ALLERGOL. ET IMMUNOPATHOL., 1998;26(1):5-8
ORIGINAL ARTICLES
Home environment and asthma in school children from the Edirne region in Turkey
M. Yazicioglu1, A. Saltik2, Ü. Öne ¸s 3, A. ¸S am4, H. Çetin Ekerbiçer5 andO. Kirçuval6
1 Assistant Professor of Pediatrics. Department of Pediatrics, Trakya University, School of Medicine, Edirne, Turkey. 2 Professor of Public Health, Trakya University, School of Medicine, Edirne, Turkey. 3 Professor of Pediatrics. Allergy Clinic of the Department of Pediatrics, Istanbul University, School of Medicine, Istanbul, Turkey. 4 Research Assistant in Pediatrics. Department of Pediatrics, Trakya University, School of Medicine, Edirne, Turkey. 5 Research Assistant in Public Health. Department of Public Health, Trakya University, School of Medicine, Edirne, Turkey. 6 Research Assistant in Pediatrics. Department of Pediatrics, Trakya University, School of Medicine, Edirne, Turkey.
SUMMARY
Studies have shown that environmental factors contribute to the development of asthma. Hence, we investigated the relation between current asthma and indoor environmental factors such as exposure to pets, tobacco smoke, home dampness, number of people living in home, and stuffed toys in child''s bedroom in a questionnaire based study in primary school children aged 6 to 12 years living in Edirne (Turkey).
In a random sample of 4 primary schools, questionnaires were completed by parents of 1000 children. Following the evaluation of 682 of these, 85 were selected as cases of asthma of which 24 were diagnosed by a physician. When required certain laboratory tests were also performed in order to confirm the diagnosis. Logistic regression was used to investigate the associations between asthma and potential risk factors.
In logistic regression analyses, the following factors were associated with asthma. Dampness in the house [(odd''s ratio (O.R) = 2.61; 95% CI 1.13 to 6.81), stuffed toys in the child''s bedroom (O.R = 2.18; 95% CI 1.27 to 3.74), and the crowding index (O.R = 2.73; 95% CI 1.08 to 6.82)].
In conclusion, it was found that presence of asthma was significantly associated with the presence of dampness in the house, and stuffed toys in the child''s bedroom. Asthma can be prevented by improvement of the indoor environment. Therefore providing education to high-risk populations for avoidance of these risk factors is particulary important.
Key words: Asthma. Children. Home environment.
Allergol et Immunopathol 1998;26:5-8.
INTRODUCTION
During recent decades, asthma prevalence has increased rapidly world wide among children (1-9). There is increasing evidence that environmental factors, besides host factors, contribute to the development of asthma (10). Differences in the prevalence of asthma between industrialized and developing countries (1), and also urban and rural differences suggest that environmental factors associated with urbanization and industrialization (10, 11) may play an important role in the increase of asthma. Environmental pollution from heavy industry and increased traffic levels has been cited as one possible reason (12), but other factors which may contribute to the higher prevalence of asthma include changes in home environment due to changes in life style (13). Home environment is especially important for children who spend most of their time indoors.
In this study, we planned to investigate the possible association of indoor risk factors with indicators of asthma among students of 4 closely located primary schools in Edirne where air pollution is quite prevalent. The families of these children are middle-class to well-to-do socioeconomically. Prior to selecting these schools, we aimed to minimize the differences pertaining to the families'' income levels and air pollution factors in the area.
MATERIAL AND METHODS
This study was performed from September 1996 to November 1996. The questionnaire concerning asthma and home environment was offered at four primary schools in Edirne.
The questionnaire was designed on the basis of the American Thoracic Society (ATS-DLD) with some revision (14, 15). With regad to the symptoms of asthma the following questions were included: (1) Does your child ever sound wheezy or whistling? (a) When he/she has a cold? or (b) Occasionally apart form colds? (2) Has your child had an attack of wheezing that has caused him/her to be short of breath? (3) Has he/she had two or more such episodes? (4) Has he/she ever required medicine or treatment for the(se) attack(s)? (5) Has a doctor ever said that this child has asthma?
Those cases who answered question 5 positively and were also diagnosed by a physician were accepted as asthmatic. Those who answered the other questions relating to asthma positively were accepted to be cases of asthma based on physical examination, laboratory tests, respiratory function tests and case histories. Those cases that answered all the questions about asthma negatively were selected as the control group.
The patients were also asked whether their vaccinations were up-to-date and the number of siblings in the house. Other questions about the house were related to its age, the means of heating, the number of rooms and windows, humidity, the existence of indoor pets, carpets and/or wall-to-wall carpeting in the house; the presence of dust-collecting items in the child''s room and the number of people sharing it; the materials of the child''s mattress and pillow as well as the particulars of the floor-surfacing. There were also some questions pertaining to the parents'' social status, health, the socioeconomic level of the family and their smoking habits.
Statistics: A step-wise logistic regression model was employed using asthma as a dependent variable and items related to home, child''s bedroom, number of children and socieconomic level of the family, and parental status as independent variables. The crowding index were calculated as the total number of persons living in the house divided by the number of rooms.
RESULTS
One thousand questionnaires were completed by the parents, from which 85 asthmatic cases were selected, while 597 others served as controls. The age-adjusted and sex-adjusted characteristics of the study population are shown in table I.
The results of the logistic regression analyses with asthma as a dependent variable and indoor risk factors such as crowding index, dampness in the house, stuffed toys, heavy curtains, sofas, bookshelves in the child''s bedroom, and numbre of people sharing the child''s room as independent variables are shown in table II. There was a significant association between asthma and dampness in the house (O.R = 2.61; 95% CI 1.13 to 6.81), stuffed toys in the child''s bedroom (O.R = 2.18; 95% CI 1.27 to 3.74), and the crowding index (O.R = 2.73; 95% CI 1.08 to 6.82).
A statistically significant protective effect of heavy curtains (O.R = .30; 95% CI .13 to .83), bookshelves (O.R = .41; 95% CI .25 to .68), and number of people sharing the child''s bedroom (O.R = .23; 95% CI .25 to .68) was noted.
| Table I | ||||||
| Age-adjusted and sex-adjusted characteristics of the subjects analysed | ||||||
| Age | Male | Female | Total | |||
| n | % | n | % | n | % | |
| 6 | 47 | 13.6 | 49 | 14,6 | 96 | 14.1 |
| 7 | 56 | 16.2 | 75 | 22.3 | 131 | 19.2 |
| 8 | 67 | 19.4 | 68 | 20.2 | 135 | 19.8 |
| 9 | 89 | 25.7 | 79 | 23.5 | 168 | 24.6 |
| 10-12 | 87 | 25.1 | 65 | 19.3 | 152 | 22.3 |
DISCUSSION
In the past twenty years, changes have occurred in life styles and in the home environment, in accordance with urbanization and industrialization, that have attributed to the increased prevalence of asthma (10, 13). Central heating was increased in buildings with more permanent carpeting. The oil crises of the early 1970''s led to campaigns to decrease energy waste and the design of buildings were modified to heat loss (12, 13). In addition to reduce the cost of warming, these changes have had the effect of increasing humidity and temperature and reducing ventilation which promotes the growth of mites and moulds and increases the risk of sensitization to such organisms (12, 13, 16). Carpeting of homes also increased as well as the introduction of wall-to-wall carpeting as a permanent fixture. With the introduction of vacuum cleaners, the people were convinced that the carpets could be cleaned without being removed which led to partial cleaning of the mites. Detergents used to wash the bedding actually may protect live mites when washed ¾ 60° C (13). Therefore changes in life styles in accordance with urbanization which involves smaller family size and higher standards of hygiene tend to prevent the encounter of various viruses and spread of infections, but on the other hand exposure to high levels of allergens promotes the symptoms of allergic disease in children with genetic predisposition (17).
In our study important associations were found between asthma and several home environmental factors such as dampness in home, stuffed toys in the child''s bedroom and the crowding index.
Respiratory symptoms including chronic cough and wheeze have been associated with dampness or damage caused by dampness in homes in previous studies among children and adults (16, 18). Airborne fungal concentrations are higher in damp houses than in dry houses (16). The prevalence of visible indoor mould was significantly associated with asthma (19). House dust mite also thrive in damp conditions (20). In our study home dampness was found to be a significant risk factor for asthma (O.R = 2.61; CI 1.13 to 6.81) (table II).
| Table II | ||
| Indoor environmental factors in relation to asthma | ||
| Independent | Odd''s | 95% |
| Variables | Ratio | Confidence |
| Interval | ||
Crowding Index | ||
| 0-0.99 | 1 | |
| 1.00 | 1.74 | 0.68-4.39 |
| 1.01 | 2.73 | 1.08-6.82* |
Dampness in home | ||
| No | 1 | |
| Yes | 2.61 | 1.13-6.81* |
Stuffed toys | ||
| No | 1 | |
| Yes | 2.18 | 1.27-3.74* |
Heavy curtains | ||
| No | 1 | |
| Yes | 0.30 | 0.13-0.83* |
Sofas | ||
| No | 1 | |
| Yes | 0.63 | 0.38-1.05 |
Bookshelves | ||
| No | 1 | |
| Yes | 0.41 | 0.25-0.68* |
No.of persons sharing the child''s room | ||
| 1 | 1 | |
| 2 | 0.64 | 0.36-1.12 |
| 3 or more | 0.23 | 0.25-0.68* |
| * p < 0.05. | ||
The stuffed toys are important reservoirs for house dust mites and other allergens such as cat and dog epithelia (21, 22). We observed that stuffed toys in the child''s bedroom tended to increase the risk for asthma (O.R = 2.18; 95% CI 1.27 to 3.74). There was a curious but unexplained protective effect of heavy curtains and bookshelves in the child''s room. It is probable that those households with asthmatic children who initially had these furniture put them away on account of the perceived effect on their children''s health, since 25% of our cases were children diagnosed with asthma before our study was performed.
The other parameter associated with excess risk of asthma was the crowding index (O.R = 2.73; 95% CI 1.08 to 6.82). But we did not find that the number of persons sharing the child''s bedroom was a significant risk factors for asthma. Mohammed et al (10) found the number of persons in the child''s bedroom to be significantly lower in the asthma group than controls which was similar to our results. Crowding people in the house causes the infections to spread easily among the family members, but in school children allergens are more related to the development of asthma (13, 23). Therefore this result should be interpreted carefully.
Fagbule et al (24) reported a strong and significant association between asthma and a damp, mouldy bedroom, household pets and cigarette smoke. There was an unexplained protective effect of indoor biomass smoke, indoor plants, mould growth elsewhere in the home, and cosmetic aerosols. They concluded that odd''s ratio associated with the presence of indoor plants indicating a protective effect could be spurious and might be due to some avoidance measures. However, the same could not be said for the apparent protective effects of other indoor risk factors. In another study reported by Leen et al (12) any clear differences in home environment between children with asthma and controls were shown. Since the values for Der p1 were found above thresholds, they proposed that in children with an atopic background exposure to high levels of allergen resulted to develop overt symptoms.
In conclusion, dampness in home, stuffed toys in child''s bedroom and crowding index are significant risk factors. Attempts should be made to avoid home dampness and stuffed toys. In order to prevent the development of allergies and asthma, education of the families and improvement of the living conditions are especially important.
RESUMEN
Tomando en consideración que el asma sea producida por factores ambientales contribuidos, si se efectúan investigaciones basadas en tipos de encuestas sobre los alumnos en Edirne (Turquía) particularmente sobre las ambientales, como los animales, el humo de cigarrillo, la humedad de casa y respecto a la cantidad de habitantes en las casas, incluso los juguetes que se encuentran dentro de casa, siempre son factores importantes a la producción del asma.
Las encuestas al azar realizadas sobre cuatro escuelas primarias, se completaron por los padres de 1.000 niños. Entre los 682 niños investigados, 24 de ellos identificados por el médico, sí son encuestados y elegidos a 85 eventos del asma. En tiempos previstos, se aplicaron tests de laboratorio por la confirmación del diagnóstico.
En los análisis de regresión logística, los siguientes factores estaban asociados con el asma. La humedad de casa [(la proporción diferencial (O.R) = 2,61; 95% de CI entre 1,13 y 6,81), los juguetes en los dormitorios de los niños (O.R = 2,18; 95% de CI entre 1,27 y 3,74), e índice de población (O.R = 2,73; 95% de CI entre 1,08 y 6,82)].
Se concluye que el asma está asociada significativamente con la humedad existente en las casas y que tiene relación con los juguetes que se encuentran en las habitaciones de los niños. En ese caso el asma se puede prevenir con la mejora de las condiciones ambientales interiores de la casa. Con ese fin es muy importante propagar informaciones instructivas al sector que tiene un riesgo superior.
Palabras clave: Asma. Niños. Entorno ambiental.
REFERENCES
1. Cookson JB. Prevalence rates of asthma in developing countries and their comparison with those in Europe and North America. Chest 1987;91:97S-103S.
2. Gergen PJ, Mullally DI, Evans R. National survey of prevalence of asthma among children in the United States 1976 to 1980. Pediatrics 1988;81:1-7.
3. Anderson HR, Butland BK, Strachan DP. Trends in prevalence and severity of childhood asthma. BMJ 1994;308:1600-4.
4. Aberg N. Asthma and allergic rhinitis in Swedish conscripts. Clin Exp Allergy 1989;19:59-63.
5. Robertson CF, Heycock E, Bishop J, et al. Prevalence of asthma in Melbourne school children: changes over 26 years. BMJ 1991;302:1116-8.
6. Özkaragöz K, Çakin F. Atopic children in Turkey. Ann Allergy 1969;27:13-7.
7. Saraçlar Y, Yi Ç g it S, Adalio Ç g lu G, Tuncer A, Tunçbilek E. Prevalence of allergic diseases and influencing factors in primary-school children in the Ankara Region of Turkey. J Asthma 1997;34(1):23-30.
8. Öne¸s Ü, Sapan N, Somer A, et al. Prevalence of childhood asthma in Istanbul, Turkey. Allergy 1997;52:570-5.
9. Lai CKW, Douglass SSHo, Chan J, Lau Wong G, Leung R. Asthma epidemiology in the Far East. Clin Exp Allergy 1996;26:5-12.
10. Mohamed N, Ng''ang''a L, Odhiambo J, et al. Home environment and asthma in Kenyan school children: a case-control study. Thorax 1995;50:74-8.
11. Addo Yobbo EO, Custovic Asthma, Taggart SC, Asafo Agyei AP, Woodcock A. Exercise induced bronchospasm in Ghana: differences in prevalence between urban and rural school children. Thorax 1997;52(2):161-5.
12. Leen MG, O''Connor T, Kelleher C, et al. Home environment and childhood asthma. Irish Med 1994;87:142-4.
13. Platts-Mills TAE, Woodfolk JA, Chapman MD, et al. Changing concepts of allergic disease: The attempt to keep up with real changes in lifestyles. J Allergy Clin Immunol 1996;98:S297-306.
14. Ferris FG. Epidemiology standardisation project. II. Recommended respiratory disease questionnaires for use with adults and children in epidemiological research. Am Rev Respir Dis 1978;118(6 Pt2):1-120.
15. Hayashi T, Kawakami N, Kondo N, et al. Prevalence of and risk factors for allergic disease: comparison of two cities in Japan. Ann Allergy Asthma & Immunol 1995;75:525-9.
16. Waegemaekers M, Wageningen N Van, Brunekreef B, Boleij JSM. Respiratory symptoms in damp homes. Allergy 1989;44:192-8.
17. Sporik R, Holgate ST, Platt-Mills TAE, Cogswell JJ. Exposure to house dust mite allergen (Der p I) and the development of asthma in childhood: a prospective study. N Engl J Med 1990;323:502-7.
18. Platt SD, Martin CJ, Hunt SM, Lewis CW. Damp housing, mould growth, and symptomatic health state. BMJ 1989;
298:1673-8.
19. Burr ML, Mullins J, Merret T, Scott N. Indoor moulds and asthma. J R Soc Health 1988;3:99-101.
20. Platt-Mills TAE. Indoor allergens. In: Middleton E JR, Reed CE, Adkinson FA Jr, Yunginger JW, Busse WW, eds. Allergy: Principles and Practice, Vol. 2, pp:514-528. 4 th ed., St Louis: Mosby, 1993.
21. Nagakura T, Yasueda H, Obata T, et al. Major Dermatophagoides mite allergen, Der 1, in soft toys. Clin Exp Allergy 1996;26(5):585-9.
22. Munir AK, Einarsson R, Dreborg SK. Mite (Der p I, Der f I), cat (Fel d I) and dog (Can f I) allergens in dust from Swedish day-care centres. Clin Exp Allergy 1995;25(2):119-26.
23. Duff AL, Pomeranz ES, Gelber LE, et al. Risk factors for acute wheezing in infants and children: viruses, passive smoke, and IgE antibodies to inhalant allergens. Pediatrics 1993;92:535-40.
24. Fagbule''D, Ekanem EE. Some environmental risk factors for childhood asthma: a case-control study. Annals of Tropical Paediatrics 1994;14:15-9.
| Correspondence: M. Yazicioglu Konaklar mah. Sogüt sok. Petek sitesi, GB Blok D: 18 Yenilevent 80620 Istanbul. TURKEY Tel. +90.284.2357810. Fax +90.284.2357810 E-mail: yazicioglu@superonline.com |
