Effect of exposure to ambient air volatile organic compounds on the severity of atopic dermatitis and lag-day effect.

BACKGROUND

Previous studies reported positive associations between exposure to air volatile organic compounds (VOCs) and daily visits for atopic dermatitis (AD).

OBJECTIVE

This population-based study investigated associations between air VOCs exposure and daily hospitals visits for AD, severity subgroup (mild and severe), and lag-day effect in central-southern Taiwan.

METHODS

The dependent variable was AD with diagnostic codes (ICD-9-CM 691.8 and ICD-10-CM L20) retrieved from the Taiwan National Health Insurance Research Database from 2008/01/01 to 2018/12/31. Independent variables included one-day 75th-percentile value of each VOC (benzene, ethylbenzene, toluene, m-/p-xylene, o-xylene, 1,3,5-trimethylbenzene, 1,2,4-trimethylbenzene, isopentane, n-pentane, n-hexane, methylcyclohexane, and cyclohexane) and four meteorological conditions from the Taiwan Air Quality Monitoring Network Database. This was a case-crossover design with multivariable conditional logistic regression, and the adjusted odds ratios (AORs) were reported.

RESULTS

Concentrations of the 12 air VOCs significantly positively affected the total number of daily visits for AD (AOR = 1.02~1.69, P < 0.001) and subgroups of mild (AOR = 1.001~1.049, P < 0.001) and severe (AOR = 1.002~1.077, P < 0.001). The effect of air VOCs on the severe AD group was higher than that on the mild group. Values of the six VOCs on the 1st lag day (benzene: AOR = 1.16, 1,3,5-trimethylbenzene: AOR = 1.5, 1,2,4-trimethylbenzene: AOR = 1.13, isopentane: AOR = 1.07, n-pentane: AOR = 1.08, methylcyclohexane: AOR = 1.5, all P < 0.05) were significantly positively associated with the number of daily visits for AD.

CONCLUSIONS

Exposure to the 12 air VOCs on the visit days increased the risks of daily visits for AD in total and severity subgroup. The effects of six certain VOCs on the 1st lag day were significant positive.