| Correlations between hospitalised incidence of serious asthma and, respectively, social deprivation and air pollutants at LSOA level across Wales# | ||
| Unadjusted correlation¶ | Adjusted correlation+ | |
| Social deprivation component (2005)§ | ||
| Income | 0.45 (<0.001) | 0.45 (<0.001) |
| Employment | 0.44 (<0.001) | 0.46 (<0.001) |
| Education | 0.40 (<0.001) | 0.39 (<0.001) |
| Health | 0.34 (<0.001) | 0.31 (<0.001) |
| Housing | 0.15 (<0.001) | 0.26 (<0.001) |
| Physical environment | 0.14 (<0.001) | 0.11 (<0.001) |
| Access to services | -0.28 (<0.001) | -0.30 (<0.001) |
| Overall | 0.45 (<0.001) | 0.45 (<0.001) |
| Air pollutant (annual mean, 2007)ƒ | ||
| Particulate matter <10.0 μm·m−3 in diameter | 0.18 (<0.001) | 0.13 (<0.001) |
| Particulate matter <2.5 μm·m−3 in diameter | 0.18 (<0.001) | 0.13 (<0.001) |
| Benzene | 0.17 (<0.001) | 0.10 (<0.001) |
| Carbon monoxide | 0.16 (<0.001) | 0.10 (<0.001) |
| Nitrogen dioxide | 0.14 (<0.001) | 0.11 (<0.001) |
| Nitric oxide | 0.13 (<0.001) | 0.10 (<0.001) |
| Sulfur dioxide | 0.12 (<0.001) | 0.08 (<0.001) |
| Ozone | 0.005 (0.839) | -0.03 (0.237) |
| Correlations between monthly means of air pollutants at measurement sites and the monthly hospitalised incidence of serious asthma to hospitals in the local authority corresponding to the measurement site | ||
| Median correlation across sites | ||
| Air pollutant (monthly means from 1999–2007) | ||
| Particulate matter <10.0 μm·m−3 in diameter | -0.01 (-0.10–0.11) | |
| Particulate matter <2.5 μm·m−3 in diameter | -0.04 (-0.16–0.08) | |
| Benzene | 0.08 (0.05–0.11) | |
| Carbon monoxide | 0.25 (0.11–0.30) | |
| Nitrogen dioxide | 0.30 (0.17–0.36) | |
| Nitric oxide | 0.22 (0.09–0.33) | |
| Sulfur dioxide | 0.16 (0.08–0.23) | |
| Ozone | -0.05 (-0.22–0.02) | |
Data are presented with p-values or interquartile ranges in parentheses. #: correlations between the hospitalised incidence of serious asthma and, respectively, social deprivation and air pollutants are based on 1,896 lower super output areas (LSOAs) across Wales (mean population 1,560 people per LSOA). ¶: excluding infants and older people (aged ≥85 yrs) made little differences to these findings. Correlations for the deprivation components were, in order of listing: 0.45, 0.45, 0.42, 0.35, 0.16, 0.15, -0.28, 0.45; and for the air pollutants they were: 0.17, 0.18, 0.18, 0.17, 0.15, 0.14, 0.12, 0.030, -0.004. +: adjusted correlations between hospitalised incidence of serious asthma and air pollutants are adjusted for social deprivation (overall). Adjusted correlations between the hospitalised incidence of serious asthma and social deprivation are adjusted for the eight air pollutants. §: correlations at the LSOA level between social deprivation (overall) and the eight air pollutants (annual mean, 2007) were as follows: particulate matter <10.0 μm·m−3 (correlation 0.14); particulate matter <2.5 μm·m−3 (0.15); benzene (0.19); carbon monoxide (0.16); nitrogen dioxide (0.11); nitric oxide (0.10); sulfur dioxide (0.11); ozone (0.07); all p<0.001. ƒ: the geographical measurement of these air pollutants (to 1 km2) was taken from 2007 as this was the best available study year, in terms of the interpolation methodology used and the number of air pollution sites used to measure each air pollutant. The annual mean for sulfur dioxide was in 2005 rather than in 2007. The 1-km2 measures were then averaged over the corresponding LSOA.