• Users Online: 18
  • Print this page
  • Email this page


 
 Table of Contents  
ORIGINAL ARTICLE
Year : 2020  |  Volume : 33  |  Issue : 1  |  Page : 22-30

The prevalence of bronchial asthma among primary school students in urban and rural areas


Department of Pediatrics, Respiratory, Allergy and Immunology Unit, Faculty of Medicine, Alexandria University, Alexandria, Egypt

Date of Submission17-Nov-2019
Date of Decision23-Nov-2019
Date of Acceptance01-Dec-2019
Date of Web Publication26-Jun-2020

Correspondence Address:
Doctorate in Pediatrics Doaa A Heiba
Department of Pediatrics, Respiratory, Allergy and Immunology Unit, Faculty of Medicine, Alexandria University, Alexandria, 21526
Egypt
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/AJOP.AJOP_11_20

Rights and Permissions
  Abstract 


Background Asthma is a major public health problem worldwide with a dramatic increase witnessed during the past half century in the urbanized and industrialized regions of the world. Observations in the differences between the prevalence of allergic disease in urban and rural areas have been documented worldwide.
Aim The aim of this study was to estimate the prevalence of bronchial asthma among primary school students in urban area (Alexandria) and rural area (Kafr El Sheik).
Patients and methods A cross-sectional descriptive study was conducted among 600 primary school students between 8 and 12 years of age. A total of 300 students were from three different schools in Alexandria and 300 students from three different schools from villages around Kafr El-Sheikh’s. The study was conducted by using a written International Study of Asthma and Allergies in Childhood standardized questionnaire and a modified version of the Weil Corneil Medicine environmental survey questionnaire.
Results There was no significant difference between the prevalence of wheezes in urban and rural areas. Some environmental risk factors were associated with increased prevalence of asthma as having wall-to-wall carpeting in the bedroom, synthetic mattresses and pillows, pets, pests, and having a smoker in the house.
Conclusion The close proximity of the urban and rural areas in Egypt and the presence of the environmental factors that are considered as a risk factor for the development of bronchial asthma in both areas led to the absence of a significant difference in the prevalence of wheezes.

Keywords: asthma, rural, students, urban, wheezes


How to cite this article:
Aref GH, Heiba DA, Marghany RM. The prevalence of bronchial asthma among primary school students in urban and rural areas. Alex J Pediatr 2020;33:22-30

How to cite this URL:
Aref GH, Heiba DA, Marghany RM. The prevalence of bronchial asthma among primary school students in urban and rural areas. Alex J Pediatr [serial online] 2020 [cited 2020 Jul 7];33:22-30. Available from: http://www.ajp.eg.net/text.asp?2020/33/1/22/287725




  Introduction Top


Bronchial asthma is a common chronic illness of childhood characterized by reversible episodic bronchial hyper-responsiveness, causing chronic airway inflammation that leads to mucosal swelling, narrowing of the airway, and hyper-reactivity of the bronchial smooth muscles. More than 300 million people worldwide have asthma [1]. Moreover, it is expected that 100 million more people will develop asthma by 2025 [2]. The WHO has estimated that 15 million disability-adjusted life years are lost annually owing to asthma, representing 1% of the total global disease burden [3].

The dramatic increase in allergic diseases has been witnessed during the past half century in the urbanized and industrialized regions of the world. Observations in the differences between the prevalence of allergic disease in urban and rural areas have been documented worldwide. Studies from Africa on populations living in rural areas have shown that they experienced a very low burden of allergic disease [4]. This suggests that the environmental factors play a critical role [5]. Environmental factors such as allergens, farm animals, endotoxin, pets, parasites, and many other factors have been linked with asthma development.

A variety of allergens were found to cause asthma including indoor allergens such as house dust mites (HDM), pets, cockroaches, and rodents and outdoor allergens such as pollens and spores. Previous studies declared that more than 80% of asthmatic school-aged children are sensitized to at least one indoor allergen and that sensitization is a strong predictor of disease persistence in later life [6]. In addition, pollution has played a critical role in the development of asthma. Exposure to tobacco smoke has been associated with wheezes; it also worsens asthma symptoms and is considered a risk factor for development of severe asthma [7].

There have been few studies evaluating the prevalence of bronchial asthma in school-aged children in Egypt.


  Aim Top


The aim was to estimate the prevalence of bronchial asthma among primary school students in Alexandria and Kafr El Sheik cities, representing the urban and rural areas, respectively, using a simple protocol that has been developed by the International Study of Asthma and Allergies in Childhood for measuring the prevalence of childhood asthma.


  Patients and methods Top


A cross-sectional descriptive study was performed among 600 primary school students between 8 and 12 years of age. The number of students were divided equally between Alexandria and Kafr El-Sheikh cities: 300 students from three different schools, each representing a different district from Alexandria’s educational districts (East, Middle, and El-Agamy educational districts) and 300 students from three different schools from villages around Kafr El-Sheikh’s, each representing a different district from Kafr El-Sheikh’s educational districts (Metobas, Fowah, and Desouk educational districts). All the schools were co-ed schools having male and female students.

The study protocol was approved by the Local Ethics Committee of Scientific Research, Faculty of Medicine, Alexandria University, on the 10/10/2018, with the serial number of 0105699. Verbal consent was taken from the caregivers of the students. The study methods and aims were explained to the caregivers. The methodological process was approved by the local authority in the ministry of education at Alexandria governorate as well as Kafr El Sheik governorate.

The study was conducted by using a written International Study of Asthma and Allergies in Childhood standardized questionnaire and a modified version of the Weil Corneil Medicine environmental survey questionnaire. The data were collected during the attendance of the school physician in the selected schools after giving complete explanation of the questionnaire items and terminology to the parents or the guardians.

Statistical methodology

Data were collected and entered to the computer using Statistical Package for Social Science program for statistical analysis (version 21) (Spss I. IBM SPSS statistics version 21, Boston, MA: International Business Machines Corp; 2012. 126. IBM Corp. Released 2012. IBM SPSS Statistics for Windows, Version 21.0. Armonk, NY: IBM Corp.) [8]. Data were entered as numerical or categorical, as appropriate. Kolmogorov–Smirnov test of normality revealed no significance in the distribution of the variables, so the parametric statistics was adopted [9]. Data were described using minimum, maximum, mean, SD, and 95% confidence interval of the mean [10]. Categorical variables were described using frequency and percentage of row and percentage of column. Comparisons were carried out between two studied independent normally distributed variables using independent sample t-test [11]. c2 test was used to test association between qualitative variables [12]. Yates’ correction for continuity (or Yates’ c2 test) was used when indicated (2 × 2 table with expected value for any cell <5 and grand total >40) [13]. Monte Carlo and Yate’s (continuity) correction were carried out when indicated (expected cells <5) [14],[15]. An alpha level was set to 5%, with a significance level of 95%, and a beta error accepted up to 20%, with a power of study of 80%.


  Results Top


The mean age in the urban area was 10.34±1.09 years and in the rural area was 9.83±1.56 years. There was almost an even split between the sexes, with a slightly higher number of boys (51.6 %) from the total number of students. From the students who had wheezes during the past 12 months, 52.48% were boys, whereas 47.52% were girls, showing insignificant relation between sex and incidence of wheezes.

The overall prevalence of wheezes in the study was 16.83%, whereas the overall percentage of cases that were diagnosed by physicians as having asthma was 13.67%. The prevalence of wheezes in urban areas in Alexandria was found to be 18% and the physician-diagnosed asthma was 16.33%, whereas the prevalence of wheezes in rural areas in Kafr El-Sheikh was 15.67% and the physician-diagnosed asthma was 11%. This difference was not statistically significant ([Figure 1]).
Figure 1 History of wheezing in the past 12 months in urban and rural areas.

Click here to view


The severity of bronchial asthma in the students with history of wheezes in the past 12 months was compared in urban and rural areas by assessing the number of attacks, sleep disturbance, and speech limitation, where they all showed insignificant difference ([Figure 2]).
Figure 2 Severity of wheezes in urban and rural areas.

Click here to view


The percentage of the students who had exercise-induced asthma was to some degree higher in urban areas than the rural areas but without any significant difference (14.67 and 11%, respectively).

The percentage of students with history of wheezing among those having solid floor or area rugs was 15% on average, whereas the prevalence of wheezes in the past 12 months among those having wall-to-wall carpeting at their homes reached 26.74%. This was statistically significant, as the children who have wall-to-wall carpeting have twice the odds of developing wheezes ([Table 1]).
Table 1 History of wheezing in the past 12 months versus room floor

Click here to view


The percentage of the students with history of wheezes in the past 12 months who have cotton mattresses was almost half of those who have synthetic mattresses, lining out the protective effect of cotton mattresses, with odds ratio of 0.372. From the students who had synthetic pillows, 20.1% had history of wheezes, whereas the percentage was 12.6% in the students who had cotton pillows and 5% in those who had feather pillows. This revealed a statistically significant difference between different types of pillows and the history of wheezes ([Table 2] and [Table 3]).
Table 2 History of wheezing in the past 12 months versus mattresses

Click here to view
Table 3 History of wheezing in the past 12 months versus pillows

Click here to view


On comparing the effect of different environmental factors on the development of wheezes, we have found that dust mite-proof covers, having weekly washed bed linens, and owning stuffed toys had statistically insignificant effect on the prevalence of wheezing during the past 12 months ([Table 4]) On the contrary, the increase in the prevalence of wheezing was statistically significant in those who owned pets, had pests at their homes, and those who had a smoker at home ([Table 5]).
Table 4 Effect of environmental factors on the prevalence of wheezes

Click here to view
Table 5 Effect of different environmental factors on the prevalence of wheezes

Click here to view



  Discussion Top


In this study, there was no significant association between asthma and age (P=0.715). Behl et al. [16], in a study in Shimla city among school children of 6–13 years of age, found that there was no significance between age and asthma, as well as an insignificant relation between sex and the incidence of wheezes. Abdallah et al. [17], in a cross-sectional study conducted among preparatory school children in Assiut, stated that the incidence of asthma was not significantly related to age, sex, or the residence of the students. The study by Akcakaya et al. [18] conducted in Istanbul has shown the same results.

The overall prevalence of wheezes in the study was 16.83%. The prevalence of wheezes in urban areas in Alexandria was found to be 18% and in in rural areas in Kafr El-Sheikh was 15.67%. This difference was not statistically significant. Zedan et al. [19], in the study conducted in 2009 to assess the prevalence of bronchial asthma among Egyptian school children, stated that there was no great difference between the prevalence of childhood asthma in urban and rural areas. Similarly, Ahmed et al. [20], in a cross-sectional study in 2016, found that there was no significant difference between asthma prevalence in rural and urban areas. In contrast, other studies conducted in central Europe (Germany, Austria, and Switzerland) revealed lower prevalence of asthma among children living in farms [21]. This difference may be explained by the fact that the diversity in the environmental conditions between rural and urban areas is much less in Egypt when compared with the European countries owing to the close proximity of these areas to each other.

There was no statistical significance detected in the severity of asthma attacks between the urban and rural areas. Similarly, Zedan et al. [19], in their study, found that there was an insignificant difference in asthma severity among urban and rural areas. This agrees with the study conducted in Brazil in 2007 by Sole et al. [22] to assess the prevalence of bronchial asthma in urban and rural areas.

There was no statistically significant difference between urban and rural areas regarding exercise-induced asthma (14.67 and 11%, respectively). Awasthi et al. [23], in a study on school-aged children in India, showed that there was no significant difference between urban and rural areas regarding exercise-induced asthma.

The presence of wall-to-wall carpeting was associated with increased prevalence of wheezes in the past 12 months, reaching 26.74% of the students. So the children who have wall-to-wall carpeting have twice the odds of developing wheezes. Bonner et al. [24] have concluded in a cross-sectional study that wall-to-wall carpeting was associated with increased rates of hospitalization owing to asthma in preschool children. In addition, Deger et al. [25] have shown in their study that wall-to-wall carpeting was associated with poorly controlled asthma.

The percentage of the students who have cotton mattresses with history of wheezes in the past 12 months was significantly lower than those who have synthetic mattresses, with odds ratio of 0.372. Yemaneberhan et al. [4] found that synthetic mattresses and pillows were associated with increased incidence of wheezing during a 12-month duration study owing to their sensitization to HDM. Similarly, other studies supported the association between the presence of synthetic pillows and mattresses in the children’s beds and the incidence of wheezes [23],[26]. Hallam et al. [27] found that synthetic pillow may be more adverse than feather pillow, as it may have higher levels of HDM allergens and that the use of feather pillow was associated with reduced respiratory symptoms and better lung function.

The presence of dust mite-proof covers showed insignificant effect on wheezes. Gotzsche and Johansen [28], in their systematic review to evaluate the effects of multiple dust mite control measures on asthma outcomes, have found that there is no significant effects of dust mite covers in the prevention of asthma symptoms. In addition, a review by MacDonald et al. [29] showed no sufficient evidence to suggest implementing dust mite cover as an avoidance measure against developing of allergic disease.

Previous studies have found that environmental measurements such as washing bed linens in hot water weekly and removing stuffed animals from the bedroom were associated with a significantly lower risk of subsequent acute asthma episodes [30]. In this study, there was no statistically significant effect of having weekly washed bed linens on wheezing (P=0.499). The percentage of students who had history of wheezes and have stuffed toys in their bedroom was 17.39%, whereas those who do not have stuffed toys was 16.73%. This shows the insignificant effect of stuffed toys on wheezes (P=0.876).

Ingram et al. [31] demonstrated that the exposure to domestic animals was associated with asthma in school children. Moreover, Chen et al. [32] found that cat owners have more significant risks for the development of sensitization and disease manifestation. These studies concurred with this study results, as there was a statistically significant difference between pets’ ownership and wheezes, with odds ratio of 1.85.

In this study, there was a significant difference in the presence of pests at homes in relation to wheezes with an odd ratio of 1.697. Do et al. [33] revealed in their study that cockroach exposure can cause severe asthma outcome and has a major effect on asthma morbidity. Eggleston et al. [34] conducted a study on 500 asthmatic children as a part in the National Cooperative Inner-City Asthma Study and revealed the relationship between exposure to a major cockroach allergen and sensitization to cockroach allergen in asthmatic children. In addition, Chew et al. [35] found that children who were allergic to cockroach and exposed to high levels of allergens in their bedroom had higher risk of hospitalization, medical visits, wheezing, and missed school days in comparison with other indoor allergens. Along with cockroach allergen exposure, mouse allergen exposure has been known to cause asthma too. A birth cohort study demonstrated that infants who were exposed to mice in the household had almost twice the odds of developing a wheeze in the first year of life and later in childhood [36]. Pongracic et al. [37] conducted a rodent intervention in a subgroup of children and found that mouse allergen reduction was associated with less school absence and sleep disruption.

Tobacco smoke exposure has been associated with increased incidence of asthma and chronic airway inflammation in asthmatic children [38]. Kumar et al. [39] suggested that passive smoke exposure at home was mainly from the caregiver and that it was more prevalent in urban low-income families. Mitchell et al. [40] noted the relation between tobacco smoke exposure from the parents and the development of early childhood wheeze. Statistical significance was detected between tobacco smoke exposure and wheezes (P=0.027), revealing that tobacco smoke exposure increases the odds ratio of wheezes by 1.621.

Limitation of this study would be related to the fact that it is based on information provided by the parents, which might carry the possibility of over or underestimating their children’s symptoms.


  Conclusion Top


There was no significant difference in the prevalence of wheezes between urban and rural areas included in this study, which may be owing to close proximity of the areas to each other, as well as exposure to outdoor air pollution. Environmental factors that are considered as a risk factor for the development of bronchial asthma were detected in both urban and rural areas, which included wall-to-wall carpeting, synthetic mattresses and pillows, presence of pets, presence of pests, as well as having a smoker at the house. The presence of wall-to-wall carpeting and synthetic mattresses and pillows was higher among urban area, whereas the presence of pets and pests was higher among rural areas.

Acknowledgements

The research was supported by Alexandria Faculty of Medicine

Financial support and sponsorship

Nil

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Xie M, Wenzel SE. A global perspective in asthma: from phenotype to endotype. Chin Med J 2013; 126:166–174.  Back to cited text no. 1
    
2.
Behera D, Sehgal IS. Bronchial asthma-Issues for the developing world. Indian J Med Res 2015; 141:380.  Back to cited text no. 2
[PUBMED]  [Full text]  
3.
Disease GBD, Injury I, Prevalence C. Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015. Lancet 2016; 388:1545–1602.  Back to cited text no. 3
    
4.
Yemaneberhan H, Bekele Z, Venn A, Lewis S, Parry E, Britton J. Prevalence of wheeze and asthma and relation to atopy in urban and rural Ethiopia. Lancet 1997; 350:85–90.  Back to cited text no. 4
    
5.
Bach JF. The effect of infections on susceptibility to autoimmune and allergic diseases. N Engl J Med 2002; 347:911–920.  Back to cited text no. 5
    
6.
Illi S, von Mutius E, Lau S, Niggemann B, Gruber C, Wahn U et al. Perennial allergen sensitisation early in life and chronic asthma in children: a birth cohort study. Lancet 2006; 368:763–770.  Back to cited text no. 6
    
7.
Stein RT, Holberg CJ, Sherrill D, Wright AL, Morgan WJ, Taussig L et al. Influence of parental smoking on respiratory symptoms during the first decade of life: the Tucson Children’s Respiratory Study. Am J Epidemiol 1999; 149:1030–1037.  Back to cited text no. 7
    
8.
Spss I. IBM SPSS statistics version 21. Boston, MA: International Business Machines Corp; 2012. 126.  Back to cited text no. 8
    
9.
Field A. Discovering statistics using IBM SPSS statistics. Thousand Oaks, California: Sage; 2013.  Back to cited text no. 9
    
10.
Snecdecor G, Cochran W. Statistical methods. New Jersey: Wiley; 1991.  Back to cited text no. 10
    
11.
Box JF. Guinness, Gosset, Fisher, and small samples. Stat Sci 1987; 2:45–52.  Back to cited text no. 11
    
12.
Pearson KX. On the criterion that a given system of deviations from the probable in the case of a correlated system of variables is such that it can be reasonably supposed to have arisen from random sampling. Lond Edinb Dubl Phil Mag J Sci 1900; 50:157–175.  Back to cited text no. 12
    
13.
Yates F. Contingency tables involving small numbers and the χ2 test. Suppl J R Stat Soc 1934; 1:217–235.  Back to cited text no. 13
    
14.
Smith PW, Forster JJ, McDonald JW. Monte Carlo exact tests for square contingency tables. J R Stat Soc Series A (Stat Soc) 1996; 159:309–321.  Back to cited text no. 14
    
15.
Haviland MG. Yates’s correction for continuity and the analysis of 2×2 contingency tables. Stat Med 1990; 9:363–367.  Back to cited text no. 15
    
16.
Behl RK, Kashyap S, Sarkar M. Prevalence of bronchial asthma in school children of 6-13 years of age in Shimla city. Indian J Chest Dis All Sci 2010; 52:145–148.  Back to cited text no. 16
    
17.
Abdallah AM, Sanusy KA, Said WS, Mahran DG, Mohamed-Hussein AA. Epidemiology of bronchial asthma among preparatory school children in Assiut district. Egypt J Pediatr Allergy Immunol 2012; 10:109–117.  Back to cited text no. 17
    
18.
Akcakaya N, Kulak K, Hassanzadeh A, Camcioglu Y, Cokugras H. Prevalence of bronchial asthma and allergic rhinitis in Istanbul school children. Eur J Epidemiol 2000; 16:693–699.  Back to cited text no. 18
    
19.
Zedan M, Settin A, Farag M, Ezz-Elregal M, Osman E, Fouda A. Prevalence of bronchial asthma among Egyptian school children. Egypt J Bronchol 2009; 3:124–130.  Back to cited text no. 19
    
20.
Ahmed EEGER, Kamel AS, Amin SA, Hashem AE. Epidemiology of childhood asthma in Fayoum City (District) Egypt. J Pharm Biosci 2016; 4:67–75.  Back to cited text no. 20
    
21.
Riedler J, Braun-Fahrlander C, Eder W, Schreuer M, Waser M, Maisch S et al. Exposure to farming in early life and development of asthma and allergy: a cross-sectional survey. Lancet 2001; 358:1129–1133.  Back to cited text no. 21
    
22.
Sole D, Cassol VE, Silva AR, Teche SP, Rizzato TM, Bandim LC et al. Prevalence of symptoms of asthma, rhinitis, and atopic eczema among adolescents living in urban and rural areas in different regions of Brazil. Allergol Immunopathol (Madr) 2007; 35:248–253.  Back to cited text no. 22
    
23.
Awasthi S, Kalra E, Roy S, Awasthi S. Prevalence and risk factors of asthma and wheeze in school-going children in Lucknow,North India. Indian Pediatr 2004; 41:1205–1210.  Back to cited text no. 23
    
24.
Bonner S, Matte TD, Fagan J, Andreopoulos E, Evans D. Self-reported moisture or mildew in the homes of Head Start children with asthma is associated with greater asthma morbidity. J Urban Health 2006; 83:129–137.  Back to cited text no. 24
    
25.
Deger L, Plante C, Goudreau S, Smargiassi A, Perron S, Thivierge RL et al. Home environmental factors associated with poor asthma control in Montreal children: a population-based study. J Asthma 2010; 47:513–520.  Back to cited text no. 25
    
26.
Wong GW, Ko FW, Hui DS, Fok TF, Carr D, von Mutius E et al. Factors associated with difference in prevalence of asthma in children from three cities in China: multicentre epidemiological survey. BMJ 2004; 329:486.  Back to cited text no. 26
    
27.
Hallam C, Custovic A, Simpson B, Houghton N, Simpson A, Woodcock A. Mite allergens in feather and synthetic pillows. Allergy 1999; 54:407–408.  Back to cited text no. 27
    
28.
Gotzsche PC, Johansen HK. House dust mite control measures for asthma: systematic review. Allergy 2008; 63:646–659.  Back to cited text no. 28
    
29.
MacDonald C, Sternberg A, Hunter PR. A systematic review and meta-analysis of interventions used to reduce exposure to house dust and their effect on the development and severity of asthma. Environ Health Perspect 2007; 115:1691–1695.  Back to cited text no. 29
    
30.
Baxi SN, Phipatanakul W. The role of allergen exposure and avoidance in asthma. Adolescent medicine: state of the art reviews 2010; 21:57–71.  Back to cited text no. 30
    
31.
Ingram JM, Sporik R, Rose G, Honsinger R, Chapman MD, Platts-Mills TA. Quantitative assessment of exposure to dog (Can f 1) and cat (Fel d 1) allergens: relation to sensitization and asthma among children living in Los Alamos,New Mexico. J Allergy Clin Immunol 1995; 96:449–456.  Back to cited text no. 31
    
32.
Chen C-M., Tischer C, Schnappinger M, Heinrich J. The role of cats and dogs in asthma and allergy − a systematic review. Int J Hyg Environ Health 2010; 213:1–31.  Back to cited text no. 32
    
33.
Do DC, Zhao Y, Gao P. Cockroach allergen exposure and risk of asthma. Allergy 2016; 71:463–474.  Back to cited text no. 33
    
34.
Eggleston PA, Rosenstreich D, Lynn H, Gergen P, Baker D, Kattan M et al. Relationship of indoor allergen exposure to skin test sensitivity in inner-city children with asthma. J Allergy Clin Immunol 1998; 102 (4 Part 1):563–570.  Back to cited text no. 34
    
35.
Chew GL, Perzanowski MS, Canfield SM, Goldstein IF, Mellins RB, Hoepner LA et al. Cockroach allergen levels and associations with cockroach-specific IgE. J Allergy Clin Immunol 2008; 121:240–245.  Back to cited text no. 35
    
36.
Phipatanakul W, Celedon JC, Sredl DL, Weiss ST, Gold DR. Mouse exposure and wheeze in the first year of life. Ann Allergy Asthma Immunol 2005; 94:593–599.  Back to cited text no. 36
    
37.
Pongracic JA, Visness CM, Gruchalla RS, Evans R III, Mitchell HE. Effect of mouse allergen and rodent environmental intervention on asthma in inner-city children. Ann Allergy Asthma Immunol 2008; 101:35–41.  Back to cited text no. 37
    
38.
Morkjaroenpong V, Rand CS, Butz AM, Huss K, Eggleston P, Malveaux FJ et al. Environmental tobacco smoke exposure and nocturnal symptoms among inner-city children with asthma. J Allergy Clin Immunol 2002; 110:147–153.  Back to cited text no. 38
    
39.
Kumar R, Curtis LM, Khiani S, Moy J, Shalowitz MU, Sharp L et al. A community-based study of tobacco smoke exposure among inner- city children with asthma in Chicago. J Allergy Clin Immunol 2008; 122:754–9 e1.  Back to cited text no. 39
    
40.
Mitchell EA, Beasley R, Keil U, Montefort S, Odhiambo J, Group IPTS. The association between tobacco and the risk of asthma, rhinoconjunctivitis and eczema in children and adolescents: analyses from Phase Three of the ISAAC programme. Thorax 2012; 67:941–949.  Back to cited text no. 40
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
Abstract
Introduction
Aim
Patients and methods
Results
Discussion
Conclusion
References
Article Figures
Article Tables

 Article Access Statistics
    Viewed35    
    Printed0    
    Emailed0    
    PDF Downloaded7    
    Comments [Add]    

Recommend this journal


[TAG2]
[TAG3]
[TAG4]