Table 2.
Subgroup Analysis by Asthma and Country Examining the Relationship Between PM2.5 and PEF in Children
| Subgroups | Estimate (n) | Included Studies | Change in PEF per 10μg/m3 of PM2.5 (95% CI) | P value | I2 | P value for Heterogeneity |
|---|---|---|---|---|---|---|
| Asthma | ||||||
| Severe Asthma group | 2 | Lu Ma/2008,22 Yamazak /201124 | −3.11 L/min (−4.54, −1.67) | <0.001 | 0% | 0.775 |
| Health group | 4 | Dandan Xu/2018,28 Liu Weiyan/ 2019,10 Yang Xiaoyan/2020,11 WU Xingbin/202030 | −1.61 L/min (−2.34, −0.91) | <0.001 | 0% | 0.634 |
| Country | ||||||
| China | 5 | Dandan Xu/2020,29 Dandan Xu/2018,28 Liu Weiyan/ 2019,10 Yang Xiaoyan/2020,11 WU Xingbin/202030 | −1.54 L/min (−2.33, −0.75) | <0.001 | 53.6% | 0.071 |
| Japan | 3 | Masanari/2016,27 Yamazak /2011,24 Lu Ma/200822 | −2.65 L/min (−3.82, −1.48) | <0.001 | 0% | 0.525 |
| Brazil | 2 | Ludmilla/2012,25 Ludmilla/201426 | −0.38 L/min (−0.91, 0.15) | 0.162 | 0% | 0.659 |
Abbreviations: PEF, peak expiratory flow; CI, confidence interval.