3.1. Distribution and correlation of childhood allergic diseases and environ-mental factors
Table 1 provides a 2023 summary of childhood allergic diseases, meteorological factors, and air pollutants from 1 January to 27 February 2015. Daily mean values for atopic dermatitis (AD) , allergic rhinitis dermatitis (AR) , and asthma were 20,5, and 3, respectively. The average daily temperature, air pressure, relative humidity and wind speed was 17.3 °C, 1016.3 hPa, 72.6% and 2.1 m/s, respectively. The average value of AQI, PM2.5, PM10, SO2, NO2, CO and O3 was 65.9, 41.5 μg/m3, 70.9 μg/m3, 12.3 μg/m3, 38.8 μg/m3, 0.9 μg/m3 and 65.1 μg/m3, respectively.
Table 1
Daily clinical visits for childhood allergic diseases, meteorological factors and air pollutants from 1 January 2015 to 27 February 2023.
Variables
|
Mean
|
Min
|
P25
|
P50
|
P75
|
Max
|
IQR
|
AD
|
20
|
0
|
9
|
20
|
29
|
60
|
20
|
AR
|
5
|
0
|
1
|
4
|
7
|
44
|
6
|
Asthma
|
3
|
0
|
1
|
3
|
5
|
20
|
4
|
Air pollutants (μg/m3)
|
|
|
|
|
|
|
|
AQI
|
65.9
|
12
|
44
|
59
|
79
|
285
|
35
|
PM2.5
|
41.5
|
4
|
23
|
34
|
52
|
235
|
29
|
PM10
|
70.9
|
7
|
43
|
61
|
89
|
315
|
46
|
SO2
|
12.3
|
3
|
7
|
10
|
15
|
79
|
8
|
NO2
|
38.8
|
5
|
26
|
35.5
|
49
|
127
|
23
|
CO
|
0.9
|
0.3
|
0.7
|
0.8
|
1
|
2.6
|
0.4
|
O3
|
65.1
|
3
|
41
|
62
|
85
|
189
|
44
|
Meteorological factors
|
|
|
|
|
|
|
|
Temperature (°C)
|
17.3
|
-6.1
|
9.3
|
17.7
|
25.1
|
36.3
|
15.8
|
Air pressure (hPa)
|
1016.3
|
988.3
|
1008.1
|
1016.6
|
1023.6
|
1041
|
15.5
|
Relative humidity (%)
|
72.6
|
27
|
63
|
73
|
82
|
100
|
19
|
Wind speed (m/s)
|
2.1
|
0.1
|
1.5
|
2
|
2.6
|
6.7
|
1.1
|
AD: atopic dermatitis;AR: allergic rhinitis;Min: minimum; Max: Maximum;P25, 25th centile; P50, 50th centile; P75, 75th centile;IQR: interquartile range.
Table 2 presents the correlation between environmental factors and allergic diseases in children for the period 2015-2023. The Spearman correlation coefficients of the three allergic diseases were as follows: -0.082 for AD and AR, 0.218 for Asthma and AD, and 0.269 for AR and Asthma. The results indicate that AD was positively correlated with PM2.5, PM10, SO2, NO2, CO, O3, and temperature, while it was negatively correlated with pressure. The study found that asthma showed a positive correlation with daily mean air temperature and NO2, while AR showed a negative correlation with PM2.5, PM10, SO2, NO2, CO, pressure, and humidity. On the other hand, AR showed a positive correlation with O3 and temperature. The study found a strong negative correlation (rs =-0.890,p <0.01) between the daily mean air pressure and the daily mean temperature. Additionally, pollutants such as NO2, SO2, PM10, and PM2.5 showed positive correlations with each other, while O3 showed a negative correlation with other pollutants.
Table 2
Spearman correlations between environmental factors and childhood allergic diseases during 2015–2023.
rs ≥ 0.7was considered as high correlation; Bold values are statistically significant (p <0.05).
AR: allergic rhinitis; AD: atopic dermatitis; Temperature: daily mean temperature; Press: daily mean air pressure. Humid: relative humidity; Wind: wind speed;
3.2. Relationships between environmental factors and childhood allergic diseases
Fig.2 show the overall exposure-response relationships of various environmental factors, including wind speed, daily mean temperature, relative humidity, daily mean air pressure, NO2, and O3, with asthma, allergic rhinitis (AR), and atopic dermatitis (AD)by using Poisson regression with distributed lag non-linear model. The study found that there was a linear correlation between environmental factors and daily outpatient visits for Asthma, AD, and AR within a particular threshold range. The different environmental factors had slightly different curve shapes. Specifically, low wind speed, low relative humidity, and high levels of NO2 and O3 were found to increase clinical visits for asthma in children. The study reveals that when the mean temperature was below 18°C, the outpatient risk increased linearly with the increase in temperature. However, there was a noticeable decrease in outpatient visits once the temperature reached 18°C. Furthermore, the study also found that asthma risk was positively associated with lower air pressure levels below 1017hpa. However, this trend decreased significantly once the air pressure reached 1017hpa. The clinical visit rate of children with AD was found to be increased by low wind speed, relative humidity, and high mean temperature, with O3 being identified as a contributing factor. Similarly, children with AR were found to have an increased clinical visit rate in the presence of low wind speed, low relative humidity, and high concentrations of CO, O3, and PM2.5.
3.3. Multivariate GLM results for the relative impact of different environ-mental exposures on childhood allergic diseases
Table 3 This study examines the relationship between environmental factors and allergic diseases in children using a multivariate GLM. The results show that NO2 and O3 were positively correlated with all three allergic diseases, while daily relative humidity was negatively correlated with AR and AD. However, asthma was positively correlated with relative humidity. The study also found that the St_β value of daily average air temperature (0.017 (95% CI: 0.013, 0.021)) and the St_β value of average air pressure (-0.009 (95% CI: -0.012, -0.006)) had a greater impact on AR in children than other environmental factors. Overall, the findings suggest that environmental factors play a significant role in the development of allergic diseases in children.
Table 3
Multivariate GLM results for the relationships between environmental factors and childhood allergic diseases after adjustment for confounders.
Data were presented with St_β and 95% confidence interval; St_β: standard regression coefficient;
temperature, humid, wind, NO2, O3, long-term trends, seasonal trends, the day of week effects were controlled in model 1, model 3, model 5; press, humid, wind, NO2, O3, long-term trends, seasonal trends, the day of week effects were controlled in model 2, model 4, model 6; Bold means statistical significant (p <0.05).