High socioeconomic status is significantly associated with psoriasis: results from a cross-sectional, population-based study of 129 855 patients.

Background: While the contribution of environmental factors (including smoking, overweight and stress) to psoriasis has been validated, data mining for the association between socioeconomic status (SES) and psoriasis prevalence has yielded contradictory observations.

Objectives: To evaluate the association between psoriasis prevalence and SES.

Methods: This was a nationwide population-based cross-sectional retrospective study that included all patients insured by 'Clalit' Health Services (N = 4 604 994). Univariable and multivariable logistic regression analyses were conducted to explore the association between psoriasis and SES while controlling for potential sociodemographic and clinical confounders.

Results: The study population included 129 855 patients with psoriasis and 4 475 139 individuals without psoriasis. Higher SES was associated with an increased prevalence of psoriasis; in a fully adjusted model, Clalit members within the highest SES were 1.43-fold more likely to have psoriasis [95% confidence interval (CI) 1.39-1.48, P < 0.001], and those in the medium SES group were 1.2-fold more likely to have psoriasis compared with those in the lowest SES group (95% CI 1.18-1.26, P < 0.001; P for linear trend < 0.001).

Conclusions: Positive correlation was found between SES and psoriasis prevalence. Further investigation is warranted to elucidate the factors accounting for this observation.