Dataset Information

Harmful Effect of Indoor Formaldehyde on Atopic Dermatitis in Children: A Longitudinal Study.

ABSTRACT:

Purpose

Evidence supporting a link between indoor formaldehyde exposure and atopic dermatitis (AD) in humans is limited. The purpose of this longitudinal study was to investigate whether AD symptoms in children could be affected by indoor formaldehyde levels in ordinary households.

Methods

Fifty-five children with moderate-to-severe AD aged under 18 years were enrolled as a panel. They were followed up from February 2019 through February 2020. Indoor formaldehyde levels of patients' houses and their AD symptoms were repeatedly measured on a daily basis. The generalized linear mixed model was utilized for statistical analysis. Subdivision analysis was performed by stratifying patients by sex, body mass index, presence of parental allergy, and indoor environments including mold/dampness, temperature, and relative humidity (RH).

Results

A total of 4,789 person-days of AD symptom data were collected. The average concentration of formaldehyde was 13.6 ± 16.4 ppb, with the highest value found in spring (18.1 ± 20.6 ppb). Higher levels of formaldehyde were observed when there was parental smoking, increased indoor temperature over 25.5°C, or RH over 60% (P < 0.0001). When the effect size was compared between each season after controlling for ambient particulate matter, temperature, and RH, an increase in 10 ppb of formaldehyde increased AD symptoms by 79.2% (95% confidence interval [CI], 19.6-168.4) in spring and by 39.9% (95% CI, 14.3-71.2) in summer. AD symptoms in children aged 6-18 years appeared to increase significantly, whereas there was no significant increase in children under 6 years. When indoor temperature was over 25.5°C, an increase in formaldehyde by 10 ppb increased AD symptoms by 17.8% (95% CI, 3.9-33.6).

Conclusions

Indoor formaldehyde can exacerbate AD symptom in children with moderate-to-severe AD, particularly in spring and summer, even at allowable levels. Thus, minimizing exposure to indoor formaldehyde may be needed for the proper management of AD in children.

SUBMITTER: Kim YM

PROVIDER: S-EPMC7984948 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:This study aimed to investigate the short-term effect of exposure to indoor fine particulate matter (PM2.5) on atopic dermatitis (AD) symptoms in children. Sixty-four children (40 boys and 24 girls) with moderate-to-severe AD, aged under 18 years were enrolled in the study. They were followed up from February 2019 through November 2020. Exposure to indoor PM2.5 in each household of the enrolled children and their AD symptoms were measured daily. The generalized linear mixed model was utilized for statistical analysis. Subdivision analysis was performed by stratifying the patients by age, sex, season, severity, the presence of family allergic diseases, sensitization, and indoor environment conditions including temperature and relative humidity. A total of 9,321 person-days of AD symptom data were collected. The average PM2.5 concentration was 28.7 ± 24.3 µg/m3, with the highest value in winter (47.1 ± 29.6 µg/m3). The overall effect of PM2.5 on AD symptoms was not statistically significant. However, an increase of 10 µg/m3 in indoor PM2.5 concentration increased AD symptom scores by 16.5% (95% CI: 6.5, 27.5) in spring and12.6% (95% CI: 4.3, 21.5) in winter, 6.7% (95% CI: 2.3, 11.3) at indoor temperatures of <25.5 °C, and by 15.0% (95% CI: 3.5, 27.7) with no use of an air purifier. The harmful effect of PM2.5 in boys, in children aged ≥6 years, and in children with inhalant allergen sensitization was significant, showing an increase in AD symptoms of 4.9% (95% CI: 1.4, 8.6), 12.0% (95% CI: 5.3, 19.1), and 7.0% (95% CI: 1.9, 12.3) per 10 µg/m3 of PM2.5, respectively. Furthermore, children with inhalant allergen sensitization plus severe symptoms (SCORing Atopic Dermatitis, SCORAD ≥ 30.7, median value) showed more harmful effects from exposure to PM2.5 (15.7% (95% CI: 4.5, 28.1) increase in AD symptom scores per 10 µg/m3 of PM2.5 increase). Indoor exposure to PM2.5 exacerbated AD symptoms in children in spring, winter, and at indoor temperatures of < 25.5 °C. In particular, this harmful effect was prominent in children with inhalant allergen sensitization and severe symptoms. Minimizing exposure to indoor PM2.5 is needed for the proper management of AD.