Short-term effects of weather and air pollution on atopic dermatitis symptoms in children: A panel study in Korea

Abstract

Introduction: The effects of weather and air pollution on the severity and persistence of atopic dermatitis (AD) are important issues that have not been investigated in detail. The objective of our study was to determine the short-term effects of meteorological variables and air pollution on AD symptoms in children.

Methods: We enrolled 177 AD patients with 5 years or younger from the Seoul Metropolitan Area, Korea, and followed for 17 months between August 2013 and December 2014. Symptoms records of 35,158 person-days, including itching, sleep disturbance, erythema, dry skin, oozing, and edema, were obtained. We estimated the effect of meteorological variables including daily mean temperature, relative humidity (RH), diurnal temperature range (DTR), rainfall and air pollutants including particulate matter with an aerodynamic diameter ≤10 μm (PM10), nitrogen dioxide (NO2), and tropospheric ozone (O3) on AD symptoms using a generalized linear mixed model with adjustment for related confounding factors.

Results: A 5°C increase in outdoor temperature and a 5% increase in outdoor RH was associated with 12.8% (95% confidence intervals (CI): 10.5, 15.2) and 3.3% (95% CI: 1.7, 4.7) decrease in AD symptoms, respectively, on the same day. An increase of rainfall by 5 mm increased AD symptoms by 7.3% (95% CI: 3.6, 11.1) for the days with <40 mm rainfall. The risk of AD symptoms increased by 284.9% (95% CI: 67.6, 784.2) according to a 5°C increase in DTR when it was >14°C. An increase in PM10, NO2, and O3 by 10 units increased the risk of AD symptoms on the same day by 3.2% (95% CI: 1.5, 4.9), 5.0% (95% CI: 1.4, 8.8), and 6.1% (95% CI: 3.2, 9.0), respectively.

Conclusion: Exposure to meteorological variables and air pollutants are associated with AD symptoms in young children.

Fig 1. Relationship of meteorological variables and air pollution with Atopic Dermatitis (AD) symptoms.

Each figure shows the spline curve (solid lines) with a 95% confidence intervals (two dashed lines). All variables are based on the same model on the same day, without using moving averages for the exposure to each risk factor. The model was controlled for the severity score at the initial visit, age, sex, presence of fever, and day of week (DOW). RH: relative humidity; DTR, diurnal temperature range; OR: odds ratio.

Fig 2. Effects of meteorological variables and air pollution on Atopic Dermatitis (AD) symptoms by moving average.

Data represent percent changes and 95% confidence intervals in AD symptoms per 5-unit increase in daily mean temperature (°C), relative humidity (%), diurnal temperature range (°C) and 10-unit increase in PM₁₀ (μg/m³), NO₂ (ppb), and O₃ (ppb). RH: relative humidity; DTR: diurnal temperature range; MA: moving average.

Fig 3. Effects of meteorological variables and air pollution on Atopic Dermatitis (AD) symptoms in boys (A) and girls (B).

Data represent percent changes and 95% confidence intervals in AD symptoms per 5-unit increase in daily mean temperature (°C), relative humidity (%), diurnal temperature range (°C), and rainfall (mm) and 10-unit increase in PM₁₀ (μg/m³), NO₂ (ppb), and O₃ (ppb). DTR: diurnal temperature range; RH: relative humidity; MA: moving average.