“Ticking Bomb”: The Impact of Climate Change on the Incidence of Lyme Disease
Table 3
The impact of climatic variables by income per capita and before vs. after 2008.
Heterogeneity
Dep. var.: LD incidence
<PCI median
≥PCI median
<2008
≥2008
(1)
(2)
(3)
(4)
Avg. temp.: below 5°C
9.8421 (7.2752)
6.5755 (8.5056)
−0.0423 (4.9830)
−6.0330 (6.8374)
Avg. temp.: 5–7°C
16.1789 (6.1200)
12.2321 (7.7779)
5.9658 (3.9566)
3.3523 (5.7814)
Avg. temp.: 7–9°C
20.0468 (7.2075)
12.3422 (7.5295)
6.7271 (3.9568)
2.3292 (4.9421)
Avg. temp.: 9–11°C
17.6905 (6.2141)
15.5235 (7.2675)
5.3618 (2.5961)
6.0453 (4.2411)
Avg. temp.: 11–13°C
7.5071 (3.0650)
8.2686 (5.6081)
2.7109 (1.8782)
−0.6243 (2.5552)
Avg. temp.: 13–15°C
6.1809 (2.3800)
5.3997 (3.3455)
2.7591 (1.2852)
−0.8361 (2.2234)
Reference: above 15°C
0
0
0
0
Total prcp.: below 70 cm
1.8066 (7.2816)
11.1090 (7.5837)
−5.7405 (5.5240)
−2.8211 (7.2106)
Total prcp.: 70–120 cm
0.0188 (6.8925)
9.6526 (6.5876)
−6.3607 (5.3531)
−3.5179 (6.2751)
Total prcp.: 120–170 cm
1.7949 (6.0951)
8.7628 (5.8681)
−2.0996 (4.7471)
−5.4875 (5.2265)
Total prcp.: 170–220 cm
−0.4551 (4.4063)
8.0211 (4.4954)
−3.3351 (4.2346)
−5.8981 (3.8901)
Total prcp.: 220–270 cm
−2.3741 (3.0281)
6.2257 (3.8928)
−1.5489 (2.9620)
−4.7632 (3.4002)
Reference: above 270 cm
0
0
0
0
Year fixed effects
Yes
Yes
Yes
Yes
County fixed effects
Yes
Yes
Yes
Yes
Linear trend by state
Yes
Yes
Yes
Yes
Quadratic trend by state
Yes
Yes
Yes
Yes
Observations
3,978
3,978
3,744
4,212
R2
0.7804
0.7658
0.8565
0.8237
Adjusted R2
0.750
0.738
0.830
0.795
Note: this table presents the estimated impacts of climatic variables on the incidence of LD—cases per 100,000 population—by counties above and below the U.S. per capita income (PCI), and by cases before and after 2008, when probable cases of LD were included in the total number of cases in each county. Avg. temp. is annual average temperature, and total prcp. is annual total precipitation. Robust standard errors clustered at the county level are reported in parentheses. Significance at 1 percent; significance at 5 percent; significance at 10 percent.
