Obesity tied to late-onset psoriasis, PsA
Obesity is a risk factor of late-onset psoriasis and psoriatic arthritis (PsA), whereas normal weight is linked with the presence of the HLA-B*27 allele and an earlier onset of PsA, a recent study has found.
A total of 314 patients with early PsA were compared with 498 patients with psoriasis without arthritis (PsC), with body mass index (BMI) at the first visit to the clinic as the primary predictor.
Researchers used linear trend test and Cochrane-Armitage trend test to compare the clinical features across three BMI groups, and logistic regression analysis to evaluate the interaction between BMI and HLA risk alleles for psoriatic disease (HLA-B*27, B*3901, B*3801, B*0801, B*4402, B*4403 and C*0602).
There were more obese patients with PsA than with PsC (odds ratio [OR], 1.77; p=0.002). Higher BMI correlated with older age at onset of PsA (p<0.0001) and psoriasis (p=0.009).
The HLA-B*27 allele was more frequent in patients with normal weight than those with higher BMI (p=0.002). Logistic regression analysis showed a significant interaction for the combined effect of HLA-B*27 and obesity (p=0.036). There was a statistically significant association between obesity and PsA in patients who were HLA-B*27‒negative. However, obesity was not common in patients with PsA who were HLA-B*27‒positive.
“These results highlight the differential risk factors that may drive the inflammatory process in psoriatic disease,” researchers said.
Psoriasis and PsA are immune-mediated diseases that carry a strong genetic component. PsA have a tendency to appear earlier in patients with HLA-B*27 positivity; these patients also have a shorter interval of time between the onset of cutaneous lesions and of joint disease. [Rheumatology (Oxford) 2014;53:1178-85]