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DE LA SALLE HEALTH SCIENCES INSTITUTE ± COLLEGE OF MEDICINEDEPARTMENT OF FAMILY AND COMMUNITY MEDICINE

CM2 SY 2011-2012

OUTPUT 2: REVIEW OF RELATED LITERATURE (REVISED)

Group 1A, Dr. Jovilia M. Abong

Research Question: Among students aged 13-14 with allergic rhinitis of selected schools in Dasmariñas,Cavite, will exposure to air-conditioned school rooms exacerbate their allergic rhinitis?

General Objective: To determine if the exposure to the air-conditioning system exacerbates allergicrhinitis in high school students, aged 13-14, of selected schools in Dasmariñas, Cavite.

y Specific Objectives:o To identify the prevalence of allergic rhinitis among high school students, aged 13-14, of

selected schools in of Dasmariñas, Cavite based on their exposure to air-conditionedrooms.

o To identify the prevalence of allergic rhinitis among high school students, aged 13-14, of selected schools in Dasmariñas, Cavite based on their exposure to non-air-conditionedclassrooms.

o To determine the severity of allergic rhinitis according to ARIA classifications.o To identify the risk factors of allergic rhinitis present in the classroom or school.o To determine the number of hours exposed to the classroom with or without air-

conditioning system.o Compare the severity of allergic rhinitis in students who are exposed to air-conditioned

classrooms and those who are not exposed to air-conditioned classrooms.o To determine which studying environment is more suitable in the prevention of allergic

rhinitis.

B ackground Information Regarding the Research Question : According to a demographic and epidemiologic study by Settipane, allergic rhinitis affects more than20% of the American population. [1] This percentage is alarming on its own, making allergic rhinitis fairlycommon among the population. Furthermore, it was observed by the ISAAC (International Study of Allergy and Asthma in Children) that the Philippines was ranked with the highest prevalence rate of common allergies (rhinitis and asthma) - encompassing countries like Thailand, Indonesia, and SouthKorea. These studies have triggered interest into the disease and have inspired us to study the diseasefurther as well. [2]

From the same study by the ISAAC, they discovered that among Filipino teenagers, 13-14 year-olds presented with the highest prevalence rate among age groups with 32.5% of them having allergicrhinitis. [2] Hence, our study will be focusing on the specific age group mentioned.

Ventilation and air-conditioning systems can be sources of microbial aerosols either fromcontaminated air entering the system or directly from microbial growth within the system. Poor ventilation may allow an accumulation of particulates, pollutants, and allergens inside school buildingsand decreased air circulation may increase transmission of respiratory infections. Building structural



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problems, such as heating or air conditioning systems venting near an air intake may contribute to theseexposures. Due to this, the associations between school absenteeism and poor ventilation, vermin, andcumulative exposure to building condition problems are greater for younger students. Young children,aged 5 to 18 years old, are also known to be more susceptible to airborne pollutants than adults because of their greater activity, smaller airways, and faster ventilation rates. [3] Therefore, it is important to look into

which of the learning environments is more likely to help students achieve their full potential and keepthem healthy.

According to Meltzer, approximately one in five children will develop symptoms of allergicrhinitis by two to three years of age. In children who are six years of age, about 40% of them will havesymptoms and up to 30% will be affected during their adolescence. [4] Furthermore, a study by Blaiss

pointed out that allergic rhinitis can interfere with a child¶s daily activities such as learning in school. Italso affects a child¶s behavior and psychosocial health thus affecting the child¶s quality of life overall.Due to this, a consensus panel was formed in 2004 to assess the impact allergic rhinitis has on schoolchildren and determine how to improve prevention and treatment, so an affected child¶s quality of life andschool performance could improve. One of the things they considered in this consensus is that poor environmental conditions, such as places that have inadequate ventilation or poor indoor quality, canexacerbate allergic rhinitis. It is advised that the best way to prevent allergic rhinitis from occurring is by

providing clean indoor environments that will reduce the amount of allergens present indoors. Thisincludes having an air-conditioning system and proper ventilation. [4], [5]

Research Hypothesis: Exposure to air-conditioned rooms alleviates the symptoms and occurrence of allergic rhinitis and poor ventilation leads to its exacerbation.

Summary of Current Knowledge Regarding Disease and Exposure of Interest

Short Description and Symptomatology of Allergic Rhinitis

Allergic rhinitis (AR), a common chronic disease, is actually a collection of symptoms that include primarily the nose and eyes. [6] From the study done in Tehran among 7-18 years old, it is observed thatrhinorrhea, rhinitis, sneezing, eye itching and nose itching are the most common with rhinorrhea as themost prevalent. [7] Aside from these symptoms, teary eyes, nasal congestion, post nasal drip are alsoincluded. AR is perennial, seasonal or perennial with seasonal exacerbation. According to the study done

by Cauwenberge et. al., perennial AR is more difficult to define as chronic structural airway changes aremore difficult to establish and recurrent infections can mimic some of the presentations of this disease. [8]

When we say allergy, it is something that is triggered by an allergen which could come indifferent forms. It could be pollen, dust, smoke, or even pet fur. When these allergens are brought into our

respiratory tract especially through our nose, it can cause an allergic reaction where the body releaseschemicals such as histamine which causes inflammatory disease of the nasal mucosa induced by an Ig E -mediated reaction. [9] But according to De-Yun Wang of National University of Singapore, genetic

background in terms of a family history of atopic disease has been the strongest risk factor for thedevelopment of allergic symptoms, irrespective of the varying prevalence and environmental risk factorsin different societies. The most convincing evidence for genetic effect in the development of atopy isderived from twin studies. And Wang concluded that atopy is a key condition in the development of allergic diseases, particularly with the Ig E-mediated mechanism. It is a disorder with strong familial



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Triggers of Allergic Rhinitis

According to Busse, an allergic reaction is usually caused by an allergen. In the cases of people withallergic rhinitis, when they breathe in these allergens such as pollens or dust, these cause their bodies torelease certain chemicals like histamine, bradykinin, and the like. These chemicals cause the persons withAR to experience symptoms of allergic reactions such as itching, swelling, and mucous production.Pollens that cause AR may differ depending on the person who inhales such pollens. Usually the smaller,hard-to-see pollens cause AR more often than the bigger ones. Examples of plants that produce the said

pollens are deciduous and evergreen trees, grasses, and ragweed. Development of symptoms may dependon the amount of pollen present in the air. During dry, hot, windy days there may be more pollens presentin the air thus, the increasing the probability of developing symptoms of AR. However, during cool,damp, rainy days pollens may not be abundant in the air since they would most likely be washed in theground. Reactions to allergens may also include eczema and asthma which are also part of the allergicreaction. The most common cause of developing AR is still genetic in nature. The chance of having AR ishigh if both parents have the disease . [15]

Togias stated that inflammatory mediators produced by mast cells that are activated by antigen-IgE cause the symptoms of AR. The mediators directly or indirectly target the end organs. For example,the histamine released by mast cells stimulates the sensory nerves which lead to sneezing, pruritus,rhinorrhea, and nasal congestion. Symptoms may also arise due to the phenomenon of hyper-responsiveness to non-allergenic stimuli like cold air and other irritants. The phenomenon is believed tohave arisen from the allergic inflammation on the sensory nerves that supply the mucosa of the upper respiratory tract mucosa. Different kinds of non-allergenic triggers were shown to act on the nasal mucosa

by the means of sensorineural stimulation. The responsiveness to these stimuli is also heightened in AR compared to healthy individuals. Also, stimulation of sensory nerves can produce inflammatory changesin AR. Such inflammation is called neurogenic inflammation but the mechanism behind this is not yetknown. However, Alkis also stated that evidence exists that neurotrophin nerve growth factor, the one

responsible for the changes in the sensory nerves, is found in elevated levels in the nasal secretions of persons with perennial AR compared to healthy individuals. The nerve growth factor is also acutelyreleased into nasal fluids after being triggered by allergens in patients with allergic disease. AR is alsovery common among patients with asthma of atopic origin. [16]

Severity of Allergic Rhinitis

Allergic rhinitis has been classified into two according to its severity : namely, ³mild´ and³moderate/severe´. The difference between the two classifications of AR is seen in the impact of theillness to the patient¶s regular daily activities. In moderate/severe AR, daily activities are impaired andsleep is disturbed because of its troublesome symptoms. On the other hand, the symptoms of mild AR are

tolerable enough so as not to impair the activities of the person. To add, AR can be further classified based on the duration of symptoms manifested by the patient ± ³intermittent´ and ³persistent.´Intermittent AR occurs when symptoms last less than four (4) days per week or less than four (4)consecutive weeks while the persistent type happens when the symptoms manifest more than four (4)days per week or for more than four (4) consecutive weeks. [17]



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Figure 1. A diagrammatic representation of the classifications of AR.

Risk Factors and Possible Confounding Variables of the Study

Allergens/IrritantsAllergens and irritants present in the environment are part of the confounding variables of the study.One of the allergens that commonly trigger allergic rhinitis is pollen. In a cohort study conducted inSweden in 2003, it has been identified that pollen accounted for seventy-three percent (73%) of thetrigger factors that cause Allergic Rhinitis. [18] Moreover, the incidence of allergic disease has beenthought to be constantly increasing [19] and this has been attributed to the increased exposure of children to air pollution, probably because of the presence of particulates in the air. [20]

Number of hours spent in air-conditioned rooms and non air-conditioned roomsSince one of the objectives of the research is to see whether or not air-conditioned rooms can helpalleviate allergic rhinitis, the number of hours is a confounder to our study. A cross-sectional studyconducted in Taiwan shows that persistent exposure to nitric oxides, carbon monoxide, and sulfur dioxide may increase the prevalence of allergic rhinitis in children. [21] This study suggests that, to acertain extent, exposure to outdoor air pollutants may increase the risk of allergic rhinitis in children.

Condition of the roomThe condition of the classroom, as will be surveyed upon implementation of the study, is aconfounding variable to this research because as already mentioned, allergens comprise a big part of the triggers of allergic rhinitis. Dust from unwashed curtains, carpets, or table cloths can beconsidered also as an allergen thus triggering a more severe allergic reaction. Furthermore, exposureto chalk dust, especially in a poorly ventilated classroom, may also trigger allergic rhinitis of the

affected students.

Summary of Related/Similar Studies

According to Kutintara, allergic rhinitis (AR) is the most common of all allergic diseases. The prevalence,which ranges from 4% to 40%, of this disease is spreading worldwide, including the Asia Pacific region.It has a great impact on a person¶s daily life. 82% of AR sufferers in the United States reported that theyalways or usually have symptoms at work or school. It is responsible for about 2 million lost school-days



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each year in the United States and a significant large number of Thai children indicated that their allergysymptoms were severe enough to limit their activities. [22]

There are currently no cures for allergic rhinitis. However, there are ways to treat the symptoms.These treatments include medication, immunotherapy, and avoidance. The most common medications for allergic rhinitis are antihistamines, decongestants, and antihistamines-decongestant combinations.Unfortunately, side effects are a main concern for taking medications. It was reported that 31% of patientsexperienced side effects from the medications and 65% of patients would not take some drugs because of the side effects. Allergen immunotherapy includes allergen vaccinations and periodic allergen shots tolessen a patient¶s sensitivity to allergens. It is for those who do not respond to medications or haveadverse side effects from the medications. Although the immunotherapy can reduce allergy symptoms,

patients should still continue practicing allergen avoidance. Practicing allergen avoidance while receivingimmunotherapy can significantly enhance the effectiveness of the treatment against AR. [22]

Avoidance is the primary method in treating AR. Those with allergies can reduce their allergicsymptoms by reducing their exposure to allergens. This includes promoting a healthy indoor environment.The main allergens that are found indoors are allergens from dust mites, cockroaches, and molds. Theseallergens can be avoided by knowing how to eliminate them. These allergens commonly survive in

environments that are warm, moist and humid. Dust mites cannot live in an environment that has arelative humidity of less than 50% while cockroaches and molds only thrive in areas of warmth andhumidity. Therefore, other than keeping an AR patient¶s surrounding environment clean, it is alsorecommended to have an air-conditioning system or proper ventilation system so that it can reduce theamount of allergens present in the patient¶s environment by reducing the humidity and heat levels. [22]

In congruence with the aforementioned study, according to Zacharisen, a member and a fellow of the American Academy of Asthma, Allergy, and Immunology, the key to reducing the severity of symptoms a child experiences at school is avoidance of these allergens. If it is possible, parents shouldtalk to school personnel to make them aware of the allergy triggers of their children so as to avoidaggravating their allergies. [23]

A study in Boston conducted by Blaisse stated that the symptoms of allergic rhinitis and theadverse effects of medications taken can diminish or lessen the cognitive function and learning of students. This can also affect the quality of student-life if aggravated. What¶s unfortunate is that mostconditions are left under-diagnosed or under-treated because symptoms are often discounted by parents as

just allergies. [24] The study further noted that aside from the loss of cognitive function in children withmoderate to severe AR, this can also cause irritability and fatigue leading to the inattentiveness anddifficulty in concentrating in school. One of the most important components of management, accordingto the study, is to educate the patient and the family about avoiding the allergens that the children areallergic to.

Another important thing to take note of is the environment of the school children in which they

will be exposed to. The most common allergens at school that may cause AR include dust mites, chalk dust, animal dander, pollen, molds, and even exercise. [23]

In response to these circumstances, there are a number of therapies than can be undertaken bychildren with AR. These include antihistamines, corticosteroids, leukotriene-receptor antagonists, mastcell stabilizers, anticholinergics, and allergen-specific immunotherapy depending on whether the AR isintermittent, persistent, severe, or mild. [24] It has been identified that second-generation antihistamines arethe more preferred treatment though it can produce some sedative effects.



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Oral and topical decongestants are also often used in addition with antihistamines. The onlydisadvantage is that it cannot alleviate any other symptoms of AR such as itching and sneezing. It canonly alleviate the nasal decongestion experienced with AR. Another therapy mentioned is with the use of corticosteroids and these corticosteroids usually act on the nasal mucosa (intranasal action) and treat mostof the symptoms of AR. This method is often recommended to children, especially those who present

with severe symptoms. However, systemic corticosteroids are not recommended to children because of itsserious side effects thus it should not be administered in chronic use. Leukotriene-receptor antagonists aremore effective antihistamines but less effective than the intranasal corticosteroids. Aside from minor sideeffects such as headache and otitis media, it is generally safe for children and teenagers. Mast cellstabilizers usually inhibit mast cell degranulation relieving the common symptoms of AR. However, thedisadvantage of this drug is that it has a short duration of action thus requiring more frequent doses.Anticholinergics inhibit the production of nasal secretions but have no effects on other symptoms of allergic rhinitis. The last therapy mentioned in the study is with the use of immunotherapy. This is theonly disease-modifying therapy for AR and it should only be considered for use to children with moderateto severe allergies. [24]

Another study in Spain conducted by Jauregui et. al. states that AR is the most common chronicdisorder that affects the pediatric population. [26] Data shows that AR and rhinoconjunctivitis represent themain cause of 55.5% of all patients seen in Spanish allergology clinics. Again, it is important to note thata third of the population of 13-14 year-old teenagers suffer from the symptoms of AR. [27] It has been alsostated in the study that AR somehow impairs daily activities such as visual coordination, retentioncapacity, and reaction time of students. [28]

The study also states that if the AR is untreated, school performance is also affected. AR causessleep disturbances, daytime sleepiness, absenteeism, ³presenteeism,´ irritability, restlessness, mooddisorders, and an altered social life. [26]

Sleep disturbances were caused by nasal congestion/blockade and also frequent awakeningsduring at night due to allergic inflammation. ³Presenteeism´ is the inattention, distraction, and lack of attention of the students while inside the classroom due to the symptoms of AR. Obviously, one of themain causes of learning difficulty and school failure is the students¶ inability to concentrate due tountreated AR²given that it is in fact one of the most common chronic illnesses that hits children andteenagers. [29]

Focusing on the building conditions wherein classrooms are situated, a study that concernstransmission of airborne diseases was conducted in Peru. Rooms that only had natural measures for encouraging airflow were compared with mechanically ventilated rooms that were built much morerecently. A comparison was also done between naturally ventilated rooms in old hospitals and naturally

ventilated rooms in newer hospitals. Results showed that natural ventilation had high rates of air exchange, with an average of 28 air changes per hour. 50 year old hospitals had the highest ventilationwith an average of 40 air changes per hour due to its structure. This rate is far higher compared to the 17air changes per hour in naturally ventilated rooms in modern hospitals, which have lower ceilings andsmaller windows. [30]



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In a study about the impact of school building conditions on student absenteeism in Upstate NewYork, researchers investigated this by obtaining data from the 2005 Building Condition Survey of Upstate

New York schools with 2005 New York State Education department students absenteeism data at theindividual school level and evaluated associations between building conditions and absenteeism at or above the 90 th percentile. As a result, researchers associated absenteeism with visible molds, humidity,

poor ventilation, vermin, building condition problems, and building system or structural problems relatedto these conditions. They also saw that schools in lower socioeconomic districts and schools attended byyounger students showed the strongest association between poor building conditions and absenteeism.With this study, there were some limitations. Some confounding variables were the external exposuressuch as traffic pollution and exposures from a student¶s home could have affected this study. In addition,absenteeism due to illness or other reasons could not be distinguished. The study's ecological design didnot allow collection of information on individual health outcomes or reasons for absenteeism. Inconclusion, they found associations between student absenteeism and adverse school building conditions.As a recommendation, further studies should confirm these findings and prioritize strategies for schoolcondition improvements. [3]

Conceptual Framework:

Exposure Variable Disease Variable

Figure 2. Conceptual framework of proposed study.

B ibliography:[1] Settipane, R.A. (2001). Demographics and Epidemiology of Allergic and Nonallergic Rhinitis

[Abstract]. Allergy Asthma Proc. 22(4) : 185-9. Retrieved July 8, 2011 from : http : //www.medscape.com/medline/abstract/11552666.

[2] Philippine Star (2008). Allergic Rhinitis Prevalent among Pinoys. Retrieved July 8, 2011 from : http : //library.pchrd.dost.gov.ph/index.php/news-archive/1080.

[3] Simons, E., Hwang, S., Fitsgerald, E., Keilb, C. & Lin, S. (2009). The Impact of School BuildingConditions on Student Absenteeism in Upstate New York. 100 (9). Research and Practice.

[4] Blaiss, MS. Allergic rhinitis and impairment issues in schoolchildren : a consensus report. CurrentMedical Research and Opinion. 2004 Dec; 20(12) : 1937-52. From : http : //www.redorbit.com/news/health/131029/allergic_rhinitis_and_impairment_issues_in_schoolchildren_a_consensus_report/index.html

[5] Meltzer, E.O. (1998). Treatment Options for the Child with Allergic Rhinitis. Clinical Pediatrics. Jan1998; 37, 1; ProQuest Research Library. Accessed July 7, 2011.

Improves allergic Rhinitis

Exacerbates Allergic Rhinitis

Exposure to Air-conditioning System

+

-

Allergens/Irritants

Number of hours spent in classroomCondition of the roomConfounders



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[6] A.D.A.M. (2011). Allergic rhinitis Hay fever Nasal allergies. Retrieved July 16 2011 fromhttp : //www.nlm.nih.gov/medlineplus/ency/article/000813.htm

[7] Ghazi, et. al. (2003). Frequency of Allergic Rhinitis in School-age Children (7-18 Years) in Tehran.Iranian Journal of Asthma, Allergy and Immunology. 2 (4).

[8] Cauwenberge, et. al. (2004). Epidemiology of Allergic Rhinitis. The UCB Institute of Allergy,Brussels.

[9] Sheikh, et al (2011). Allergic Rhinitis. Retrieved July 16, 2011 from http : //emedicine.medscape.com/article/134825-overview#a0104

[10] Wang (2005). Risk factors of allergic rhinitis : genetic or environmental? Retrieved July 16 2011from http : //www.ncbi.nlm.nih.gov/pmc/articles/PMC1661616/

[11] Settipane, R.J., Hagy, G.W., Settipane, G.A.(1994). Long-term risk factors for developing asthmaand allergic rhinitis : a 23-year follow-up study of college students. Allergy Proc. 15 : 21-25.

[12] Ryan, D., Yusuf, O., Ostergaard, M.S. & Rodriguez, M.R. (2011). Supporting statement by theinternational primary care respiratory group. Retrieved fromhttp : //www.worldallergy.org/UserFiles/file/WAO-White-Book-on-Allergy_web.pdf

[13] Pawankar, R., Canonica, G.W., Holgate, S.T. & Lockey, R.F. (2011). WAO (World AllergyOrganization) White Book on Allergy [pp. 11]. (PDF version), Retrieved fromhttp : //www.worldallergy.org/UserFiles/file/WAO-White-Book-on-Allergy_web.pdf

[14] Mösges, R. et. al. (2011). Emerging Areas of Interest in the Management and Treatment of AllergicRhinitis. Retrevied from http : //www.touchrespiratory.com/files/article_pdfs/Hassan.pdf

[15] Busse, P. (2010). Allergic rhinitis. M edlineplus . Retrieved July 16, 2011, fromhttp : //www.nlm.nih.gov/medlineplus/ency/article/000813.htm.

[16] Togias, A. (2004). Unique mechanistic features of allergic rhinitis. Journal of allergy and clinical

immunology . Retrieved July 16, 2011, fromhttp : //www.sciencedirect.com/science/article/pii/S0091674900093143.[17] Bousquet, J., Reid, J., Van Weel, C., Baena Cagnani, C., Demoly, P., Denburg, J., Fokkens, W.J.,

Grouse, L., Mullol, K., Ohta, K., Schermer, T., Valovirta, E. & Zhong, N. (2008). Management of Allergic Rhinitis and its Impact on Asthma. ARIA Pocket Guide [Internet]. MCR Inc. [cited2011 July 24]; [7 pages]. Available from : http : //whiar.org/docs/ARIA_PG_08_View_WM.pdf

[18] Alm B, Gokso¨ r E, Thengilsdottir H, Pettersson R, Mo¨ llborg P, Norvenius G, Erdes L, A ° berg N,Wennergren G. Early protective and risk factors for allergic rhinitis at age 4½ years. Pediatric

Allergy and Immunology 2011; 22 : 398±404. Retrieved July 22, 2011 fromhttp : //onlinelibrary.wiley.com/doi/10.1111/j.1399-3038.2011.01153.x/pdf

[19] Nakagomi T, Itaya H, Tominaga T, et al. Is atopy increasing? Lancet 1994 ;343:121 ±2. RetrievedJuly 22, 2011 from http : //www.ncbi.nlm.nih.gov/pubmed/7903758

[20] Hajat S, et al. Association between air pollution and daily consultations with general practitioners for allergic rhinitis in London, United Kingdom. American Journal of Epidemiology (2001) 153 (7) : 704-714. Retrieved July 22, 2011 from http : //aje.oxfordjournals.org/content/153/7/704.full

[21] Hwang B, et al. Relationship of air pollution and allergic rhinitis in Taiwanese school children. Respiratory Research 2006, 7 : 23. Retrieved July 22, 2011 from http : //respiratory-research.com/content/7/1/23

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