Table 3.
Risk ratios of emergency department visits for pediatric asthma for days in the terminal nodes as compared to the referent group, a Atlanta, Georgia, 1999–2009
|
Terminal node
b
|
N
c
|
Risk ratio |
95% Confidence interval |
Type of days (pollutant quartiles) |
|||
|---|---|---|---|---|---|---|---|
| CO | NO2 | O3 | PM2.5 | ||||
| Referent |
131 |
1.00 |
|
1 |
1 |
1 |
1 |
| T1 |
316 |
1.10 |
(1.05, 1.16) |
1-4 |
1,2 |
1-4 |
4 |
| T2 |
279 |
1.08 |
(1.03, 1.14) |
1-4 |
3,4 |
1-4 |
1 |
| T3 |
1039 |
1.05 |
(1.01, 1.1) |
1-4 |
3,4 |
1-4 |
2,3 |
| T4 |
441 |
1.07 |
(1.02, 1.13) |
1-4 |
3,4 |
4 |
4 |
| T5 |
91 |
1.03 |
(0.97, 1.1) |
1,2 |
1,2 |
4 |
1-3 |
| T6 |
68 |
1.07 |
(0.98, 1.17) |
3,4 |
1,2 |
4 |
1-3 |
| T7 |
76 |
1.08 |
(1.01, 1.15) |
1-4 |
3 |
1-3 |
4 |
| T8 |
168 |
1.07 |
(1.01, 1.14) |
1-4 |
4 |
1-3 |
4 |
| T9 |
458 |
1.01 |
(0.97, 1.05) |
1-4 |
1 |
1,2 |
1-3 |
| T10 |
263 |
1.04 |
(0.99, 1.09) |
1-4 |
2 |
1 |
1-3 |
| T11 |
435 |
1.03 |
(0.98, 1.07) |
1-4 |
2 |
2,3 |
1-3 |
| T12 |
160 |
1.02 |
(0.97, 1.08) |
1-4 |
1 |
3 |
1,2 |
| T13 | 85 | 1.04 | (0.97, 1.11) | 1-4 | 1 | 3 | 3 |
aDays when all pollutants are in the lowest quartile.
bTerminal nodes represent different types of days that can be described in terms of the pollutant quartiles.
cEach day is in one and only one terminal node; the column sums to 4010.
dP-values are associated with the null hypothesis that the risk ratio for the pollutant indicator is 1.0.