Association between atopic dermatitis with hyperparathyroidism not mediated by vitamin D in the United States (NHANES 2005-2006).

The association between atopic eczema and hyperparathyroidism remains doubtful. Participants with atopic dermatitis have lower serum vitamin D levels. Whether it is mediated by vitamin D or other potential factors remains uncertain as well. This study aims to determine the impact of AD on hyperparathyroidism and the direct mediators. A total of 7266 subjects in the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2006 were included in this study. Diagnoses of AD were based on questionnaire answering. Hyperparathyroidism was assessed by biochemical examination. Weighted logistic regression analysis reported odds ratios (ORs), and mediation analysis was applied to evaluate the mediating effect. Subgroup analysis stratified by age and vitamin D level was further performed after the confirmation of the association. Participants with AD had higher odds of developing hyperparathyroidism (OR [95% CI], 1.86 [1.040, 3.326], P = 0.041). The association was not mediated by vitamin D or other potential factors, including calcium, phosphorus, BMI and CRP. Otherwise, subgroup analysis demonstrated that the association exhibited variations based on age and vitamin D level, especially in subjects older than 60 years old and with normal vitamin D levels. Participants with AD are inclined to have hyperparathyroidism. We recommend a more rigorous focus on hyperparathyroidism in patients with AD, especially those over 60 years of age and with normal serum vitamin D levels.