Table 11.
ORs and 95% CIs for one additional previous day on which the observed HI was above the indicated threshold in Anchorage, Fairbanks, and the Matanuska-Susitna Valley, Alaska, 2015–2019.
| Reason for ED visit | Number of cases | 21.1°C (70°F) HI threshold | 22.2°C (72°F) HI threshold | 23.3°C (74°F) HI threshold | 24.4°C (76°F) HI threshold | 25.6°C (78°F) HI threshold | 26.7°C (80°F) HI threshold | 27.8°C (82°F) HI threshold | 28.9°C (84°F) HI threshold | 30°C (86°F) HI threshold |
|---|---|---|---|---|---|---|---|---|---|---|
| Heat illness | 35 | 1.05 (0.98, 1.11) | 1.07 (0.98, 1.17) | 1.08 (0.98, 1.20) | 1.20 (0.95, 1.51) | 1.18 (0.91, 1.53) | 1.31 (0.89, 1.92) | 1.17 (0.39, 3.54) | 3.56 (1.06, 11.92)a | — |
| Asthma | 2,911 | 1.01 (0.99, 1.02) | 1.01 (0.99, 1.02) | 1.01 (0.99, 1.03) | 1.00 (0.97, 1.03) | 1.01 (0.97, 1.05) | 1.04 (0.98, 1.10) | 1.04 (0.92, 1.17) | 1.04 (0.77, 1.41) | 0.74 (0.27, 2.04) |
| COPD | 2,158 | 0.99 (0.98, 1.01) | 0.98 (0.97, 1.00) | 0.98 (0.96, 1.00) | 0.97 (0.93, 1.01) | 0.93 (0.88, 0.99)a | 0.89 (0.81, 0.97)a | 0.88 (0.74, 1.05) | 0.88 (0.60, 1.30) | 1.24 (0.44, 3.48) |
| Pneumonia | 2,081 | 1.00 (0.99, 1.01) | 0.99 (0.97, 1.01) | 1.00 (0.97, 1.02) | 1.01 (0.97, 1.05) | 1.03 (0.97, 1.08) | 1.05 (0.98, 1.13) | 1.10 (0.96, 1.25) | 1.25 (0.93, 1.68) | 0.78 (0.19, 3.27) |
| Bronchitis | 1,972 | 0.99 (0.97, 1.00) | 0.97 (0.95, 0.99)a | 0.96 (0.93, 0.98)a | 0.94 (0.90, 0.99)a | 0.95 (0.89, 1.01) | 0.91 (0.83, 1.00)a | 0.92 (0.78, 1.09) | 0.95 (0.66, 1.35) | 0.89 (0.32, 2.46) |
| Arrhythmia | 1,617 | 1.00 (0.99, 1.02) | 1.01 (0.99, 1.03) | 1.00 (0.97, 1.02) | 1.00 (0.96, 1.05) | 1.02 (0.97, 1.08) | 1.00 (0.93, 1.09) | 1.03 (0.88, 1.20) | 0.98 (0.64, 1.50) | 2.30 (0.79, 6.71) |
| Cerebrovascular | 434 | 0.98 (0.95, 1.01) | 0.98 (0.94, 1.03) | 0.99 (0.94, 1.04) | 0.99 (0.91, 1.09) | 0.98 (0.88, 1.10) | 0.96 (0.81, 1.14) | 0.73 (0.48, 1.11) | 0.20 (0.03, 1.31) | — |
| Ischemia | 200 | 1.04 (1.00, 1.08) | 1.06 (1.01, 1.12)a | 1.05 (0.98, 1.11) | 1.03 (0.92, 1.16) | 1.09 (0.94, 1.25) | 1.15 (0.98, 1.36) | 1.12 (0.79, 1.60) | 1.93 (0.92, 4.07) | 4.89 (0.95, 25.32) |
| Myocardial | 81 | 1.07 (1.01, 1.14)a | 1.08 (1.00, 1.18) | 1.09 (0.98, 1.20) | 0.98 (0.81, 1.17) | 1.03 (0.83, 1.28) | 1.11 (0.88, 1.41) | 1.15 (0.70, 1.90) | 1.17 (0.25, 5.59) | — |
| Heart failure | 441 | 1.00 (0.97, 1.03) | 1.01 (0.96, 1.05) | 1.00 (0.95, 1.05) | 0.97 (0.88, 1.07) | 1.01 (0.89, 1.14) | 0.97 (0.82, 1.15) | 0.99 (0.72, 1.37) | 0.45 (0.12, 1.64) | 1.89 (0.41, 8.57) |
Note: For the ongoing heat wave analysis, the results of which are reported in this table, the effect of prolonged elevated HI was estimated via a linear variable in the model that represented the number of previous consecutive days on which the observed HI was above the relevant threshold. An indicator variable was also included to control for same-day elevated HI. As with the threshold analysis, a value of “1” indicated that the same-day HI was above the relevant threshold, and a value of “0” indicated that the same-day HI was below the relevant threshold. Conditional logistic regression models adjusted for daily concentration were used to estimate ORs. —, no data; CI, confidence interval; COPD, chronic obstructive pulmonary disease; HI, heat index; OR, odds ratio.
95% CI does not include the null.