Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

Volume 23, Number 11—November 2017

Research

Weather-Dependent Risk for Legionnaires’ Disease, United States

Jacob E. Simmering, Linnea A. Polgreen, Douglas B. Hornick, Daniel K. Sewell, and Philip M. PolgreenComments to Author 
Author affiliations: The University of Iowa, Iowa City, Iowa, USA

Main Article

Table 4

Effects of humidity and temperature on Legionnaires’ disease risk, United States, 1998–2011*

Variable Odds ratio 95% CI
Age, y
18–30 1.00 Ref
31–40 2.60 2.30–2.95
41–50 2.23 2.87–3.62
51–60 3.22 2.88–3.61
61–70 2.29 2.04–2.57
71–80 1.74 1.54–1.96
81–90 1.37 1.21–1.55
>91
0.78
0.66–0.93
Race/ethnicity
White 1.00 Ref
Black 1.37 1.31–1.44
Hispanic 1.05 0.96–1.13
Other
1.00
0.93–1.10
Payer
Medicare 1.00 Ref
Medicaid 0.87 0.81–0.93
Private 2.43 2.32–2.53
Uninsured 1.86 1.71–2.03
Other
1.65
1.48–1.83
Sex
M 1.00 Ref
F
0.75
0.73–0.78
Hospital admission mo
Jan 1.00 Ref
Feb 0.85 0.77–0.94
Mar 0.74 0.67–0.82
Apr 0.91 0.82–1.00
May 1.10 0.99–1.23
1.35–1.71
Jun 1.52
Jul 2.24 1.99–2.52
Aug 2.49 2.21–2.80
Sep 2.35 2.10–2.64
Oct 2.58 2.37–2.80
Nov 1.63 1.49–1.79
Dec
1.14
1.04–1.25
Year
1.06
1.06–1.07
Hospital latitude, °N
Latitude 3.06 2.67–3.50
Latitude squared
0.99
0.99–0.99
Total monthly rainfall†
Dry 1.00 Ref
Normal 1.36 1.29–1.44
Wet
1.47
1.38–1.57
Mean monthly temperature, °F
<60 1.00 Ref
60–80 0.55 0.44–0.68
>80
1.57
1.24–1.98
Mean RH, %
0–50.0 1.00 Ref
50.1–55.0 0.85 0.68–1.06
55.1–60.0 0.58 0.48–0.70
60.1–65.0 0.66 0.56–0.78
65.1–70.0 0.79 0.67–0.93
70.1–75.0 0.80 0.68–0.94
75.1–80.0 0.76 0.64–0.90
80.1–100.0
0.65
0.53–0.78
Interactions
Temperature 60°–80°F
RH <50% 1.0 Ref
RH 50.1%–55.0% 1.65 1.19–2.28
RH 55.1%–60.0% 1.54 1.13–2.09
RH 60.1%–65.0% 2.15 1.68–2.75
RH 65.1%–70.0% 2.27 1.83–2.83
RH 70.1%–75.0% 2.93 2.36–3.64
RH 75.1%–80.0% 3.27 2.62–4.08
RH 80.1%–100.0% 4.79 3.71–6.17
Temperatures >80°F
RH <50% 1.0 Ref
RH 50.1%–55.0% 0.00
RH 55.1%–60.0% 0.00
RH 60.1%–65.0% 1.23 0.77–1.95
RH 65.1%–70.0% 0.62 0.42–0.91
RH 70.1%–75.0% 0.38 0.24–0.60
RH 75.1%–80.0% 0.91 0.54–1.54
RH 80.1%–100.0% 0.00

*Based on a multivariable logit model with a diagnosis of Legionnaires’ disease as the outcome variable. The analysis comprised data from 26 states: Arizona, Arkansas, California, Colorado, Connecticut, Illinois, Iowa, Kentucky, Maryland, Massachusetts, Mississippi, Missouri, Montana, Nevada, New Hampshire, New Jersey, New York, North Carolina, Oregon, Pennsylvania, Rhode Island, Utah, Vermont, Virginia, Washington, Wisconsin. Dash indicates 95% CIs not defined because there were no data for cases or controls in that particular strata.
†Dry, <18 mm; normal, 18–85.85 mm; wet, >85.85 mm.

Main Article

TOP