Association between red blood cell distribution width and psoriasis among the US adults

The association between red blood cell distribution width (RDW) and psoriasis among the US adults is still unknown. We aimed to assess whether RDW is associated with psoriasis in the US adults.

We conducted a cross-sectional study consisting of 14,089 participants from National Health and Nutrition Examination Survey (NHANES) 2009-2014. Psoriasis status were assessed by self-reported questionnaire. We evaluated the association between RDW and risk of psoriasis using multivariate regression models. Subgroup and interaction analysis were performed.

The higher RDW level was associated with an increased risk of psoriasis (OR = 1.10 [95% CI, 1.01, 1.19]; p = 0.025) after adjusting for confounders in female. However, there is no significant association between RDW and risk of psoriasis among male (OR = 0.99 [95% CI, 0.87, 1.15]; p = 0.992). Subgroup and interaction analysis found that the strongest positive association mainly exists in female participants with BMD greater than 29.9 kg/m² (OR = 1.20 [95% CI, 1.09, 1.32], Pint = 0.004).

In conclusion, we found that increased RDW levels were associated with an increased risk of psoriasis in females, which could provide clinicians with auxiliary data for the early diagnosis of psoriasis.