1. ¹Department of Occupational and Environmental Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
2. ²Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University, Tainan, Taiwan
3. ³Department of Dermatology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
4. ⁴Department of Dermatology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
5. ⁵Department of Environmental and Occupational Medicine, National Taiwan University (NTU) and NTU Hospital, Taipei, Taiwan

Correspondence: Professor Yueliang Leon Guo, Department of Environmental and Occupational Medicine, National Taiwan University (NTU) and NTU Hospital, 1 Sec 1, Jen-Ai Road, Taipei 100, Taiwan. E-mail: leonguo@ntu.edu.tw

Received 13 August 2007; Revised 11 March 2008; Accepted 15 March 2008; Published online 1 May 2008.

Abstract

The prevalence of childhood eczema is increasing in many countries. Epidemiological studies, however, say little of its association to outdoor air pollution and climate factors. We conducted a nationwide survey of middle-school students in Taiwan from 1995 to 1996. The 12-month prevalence of eczema was compared with air monitoring station data of temperature, relative humidity, and criteria air pollutants. A total of 317,926 children attended schools located within 2 km of 55 stations. Prevalence rates of recurrent eczema were 2.4 and 2.3% in boys and girls, respectively, with prevalence rates of flexural eczema 1.7% in both sexes. After adjustment for possible confounders, flexural eczema was found to be associated with traffic-related air pollutants, including nitrogen oxides and carbon monoxide. Recurrent eczema was associated with traffic-related air pollution only in girls. There were no associations for the highest monthly means of temperature, whereas the annual means and the lowest monthly means of temperature were negatively related to flexural eczema, but only in girls. The lowest monthly mean relative humidity was positively related to eczema. The results suggest that air pollution and climatic factors, which showed stronger associations in girls than boys, may affect the prevalence of childhood eczema.