Association between Exposure to Traffic-Related Air Pollution and Prevalence of Allergic Diseases in Children, Seoul, Korea

Table 1

Summary statistics of TRAP exposures for each allergic disease and prevalence of three allergic diseases for each individual characteristic in 14,765 children from the Seoul Atopy Friendly School Project survey in 2010 in Seoul, Korea.

	Total		Prevalent cases (prevalence rate, %)
	(%)		Atopic eczema		Asthma		Allergic rhinitis
	14,765	(100)	2,351	(15.9)	1,187	(8.0)	5,338	(36.2)
TRAP
0–150 m	4,494	(30.4)	724	(30.8)	314	(26.5)	1,601	(30.0)
150–300 m	3,873	(26.2)	629	(26.8)	332	(28.0)	1,432	(26.8)
300–500 m	3,284	(22.2)	536	(22.8)	261	(22.0)	1,193	(22.3)
>500 m	3,114	(21.1)	462	(19.7)	280	(23.6)	1,112	(20.8)
(1,000 m^2)	7.2	(8.6)	7.5	(8.8)	6.7	(8.2)	7.1	(8.6)
Sex
Girls	7,356	(49.8)	1,198	(16.3)	468	(6.4)	2,341	(31.8)
Boys	7,409	(50.2)	1,153	(15.6)	719	(9.7)	2,997	(40.5)
Age
1–3	1,322	(9.0)	223	(16.9)	235	(17.8)	369	(27.9)
4–6	2,447	(16.6)	450	(18.4)	271	(11.1)	890	(36.4)
7–9	5,453	(36.9)	898	(16.5)	386	(7.1)	2,089	(38.3)
10–12	5,543	(37.5)	780	(14.1)	295	(5.3)	1,990	(35.9)
Body fatness
Normal	11,948	(80.9)	1,944	(16.3)	930	(7.8)	4,214	(35.3)
Overweight or obese	769	(5.2)	122	(15.9)	89	(11.6)	283	(36.8)
Underweight	2,048	(13.9)	285	(13.9)	168	(8.2)	841	(41.1)
Breastfeeding duration
<4 months	8,042	(54.5)	1,124	(14.0)	597	(7.4)	2,977	(37.0)
4–11	3,876	(26.3)	637	(16.4)	318	(8.2)	1,342	(34.6)
≥12	2,847	(19.3)	590	(20.7)	272	(9.6)	1,019	(35.8)
Residential area
Downtown	1,729	(11.7)	315	(18.2)	191	(11.0)	543	(31.4)
Area 1	1,803	(12.2)	270	(15.0)	106	(5.9)	665	(36.9)
Area 2	3,010	(20.4)	552	(18.3)	366	(12.2)	1,048	(34.8)
Area 3	2,303	(15.6)	318	(13.8)	140	(6.1)	807	(35.0)
Area 4	973	(6.6)	154	(15.8)	59	(6.1)	359	(36.9)
Area 5	1,282	(8.7)	196	(15.3)	73	(5.7)	492	(38.4)
Area 6	1,678	(11.4)	246	(14.7)	122	(7.3)	639	(38.1)
Area 7	1,987	(13.5)	300	(15.1)	130	(6.5)	785	(39.5)
Household SES
High	5,545	(37.6)	770	(13.9)	423	(7.6)	2,120	(38.2)
Middle	6,539	(44.3)	1,097	(16.8)	532	(8.1)	2,367	(36.2)
Low	2,681	(18.2)	484	(18.1)	232	(8.7)	851	(31.7)
Regional
High	2,702	(18.3)	469	(17.4)	250	(9.3)	902	(33.4)
Middle	6,991	(47.3)	1,116	(16.0)	628	(9.0)	2,494	(35.7)
Low	5,072	(34.4)	766	(15.1)	309	(6.1)	1,942	(38.3)

of children (percent) for each allergic disease is displayed for proximity, whereas mean (standard deviation) is presented for summarizing road density. is a categorical variable indicating children live within a specific distance from the closest major roads. is a continuous variable defined as the sum of road lengths multiplied by numbers of lanes and road widths of major roads within a 300 m radius buffer from a child’s home. socioeconomic status (SES) was categorized based on fiscal self-sufficiency of residential areas (see Figure 2).