Effects of changing risk factors on increasing asthma prevalence in southern Taiwan

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

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 (PM₁₀) (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

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Lagged Influence of Fine Particulate Matter and Geographic Disparities on Clinic Visits for Children's Asthma in Taiwan

Recent studies have revealed the influence of fine particulate matter (PM_2.5) on increased medication use, hospital admission, and emergency room visits for asthma attack in children, but the lagged influence of PM_2.5 on children’s asthma and geographic disparities of children’s asthma have rarely been discussed simultaneously. This study investigated the documented diagnosis of children’s asthma in clinic visits for children aged less than 15 years old that were associated with PM_2.5 in two counties located in west-central Taiwan during 2005–2010. The result shows that PM_2.5 had a significant lagged effect on children’s asthma for up to 6 days. A significantly higher relative risk for children’s asthma was more likely to happen at 2-day lag compared to the present day when PM_2.5 increased from 36.17 μg/m³ to 81.26 μg/m³. Considering all lagged effects, the highest relative risk for children’s asthma was 1.08 (95% CI = 1.05, 1.11) as PM_2.5 increased as high as 64.66 μg/m³. In addition, geographic disparities of children’s asthma were significant, and 47.83% of areas were identified to have children vulnerable to asthma. To sum up, our findings can serve as a valuable reference for the implementation of an early warning to governmental agencies about a susceptible population of children.

Interaction of intercellular adhesion molecule 1 (ICAM1) polymorphisms and environmental tobacco smoke on childhood asthma

Asthma is a chronic disease that is particularly common in children. The association between polymorphisms of the gene encoding intercellular adhesion molecule 1 (ICAM1) and gene-environment interactions with childhood asthma has not been fully investigated. A cross-sectional study was undertaken to investigate these associations among children in Taiwan. The effects of two functional single-nucleotide polymorphisms (SNPs) of ICAM1, rs5491 (K56M) and rs5498 (K469E), and exposure to environmental tobacco smoke (ETS) were studied. Two hundred and eighteen asthmatic and 877 nonasthmatic children were recruited from elementary schools. It was found that the genetic effect of each SNP was modified by the other SNP and by exposure to ETS. The risk of asthma was higher for children carrying the rs5491 AT or TT genotypes and the rs5498 GG genotype (odds ratio = 1.68, 95% confidence interval 1.09–2.59) than for those with the rs5491 AA and rs5498 AA or AG genotypes (the reference group). The risk for the other two combinations of genotypes did not differ significantly from that of the reference group (p of interaction = 0.0063). The two studied ICAM1 SNPs were associated with childhood asthma among children exposed to ETS, but not among those without ETS exposure (p of interaction = 0.05 and 0.01 for rs5491 and rs5498, respectively). Both ICAM1 and ETS, and interactions between these two factors are likely to be involved in the development of asthma in childhood.

Feeding bottles usage and the prevalence of childhood allergy and asthma

This study aimed to examine the association between the length of use of feeding bottles or pacifiers during childhood and the prevalence of respiratory and allergic morbidities. A large-scale questionnaire survey was performed in day care centers and kindergartens (with children's ages ranging from 2 to 7 years) in southern Taiwan, and a total of 14,862 questionnaires completed by parents were finally recruited for data analysis. Effects of using feeding bottles on children's wheezing/asthma (adjusted OR: 1.05, 95% CI 1.00–1.09), allergic rhinitis (adjusted OR: 1.04, 95% CI 1.00–1.08), and eczema (adjusted OR: 1.07, 95% CI 1.01–1.2) were found. Moreover, significant dose-dependent relationships were further established after an adjustment for confounders was performed that included children's ages, gender, gestational age, birth weight, length of breastfeeding, the age when first given infant formula or complementary foods, family history, parental educational levels, and smoking status, as well as the problem of indoor water damage. This study was the first to reveal the potential risk of using plastic consumer products such as feeding bottles on the reported health status of preschool children in Asian countries.

Paternal heredity and housing characteristics affect childhood asthma and allergy morbidity

A birth cohort was initiated when each pregnant woman was asked for her own and her husband's history of asthma and allergic diseases at the time of recruitment. They were further inquired to verify their housing conditions, and current health status of children 3 to 5 years old at the time of interview. Paternal history was the most significant risk factor associated with reporting childhood morbidities at age of 3 to 5 years. Housing characteristics became meaningful variables only if the fathers were asthmatic or atopic. A 9-fold increase of risk was found if children with paternal history and also exposed to incense burning and water damage at home. This is the first epidemiological evidence of East Asia suggesting paternal heredity, with concurrent indoor hazardous exposures, as a predominant risk on developing childhood asthma and allergy.

Expression status of ribonucleotide reductase small subunits hRRM2/p53R2 as prognostic biomarkers in stage I and II non-small cell lung cancer

Overexpression of ribonucleotide reductase M2 (hRRM2) and p53-dependent RR small subunit (p53R2) has been correlated with tumor malignancy and progression in several types of cancer. The aim of this study was to determine the association of p53R2/hRRM2 expression with clinicopathological characteristics of stage I and II non-small cell lung cancer (NSCLC). Immunohistochemistry was conducted on a tissue array that included 92 samples. Correlations between hRRM2 and p53R2 expression and clinicopathological factors, recurrence/metastasis, and outcomes were analyzed. The analyses revealed that there was no correlation between p53R2 expression and clinicopathological factors; hRRM2 was only positively related to poor tumor differentiation (p=0.006). Regarding overall survival during the follow-up period, patients with p53R2+/hRRM2- tumors had the best outcomes (p<0.01). Multivariant Cox analysis revealed that p53R2 (risk=0.232, 95% CI=0.086-0.626, p=0.004) not only served as a prognostic biomarker to predict survival, but also as an independent biomarker to predict disease-free survival (risk=0.545, 95% CI=0.301-0.987, p=0.045) of patients with NSCLC. Therefore, we consider that the expression of p53R2 can be used not only as a biomarker for overall survival, but also as an indicator for tumor recurrence. Based on our finding, p53R2 expression seems more important than that of hRRM2 in prognosis of early-stage lung cancer.

Antenatal steroid treatment reduces childhood asthma risk in very low birth weight infants without bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) and very low birth weight (VLBW) are associated with increased incidences of asthma and pulmonary dysfunction in childhood. However, no studies exist which examine asthma risk factors in children who were VLBW infants and did not have BPD. To address this issue, we assessed the asthma incidence and risk factors for asthma in 117 children (approximate mean age of 5 years) who were VLBW [<1500 g, mean gestational age (GA): 30 weeks] infants without BPD. The risk factors were both perinatal (such as steroid treatment, mechanical ventilation, surfactant treatment) and environmental (parental smoking, pet adoption, etc). The asthma incidence was 18.8%. Following multivariate analysis, it was determined that a family history of atopy was a strong risk factor for childhood asthma. Maternal antenatal steroid treatment was associated with a significantly reduced risk for asthma. GA and birth weight were not predictive of childhood asthma. These findings indicate that a history of familial atopy and antenatal steroid treatment are positively and negatively associated (independent of BPD) with childhood asthma in VLBW infants. The finding regarding antenatal steroid treatment warrants more extensive investigations.

Prevalence of allergic diseases of schoolchildren in central taiwan. From ISAAC surveys 5 years apart

The prevalence of allergic disorders is increasing around the world. This study used the standardized written questionnaire from International Study of Asthma and Allergies in Childhood (ISAAC, phase III) to collect two cross-sectional appraisals of schoolchildren 5 years apart-one performed 2002 and another on 2007, to focus on the secular trends in prevalence of allergies in central Taiwan. This questionnaire was administered to schoolchildren from over 46 schools across Changhwa County in 2002, and again in 2007. The present study is a follow-up study and uses data collected from a previously reported study conducted in the year 2002 of the same location using the same methodology. Although the repeated cross-sectional survey after a 5-year lapse suggests a mere increase of diagnosed asthma cases from 7.1% to 7.4%, the prevalence of its related symptoms--nocturnal cough, rhinitis, and eczema--was found to increase significantly by 2.6% (p < 0.0001), 6.8% (p < 0.001), and 5.9% (p < 0.001), respectively. Additionally, comparing the secular trends in asthma prevalence, rhinitis, and eczema between several polluted areas in Changhwa County with its less polluted neighbors in 2002 and 2007 indicates that schoolchildren in TaiHao area, which is noted to be polluted by a petrochemical company, has a significantly increased prevalence of wheezing (3.7%, p < 0.05) and nocturnal cough (3.6%, p < 0.05). For schoolchildren living in the coastal areas, a 6% (p < 0.05) increase in the prevalence of rhinitis is noted. The prevalence of eczema uniformly increased for all areas of Changhwa County (p < 0.01). In the downtown areas, besides eczema, the prevalence of asthma and rhinitis also increased significantly (p < 0.05). Of note is the consistent finding in these two periods of the higher prevalence of childhood asthma, rhinitis, and eczema in the downtown areas compared with that from both the polluted and coastal areas. The secular trends in prevalence of asthma, rhinitis, and eczema in these two periods seem to correlate to environmental factors. While the symptoms of asthma, rhinitis, and eczema in schoolchildren affected boys more than girls, it is observed that affected girls have more marked manifestations, although it did not reach statistical significance.

Spatiotemporal analysis of air pollution and asthma patient visits in Taipei, Taiwan

Background

Buffer analyses have shown that air pollution is associated with an increased incidence of asthma, but little is known about how air pollutants affect health outside a defined buffer. The aim of this study was to better understand how air pollutants affect asthma patient visits in a metropolitan area. The study used an integrated spatial and temporal approach that included the Kriging method and the Generalized Additive Model (GAM).

Results

We analyzed daily outpatient and emergency visit data from the Taiwan Bureau of National Health Insurance and air pollution data from the Taiwan Environmental Protection Administration during 2000–2002. In general, children (aged 0–15 years) had the highest number of total asthma visits. Seasonal changes of PM₁₀, NO₂, O₃ and SO₂ were evident. However, SO₂ showed a positive correlation with the dew point (r = 0.17, p < 0.01) and temperature (r = 0.22, p < 0.01). Among the four pollutants studied, the elevation of NO₂ concentration had the highest impact on asthma outpatient visits on the day that a 10% increase of concentration caused the asthma outpatient visit rate to increase by 0.30% (95% CI: 0.16%~0.45%) in the four pollutant model. For emergency visits, the elevation of PM₁₀ concentration, which occurred two days before the visits, had the most significant influence on this type of patient visit with an increase of 0.14% (95% CI: 0.01%~0.28%) in the four pollutants model. The impact on the emergency visit rate was non-significant two days following exposure to the other three air pollutants.

Conclusion

This preliminary study demonstrates the feasibility of an integrated spatial and temporal approach to assess the impact of air pollution on asthma patient visits. The results of this study provide a better understanding of the correlation of air pollution with asthma patient visits and demonstrate that NO₂ and PM₁₀ might have a positive impact on outpatient and emergency settings respectively. Future research is required to validate robust spatiotemporal patterns and trends.

The association of BMI and sedentary time with respiratory symptoms and asthma in 5th grade schoolchildren in Kaohsiung, Taiwan

This study aimed to evaluate the association of body fatness and sedentary status with asthma and respiratory symptoms in schoolchildren in Kaohsiung, Taiwan. A questionnaire study elicited episodes of respiratory symptoms and data on lifestyle and anthropometric parameters in 1329 5th grade schoolchildren. Results showed that 12.4% of boys and 9.5% of girls had physician-diagnosed asthma, whereas 15.1% of boys and 12.4% of girls had suspected asthma. Significantly greater proportions of boys had non-exercise-induced respiratory symptoms than girls (p < 0.05). The number of respiratory symptoms was positively correlated with TV-watching time per day and self-reported sedentary time per weekend-day in girls (p < 0.05). Underweight was positively associated with one of the seven respiratory symptoms in girls (p < 0.05). At risk of overweight was positively associated with two of the seven respiratory symptoms in boys and one of the seven respiratory symptoms in girls (all p < 0.05). The risk of having physician-diagnosed asthma and suspected asthma increased 93% and 72%, respectively, in schoolchildren at risk of overweight (p < 0.05). Overweight was associated with a 78% increase in physician-diagnosed asthma (adjusted odd ratio (aOR) = 1.78, 95% CI = 1.08-2.91, p < 0.05). Higher sedentary time was significantly associated with more occurrences of one of the seven respiratory symptoms in girls (aOR = 1.05, 95% CI = 1.00-1.11, p < 0.05). Higher body mass index (BMI) was significantly correlated with longer TV-watching time per day in girls and longer self-reported sedentary time per weekday in boys (p < 0.05). In summary, schoolchildren who are at risk of overweight or overweight and/or have more sedentary time have increased risk of respiratory symptoms and asthma. Weight and sedentary statuses of schoolchildren can affect their respiratory health.

Prevalence of childhood allergic diseases in central Taiwan over the past 15 years

BACKGROUND

The prevalence of asthma, allergic rhinitis and atopic eczema in children from the developed and developing countries has been increasing.

METHODS

Three epidemiological surveys of the prevalence of bronchial asthma, allergic rhinitis and atopic eczema in schoolchildren in Taichung, located in central Taiwan, were conducted in 1987, 1994, and 2002. The first questionnaire was used before the International Study of Asthma and Allergies in Childhood (ISAAC) written questionnaire was developed; the last two surveys were modified using ISAAC questionnaires.

RESULTS

A total of 37,801, 75,960, and 11,580 children were studied in 1987, 1994 and 2002, respectively. The prevalence of allergic diseases had increased in the past two decades. Results indicate that the prevalence of bronchial asthma had risen, from 2.19% in 1987, and 3.54% in 1994, to 6.99% in 2002. Regardless of sex, the prevalence of bronchial asthma decreased with increasing age. The prevalence of allergic rhinitis was 5.1% in 1987, 12.46% in 1987, and 27.59% in 2002, and the prevalence of atopic eczema was 1.10% in 1987, 1.88% in 1994, and 3.35% in 2002.

CONCLUSION

There has been a significant increase in the prevalence of bronchial asthma, allergic rhinitis and atopic dermatitis in Taichung schoolchildren from 1987 to 2002.

Exercise behavior in asthmatic children: effects of a summer camp fitness program in Taiwan

This quasi experimental study aimed to examine the effects of a swimming-focused summer camp program on self-efficacy and exercise behavioral change in schoolchildren with asthma and their parental support. Forty-one asthmatic schoolchildren were recruited from a medical center and an asthma education association in southern Taiwan. The participants in the summer camp program were assigned to the experimental group; the control group comprised those who did not attend the summer camp program. Each child was paired with a parent. A total of 16 child-parent pairs in the experimental group and 25 pairs in the control group were followed-up. This 1.5-day asthma summer camp program included 20 minutes of health education in physical activity, two sessions of swimming practice for the children, and a 2-hour conference with the parents. The outcome measures included an Exercise Self-Efficacy Questionnaire, Stages of Exercise Behavior Change Questionnaire, and a Parental Support for Exercise Questionnaire. Before implementing the program, the two groups differed significantly in terms of the severity of their asthma, as well as their pre-camp test scores of exercise self-efficacy. Therefore, asthma severity levels and scores from the pre-camp exercise self-efficacy test were selected as two ANCOVA covariates. The adjusted means for stages of exercise behavior change on the 2-month post-camp test were significantly different between the two groups, F(1, 37) = 5.88 and p = 0.02. Compared with the control group, subjects who attended the summer camp reported more regular exercise behavior at the 2-month post-camp test. Thus, a summer camp program with swimming instruction can enhance the exercise behavior of schoolchildren with asthma. This program is highly recommended for managing schoolchildren with asthma.

Time trend of asthma prevalence among school children in Taiwan. [corrected]

The standardized International Study of Asthma and Allergies in Childhood (ISAAC) is a valid tool in assessing prevalence of asthma indices. In order to determine the time trends of childhood asthma in Taiwan, we compared data from nationwide ISAAC surveys from a very large sample of Taiwanese 12- to 15-year-old school children, using ISAAC core written and video questionnaires. The number of participants was 44,104 in 1995-96 (phase I) and 11,048 in 2001 (phase III). We found a general tendency towards an increase in lifetime prevalence of physician-diagnosed asthma and asthma symptoms between two surveys, more marked for girls than for boys. Most of the 12-month prevalence of asthma symptoms decreased among boys but stabilized among girls. When comparing different severity levels, we also noted that the decreasing trends of current symptoms were more marked with regard to severe symptoms than mild symptoms in both sexes. A combination of both improved awareness and management of asthma might in part explain this circumstance. Over the past decade in Taiwan, the lifetime prevalence of childhood asthma was increasing, more marked among girls; however, the 12-month prevalence of asthma symptoms was decreasing, mostly among boys. The exact reasons for such trends remain to be explored.

Seasonality in pediatric asthma admissions: the role of climate and environmental factors

BACKGROUND

Population-based data from Taiwan are used to examine seasonality in pediatric asthma admissions (proxy for asthma exacerbations) and associations with air pollutants and climatic factors. Monthly admission rates per 100,000 population, classified into three age groups, 0 approximately 2, 2 approximately 5, and 6 approximately 14 years (calculated from a total of 27,275 hospitalizations during 1998-2001) were subjected to autoregressive integrated moving average (ARIMA) modeling to examine seasonality. Spearman rank correlations were used to examine associations with criterion air pollutants (PM(10), SO(2), CO, O(3), NO(2)) and meteorological factors (ambient temperature, relative humidity, atmospheric pressure, rainfall, and sunshine hours).

RESULTS

Both seasonality and associations with air pollutants and climate factors vary by age group. Among under-twos, the rates are lowest in January-February and highest in November, with a trough in June-July. Among preschoolers, the rates are lowest in June-July and highest in November, with two upsurges in August and March. Among school-goers, admission rates are lowest during June-August, with upsurges in March and September. The number of weather and pollutant predictors increases with age. Among under-twos, only two factors, PM(10) and rainfall, significantly predict admissions. For preschoolers, five factors (PM(10), CO, O(3), temperature, and pressure), and for school-goers, all air pollutants except NO(2,) and all climatic factors except rainfall are significant.

CONCLUSION

Seasonality in pediatric asthma admissions vary by age in a subtropical island setting.

Risk factors for respiratory symptoms and asthma in the residential environment of 5th grade schoolchildren in Taipei, Taiwan

This study examined the association of residential environmental factors with respiratory symptoms and asthma in 2,290 fifth graders in Taipei, Taiwan. A self-report survey questionnaire elicited experiences of respiratory symptoms, disease history, and characteristics of residential environmental factors from schoolchildren. The proportion of schoolchildren having physician-diagnosed asthma was 9.8% and suspected asthma was 16.1%. The proportions of having respiratory symptoms in the past 12 months ranged from 9.8% for wheezing without a cold to 40.5% for exercise-induced cough. Higher proportions of boys had non-exercise-induced respiratory symptoms, physician-diagnosed asthma, and suspected asthma than girls (p < 0.05). Exposure to odoriferous chemical vapor was significantly associated with all seven respiratory symptoms considered in the study (p < 0.05). After adjusting for confounding factors including residential districts, gender, diagnosed allergy, and parental history of respiratory symptoms, odoriferous chemical vapors, gas leaks, dehumidifier use, presence of cockroaches at home, and leaky water/water puddle at home were significantly associated with the proportions of physician-diagnosed asthma or suspected asthma of the schoolchildren. The adjusted odds ratio (aOR) of physician-diagnosed asthma was 2.35 (95% confidential interval = 1.45-3.82) for odoriferous chemical vapor. The aOR of suspected asthma measure was 2.14 (95% CI = 1.40-3.26) for odoriferous chemical vapor. Odoriferous chemical vapor was the major risk factor of respiratory illness in the residential environment of schoolchildren in Taipei. Other household risk factors included gas leaks, dampness, and cockroaches at home.

Length of stay and costs for asthma patients by hospital characteristics--a five-year population-based analysis

This study sets out to explore the relationship between hospital characteristics, asthma length of stay (LOS), and costs per discharge. The study adopts hospitalization data from the Taiwan National Health Insurance Research Database covering the period from 1997 to 2001. Study subjects were identified from the database by principal diagnosis of asthma or asthmatic bronchitis, with a total of 139,630 cases being included in the study. Multiple-regression analyses were performed to explore the relationship between LOS, costs per discharge and hospital characteristics, adjusting for age, gender, and discharge status of patients, as well as complications or comorbidities. The regression analyses showed that, compared with district hospitals, medical centers and regional hospitals have longer and more statistically significant LOS, as well as higher costs. Hospitals operating on a for-profit basis have shorter LOS and lower costs than public and not-for-profit hospitals. This study shows the existence of wide variations in LOS and costs per discharge for asthma hospitalizations, between the various types of hospitals in Taiwan.

Are maternal psychosocial factors associated with cord immunoglobulin E in addition to family atopic history and mother immunoglobulin E?

BACKGROUND

Atopy in maternal and family histories is known to be a risk factor for elevated umbilical cord immunoglobulin E (cIgE). However, the association between cIgE and psychosocial factors remains under investigation.

OBJECTIVE

To explore whether psychosocial factors in addition to atopy contribute to elevated cIgE.

METHODS

Four private maternity hospitals fitting the quantile levels of SO(2) in 2000 cooperated with us by recruiting participants for this study: pairs of mothers and neonates living within 3-km catchment areas of air-monitoring stations. We used a questionnaire to collect exposure data, and the Pharmacia UniCap IgE assay test system to determine the levels of IgE in gravidas and cord blood.

RESULTS

Between July 2001 and March 2003, 334 mother and neonate pairs participated in this study. The frequencies of sensitization, serum IgE (sIgE)>100 IU/mL, or cIgE> or =0.35 IU/mL were not different between the four different hospitals. By multi-variate logistic regression analysis adjusted for environmental factors, genetic factors, and psychosocial factors, the risk factors for elevated cIgE were being a male neonate (odds ratio (OR)=3.5, 95% confidence interval (CI)=[1.5, 8.5]), carpets at home (OR=3.0, 95% CI=[1.02, 8.4]), maternal allergy to dog dander (OR=9.7, 95% CI=[1.2, 98.8], maternal total serum IgE>100 IU/mL (OR=5.1, 95% CI=[2.2, 12.8]), maternal regularly/mostly/often self-reported nervousness (OR=4.0, 95% CI=[1.3, 12.8]), family income 11,574-17 361 US dollars/year (OR=3.7, 95% CI=[1.3, 11.5]), incense burning (OR=4.0, 95% CI=[1.4, 13.3]), and atopy in maternal grandparents (OR=4.8, 95% CI=[1.7, 14.0]). By principle component analysis and logistic regression, psychosocial stress (beta +/- standard error=0.26+/-0.13, P=0.04) was associated with increased cIgE.

CONCLUSION

Psychosocial factors are potentially important risk factors for elevated cIgE.