Decreasing ten-year (2008–2018) trends of the prevalence of childhood asthma and air pollution in Southern Taiwan

Abstract

Background Asthma is a common pediatric chronic respiratory disease worldwide. Previous studies showed the prevalence of childhood asthma increased in developed countries as well as in Taiwan in the late 20th century. Recently, several reports from different parts of the world showed a reversed trend in this epidemic of childhood asthma prevalence. This study investigated the trend of childhood asthma through serial cross-section questionnaire surveys in the southern part of Taiwan, and identified associated factors related to this trend in elementary school children. Methods We used the Chinese version of the International Study of Asthma and Allergies in Childhood (ISAAC) 29 questionnaire to assess the asthma status of elementary school students aged 6–12 years in Tainan city in 3 independent study periods, namely, 2008–2009, 2010–2012, and 2017–2018. We assessed the trend of “asthma” and “related respiratory symptoms” across 3 study periods. Results Of the 19,633 respondents, 17,545 (89.4%) completed the questionnaires. After adjustment for covariates, the prevalence of asthma and related respiratory symptoms was significantly lower in 2017–2018 than in the 2 earlier periods. Among the protective factors, the increasing rate of breastfeeding might be partly responsible for the observed reduced prevalence of current asthma and exercise-induced wheeze, but not physician-diagnosed asthma. The presence of pets in the house was the risk factor that correlated with the prevalence of nocturnal cough. Pearson correlation analysis showed a significant correlation of the prevalence of physician-diagnosed asthma, current asthma, and exercise-induced wheezing with the concentrations of air pollutant particles with aerodynamic diameter ≤10 μM (PM 10 ) (r = 0.84, 0.77 and 0.81, respectively). Conclusion The prevalence of asthma and related respiratory symptoms has declined in elementary school-age children in southern Taiwan. The increased prevalence of breastfeeding, decreased rate of the presence of pets in the house, and improvement in outdoor air pollution seem to be related to this decreasing trend of asthma in school children. Our findings will provide the scientific base to empower prevention policy to reverse the trend of childhood asthma prevalence. Trial registration N/A

Asthma, rhinitis and eczema symptoms in Quito, Ecuador: a comparative cross-sectional study 16 years after ISAAC

“…19 Similarly, a study conducted in southern Taiwan showed a decline in the prevalence of asthma symptoms as doctor diagnosis, exercise-induced wheeze and nocturnal cough. 20 However, contrary to our results, many studies suggest a continued increase in asthma prevalence, especially in LMICs. 21 In Ecuador, several studies conducted in different cities have estimated the prevalence of asthma and other RAD.…”

Trends (2007–2019) of major atopic diseases throughout the life span in a large Mexican population

“…In the last few years, a number of reports from several countries have evaluated the time trends of major atopic diseases by analyzing at least 3 different time-points. 36 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 As can be seen in the Supplementary Fig. 4 , in general terms their results are in agreement with ours in the sense that the frequency of these diseases appear to be decreasing in recent years.…”

Can air handling equipment be beneficial to children’s health? Results from a cross-sectional survey in 2010 and 2019 in China

“…Compared with the 2010 survey, the prevalence of children’s respiratory diseases in the 2019 survey was decreased (shown in Table 3 and Figure 1), especially in urban areas, consistent with some other studies. 43,44 Boys and children with a family history of allergies have a higher prevalence. The prevalence of children’s respiratory diseases and allergic diseases in Shanghai is generally higher.…”