Air pollutants appear to contribute to the increased incidence of atopic dermatitis (AD), results of a Taiwan study have shown.
The authors used the nationwide cohort in the Taiwan National Health Insurance Research Databases (NHIRD) to examine the relationship between air quality index (AQI) and incidence of AD. A total of 21,278,938 participants from NHIRD without an AD diagnosis before 2008 were included in the analysis.
Participants were stratified into four quintiles (Q) by AQI value. The authors then calculated the long-term average AQI value, obtained from the Taiwan Air Quality Monitoring System Network, prior to AD diagnosis and linked this to each participant.
From 2008 to 2018, a total of 199,205 incident cases of AD were documented. Using the lowest quintile (Q1) as reference, AD risk was significantly higher in the Q2 (adjusted hazard ratio [aHR], 1.29, 95 percent confidence interval [CI], 1.04‒1.65) and Q3 groups (aHR, 4.71, 95 percent CI, 3.78‒6.04) and highest in the Q4 group (aHR, 13.20, 95 percent CI, 10.86‒16.60).
When AQI was treated as a continuous variable, each 1-unit increase in AQI led to a 7-percent elevation in AD risk (aHR, 1.07, 95 percent CI, 1.07‒1.08).
“The results demonstrated a significant positive association between AQI and incidence of AD with a clear dose-response relationship,” the authors said.
This study was limited by the lack of detailed information on individuals by the NHIRD.