy in childhood-onset systemic lupus erythematosus patients but further research on the generalizability of body adiposity index to other patient groups needs to be done.