Interaction between body weight status and spicy food consumption on the risk of rosacea: A multi-central, hospital-based, case-control study

Background: No researches about the interaction among the risk factors for rosacea were conducted. Some studies prompted obesity and spicy food may have some common pathways. Aims: To clarify the relationship between body mass index (BMI) and rosacea, and explore the interaction between BMI and spicy food consumption in rosacea. Methods: This hospital-based case-control study enrolled 1347 rosacea patients and 1290 healthy subjects. The demographic data and clinical data were collected. The association between BMI and rosacea, and the relative excess risk due to interaction of BMI and spicy food consumption was calculated. Results: No interaction was found between underweight, overweight/obesity, and spicy food consumption with regard to the risk of rosacea, mild-to-moderate rosacea, papulopustular rosacea (PPR), or phymatous rosacea (PhR). And underweight and overweight/obesity were not significant associated with rosacea, mild-to-moderate rosacea, PPR, or PhR (p > 0.05). However, spicy food consumption was significantly interacted with underweight on the risk of erythematotelangiectatic rosacea (ETR), and with overweight/obesity on the risk of severe rosacea. Underweight was associated with increased risk of ETR (adjusted odds ratio [aOR] = 1.91, 95% confidence interval [CI]: 1.21, 3.03) among spicy no users, but the association was attenuated into insignificant level when mixed with spicy food factor (p > 0.05). Among moderated spicy food consumers, overweight/obesity was associated with decreased risk of severe rosacea (aOR = 0.70, 95% CI: 0.50, 0.98), but overweight/obesity was insignificant associated with severe rosacea among spicy no users and heavy spicy food consumers (p > 0.05). Conclusions: Body weight status alone was not significantly associated with rosacea, but the interaction between body weight status and spicy food consumption is involved in the rosacea.