Table 2.
Association between eczema prevalence and mean relative humidity, issued UV index, annual temperature, heating degree days (HDD) and precipitation.
| Quartile (min, max) | Eczema Frequency |
Eczema Prevalence (95% CI) |
OR* (95% CI) |
P-value | Adjusted OR** (95% CI) |
P-value |
|---|---|---|---|---|---|---|
| Mean relative humidity (%)# | ||||||
| 1st (24.3, 62.8) | 2572 | 13.6 (12.7 14.5) |
1.00 | – | 1.00 | – |
| 2nd (63.0, 66.9) | 2528 | 14.7 (13.7, 15.6) |
1.09 (0.98, 1.22) |
0.10 | 1.08 (0.97, 1.21) |
0.15 |
| 3rd (67.0, 69.5) | 2556 | 13.5 (12.6, 14.4) |
1.00 (0.89, 1.11) |
0.93 | 1.00 (0.90, 1.12) |
0.97 |
| 4th (69.7, 74.3) | 2350 | 11.2 (9.9, 12.4) |
0.80 (0.69, 0.93) |
0.003 | 0.82 (0.71, 0.96) | 0.01 |
| Issued UV index## | ||||||
| 1st (1.8 – 4.1) | 2959 | 14.0 (13.1 – 15.0) |
1.00 | – | 1.00 | – |
| 2nd (4.1 – 4.6) | 2854 | 13.3 (12.5 – 14.1) |
0.94 (0.84 – 1.04) |
0.24 | 0.92 (0.83 – 1.03) |
0.13 |
| 3rd (4.7 – 5.7) | 2720 | 12.4 (11.7 – 13.1) |
0.87 (0.78 – 0.96) |
0.006 | 0.83 (0.75 – 0.92) |
0.0006 |
| 4th (5.9 – 9.2) | 2797 | 10.8 (9.8 – 11.7) |
0.74 (0.65 – 0.84) |
<0.0001 | 0.73 (0.64 – 0.84) |
<0.0001 |
| Annual mean temperature (deg F)### | ||||||
| 1st (42.7 – 47.2) | 2384 | 14.8 (13.5, 16.0) |
1.00 | – | 1.00 | – |
| 2nd (47.2 – 53.3) | 2482 | 13.8 (12.9, 14.7) |
0.93 (0.82, 1.05) |
0.23 | 0.95 (0.84, 1.07) |
0.40 |
| 3rd (53.4 – 57.5) | 2430 | 11.5 (10.4, 12.7) |
0.76 (0.65, 0.87) |
0.0002 | 0.75 (0.65, 0.88) |
0.0002 |
| 4th (59.2 – 72.9) | 2397 | 12.9 (11.9, 13.9) |
0.85 (0.75, 0.98) |
0.02 | 0.80 (0.70, 0.92) |
0.002 |
| Mean annual HDD#### | ||||||
| 1st (51.2 – 290.3) | 2397 | 12.9 (11.9, 13.9) |
1.00 | – | 1.00 | – |
| 2nd (297.1 – 427.3) | 2430 | 11.5 (10.4 12.7) |
0.88 (0.76, 1.02) |
0.09 | 0.94 (0.81, 1.09) |
0.41 |
| 3rd (431.6 – 562.2) | 2615 | 14.7 (13.8, 15.7) |
1.17 (1.04, 1.31) |
0.01 | 1.26 (1.11, 1.43) |
0.0003 |
| 4th (571.3 – 707.1) | 2251 | 13.1 (12.1, 14.2) |
1.02 (0.90, 1.17) |
0.72 | 1.11 (0.97, 1.27) |
0.14 |
| Mean annual precipitation (in)##### | ||||||
| 1st (0.6 – 2.3) | 2111 | 10.2 (8.6 – 11.8) |
1.00 | – | 1.00 | – |
| 2nd (2.3 – 3.5) | 2376 | 13.1 (12.2, 14.1) |
1.33 (1.11 – 1.60) |
0.002 | 1.22 (1.01 – 1.47) |
0.03 |
| 3rd (3.5 – 3.8) | 2360 | 14.3 (13.4, 15.3) |
1.47 (1.22 – 1.76) |
< 0.0001 | 1.34 (1.11 – 1.62) |
0.002 |
| 4th (3.9 – 4.5) | 2406 | 13.6 (12.8, 14.4) |
1.39 (1.16 – 1.66) |
0.0003 | 1.29 (1.07 – 1.54) |
0.007 |
Annual statewide mean values of relative humidity (%) for 2006 – 2007 were downloaded from National Oceanic & Atmospheric Administration (NOAA), National Climate Data Center (NCDC) at http://www7.ncdc.noaa.gov/CDO/dataproduct. Relative humidity is a measure of water vapor in the air that is dependent on both the air temperature and pressure.
Monthly statewide mean values of issued UV indices for 2006 – 2007 were downloaded from the NOAA, National Weather Service, Climate Prediction Center at ftp://ftp.cpc.ncep.noaa.gov/long/uv/cities. The issued UV index accounts for the cloud effects on UV transmission. N.B. There were no states with extreme issued UV indices (≥ 11) during the time period of 2006 – 2007.
Annual statewide mean values of “time-bias” corrected temperatures (Degrees Fahrenheit to 10ths) for 2006–2007 were downloaded from the NOAA, NCDC at ftp://ftp.ncdc.noaa.gov/pub/data/cirs/.
Annual statewide mean HDD for 2006 – 2007 were downloaded from the NOAA, NCDC at ftp://ftp.ncdc.noaa.gov/pub/data/cirs/. HDD is a statewide population-weighted measure of energy demand to heat indoor structures by one degree for one day using a baseline temperature of 65 degrees Fahrenheit. HDD are calculated as the sum of differences between the average daily temperature and a base of 65 deg Fahrenheit averaged over the span of 12 months.
Monthly statewide mean values of “time-bias” corrected annual precipitation (in) for 2006 – 2007 were downloaded from the NOAA, NCDC at ftp://ftp.ncdc.noaa.gov/pub/data/cirs/.
Univariate logistic regression models were constructed with eczema (yes/no) modeled as the dependent variable and relative humidity, issued UV index, mean annual temperature, HDD and precipitation values as independent variables.
Multivariate logistic regression models were constructed with eczema (yes/no) modeled as the dependent variable and relative humidity values, issued UV index, mean annual temperature, HDD and precipitation as independent variables, including age (continuous), race/ethnicity (African-American, Hispanic, Caucasian, or Multi/Other), sex (male or female), household income (0–99%, 100–199%, 200–399%, 400+% of poverty level).