Association between phthalate exposure and rash eczema disease: based on NHANES 2005-2006

Phthalates are commonly found in plastic products, personal care products, and food packaging. In recent years, the relationship between phthalates and skin diseases such as eczema has been gaining attention. As endocrine disruptors, phthalates may increase the risk of eczema by affecting the immune system or skin barrier function. This study used a cross-sectional design based on data from the 2005-2006 National Health and Nutrition Examination Survey to assess the association between phthalate exposure and eczema in adults using generalized linear models, restricted cubic spline plots and weighted quantile sum regression. Eczema diagnosis was determined by participants' self-report of whether they had ever been diagnosed with eczema by doctors. Phthalate exposure was assessed by urinary concentrations of phthalates. A total of 1203 subjects, aged 18 years and over, were recruited for the study, comprising 627 males and 576 females. We found that females had significantly higher phthalate exposure concentrations than males. There was a significant positive correlation between monoisononyl phthalate (MiNP) and eczema. Mixture analysis similarly found a positive correlation between phthalates and rash eczema, and MiNP was the main contributor. Further sex-stratified analyses showed that this association occurred predominantly in females, while no significant association was found in the male population. Phthalates may have adverse effects on skin health, particularly in women. Future studies should further investigate the mechanisms of this association and focus on other types of phthalates and their effects on skin health.