Table 2.
Baseline characteristics of participants exposed to quartile (Q1-Q4) daily average concentrations of total hydrocarbons (THC)
| Variables | THC N = 246,844 |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Q1 N = 63,003 |
Q2 N = 60,660 |
Q3 N = 70,328 |
Q4 N = 52,853 |
p-value | ||||||
| n | % | n | % | N | % | n | % | |||
| Age | mean, SDa | 5.58 | 2.61 | 5.66 | 2.76 | 7.15 | 3.71 | 7.71 | 3.83 | < 0.001 |
| Boys | 32,841 | 52.1 | 31,400 | 51.8 | 36,293 | 51.6 | 26,722 | 50.6 | < 0.001 | |
| Monthly income (NTD)b | < 0.001 | |||||||||
| < 15,000 | 55,885 | 88.7 | 53,572 | 88.3 | 56,140 | 79.8 | 40,274 | 76.2 | ||
| 15,000 − 19,999 | 5794 | 9.20 | 5428 | 8.95 | 10,531 | 15.0 | 9118 | 17.3 | ||
| ≥ 20,000 | 1324 | 2.10 | 1660 | 2.74 | 3657 | 5.20 | 3461 | 6.55 | ||
| Urbanization levelc | < 0.001 | |||||||||
| 1 (highest) | 17,524 | 27.8 | 13,907 | 22.9 | 24,184 | 34.4 | 26,212 | 49.6 | ||
| 2 | 15,355 | 24.4 | 24,605 | 40.6 | 23,393 | 33.3 | 15,832 | 30.0 | ||
| 3 | 14,606 | 23.2 | 10,230 | 16.9 | 14,777 | 21.0 | 7400 | 14.0 | ||
| 4 (lowest) | 15,518 | 24.6 | 11,918 | 19.7 | 7974 | 11.3 | 3409 | 6.45 | ||
| Outcome | ||||||||||
| Atopic dermatitis | 504 | 0.80 | 788 | 1.30 | 2863 | 4.07 | 3149 | 5.96 | < 0.001 | |
Chi-square test; aOne-way ANOVA; SD standard deviation
bMonthly income: New Taiwan Dollar (NTD), 1 NTD is equal to 0.03 USD
cUrbanization level: The urbanization level was categorized by the population density of the residential area into 4 levels, with level 1 as the most urbanized and level 4 as the least urbanized