According to Amy S. Paller, MD, from the Department of Dermatology at Northwestern University in Chicago, Illinois, and colleagues, of a total 409 children with psoriasis (206 with severe psoriasis and 203 with mild psoriasis), 37.9% were overweight compared with 20.5% of 205 children without the inflammatory skin condition matched by age and sex. Similarly, a higher percentage of the children with psoriasis were obese (20.2% vs 7.3%). Both differences were statistically significant (P < .001).
The authors wrote, "Should further studies show excess adiposity to be a precursor for psoriasis, attempts at early weight loss and lifestyle modification will be important, not only to decrease the risk of metabolic disease but also to modulate the course of pediatric psoriasis."
The precise mechanism linking childhood psoriasis and excess adiposity remains unknown. Chronic inflammation likely drives both conditions, the authors note, because studies in adults support a role for type 1 and type 17 T-cell inflammatory cytokines in both clinical presentations.
"One of the questions in the article is which came first, the psoriasis or the obesity. I would bet my last dollar that the obesity came first," Dr. Green one of the authors of the study said. "It’s very clear in adults that the more overweight you are or the more obese you are the worse your psoriasis." "It’s very likely obesity is a trigger."
Factors that did not significantly modify the association between psoriasis and excess adiposity include age (P = .91), pubertal status (P = .58), and specific age group (P = .97). In addition, disease duration did not correlate with excess adiposity (Spearman correlation coefficient, 0.008).
Dr. Paller and colleagues at 18 dermatology centers in 9 countries around the world used the Physician’s Global Assessment to classify severity of disease, with affected body surface area as a secondary measure. The children with psoriasis were almost evenly split: 203 had mild disease and 206 had severe disease.
Compared with control patients, children with psoriasis were more likely to be overweight (odds ratio [OR], 2.65; 95% confidence interval [CI], 1.70 – 4.15] or obese (OR, 4.29; 95% CI, 1.96-9.39), regardless of disease severity. The investigators also performed a subanalysis of just US children and found an even stronger association between psoriasis and the likelihood of being overweight (OR, 4.02; 95% CI, 2.11 – 7.63) or obese (OR, 6.61; 95% CI, 2.16 – 20.17).
Arch Dermatol. Published online November 19, 2012. Abstract