Exposure to air pollution and scarlet fever resurgence in China: a six-year surveillance study

Yonghong Liu,Zhi Yu,Enfu Chen,Ta‐Chien Chan ,Yīmíng Bào ,Yuan Li,Wei Xu ,Tzong-Shyan Lin ,Shuwen Qin,Hui Ding,Shu‐Ting Chang ,Ran Lu,Supen Wang,Yu Zhao,Li-Wei Yap ,Minyi Wang,Hui Zhong,Na Zhao,Xin Geng ,Shelan Liu

doi:10.1038/s41467-020-17987-8

Abstract

Scarlet fever has resurged in China starting in 2011, and the environment is one of the potential reasons. Nationwide data on 655,039 scarlet fever cases and six air pollutants were retrieved. Exposure risks were evaluated by multivariate distributed lag nonlinear models and a meta-regression model. We show that the average incidence in 2011–2018 was twice that in 2004–2010 [RR = 2.30 (4.40 vs. 1.91), 95% CI: 2.29–2.31; p < 0.001] and generally lower in the summer and winter holiday (p = 0.005). A low to moderate correlation was seen between scarlet fever and monthly NO2 (r = 0.21) and O3 (r = 0.11). A 10 μg/m3 increase of NO2 and O3 was significantly associated with scarlet fever, with a cumulative RR of 1.06 (95% CI: 1.02–1.10) and 1.04 (95% CI: 1.01–1.07), respectively, at a lag of 0 to 15 months. In conclusion, long-term exposure to ambient NO2 and O3 may be associated with an increased risk of scarlet fever incidence, but direct causality is not established.

Highlights

Scarlet fever has resurged in China starting in 2011, and the environment is one of the potential reasons
We found that the cumulative risks at lag 0–15 months of long-term exposure to ambient NO2 were associated with scarlet fever incidence, and found that high O3, low mean temperature, and low wind speed were associated with an increase in scarlet fever incidence (Fig. 7)
NO2 and O3 are significantly associated with scarlet fever incidence (NO2: with reference to 40 μg/m3; O3: with reference to 160 μg/m3) with a cumulative relative risk (RR) of 1.06 and 1.04, respectively, at a lag of 0−15 months by the multiplevariables model (Supplementary Table 3)

Summary

Results

AThere were a number of missing values in the following variables: mean temperature: 3, relative humidity: 3, air pressure: 3, precipitation: 26, wind speed: 3, and sunlight: 63. We found that the cumulative risks at lag 0–15 months of long-term exposure to ambient NO2 were associated with scarlet fever incidence, and found that high O3, low mean temperature, and low wind speed were associated with an increase in scarlet fever incidence (Fig. 7). NO2 and O3 are significantly associated with scarlet fever incidence (NO2: with reference to 40 μg/m3; O3: with reference to 160 μg/m3) with a cumulative RR of 1.06 (95% CI: 1.02–1.10) and 1.04 (95% CI: 1.01–1.07), respectively, at a lag of 0−15 months by the multiplevariables model (Supplementary Table 3). The predicted exposure–response relationship in terms of relative risk between precipitation, wind speed, and sunlight had no significant difference before and after 2011 (Supplementary Fig. 10a–c)

Discussion

Methods

Code availability