Association of dietary diversity score and severity of pemphigus vulgaris: a cross-sectional study

Previous studies support the protective role of a balanced diet containing several foods and nutrients in controlling the autoimmune bullous disease. Dietary diversity score (DDS) is a measure of diet quality based on the number of different food groups consumed, which may influence immune function and inflammatory responses relevant to autoimmune diseases such as pemphigus vulgaris. The present study was designed to investigate the potential the association between DDS and the risk of high-severity Pemphigus Vulgaris (PV) disease in adult Iranian patients.

A cross-sectional study was performed on 138 patients, aged 18-65 years, with confirmed diagnoses of PV in a referral university center for autoimmune bullous diseases. Dietary intakes were assessed using a 168-item semi-quantitative food frequency questionnaire. Anthropometric measures, biochemical markers, and sociodemographic characteristics were collected using standardized methods. DDS was defined according to the Diet Quality Index, revised. To assess PV severity, the pemphigus disease area index (PDAI) score was used. Logistic regression was used to evaluate the association between DDS and PDAI.

Mean (± standard deviation) DDS was 4.98 ± 1.21. After adjusting for potential confounders, patients in the third and second quartiles of DDS had lower odds for disease severity based on the PDAI score (OR: 0.14, 95% CI: 0.03-0.69 and OR: 0.18, 95% CI: 0.04-0.86; respectively) compared to the reference group. This inverse relationship was observed even after stratification by the oral lesion (OR _crude: 0.27, 95% CI: 0.08-0.96). In addition, the probability of having a high PDAI score decreased with increasing adherence to the diversity score for fruit compared with those with the lowest adherence (OR _crude: 0.40, 95% CI: 0.17-0.92).

Our findings suggest that a diversified diet intake may be associated with a lower severity of disease in PV patients. However, Additional studies are required to replicate these findings.