Factors associated with difference in prevalence of asthma in children from three cities in China: multicentre epidemiological survey

Children's food allergy: Effects of environmental influences and antibiotic use across critical developmental windows

BACKGROUND

Increasing studies linked outdoor air pollution (OAP), indoor environmental factors (IEFs), and antibiotics use (AU) with the first wave of allergies (i.e., asthma, allergic rhinitis, and eczema), yet the role of their exposures on children's second wave of allergy (i.e., food allergy) are unknown.

OBJECTIVES

To investigate the association between exposure to OAP and IEFs and childhood doctor-diagnosed food allergy (DFA) during the pre-pregnancy, prenatal, early postnatal, and current periods, and to further explore the effect of OAP and IEFs on DFA in children co-exposed to antibiotics.

METHODS

A retrospective cohort study involving 8689 preschoolers was carried out in Changsha, China. Data on the health outcomes, antibiotic use, and home environment of each child were collected through a questionnaire. Temperature and air pollutants data were obtained from 8 and 10 monitoring stations in Changsha, respectively. Exposure levels to temperature and air pollutants at individual home addresses were calculated by the inverse distance weighted (IDW) method. Multiple logistic regression models were employed to assess the associations of childhood DFA with exposure to OAP, IEF, and AU.

RESULTS

Childhood ever doctor-diagnosed food allergy (DFA) was linked to postnatal PM10 exposure with OR (95% CI) of 1.18 (1.03-1.36), especially for CO and O3 exposure during the first year with ORs (95% CI) = 1.08 (1.00-1.16) and 1.07 (1.00-1.14), as well as SO2 exposure during the previous year with OR (95% CI) of 1.13 (1.02-1.25). The role of postnatal air pollution is more important for the risk of egg, milk and other food allergies. Renovation-related IAP (new furniture) and dampness-related indoor allergens exposures throughout all time windows significantly increased the risk of childhood DFA, with ORs ranging from 1.23 (1.03-1.46) to 1.54 (1.29-1.83). Furthermore, smoke-related IAP (environmental tobacco smoke [ETS], parental and grandparental smoking) exposure during pregnancy, first year, and previous year was related to DFA. Additionally, exposure to pet-related indoor allergens (cats) during first year and total plant-related allergens (particularly nonflowering plants) during previous year were associated with DFA. Moreover, exposure to plant-related allergy during first and previous year was specifically associated with milk allergy, while keeping cats during first year increased the risk of fruits/vegetables allergy. Life-time and early-life AU was associated with the increased risk of childhood DFA with ORs (95% CI) = 1.57 (1.32-1.87) and 1.46 (1.27-1.67), including different types food allergies except fruit/vegetable allergy.

CONCLUSIONS

Postnatal OAP, life-time and early-life IEFs and AU exposure played a vital role in the development of DFA, supporting the "fetal origin of childhood FA" hypothesis.

Greater fruit and vegetables consumption, and adherence to a Mediterranean type of diet reduces the risk for asthma in children; a systematic review and meta-analysis

The objective of this study was to explore the relationship between the consumption of fruits, vegetables and adherence to the Mediterranean diet with childhood asthma development and severity. A systematic literature search and synthesis of the results was performed throughout the last two decades. A total of 45 studies were analysed and 392,797 children were included. Greater adherence to a Mediterranean type of diet was inversely associated with asthmatic outcomes (OR:0.71,95% CI:0.54,0.88). Regarding fruits, vegetables consumption, a significant inverse association between increased fruits or vegetable intake and asthma was found (OR:0.82,95% CI:0.77,0.86; 0.84,95% CI:0.77,0.91, respectively). Fruits and vegetables consumption combined was also inversely related to all asthmatic outcomes (OR:0.65,95% CI:0.49,0.78). The level of heterogeneity was moderate-to-high (30%-97%). The present review and meta-analysis show a trend to an inverse association between adherence to the Mediterranean diet or a healthy diet rich in fruits and vegetables and the occurrence of childhood asthma but with a low level of certainty.

Gas cooking and respiratory outcomes in children: A systematic review

The most recent meta-analysis of gas cooking and respiratory outcomes in children was conducted by Lin et al. [93] in 2013. Since then, a number of epidemiology studies have been published on this topic. We conducted the first systematic review of this epidemiology literature that includes an in-depth evaluation of study heterogeneity and study quality, neither of which was systematically evaluated in earlier reviews. We reviewed a total of 66 relevant studies, including those in the Lin et al. [93] meta-analysis. Most of the studies are cross-sectional by design, precluding causal inference. Only a few are cohort studies that could establish temporality and they have largely reported null results. There is large variability across studies in terms of study region, age of children, gas cooking exposure definition, and asthma or wheeze outcome definition, precluding clear interpretations of meta-analysis estimates such as those reported in Lin et al. [93]. Further, our systematic study quality evaluation reveals that a large proportion of the studies to date are subject to multiple sources of bias and inaccuracy, primarily due to self-reported gas cooking exposure or respiratory outcomes, insufficient adjustment for key confounders (e.g., environmental tobacco smoke, family history of asthma or allergies, socioeconomic status or home environment), and unestablished temporality. We conclude that the epidemiology literature is limited by high heterogeneity and low study quality and, therefore, it does not provide sufficient evidence regarding causal relationships between gas cooking or indoor NO2 and asthma or wheeze. We caution against over-interpreting the quantitative evidence synthesis estimates from meta-analyses of these studies.

Associations between home environmental factors and childhood eczema and related symptoms in different cities in China

Previous studies have shown significant associations between home environmental factors and childhood eczema. However, few studies have compared how associations differ in different regions. This study investigated associations between home environmental factors and childhood eczema ever, and related symptoms including itchy rash (IR) and being awakened by itchy rash at night (awake by IR) in 4 cities located in different regions of China, based on cross-sectional investigations during 2010-2012. We used two-step analysis to explore the associations between influencing factors and eczema/related symptoms: first, group Least Absolute Shrinkage and Selection Operator (LASSO) was conducted to identify important factors among a list of candidates; then, the associations in total study population and in each city were estimated using logistic regression. We found these home environmental factors to be risk factors for eczema or related symptoms: large residence size, shared room, air cleaner at home, abnormal smell, perceived dry air, visible mold or damp stains, cooking with coal or wood, painted wall, incense, mice, new furniture during pregnancy, abnormal smell at birth, window condensation at birth and environmental tobacco smoke at birth. Environmental protective factors were rural house location and window ventilation. Associations of factors with eczema/related symptoms differed across cities. For example, air conditioning was protective for eczema in Beijing and awakening by IR in Shanghai with ORs of 0.70 (95%CI: 0.52, 0.95) and 0.33 (95%CI: 0.14, 0.81) respectively, but not significant in other cities. Our results have implications for improving home environments to reduce the risk of childhood eczema/related symptoms in different regions of China.

The Effects of a Healthy Diet on Asthma and Wheezing in Children and Adolescents: A Systematic Review and Meta-Analysis

Background

Asthma is a public health problem requiring focused attention. This study aimed to systematically evaluate the association between dietary structure and asthma or wheezing in children.

Methods

The study protocol of this meta-analysis has been registered in the International Prospective Register of Systematic Reviews (PROSPERO) with the registration code CRD42023390191. A total of 8397 articles were retrieved, searching PubMed, Medline, Embase, Web of Science, and Scopus databases as of November 21, 2022. Two independent authors were responsible for independently conducting the literature screening process. Effect-size estimates were expressed as odds ratio (OR) in cross-sectional studies and risk ratio (RR) in cohort studies with a 95% confidence interval (CI). Summary effect estimates were evaluated with random-effect models. Meanwhile, subgroup and sensitivity analyses were performed to assess the potential sources of heterogeneity and the robustness of the pooled estimation.

Results

A total of 65 studies, including 567,426 subjects had been analyzed. Overall analyses of cross-sectional studies revealed that a healthy diet was protective against asthma (adjusted OR=0.85, 95% CI: 0.80-0.89, P <0.001, I2=69.8%, Tau2=0.026) and wheezing (adjusted OR=0.85, 95% CI: 0.81-0.89, P <0.001, I2=66.8%, Tau2=0.015) in children and adolescents. Conversely, unhealthy diets can exacerbate asthma (adjusted OR=1.28, 95% CI: 1.20-1.36, P <0.001, I2=64.9%, Tau2=0.019) and wheeze (adjusted OR=1.09, 95% CI: 1.02-1.16, P =0.006, I2=75.2%, Tau2=0.023) in children and adolescents. The same trend was found in cohort studies (adjusted RR=0.72, 95% CI: 0.58-0.90, P =0.003, I2=83.5%, Tau2=0.105). A clear trend was observed between high-frequency healthy diets (OR=0.80; 95% CI: 0.71-0.89; P <0.001) is more protective against asthma than low-frequency healthy diets (OR=0.81; 95% CI: 0.70-0.94; P =0.007).

Conclusion

Our findings highlight the protective effects of a healthy diet on asthma and wheezing in children, including fruit, seafood, cereals, and the Mediterranean diet.

From Amish farm dust to bacterial lysates: The long and winding road to protection from allergic disease

Allergic diseases typically begin in early life and can impose a heavy burden on children and their families. Effective preventive measures are currently unavailable but may be ushered in by studies on the "farm effect", the strong protection from asthma and allergy found in children born and raised on traditional farms. Two decades of epidemiologic and immunologic research have demonstrated that this protection is provided by early and intense exposure to farm-associated microbes that target primarily innate immune pathways. Farm exposure also promotes timely maturation of the gut microbiome, which mediates a proportion of the protection conferred by the farm effect. Current research seeks to identify allergy-protective compounds from traditional farm environments, but standardization and regulation of such substances will likely prove challenging. On the other hand, studies in mouse models show that administration of standardized, pharmacological-grade lysates of human airway bacteria abrogates allergic lung inflammation by acting on multiple innate immune targets, including the airway epithelium/IL-33/ILC2 axis and dendritic cells whose Myd88/Trif-dependent tolerogenic reprogramming is sufficient for asthma protection in adoptive transfer models. To the extent that these bacterial lysates mimic the protective effects of natural exposure to microbe-rich environments, these agents might provide an effective tool for prevention of allergic disease.

Prevalence, Management, and Risk Factors of Asthma Among School-Age Children in Yogyakarta, Indonesia

Purpose

Childhood asthma in developing countries has been increasing, but underdiagnosed and undertreated. We reported prevalence, management, and risk factors of asthma among school-age children in Yogyakarta, Indonesia.

Patients and Methods

We recruited children aged 6-7 years and 13-14 years attending schools in all districts in Yogyakarta, Indonesia. The schools were randomly selected via cluster random sampling. We used the Indonesian version of the Global Asthma Network (GAN) questionnaire, and the methodology employed by this study was in accordance with the GAN's protocol.

Results

A total of 2106 children aged 6-7 years and 3142 adolescents aged 13-14 years were eligible for analysis. The prevalence of current wheeze in children and adolescents was similar, which was 4.6%. Inhalation therapy was reported in <30% of those with asthma. Risk factors for current wheeze in children were wheezing in infancy period, ever had pneumonia, the house was passed by trucks every day, and fast-food consumption in the previous 12 months; whereas exclusive breastfeeding for more than 6 months decreased the risk of current wheeze. In adolescence, obesity, consumption of fast food once or twice a week, and paracetamol in the previous 12 months increased the risk of current wheeze.

Conclusion

The prevalence of current wheeze in children and adolescents in Indonesia was quite low. The use of inhalation therapy was limited. Respiratory problems during infancy, environmental, and nutritional factors play a role in the development of asthma.

Characteristics of medicine use for children with asthma in China: a nationwide population-based study

OBJECTIVE

To analyze the asthma medication use in Chinese children of different age groups, regions, and levels of cities in China, based on the 2015 Healthcare Insurance Data in China.

METHODS

The China Healthcare Insurance Research Association (CHIRA) database was searched for children from 0 to 14 years old diagnosed as asthma based on the "J45" and "J46" coded in ICD-10. A cross-sectional study design was employed.

RESULTS

A total of 308,550 children were identified, all of whom were treated under the coverage of healthcare insurance. Among them, 2,468 children were eligible for inclusion in the present study. Compared with the current status of asthma care in European and American countries, under the guidelines for the diagnosis and treatment of asthma in China, the use percentages of ICS and short-acting β2 receptor agonist in children with asthma in China were lower, but the use percentages of oral corticosteroids, long-acting β2 receptor agonist, and theophylline (especially intravenous theophylline) were higher, especially in the Central and West China.

CONCLUSION

The asthma medication use was attributed to many factors, thus efforts are still needed to further popularize the GINA programs and China's guidelines for asthma diagnosis and treatment, especially in the Central and West China.

A review of critical residential buildings parameters and activities when investigating indoor air quality and pollutants

Indoor air in residential dwellings can contain a variety of chemicals, sometimes present at concentrations or in combinations which can have a negative impact on human health. Indoor Air Quality (IAQ) surveys are often required to characterize human exposure or to investigate IAQ concerns and complaints. Such surveys should include sufficient contextual information to elucidate sources, pathways, and the magnitude of exposures. The aim of this review was to investigate and describe the parameters that affect IAQ in residential dwellings: building location, layout, and ventilation, finishing materials, occupant activities, and occupant demography. About 180 peer-reviewed articles, published from 01/2013 to 09/2021 (plus some important earlier publications), were reviewed. The importance of the building parameters largely depends on the study objectives and whether the focus is on a specific pollutant or to assess health risk. When considering classical pollutants such as particulate matter (PM) or volatile organic compounds (VOCs), the building parameters can have a significant impact on IAQ, and detailed information of these parameters needs to be reported in each study. Research gaps and suggestions for the future studies together with recommendation of where measurements should be done are also provided.

Poultry exposure and environmental protection against asthma in rural children

BACKGROUND

Asthma is one of the most common chronic diseases in childhood, and the prevalence has been increasing over the past few decades. One of the most consistent epidemiological findings is that children living in a farming or rural environment are protected from development of asthma and allergies, but the protective factors in rural China are not clear.

METHODS

A community-based, cross-sectional epidemiological study was performed in a total of 17,587 children aged 5-8 years, 3435 from Hong Kong (urban) and 14,152 from Conghua (rural county in southern China). Asthma and allergic symptoms as well as environmental exposures were ascertained by using a standardized and validated questionnaire.

RESULTS

The prevalence of current wheeze was significantly lower in rural Conghua than that of urban Hong Kong (1.7% vs. 7.7%, p < 0.001). A lower rate of asthma ever was also reported in rural children compared with their urban counterparts (2.5% vs. 5.3%, p < 0.001). After adjusting for confounding factors, exposure to agricultural farming (adjusted odds ratio 0.74, 95% confidence interval: 0.56-0.97) and poultry (0.75, 0.59-0.96) were the most important factors associated with the asthma-protective effect in the rural area. Further propensity score-adjusted analysis indicated that such protection conferred by living in the rural environment was mainly attributable to poultry exposure.

CONCLUSIONS

We confirmed that the prevalence of asthma and atopic disorders was significantly lower in rural children when compared with their urban peers. Exposure to poultry and agricultural farming are the most important factors associated with asthma protection in the rural area.

The application of arterio-venous ratio (AVR) cut-off values in clinic to stratify cardiovascular risk in patients

INTRODUCTION

Cardiovascular risk calculators are a useful tool for identifying at-risk individuals. There are standardised methods for assessing the retinal microcirculation which alters as a consequence of cardiovascular disease (CVD). This study aimed to explore if a standardised retinal vessel assessment conducted in primary optometric care reflects current cardiovascular risk, as measured using two validated CVD risk calculators (QRISK 2; Mayo Clinic).

METHODS

A total of 120 subjects were included in the analyses. Following a routine eye examination, participants had disc-centred retinal photographs and systemic blood pressure taken. Retinal vessel parameters (central retinal artery and vein equivalent and arterio-venous ratio (AVR)) were calculated using semi-automated software. Participants were then grouped into AVR quintiles as defined by the Atherosclerosis Risk in Communities Study (ARIC). Cardiovascular risk was calculated with the validated QRISK and Mayo Clinic health calculators.

RESULTS

Systolic blood pressure was significantly greater in those with an AVR value falling in the lowest quintile compared to the highest quintile (150.65 mmHg vs. 132.21 mmHg [p = 0.001]). Similarly, CVD risk was significantly higher in those with the lowest AVR compared to the highest (QRISK: 14.28% vs. 9.87% [p = 0.05]; MAYO risk: 36.35% vs. 19.21% [p = 0.01]). Chi squared analyses showed a significant difference in the number of hypertensives in the lowest AVR quintile compared to those in the highest [p = 0.02].

CONCLUSION

Whilst the ARIC population is not directly comparable to the population used to develop the QRISK calculator, it has been shown that its application could help to identify at risk individuals using retinal vessel analyses.

A Multicenter Study Assessing Risk Factors and Aeroallergens Sensitization Characteristics in Children with Self-Reported Allergic Rhinitis in China

Background

Up to now, epidemiological studies on allergy rhinitis (AR) have primarily focused on determining the risk of disease in Chinese adults, with the majority of them designed by single centers, while cross-sectional and epidemiological data describing allergic sensitization in children with self-reported AR are scarce.

Objective

This study was estimating of the latest information about the sensitization patterns and risk factors of clinical AR to develop effective strategies for the prevention and treatment of AR.

Methods

We conducted a cross-sectional survey between January 2020 and June 2021 involving children from seven cities in China who reported AR. A total of 762 children participated in this survey. To evaluate the risk factors and specific sensitization patterns of clinical AR through questionnaires and specific immunoglobulin E to 11 aeroallergens.

Results

Of the 762 patients, 593 (77.8%) had at least one positive IgE level. Aged 7–14 years (OR 1.503, (95% CI 1.058–2.136), P = 0.023); With allergic conjunctivitis (OR 1.843, (95% CI 1.297–2.620), P = 0.001) and living in the Eastern (OR 1.802, (95% CI 1.263–2.573), P = 0.001) all elevated the risk of clinical AR associated with aeroallergens. The sensitization rates of D. pteronyssinus and D. farinae were higher than those of other allergens in the 0–6 and 7–14 years old age groups. The most common aeroallergens among self-reported children with AR in the eastern were D. farinae (74.9%) and D. pteronyssinus (74.3%), while in the western were mugwort (60.0%) and marguerite (56.6%). Majority of sIgE-positive subjects were sensitized to three or more of the tested pollen allergens in the Western (52.1%), compared with 5.7% in the Eastern.

Conclusion

There was an apparent geographic variation in childhood allergies in China. Age factors also had strong impacts on the allergen sensitization rate of children, but these impacts differed across regions.

Risk factors of asthma in the Asian population: a systematic review and meta-analysis

Background and objective

An increasing trend of asthma prevalence was observed in Asia; however, contributions of environmental and host-related risk factors to the development of this disease remain uncertain. This study aimed to perform a systematic review and meta-analysis for asthma-associated risk factors reported in Asia.

Methods

We systematically searched three public databases (Web of Science, PubMed, and Scopus) in Feb 2021. We only included articles that reported environmental and host-related risk factors associated with asthma in the Asian population. Random-effect meta-analyses were conducted for frequently reported asthma-associated risk factors to provide an overall risk estimate of asthma development.

Results

Of 4030 records obtained from public databases, 289 articles were selected for review. The most frequently reported asthma-associated risk factor was the family history of allergy-related conditions. The random-effect asthma risk estimates (pooled odds ratio, OR) were 4.66 (95% confidence interval (CI): 3.73–5.82) for the family history of asthma, 3.50 (95% CI: 2.62–4.67) for the family history of atopy, 3.57 (95% CI: 3.03–4.22) for the family history of any allergic diseases, 1.96 (95% CI: 1.47–2.61) for the family history of allergic rhinitis, and 2.75 (95% CI: 1.12–6.76) for the family history of atopic dermatitis. For housing-related factors, including the presence of mold, mold spots, mold odor, cockroach, water damage, and incense burning, the random-effect pooled OR ranged from 1.43 to 1.73. Other risk factors with significant pooled OR for asthma development included male gender (1.30, 95% CI: 1.23–1.38), cigarette smoke exposure (1.44, 95% CI: 1.30–1.60), cigarette smoking (1.66, 95% CI: 1.44–1.90), body mass index (BMI)–related parameters (pooled OR ranged from 1.06 to 2.02), various types of air pollution (NO₂, PM10, and O₃; pooled OR ranged from 1.03 to 1.22), and pre- and perinatal factors (low birth weight, preterm birth, and cesarean section; pooled OR ranged from 1.14 to 1.32).

Conclusions

The family history of asthma was the most frequently reported risk factor for asthma development in Asia with the highest risk estimate for asthma development. This suggests a major role of the genetic component in asthma pathogenesis. Further study on asthma genetics is required to improve the current understanding of asthma etiology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40101-021-00273-x.

The role of the environment in shaping the trends of childhood asthma - An Asian perspective

Asthma has now become one of the most common atopic disorders not only in developed countries but also in many developing countries. The etiology is likely due to a complex interaction between genetic and environmental factors. In many Asian countries, the prevalence of asthma has also been documented by validated instruments to be increasing rapidly over the past two decades. However, studies in rural areas in Asia with a traditional farming environment revealed markedly lower asthma prevalence when compared with residents in nearby cities despite having similar genetic background. Among the environmental factors implicated in the pathogenesis of asthma, air pollution, dietary patterns, viral infections, and early microbial exposure have been studied extensively around the world. Asia provides many opportunities to study these potential factors as there are many ethnic groups living in distinctly different environments. The understanding of the roles of these factors in affecting the early immune system and subsequent development of asthma will enable us to develop potential primary preventive strategies against a disease which affects millions worldwide.

Parental Education and the Association between Fruit and Vegetable Consumption and Asthma in Adolescents: The Greek Global Asthma Network (GAN) Study

BACKGROUND

Evidence suggests that nutritional factors, such as consumption of fruits and vegetables, along with socioeconomic factors such as parental education level, are associated with asthma prevalence. Our study examined the role of parental education in the association between fruit and vegetable consumption and adolescent asthma.

METHODS

1934 adolescents (mean age: 12.7 years, standard deviation: 0.6 years, boys: 47.5%) and their parents were voluntarily enrolled and completed a validated questionnaire assessing current asthma status, fruit and vegetable consumption and parental educational level. Participants were categorized as high or low intake for five food groups: fruits, cooked vegetables, raw vegetables, all vegetables (cooked and raw), and all three food groups together (fruits and all vegetables).

RESULTS

Adolescents who were high consumers of all three food groups (fruits, cooked and raw vegetables) were less likely to have asthma, adjusted for several confounders (adjusted odds ratio (aOR): 0.53, 95% confidence interval (CI): 0.25-0.97). Moreover, in adolescents who had parents with tertiary education and were in the high consumption of all three food groups, the inverse association was almost twofold higher than the one for adolescents with parents of primary/secondary education (aOR: 0.35, 95% CI: (0.21-0.89) and aOR: 0.61, 95% CI: (0.47-0.93) respectively).

CONCLUSIONS

Our findings highlight the importance of the adoption of a diet rich in fruits and vegetables for all asthmatic adolescents and emphasize the important role of parental influences in this association.

The economic burden of medical treatment of children with asthma in China

Background

At present, there are few studies on the economic burden and medical treatment of children with asthma in China. Thus this study aimed to investigate the economic burden of medical treatment of children with asthma in China.

Method

The 2015 China Medical Insurance Research Association (CHIRA) database was searched for patients with asthma from 0 to 14 years old. A cross-sectional study with cost analysis was conducted.

Results

The annual per capita direct medical cost was RMB 525 (US$75) related to asthma. Totaling 58% of the medical expenditure for asthma was covered by insurance in China, the majority of which were direct medical costs. Those that have the highest rates of using antibiotics were central China (100.0%), children aged 3 years and under (63.6%), as well as fourth-tier and fifth-tier cities (77.1%). Outpatient clinics (98.58% vs 1.42%, P < 0.01), tertiary hospitals (62.08% vs 37.92%, P < 0.01), and general hospitals (72.27% vs 27.73%, P < 0.01) were more often visited than the inpatient clinics, secondary and primary as well as the specialized clinics, respectively.

Conclusion

The economic burden of childhood asthma in China is relatively low, and the national medical insurance reduces their economic burden to a large extent. Abuse of antibiotics in treating asthma was found in China. There remain opportunities to strengthen the hierarchical medical system, reducing hospitalization and emergency visits, and ultimately reducing the economic burden of children with asthma.

Current challenges for shaping the sustainable and mold-free hygienic indoor environment in humid regions

Indoor mold grows ubiquitously in humid areas and can affect occupants' health. To prevent indoor mold contamination, one of the key measures suggested by the World Health Organisation and United States Environmental Protection Agency is to maintain an indoor relative humidity (RH) level below 75% or at 30-60%, respectively. However, in tropical and subtropical areas, maintaining these suggested RH levels is equivalent to operating a 24-h air-conditioner (AC) or dehumidifier, which is energy-consuming. As a large part of building expense, the operation time of ACs has been regularly proposed to be cut down because of the requirement of building sustainability. This leads to a trade-off between sustainable building performance and indoor mold hygiene. To balance this trade-off, more sustainable alternatives, such as those that target physical environments (e.g. nutrient and temperature level) or apply new surface coating technologies to inhibit mold growth, have been launched. Despite these initiatives, indoor mold contamination remains an unresolved issue, mainly because these alternative measures only exhibit limited effectiveness or require extra effort. This review aims to summarize the currently adopted mold control measures and discuss their limitations as well as the direction for the future development of sustainable mold control strategies. SIGNIFICANCE AND IMPACT OF THE STUDY: People spend most of their time indoors and hence the presence of indoor mold contamination can compromise the occupants' health. With the wake of climate change which is expected to see an increase in RH and temperature, tropical and subtropical areas are even more prone to mold contamination than they used to be. This study may help facilitate the development of sustainable and effective mold control strategies in the indoor environment.

Comparative Study of Food Allergies in Children from China, India, and Russia: The EuroPrevall-INCO Surveys

BACKGROUND

A clear understanding of the differences in the epidemiology of food allergy between rural and urban populations may provide insights into the causes of increasing prevalence of food allergy in the developed world.

OBJECTIVE

We used a standardized methodology to determine the prevalence and types of food-specific allergic sensitization and food allergies in schoolchildren from urban and rural regions of China, Russia, and India.

METHODS

The current study is a multicenter epidemiological survey of children recruited from 5 cities in China (Hong Kong and Guangzhou), Russia (Tomsk), and India (Bengaluru and Mysore) and 1 rural county in Southern China (Shaoguan). A total of 35,549 children aged 6 to 11 years from 3 countries participated in this survey. Random samples of children from 3 countries were first screened by the EuroPrevall screening questionnaire. Children with and without a history of adverse reactions to foods were then recruited for the subsequent case-control comparative studies. We determined the prevalence rates of food-specific IgE sensitization and food allergies using the predefined criteria.

RESULTS

The prevalence rates of food-specific IgE sensitization (≥0.7 kU/L) to at least 1 food were 16.6% in Hong Kong, 7.0% in Guangzhou, 16.8% in rural Shaoguan, 8.0% in Tomsk, and 19.1% in India. Using a definition of probable food allergy as reporting allergic symptoms within 2 hours of ingestion of a specific food plus the presence of allergic sensitization to the specific food (positive IgE and/or positive skin prick test result), the prevalence of food allergy was highest in Hong Kong (1.50%), intermediate in Russia (0.87%), and lowest in Guangzhou (0.21%), Shaoguan (0.69%), and India (0.14%). For children recruited from Hong Kong, both sensitization and food allergy were significantly higher in children who were born and raised in Hong Kong when compared with those who were born in mainland China and migrated to Hong Kong, highlighting the importance of early-life exposures in affecting the subsequent development of food sensitization and food allergy.

CONCLUSIONS

There are wide variations in the prevalence of food-specific IgE sensitization and food allergy in the 3 participating countries. Food allergy appears to be less common when compared with developed countries. The variations in the prevalence of food allergen sensitization cannot be explained by the differences in the degree of urbanization. Despite the high prevalence of food-specific IgE sensitization in India and rural China, food allergy is still extremely uncommon. In addition to IgE sensitization, other factors must play important roles resulting in the clinical manifestations of food allergies.

Can environment or allergy explain international variation in prevalence of wheeze in childhood?

Asthma prevalence in children varies substantially around the world, but the contribution of known risk factors to this international variation is uncertain. The International Study of Asthma and Allergies in Childhood (ISAAC) Phase Two studied 8-12 year old children in 30 centres worldwide with parent-completed symptom and risk factor questionnaires and aeroallergen skin prick testing. We used multilevel logistic regression modelling to investigate the effect of adjustment for individual and ecological risk factors on the between-centre variation in prevalence of recent wheeze. Adjustment for single individual-level risk factors changed the centre-level variation from a reduction of up to 8.4% (and 8.5% for atopy) to an increase of up to 6.8%. Modelling the 11 most influential environmental factors among all children simultaneously, the centre-level variation changed little overall (2.4% increase). Modelling only factors that decreased the variance, the 6 most influential factors (synthetic and feather quilt, mother's smoking, heating stoves, dampness and foam pillows) in combination resulted in a 21% reduction in variance. Ecological (centre-level) risk factors generally explained higher proportions of the variation than did individual risk factors. Single environmental factors and aeroallergen sensitisation measured at the individual (child) level did not explain much of the between-centre variation in wheeze prevalence.

Relationship between 25-hydroxyvitamin D levels and inflammatory factors in children with asthma attack

The level of 25-hydroxyvitamin D [25-(OH)D] associated with inflammatory factors in children during an asthma attack was investigated. In total, 60 child patients, who were admitted and treated in the Affiliated Children's Hospital of Xuzhou Medical University from March 2015 to March 2017, during their asthma attacks, were selected as the observation group. The patients were divided into the high 25-(OH)D (n=28) and low 25-(OH)D (n=32) groups according to the median level of 25-(OH)D. A total of 30 healthy children were selected as the control group. Biochemical indexes, humoral immunity, the level of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) contents as well as pulmonary function indexes were examined. The correlations in the levels of 25-(OH)D, IL-6 and TNF-α were also analysed. The results showed that the quantities of leukocytes, neutrophils and eosinophils of patients in the observation group were significantly increased compared with those in the control group (P<0.05). The contents of IL-6 and TNF-α in the observation group were obviously higher than those in the normal control group (P<0.05). The contents of serum IL-6 and TNF-α in the high 25-(OH)D group were lower than those in the low 25-(OH)D group 3 days after treatment (P<0.05). Moreover, the treatment effect in the high 25-(OH)D group was better than that in the low 25-(OH)D group (P<0.05). In addition, 25-(OH)D had a positive correlation with pulmonary function indexes (P<0.05), while TNF-α and IL-6 were negatively associated with pulmonary function indexes (P<0.05). The serum 25-(OH)D level in asthmatic children was negatively associated with the levels of inflammatory factors TNF-α and IL-6. The results showed that the level of 25-(OH)D was decreased in children with asthma attack, which is associated with the inflammatory mediators, IL-6 and TNF-α, as well as pulmonary functions (P<0.05). Therefore, the level of 25-(OH)D can be used as a test indicator for the prevention and control of childhood asthma.

Pediatric allergy and immunology in China

Over the past 30 years, China has enjoyed rapid economic development along with urbanization at a massive scale that the world has not experienced before. Such development has also been associated with a rapid rise in the prevalence of allergic disorders. Because of the large childhood population in the country, the burden of childhood allergic disorders has become one of the major challenges in the healthcare system. Among the Chinese centers participating in the International Study of Asthma and Allergies in Childhood, the data clearly showed a continuing rise in the prevalence of asthma, allergic rhinitis, and atopic eczema. However, the discipline of pediatric allergy in mainland China is still in its infancy due to the lack of formal training program and subspecialty certification. Clinicians and researchers are increasingly interested in providing better care for patients with allergies by establishing pediatric allergy centers in different regions of the country. Many of them have also participated in national or international collaborative projects hoping to answer the various research questions related to the discipline of pediatric allergy and immunology. It is our hope that the research findings from China will not only improve the quality of care of affected children within this country but also the millions of patients with allergies worldwide.

Quail egg homogenate alleviates food allergy induced eosinophilic esophagitis like disease through modulating PAR-2 transduction pathway in peanut sensitized mice

The present pharmacotherapy for eosinophilic esophagitis (EoE) fundamentally depend on inhaled corticosteroids. Despite the fact that oral intake of topical steroids can be successful in restricting EoE-related inflammation, there are concerns with respect to the long term utilization of steroids, especially in kids. In the current research, we assess the effect of quail egg, which is reportedly a known serine protease inhibitor, on symptomatology and immune responses in a peanut-sensitized mouse model of food allergy induced EoE. Daily oral treatment with quail egg attenuated mice symptomatology and immune response. Treatment with quail egg inhibited antigen-prompted increments in mouse tryptase and eosinophil cationic protein (ECP) in serum and eosinophil in inflamed tissues like oesophagus, lung, and digestive system. Quail egg treatment resulted in decreased antibody specific IgE and IgG1 and a variety of inflammatory genes that were abnormally expressed in EoE. Other effects included increased IL-10, decreased PAR-2 activation and NF-kB p65 in inflamed tissues. Our results suggest that quail egg treatment may have therapeutic potential in attenuating the symptoms of food allergy induced EoE like disease through regulating PAR-2 downstream pathway by blocking the activation of the transcription factor NF-kB p65 activity.

Effects of Fruit and Vegetable Consumption on Risk of Asthma, Wheezing and Immune Responses: A Systematic Review and Meta-Analysis

Evidence suggests that reduced intake of fruit and vegetables may play a critical role in the development of asthma and allergies. The present review aimed to summarize the evidence for the association between fruit and vegetable intake, risk of asthma/wheeze and immune responses. Databases including PubMed, Cochrane, CINAHL and EMBASE were searched up to June 2016. Studies that investigated the effects of fruit and vegetable intake on risk of asthma/wheeze and immune responses were considered eligible (n = 58). Studies used cross-sectional (n = 30), cohort (n = 13), case-control (n = 8) and experimental (n = 7) designs. Most of the studies (n = 30) reported beneficial associations of fruit and vegetable consumption with risk of asthma and/or respiratory function, while eight studies found no significant relationship. Some studies (n = 20) reported mixed results, as they found a negative association between fruit only or vegetable only, and asthma. In addition, the meta-analyses in both adults and children showed inverse associations between fruit intake and risk of prevalent wheeze and asthma severity (p < 0.05). Likewise, vegetable intake was negatively associated with risk of prevalent asthma (p < 0.05). Seven studies examined immune responses in relation to fruit and vegetable intake in asthma, with n = 6 showing a protective effect against either systemic or airway inflammation. Fruit and vegetable consumption appears to be protective against asthma.

The Danish urban-rural gradient of allergic sensitization and disease in adults

BACKGROUND

The reported prevalence of allergic sensitization among children is lower in rural areas than in urban areas of the world. The aim was to investigate the urban-rural differences of allergic sensitization to inhalant allergens in adults depending on childhood exposure living in an industrialized country as Denmark.

METHODS

A total of 1236 male participants of 30-40 years of age recruited from two epidemiological studies were divided into four groups with regard to place of upbringing; city, town, rural area and farm. Allergic sensitization was assessed by skin prick tests (SPTs) to 10 inhalant allergens and measurements of serum specific IgE (sIgE) to four inhalant allergens (grass, birch, cat and house dust mite).

RESULTS

The prevalence of allergic sensitization to inhalant allergens decreased with decreasing degree of urbanized childhood. The risk of being sensitized to one or more allergens also decreased with decreasing degree of urbanized upbringing measured by sIgE to 4 common allergens as odds ratio with 95% confidence intervals with city as reference; town 0.60 (0.39-0.92), rural area 0.34 (0.22-0.52) and farm 0.31 (0.21-0.46). Furthermore, it was measured by SPT to 10 common allergens; town 0.52 (0.33-0.84), rural area 0.34 (0.21-0.53) and farm 0.29 (0.19-0.45). This urban-rural association was also seen for the risk of sensitization to specific allergens, rhinitis and allergic asthma.

CONCLUSION

This is the first study to show an urban-rural gradient of overall allergic sensitization and specific allergen sensitization in adults depending on their childhood exposure. In this highly homogenous western population, exposure to a less urbanized childhood was associated with lower risk of allergic sensitization and disease as an adult.

Associations of Early Life Exposures and Environmental Factors With Asthma Among Children in Rural and Urban Areas of Guangdong, China

BACKGROUND

Environmental factors may play important roles in asthma, but findings have been inconsistent.

OBJECTIVE

The goal of this study was to determine the associations between early life exposures, environmental factors, and asthma in urban and rural children in southeast China.

METHODS

A screening questionnaire survey was conducted in 7,164 children from urban Guangzhou and 6,087 from rural Conghua. In the second stage, subsamples of 854 children (419 from Guangzhou, 435 from Conghua) were recruited for a case-control study that included a detailed questionnaire enquiring on family history, early life environmental exposures, dietary habits, and laboratory tests (including histamine airway provocation testing, skin prick tests, and serum antibody analyses). House dust samples from 76 Guangzhou families and 80 Conghua families were obtained to analyze levels of endotoxins, house dust mites, and cockroach allergens.

RESULTS

According to the screening survey, the prevalence of physician-diagnosed asthma was lower in children from Conghua (3.4%) than in those from Guangzhou (6.9%) (P < .001). A lower percentage of asthma was reported in rural subjects compared with urban subjects (2.8% vs. 29.4%; P < .001) in the case-control study. Atopy (OR, 1.91 [95% CI, 1.58-2.29]), parental atopy (OR, 2.49 [95% CI, 1.55-4.01]), hospitalization before 3 years of age (OR, 2.54 [95% CI, 1.37-4.70]), high consumption of milk products (OR, 1.68 [95% CI, 1.03-2.73]), and dust Dermatophagoides farinae group 1 allergen (OR, 1.71 [95% CI, 1.34-2.19]) were positively associated with asthma. Living in a crop-farming family at < 1 year of age (OR, 0.15 [95% CI, 0.08-0.32]) and dust endotoxin levels (OR, 0.69 [95% CI, 0.50-0.95]) were negatively associated with asthma.

CONCLUSIONS

Rural children from an agricultural background exhibited a reduced risk of asthma. Early life exposure to crop farming and high environmental endotoxin levels might protect the children from asthma in southern China.

ADRB2 polymorphisms in allergic asthma in Han Chinese children

BACKGROUND

Single-nucleotide polymorphisms (SNPs) in the human β2 adrenergic receptor (ADRB2) gene have been linked to pathogenesis of and treatment responses in asthma. In China, where asthma is common, little information exists regarding ADRB2 variants and their effects on asthma. The current study sought to investigate the relationship between variations in ADRB2 and childhood asthma.

METHODS

Blood samples were collected from 298 pediatric asthma cases treated in our hospital from July 2013 to September 2014; 304 samples were collected from healthy children for a control group. Six loci (at base positions -47, 79, -2387, 46, 523, and 491) of ADRB2 were genotyped using the TaqMan probe assay; SHEsis was used to determine haplotypes. Allele frequencies and genotype distributions were compared between groups using chi square and t tests.

RESULTS

No significant differences in genotype or allele frequencies were found between the groups for the polymorphic loci -2387 bp (T>C), 46 bp (G>A), and 523 bp (C>A) (p > 0.05). However, genotype frequencies for the ADRB2 SNPs at -47 bp (C>T) and 79 bp (G>C) differed significantly between asthma and control groups (p < 0.05). Further, linkage disequilibrium was found between these 2 SNPs (D' = 0.990, r(2) = 0.962), as well as between SNPs at 46 and 523 bp (D' = 0.985, r(2) = 0.607). Finally, of the 4 haplotypes analyzed in these samples (haplotypes III, IV, IX, and XI), the frequency of haplotype III was significantly lower in the asthma group than the control group (p < 0.05; odds ratio [OR] = 0.72; 95% confidence interval [CI], 0.48 to 0.97).

CONCLUSION

Variations of ADRB2 at base positions -47 (C>T) and 79 (G>C), as well as haplotype III, may contribute to susceptibility to childhood asthma.

Characterization of particulate-bound PAHs in rural households using different types of domestic energy in Henan Province, China

The concentrations and composition of sixteen PAHs adsorbed to respirable particulate matter (PM10≤10 μm) and inhalable particulate matter (PM2.5≤2.5 μm) were determined during autumn and winter in rural households of Henan Province, China, which used four types of domestic energy [crop residues, coal, liquid petroleum gas (LPG) and electricity] for cooking and heating. The present results show that there were significantly (p<0.05) seasonal variations of particulate-bound PAHs in the rural households. The daily mean concentrations of particulate-bound PAHs in the kitchens, sitting rooms and outdoors were apparently higher in winter than those in autumn, except those in the kitchens using coal. The present study also shows that there were obvious variations of particulate-bound PAHs among the four types of domestic energy used in the rural households. The households using LPG for cooking can, at least in some circumstances, have higher concentrations of PAHs in the kitchens than using crop residues or electricity. In addition, using coal in the sitting rooms seemed to result in apparently higher concentrations of particulate-bound PAHs than using the other three types of domestic energy during winter. The most severe contamination occurred in the kitchens using LPG in winter, where the daily mean concentrations of PM2.5-bound PAHs were up to 762.5±931.2 ng m(-3), indicating that there was serious health risk of inhalation exposure to PAHs in the rural households of Henan Province. Rural residents' exposure to PM2.5-bound PAHs in kitchens would be roughly reduced by 69.8% and 85.5% via replacing coal or crop residues with electricity in autumn. The pilot research would provide important supplementary information to the indoor air pollution studies in rural area.

Breastfeeding and childhood hospitalizations for asthma and other wheezing disorders

PURPOSE

Observationally in Western settings, breastfeeding is associated with less childhood wheezing disorders but may be confounded by socioeconomic position. We examined the association of breastfeeding with asthma and other wheezing disorders in a developed non-Western setting with unique social patterning of breastfeeding.

METHODS

Using Cox regression, we examined the adjusted associations of breastfeeding with public hospital admissions for asthma, bronchitis, and bronchiolitis (International Classification of Diseases, Ninth Version. Clinical Modification: 466, 490, and 493) from 3 months to 12 years in a population-representative birth cohort of 8327 Hong Kong Chinese children.

RESULTS

We did not find an association of exclusive breastfeeding for 3 months or more, compared with never breastfeeding, with hospitalization for asthma, bronchitis, and bronchiolitis to 12 years (hazard ratio [HR], 0.89; 95% confidence interval [CI], 0.63-1.25) nor for partial breastfeeding for any length of time or exclusive breastfeeding for less than 3 months (HR, 1.02; 95% CI, 0.86-1.21), adjusted for infant and parental characteristics and socioeconomic position. We also did not find an association of exclusive breastfeeding for 3 months or more with hospitalization for asthma only (International Classification of Diseases, Ninth Version. Clinical Modification: 493) (HR, 1.27; 95% CI, 0.82-1.98).

CONCLUSIONS

In a large population-representative Chinese birth cohort, we did not find an association of breastfeeding with childhood hospitalizations for asthma and other wheezing disorders.

Levels of PM2.5/PM10 and associated metal(loid)s in rural households of Henan Province, China

Although a majority of China's rural residents use solid fuels (biomass and coal) for household cooking and heating, clean energy such as electricity and liquid petroleum gas is becoming more popular in the rural area. Unfortunately, both solid fuels and clean energy could result in indoor air pollution. Daily respirable particulate matter (PM≤10 μm) and inhalable particulate matter (PM≤2.5 μm) were investigated in kitchens, sitting rooms and outdoor area in rural Henan during autumn (Sep to Oct 2012) and winter (Jan 2013). The results showed that PM (PM2.5 and PM10) and associated metal(loid)s varied among the two seasons and the four types of domestic energy used. Mean concentrations of PM2.5 and PM10 in kitchens during winter were 59.2-140.4% and 30.5-145.1% higher than those during autumn, respectively. Similar with the trends of PM2.5 and PM10, concentrations of As, Pb, Zn, Cd, Cu, Ni and Mn in household PM2.5 and PM10 were apparently higher in winter than those in autumn. The highest mean concentrations of PM2.5 and PM10 (368.5 and 588.7 μg m(-3)) were recorded in sitting rooms in Baofeng during winter, which were 5.7 and 3.9 times of corresponding health based guidelines for PM2.5 and PM10, respectively. Using coal can result in severe indoor air pollutants including PM and associated metal(loid)s compared with using crop residues, electricity and gas in rural Henan Province. Rural residents' exposure to PM2.5 and PM10 would be roughly reduced by 13.5-22.2% and 8.9-37.7% via replacing coal or crop residues with electricity. The present study suggested that increased use of electricity as domestic energy would effectively improve indoor air quality in rural China.

Role of the fixed combination of fluticasone and salmeterol in adult Chinese patients with asthma and COPD

Chronic obstructive pulmonary disease (COPD) and asthma are common airway disorders characterized by chronic airway inflammation and airflow obstruction, and are a leading cause of morbidity and mortality in the People's Republic of China. These two diseases pose a high economic burden on the family and the whole of society. Despite evidence-based Global Initiative for Chronic Obstructive Lung Disease and Global Initiative for Asthma guidelines being available for the diagnosis and management of COPD and asthma, many of these patients are not properly diagnosed or managed in the People's Republic of China. The value of combination therapy with inhaled corticosteroids and long-acting β2-agonists has been established in the management of asthma and COPD globally. Combinations of inhaled corticosteroids and long-acting β2-agonists such as fluticasone and salmeterol, have been shown to be effective for improving symptoms, health status, and reducing exacerbations in both diseases. In this review, we discuss the efficacy and safety of this combination therapy from key studies, particularly in the People's Republic of China.

The good and bad of antioxidant foods: An immunological perspective

Maintenance of redox homeostasis plays a central role in health and disease prevention, and antioxidant foods are thought to exert protective effects by counteracting oxidative stress. The term "dietary antioxidant" implies a classical reducing or radical-scavenging capacity, but more data on the in vivo bioactivity of such compounds are needed. Indeed, several dietary antioxidants activate signaling cascades that lead to effects that extend beyond radical scavenging, such as the induction of endogenous cytoprotective mechanisms and detoxification. Currently, the overall uptake of antioxidants with diet exceeds actual needs, as food additives that include vitamins, colorants, flavoring agents, and preservatives are often also relatively strong antioxidants. Chronic antioxidative stress favors adverse effects, such as the suppression of T helper (Th) type 1 immune responses and consequent activation of Th2 reactions that support the development of asthma, allergies, and obesity. In this context, we discuss the immunoregulatory pathway of tryptophan breakdown by enzyme indoleamine 2,3-dioxygenase (IDO), which represents a central regulatory hub for immune, metabolic, and neuroendocrine processes. Activation of IDO-mediated tryptophan metabolism is strongly redox-sensitive and is therefore susceptible to modulation by dietary components, phytochemicals, preservatives, and drugs.

Impact of close-proximity air pollution on lung function in schoolchildren in the French West Indies

Background

High levels of asthma prevalence and severity of respiratory symptoms have been found in the Caribbean but little is known about the impact of air pollution in these regions.

This study aimed to describe air pollution and measure the associations with child lung function in Guadeloupe (French West Indies).

Methods

Data from 30 randomly chosen elementary schools (8–13 years old) were obtained using a standardized protocol adapted from the ISAAC2 study. We considered two health outcomes: peak expiratory flow (PEF) before running and the variation in peak expiratory flow (ΔPEF) after running. The associations between pollutants and outcomes were investigated using several air pollution exposure models: i) medium-term exposure to close-proximity pollution both indoor and outdoor for ozone (O₃) and nitrogen dioxide (NO₂) and ii) short- and medium-term exposure to background pollution for O₃, NO₂, sulphur dioxide (SO₂) and small particulate matter (PM₁₀).

Results

Of 1,463 children, 277 (16%) were found to have asthma. A 1-μg/m3 increase in medium-term exposure to outdoor close-proximity pollution by O₃ was associated with a PEF decrease (β = −0.32; 95% CI: −0.61;-0.03). No association was found with NO₂ regarding close-proximity pollution. The association between medium-term exposure to background pollution and PEF decrease was stronger in asthmatic children than in non-asthmatic children for O_3. No reduction in PEF or ΔPEF was shown with NO₂, SO₂ and PM₁₀ pollutants but a significant association was found between PM₁₀ and PEF increase.

Conclusions

Our results suggest that O₃ could have an acute effect on child lung function in the Caribbean even at a low concentration (below the WHO guidelines). Further research in the Caribbean is needed to confirm these findings.

Association between polymorphisms and haplotypes of the beta-2 adrenergic receptor gene and asthma in a Chinese Han population

Conflicting data have been reported on the association of variants of the beta-2 adrenergic receptor (ADRB2) gene with asthma etiology. To provide a scientific basis for the prevention and treatment of asthma, the relationship between single nucleotide polymorphisms and haplotypes of ADRB2 and asthma was examined in a Chinese Han population. Six loci (base positions -2387, -47, 46, 79, 491, and 523) of ADRB2 were examined in a group of individuals with asthma (n = 429) and a control group of individuals who do not have the disease (n = 483). Polymorphisms at the -47 locus [odds ratio (OR) = 0.789, 95% confidence interval (CI): 0.398~0.961, P < 0.05) and the 79 locus (OR = 0.788, 95% CI: 0.394~0.948, P < 0.05) and haplotype III (CCGGC; OR = 0.705, 95% CI: 0.412~0.973, P < 0.05) were correlated with asthma susceptibility and may affect the incidence of asthma in a Chinese Han population by conferring a protective effect. By examining several polymorphisms and haplotypes, this study yields a more comprehensive examination of the role of the ADRB2 gene in the pathogenesis of asthma.

Home dampness, childhood asthma, hay fever, and airway symptoms in Shanghai, China: associations, dose-response relationships, and lifestyle's influences

Numerous studies of associations between dampness and respiratory diseases have been conducted, but their implications remain inconclusive. In this study of 13,335 parent-reported questionnaires (response rate: 85.3%), we analyzed associations between home dampness and asthma and related symptoms in 4- to 6-year-old children in a cross-sectional study of Shanghai. Indicators of home dampness were strongly and significantly associated with dry cough, wheeze, and rhinitis symptoms. In the current residence, children with visible mold spots (VMS) exposure had 32% higher risk of asthma (adjusted OR, 95% CI: 1.32, 1.07-1.64); damp clothing and/or bedding (frequently) was strongly associated with dry cough (1.78, 1.37-2.30); condensation on windows was strongly associated with hay fever (1.60, 1.27-2.01). In the early-life residence, VMS or damp stains (frequently) were strongly associated with dry cough (2.20, 1.55-3.11) and rhinitis ever (1.57, 1.11-2.21). Associations between dampness and diseases among children with or without family history of atopy were similar. The total number of dampness indicators had strong dose-response relationships with investigated health outcomes. Actions, including opening windows of the child's room at night and cleaning the child's room frequently, could potentially mitigate 25% of home VMS, thereby preventing more than 1.5% of attributable risk of the studied symptoms.

A hospital-based survey on the prevalence of bronchial asthma in patients with allergic rhinitis in southern China

BACKGROUND

The prevalence of bronchial asthma (BA) and the underlying risk factors in patients with allergic rhinitis (AR) in China are largely unknown. Thus, this study is designed to assess the BA comorbidity in AR patients in two cities (Guangzhou and Zhuhai) of southern China and to determine the risk factors of BA in these AR patients.

METHODS

We performed a cross-sectional, hospital-based survey in two modernized cities in southern China. The BA prevalence was evaluated in 1931 AR patients. Participants were asked to complete a questionnaire containing specific items for AR and BA. A logistic regression analysis was used to assess the risk factors of BA comorbidity in AR patients.

RESULTS

The prevalence of concomitant BA in AR patients is 5.33% (103/1931). Most of the participants (98.4%) were sensitized to more than one allergen, and the most common sensitization was to house-dust mites. The strongest risk factor of BA determined by a multiple logistic regression analysis was a duration of AR of >5 years (adjusted odds ratio [OR], 8.67; 95% confidence interval [CI], 3.74-20.06), followed by smoking (adjusted OR, 7.21; 95% CI, 1.86-8.23) and self-medication with antibiotics (adjusted OR, 6.35; 95% CI, 3.43-11.78).

CONCLUSION

Our findings suggested the risk factors of concomitant BA in AR patients may be helpful to establish preventive strategies.

Trends in prevalence and risk factors of childhood asthma in Fuzhou, a city in Southeastern China

Abstract Objective: The prevalence of asthma in children age 0-14 years in Fuzhou, a city in Southeast China, was 1.57% in 1990 and 3.28% in 2000. The aim of this study was to investigate the asthma prevalence and risk factors in children in the same city in 2010.

METHODS

This was a cross-sectional study with a two-stage, clustered, stratified random sample design. Parents of 12235 children 0-14 years of age in Fuzhou were surveyed using a questionnaire. Children with history and/or symptoms of asthma were then interviewed by pediatricians in a nearby clinic to confirm the diagnosis of asthma, and a second questionnaire listing reported risk factors of asthma was completed by the parents in the clinic.

RESULTS

About 11738 questionnaires were completed with a response rate of 95.9%. Among the responders, 648 children had history and/or symptoms of asthma but only 485 (4.13%) were confirmed with asthma. The prevalence was 1.83%, 7.64% and 6.27% in the age groups of 0-1 years, 3-4 years and 13-14 years, respectively. The most significant (binary logistic regression test) factors associated with asthma were presence of atopic or allergic diseases (OR=21.5, 95% CI: 12-38.5), family history of allergy or asthma (OR=29.4, 95% CI: 12.6-68.6), use of at least one course of antibiotics in the first year of life (OR=7.61, 95% CI: 3.4-17.06), supplementary protein feedings before 6 months (OR=1.90, 95% CI: 1.23-2.95). Natural ventilation at home (versus frequent use of air-conditioning) appeared to be a protective factor (OR = 0.5, 95% CI: 0.3-0.8).

CONCLUSION

The prevalence of asthma in childhood has increased significantly during the past 20 years in Fuzhou.

Burden of asthma among children in a developing megacity: childhood asthma study, Pakistan

OBJECTIVES

Global burden of childhood asthma has increased in the past few decades, particularly in low-income countries. In Pakistan, there is a lack of community-based epidemiological studies estimating the burden of asthma among children. This study determined the prevalence and predictors of asthma among children 3-17 years of age in Karachi, Pakistan.

METHODS

A two-stage community-based representative cross-sectional survey was conducted in Karachi from March 2012 to April 2013 comprising 1046 children aged 3-17 years. Of 7500 clusters, 80 were randomly selected, and of these, 15 children per cluster were enrolled randomly. A translated and pre-tested version of International Study of Asthma and Allergies in Children questionnaire was administered.

RESULTS

The overall prevalence of asthma among study participants was 10.2% (95% CI: 8.4-12.0). Asthma was more likely to occur among boys (adj. OR: 2.5, 95% CI: 1.6-4.0), children in the younger age group (3-7 years) (adj. OR: 2.9, 95% CI: 1.7-4.8), those living in households with ill-ventilated kitchens (adj. OR: 1.8, 95% CI: 1.1-3.1), having family history of asthma (adj. OR: 2.3, 95% CI: 1.3-3.9) and those of the Sindhi ethnicity (adj. OR: 2.2, 95% CI: 1.1-4.4).

CONCLUSION

This study is the first robust evidence regarding asthma among children in Pakistan, reporting a high burden in this group. Family history, male gender, Sindhi ethnicity and ill-ventilated kitchen were identified as important predictors of asthma. Targeted preventive measures and intervention studies are required to better understand and reduce the burden of asthma among children in Pakistan.

Fruit and vegetable intake and risk of wheezing and asthma: a systematic review and meta-analysis

Major bibliographic databases were searched for studies examining the relationship between fruit and vegetable consumption and the risk of wheezing and asthma. Random-effects models were used to pool study results. Subgroup analyses were conducted by fruit and vegetable categories, study design, and age group. Twelve cohorts, 4 population-based case-control studies, and 26 cross-sectional studies published between January 1990 and July 2013 were identified. For the meta-analysis of adults and children, the relative risk (RR) and confidence intervals (CI) when comparing the highest intake group with the lowest intake group were 0.78 (95%CI, 0.70-0.87) for fruit and 0.86 (95%CI, 0.75-0.98) for vegetables. High intake of fruit and vegetables (RR = 0.76; 95%CI, 0.68-0.86 and RR = 0.83; 95%CI, 0.72-0.96) reduced the risk of childhood wheezing. Total intake of fruit and vegetables had a negative association with risk of asthma in adults and children (RR = 0.54; 95%CI, 0.41-0.69). Consuming fruit and vegetables during pregnancy had no association with the risk of asthma in offspring. High intake of fruit and vegetables may reduce the risk of asthma and wheezing in adults and children.

Cross-sectional epidemiological survey of asthma in Jinan, China

BACKGROUND AND OBJECTIVE

The prevalence and control of asthma in all ages are seldom known in Jinan, China. This study aims to determine the prevalence, related factors and control of asthma in populations of all ages in Jinan, China.

METHODS

A cross-sectional epidemiological questionnaire survey was performed with all members from approximately 4500 randomly selected families from 60 communities in the urban area and in 40 villages in the rural area. The completed questionnaires were focused on asthma, asthma-like respiratory symptoms and asthma control.

RESULTS

A total of 13,645 individuals were interviewed in the survey, and the number of effective questionnaires reached 13,419. The asthma prevalence of all ages in Jinan was 1.1%. Atopy, asthma family history, household size and age were independent factors related to asthma. The control of asthma in Jinan was suboptimal in a high proportion of patients and even worse in the rural area.

CONCLUSIONS

The asthma prevalence for all ages in Jinan was relatively low compared with that in western countries; however, local asthma control fell markedly short from the goals of the Global Initiative for Asthma (GINA) criteria for asthma management, which may be attributed to the poor adherence to GINA guidelines, especially the underuse of preventative medication of inhaled corticosteroids.

Meta-analysis of the effects of indoor nitrogen dioxide and gas cooking on asthma and wheeze in children

BACKGROUND

Since the meta-analysis on the association between indoor nitrogen dioxide (NO2) and childhood respiratory illness in 1992, many new studies have been published. The quantitative effects of indoor NO2 on respiratory illness have not been estimated in a formal meta-analysis since then. We aimed to quantify the association of indoor NO2 and its main source (gas cooking) with childhood asthma and wheeze.

METHODS

We extracted the association between indoor NO2 (and gas cooking) and childhood asthma and wheeze from population studies published up to 31 March 2013. Data were analysed by inverse-variance-weighted, random-effects meta-analysis. Sensitivity analyses were conducted for different strata. Publication bias and heterogeneity between studies were investigated.

RESULTS

A total of 41 studies met the inclusion criteria. The summary odds ratio from random effects meta-analysis for asthma and gas cooking exposure was 1.32 [95% confidential interval (CI) 1.18-1.48], and for a 15-ppb increase in NO2 it was 1.09 (95% CI 0.91-1.31). Indoor NO2 was associated with current wheeze (random effects OR 1.15; 95% CI 1.06-1.25). The estimates did not vary much with age or between regions. There was no evidence of publication bias.

CONCLUSIONS

This meta-analysis provides quantitative evidence that, in children, gas cooking increases the risk of asthma and indoor NO2 increases the risk of current wheeze.

Flavonoids and asthma

Asthma is a chronic disease, characterized by airway inflammation, airflow limitation, hyper-reactivity and airway remodeling. It is believed that asthma is caused by the interaction between genetic and environmental factors. The prevalence of allergic diseases, including asthma, has increased worldwide during the past two decades. Although the precise reasons that have caused this increase remain unknown, dietary change is thought to be one of the environmental factors. Flavonoids, which are polyphenolic plant secondary metabolites ubiquitously present in vegetables, fruits and beverages, possess antioxidant and anti-allergic traits, as well as immune-modulating activities. Flavonoids are powerful antioxidants and anti-allergic nutrients that inhibit the release of chemical mediators, synthesis of Th2 type cytokines, such as interleukin (IL)-4 and IL-13, and CD40 ligand expression by high-affinity immunoglobulin E (IgE) receptor-expressing cells, such as mast cells and basophils. They also inhibit IL-4-induced signal transduction and affect the differentiation of naïve CD4+ T cells into effector T-cells through their inhibitory effect on the activation of the aryl hydrocarbon receptor. Various studies of flavonoids in asthmatic animal models have demonstrated their beneficial effects. The results of several epidemiological studies suggest that an increase in flavonoid intake is beneficial for asthma. Moreover, clinical trials of flavonoids have shown their ameliorative effects on symptoms related to asthma. However, these human studies are currently limited; further validation is required to clarify whether an appropriate intake of flavonoids may constitute dietary treatment and for part of a preventive strategy for asthma.

Cooking fuels and prevalence of asthma: a global analysis of phase three of the International Study of Asthma and Allergies in Childhood (ISAAC)

BACKGROUND

Indoor air pollution from a range of household cooking fuels has been implicated in the development and exacerbation of respiratory diseases. In both rich and poor countries, the effects of cooking fuels on asthma and allergies in childhood are unclear. We investigated the association between asthma and the use of a range of cooking fuels around the world.

METHODS

For phase three of the International Study of Asthma and Allergies in Childhood (ISAAC), written questionnaires were self-completed at school by secondary school students aged 13-14 years, 244,734 (78%) of whom were then shown a video questionnaire on wheezing symptoms. Parents of children aged 6-7 years completed the written questionnaire at home. We investigated the association between types of cooking fuels and symptoms of asthma using logistic regression. Adjustments were made for sex, region of the world, language, gross national income, maternal education, parental smoking, and six other subject-specific covariates. The ISAAC study is now closed, but researchers can continue to use the instruments for further research.

FINDINGS

Data were collected between 1999 and 2004. 512,707 primary and secondary school children from 108 centres in 47 countries were included in the analysis. The use of an open fire for cooking was associated with an increased risk of symptoms of asthma and reported asthma in both children aged 6-7 years (odds ratio [OR] for wheeze in the past year, 1·78, 95% CI 1·51-2·10) and those aged 13-14 years (OR 1·20, 95% CI 1·06-1·37). In the final multivariate analyses, ORs for wheeze in the past year and the use of solely an open fire for cooking were 2·17 (95% CI 1·64-2·87) for children aged 6-7 years and 1·35 (1·11-1·64) for children aged 13-14 years. Odds ratios for wheeze in the past year and the use of open fire in combination with other fuels for cooking were 1·51 (1·25-1·81 for children aged 6-7 years and 1·35 (1·15-1·58) for those aged 13-14 years. In both age groups, we detected no evidence of an association between the use of gas as a cooking fuel and either asthma symptoms or asthma diagnosis.

INTERPRETATION

The use of open fires for cooking is associated with an increased risk of symptoms of asthma and of asthma diagnosis in children. Because a large percentage of the world population uses open fires for cooking, this method of cooking might be an important modifiable risk factor if the association is proven to be causal.

FUNDING

BUPA Foundation, the Auckland Medical Research Foundation, the Health Research Council of New Zealand, the Asthma and Respiratory Foundation of New Zealand, the Child Health Research Foundation, the Hawke's Bay Medical Research Foundation, the Waikato Medical Research Foundation, Glaxo Wellcome New Zealand, the NZ Lottery Board, Astra Zeneca New Zealand, Hong Kong Research Grant Council, Glaxo Wellcome International Medical Affairs.

Changing prevalence of allergic diseases in the Asia-pacific region

Asia-Pacific is one of the most densely populated regions of the world and is experiencing rapid economic changes and urbanization. Environmental pollution is a significant problem associated with the rapid modernization of many cities in South Asia. It is not surprising that the prevalences of asthma and allergies are increasing rapidly, although the underlying reasons remain largely unknown. Many studies from this region have documented the changing prevalence of allergic diseases in various parts of the world. However, the methodologies used were neither standardized nor validated, making the results difficult to evaluate. The International Study of Asthma and Allergies in Childhood (ISAAC) has provided a global epidemiology map of asthma and allergic diseases, as well as the trend of changes in the prevalence of these diseases. Allergic sensitization is extremely common in many Asian communities. However, the prevalence of allergic diseases remains relatively rare. The rapid urbanization in the region, which increases environmental pollution and can affect the rural environment, will likely increase the prevalence of asthma and allergies in Asia.

Critical review: vegetables and fruit in the prevention of chronic diseases

BACKGROUND

Vegetables and fruit provide a significant part of human nutrition, as they are important sources of nutrients, dietary fibre, and phytochemicals. However, it is uncertain whether the risk of certain chronic diseases can be reduced by increased consumption of vegetables or fruit by the general public, and what strength of evidence has to be allocated to such an association.

METHODS

Therefore, a comprehensive analysis of the studies available in the literature and the respective study results has been performed and evaluated regarding obesity, type 2 diabetes mellitus, hypertension, coronary heart disease (CHD), stroke, cancer, chronic inflammatory bowel disease (IBD), rheumatoid arthritis (RA), chronic obstructive pulmonary disease (COPD), asthma, osteoporosis, eye diseases, and dementia. For judgement, the strength of evidence for a risk association, the level of evidence, and the number of studies were considered, the quality of the studies and their estimated relevance based on study design and size.

RESULTS

For hypertension, CHD, and stroke, there is convincing evidence that increasing the consumption of vegetables and fruit reduces the risk of disease. There is probable evidence that the risk of cancer in general is inversely associated with the consumption of vegetables and fruit. In addition, there is possible evidence that an increased consumption of vegetables and fruit may prevent body weight gain. As overweight is the most important risk factor for type 2 diabetes mellitus, an increased consumption of vegetables and fruit therefore might indirectly reduces the incidence of type 2 diabetes mellitus. Independent of overweight, there is probable evidence that there is no influence of increased consumption on the risk of type 2 diabetes mellitus. There is possible evidence that increasing the consumption of vegetables and fruit lowers the risk of certain eye diseases, dementia and the risk of osteoporosis. Likewise, current data on asthma, COPD, and RA indicate that an increase in vegetable and fruit consumption may contribute to the prevention of these diseases. For IBD, glaucoma, and diabetic retinopathy, there was insufficient evidence regarding an association with the consumption of vegetables and fruit.

CONCLUSIONS

This critical review on the associations between the intake of vegetables and fruit and the risk of several chronic diseases shows that a high daily intake of these foods promotes health. Therefore, from a scientific point of view, national campaigns to increase vegetable and fruit consumption are justified. The promotion of vegetable and fruit consumption by nutrition and health policies is a preferable strategy to decrease the burden of several chronic diseases in Western societies.

Confounding and effect modification in studies of diet and childhood asthma and allergies

OBJECTIVE

To propose a comprehensive set of confounders and effect modifiers that should be considered in epidemiologic investigations.

METHODS

Two reviewers independently critiqued studies included in a recent systematic review and extracted data on the confounders and effect modifiers that were considered and the approaches used to justify inclusion.

RESULTS

Of the 62 studies reviewed, 20 were cohort, 16 case-control, 25 cross-sectional studies, and one ecologic study. All cohort, cross-sectional, and ecologic studies had some adjustment for confounding or consideration of effect modification, but this was only the case for 7/16 (44%) case-control studies. Of the 53 studies that considered confounding or effect modification, 39/53 (74%) gave no justification for the inclusion of the variables considered. Studies that justified the inclusion of the variables did so based on empirical evidence (n = 10), conceptual justification (n = 7), or a combination of the two (n = 3). Confounding was handled mainly by using regression modeling, but some case-control studies utilized matching and anova. Ten studies handled effect modification by stratification, eight tested for interaction, and five used both strategies.

CONCLUSIONS

We have found substantial shortcomings in the handling of confounding and effect modification in studies of diet and development of childhood asthma/allergies. Selection of variables should be based on conceptual considerations and empirical evidence. Using this approach, we have proposed a comprehensive set of confounders and effect modifiers that need to be considered in future studies.

The association between cold spells and pediatric outpatient visits for asthma in Shanghai, China

BACKGROUND

Asthma is a serious global health problem. However, few studies have investigated the relationship between cold spells and pediatric outpatient visits for asthma.

OBJECTIVE

To examine the association between cold spells and pediatric outpatient visits for asthma in Shanghai, China.

METHODS

We collected daily data on pediatric outpatient visits for asthma, mean temperature, relative humidity, and ozone from Shanghai between 1 January 2007 and 31 December 2009. We defined cold spells as four or more consecutive days with temperature below the 5(th) percentile of temperature during 2007-2009. We used a Poisson regression model to examine the impact of temperature on pediatric outpatient visits for asthma in cold seasons during 2007 and 2009. We examined the effect of cold spells on asthma compared with non-cold spell days.

RESULTS

There was a significant relationship between cold temperatures and pediatric outpatient visits for asthma. The cold effects on children's asthma were observed at different lags. The lower the temperatures, the higher the risk for asthma attacks among children.

CONCLUSION

Cold temperatures, particularly cold spells, significantly increase the risk of pediatric outpatient visits for asthma. The findings suggest that asthma children need to be better protected from cold effects in winter.