Assessment of Adiposity in Patients with Psoriasis and its Correlation with Disease Severity: A Case-Control Study

Psoriasis and obesity are known to share many mediators of inflammation with each other such as TNF-α and IL-6. Obesity, being a low-grade inflammatory state, is known to affect the disease course, severity, predisposition, and response to therapy in psoriatic patients. Whole-body dual-energy X-ray absorptiometry (DEXA) is a proven method to estimate total, abdominal, and extremity fat mass.

The present study aimed to assess the correlation of the severity of psoriasis with adiposity using regional fat mass DEXA indices.

This was a case-control study involving 153 cases followed through till the completion of the study. A total of 153 age and gender-matched controls were included in the study after ruling out confounding factors. DEXA scans were conducted on both cases and controls; the following indices, including total body fat percentage, android-gynoid ratio, and trunk/limb fat mass ratio, were analyzed.

The total fat percentage, as assessed by DEXA scan, had a mean of 29.13 ± 9.66 (32.12 ± 9.51 for cases and 26.13 ± 8.87 for controls) with a significant P value of <0.001. The android/gynoid ratio had a mean of 1.01 ± 0.22 (1.09 ± 0.21 for cases and 0.93 ± 0.21 for controls). Percentage fat trunk/percentage fat limbs (central/peripheral fat) had a mean of 1.05 ± 0.16 (1.08 ± 0.15 for cases and 1.03 ± 0.16 for controls) with a significant P value of <0.001. The correlation of DEXA adiposity grading with the severity of psoriasis was found to be significant, with a P value of <0.001.

The cross-sectional design restricts assessment to associations rather than causality. Although major confounding factors were ruled out during recruitment, variables such as lifestyle and dietary habits, physical activity levels, and treatment history were not the primary focus and hence not extensively analyzed. The sample size analyses, such as stratification by gender or treatment modalities, may benefit from larger cohorts in future research.

DEXA is a useful indicator of adiposity, with greater total fat percentage, android/gynoid ratio, and trunk/limb fat mass ratio in cases compared to controls and it was positively correlated with the severity of psoriasis in our study.