asthma is a chronic inflammatory disorder of the airways characterized by bronchial hyperresponsiveness , reversible airflow limitation , and respiratory symptoms ( 1 , 2 ) .
internationally , the prevalence of asthma has increased over the last 3 decades ( 3 - 5 ) , and in the asia - pacific region asthma causes considerable morbidity , with 15% of teenagers troubled by exercise - induced symptoms during the past 12 months ( 6 ) .
furthermore , asthma mortality rates in more affluent areas , such as hong kong and japan , are similar to those reported in western countries ( 6 ) .
the reported prevalence of asthma in korea ranges from 2 to 13% ( 9 - 18 ) .
however , its prevalence in the elderly has been reported to be very high , at 12.7% in those aged 65 or more ( 15 ) .
indeed , with a population estimated at more than 48 million , and a life expectancy of 72.0 yr for males and 79.5 yr for females ( 19 ) , korea faces an important public health challenge in terms of dealing with chronic diseases such as asthma .
in addition to its increasing prevalence , the economic impact of asthma is also substantial and continues to grow .
the total cost of the disease in the united states was estimated to be u$4.5 billion in the mid-1980s , whereas in the first half of the 1990s , this estimate had increased to between u$6.2 and u$10.7 billion ( 20 - 22 ) . in korea , where health insurance is mandatory and the cost of medical care is only covered in part by health insurance , the importance of economic outcomes also continues to grow although little data is currently available .
the purpose of this review is to present an overview of the current disease status with respect to the prevalence , mortality rate , socioeconomic burden , quality of life and the treatment patterns of asthma in korea , to identify barriers to improvements in asthma care and to provide recommendations for action at the national , organizational and individual levels . for this ,
all relevant english and korean language articles were retrieved using pubmed ( www.ncbi.nlm.nih.gov/entrez/query.fcgi ) and koreamed ( www.koreamed.com ) from november 2004 to january 2005 .
recently , several large - scale studies of different population in korea ( 9 - 17 ) have reported asthma prevalence ranging from 2 to 13% ( table 1 ) .
these differences are probably ascribable to different case definitions , methodologies , and a tendency to survey children rather than adults due to the relative ease of implementing studies in a school environment . according to the latest summary issued by the global burden of asthma by the global initiative for asthma ( gina ) program ,
the prevalence of clinical asthma in korea is estimated to be 3.9% ( 23 ) .
the prevalence of asthma tended to be higher in children than in adults and was found to depend significantly on their place of residence , for example , it was found to be higher in seoul than in provincial cities ( 7 ) . according to 1998 data ( 11 ) ,
childhood asthma was less prevalent in korea than in other developed countries . however , among the elderly ( aged 65 yr or older ) , its prevalence was found to be high at 12.7% in 2001 ( 15 ) , which is about three times higher than among english or us elderly ( 24 , 25 ) .
although estimations of asthma prevalence in older age groups differ greatly between countries because of overlapping diagnoses , and poor patient perception of symptoms ( 24 ) , this rate is unexpectedly high . in the elderly , asthma is an important problem because it is usually underdiagnosed and hence inadequately treated ( 24 - 26 ) .
interestingly , korean adults and children appear to have a later average age of asthma onset than other asian populations ( 12 ) ( fig .
this is likely to be due to the underdiagnosis of early stage asthma by general physicians .
some investigators have reported that an underdiagnosis rate by general physicians was 21% ( 27 ) .
another contributable factor may be that a high proportion of korean people , at least initially , turn to traditional medicine for medical help ( 28 - 30 ) , which delays the diagnosis until they are referred to hospitals or emergency department with severe symptoms .
age , sex , affluence , genetic predisposition , climate , outdoor air quality and cigarette smoking have all been found to be associated with asthma ( 7 , 12 , 15 , 31 - 33 ) .
studies suggest a higher incidence of asthma in children than in adults ( 9 - 15 , 17 , 34 ) , and male asthmatic patients were found to be more often hospitalized or treated at a tertiary medical centers than their female counterparts ( 34 , 35 ) . in a regression analysis of the asthma insights and reality in asia - pacific ( airiap ) data for the eight areas of asia - pacific countries including korea , it was found that a low household income is significantly associated with the likelihood of having moderate or severe persistent asthma symptoms ( p=0.002 compared with a high income status ) ( 12 ) .
it has been reported that the genetic variations of the chemokine ( c - x - c motif ) receptor 3 ( cxcr3 ) ( 36 ) , the signal transducer and activator of transcription 4 ( stat4 ) ( 37 ) , a disintegrin and metalloprotease 33 ( adam33 ) ( 38 ) , and tumor necrosis factor - alpha ( tnf- ) ( 39 ) are associated with the susceptibilities to the development of asthma and its intermediate phenotypes in the korean population . the il-4 cytokine gene cluster and/or the t cell receptor / gene complex
are believed to be associated with the expression of bronchial responsiveness to methacholone in nuclear families ( 40 ) , and a polymorphism in exon 7 of chromosome 11q13 was found to be significantly associated with histamine release from basophile to anti - ige stimuli in 80 randomly recruited asthmatic children ( 41 ) .
spider mites ( citrus red mite ) ( 42 , 43 ) , the european red mite ( panonychus ulmi ) , ( 44 ) and the two - spotted spider mite ( tetranychus urtcae ) ( 44 ) , have been identified as important allergens in the development of work - related asthma and rhinitis symptoms and toluene diisocyanate has been most commonly implicated allergen in occupational asthma in korea ( 45 ) .
a number of studies have documented an association between air pollution and asthma - related morbidity in korean cities and have linked active smoking with asthma prevalence and severity ( 15 , 28 , 29 , 46 - 48 ) .
the accurate determination of the asthma mortality in korea is difficult . because large - scale medical databases tend to group asthma data along with those of other disease states , or to group it with less specific group diagnoses such as ' chronic lower respiratory diseases ' ( 49 ) .
according to the korea national statistical office data , the death rate from chronic lower respiratory diseases ( including asthma ) between 1992 and 2002 increased from 12.9 to 22.6 deaths per 100,000 of the population ( 50 ) . in 1992 ,
chronic lower respiratory diseases were ranked as the eighth leading cause of death in korea , and in 2002 , this had risen to fifth place proceeded only by diabetes mellitus , heart disease , cerebrovascular disease , and cancer ( 50 ) ( fig .
2 ) . according to the latest gina estimates , there are 4.9 asthma related deaths per 100,000 asthmatics each year in korea ( 23 ) .
globally , respiratory diseases are responsible for 6.3% of all death and asthma for 0.4% ( 51 ) .
these include cigarette smoking , chronic asthma severity , frequent hospitalization , the duration of recent asthma exacerbations , age and a female sex ( 28 , 52 , 53 ) .
at present , little data is available on the economic burden posed by asthma in korea .
however , indirect estimates may be made based on the market shares of asthma medications in korea . according to the data from the pharmaceutical industry ( 54 ) , from 2001 to 2004 , the annual gross value of drugs sold in korea increased by nearly 50% ( from u$3.48 to u$5.21 billion ) and the proportion shared by drugs for asthma treatment in respiratory drug market increased by approximately 36% ( from u$51.8 to u$70.6 million ) .
research in this area is underway , with a large - scale analysis being performed using data from health insurance review agency ( hira ) , the 1998 national survey on health and nutrition in korea , and an ongoing patient survey .
to adequately account for cultural and behavioral factors , a quality of life questionnaire for adult korean asthmatics ( qlqaka ) was developed ( 55 ) , and in a multicenter study 5 using qlqaks , it was found that dyspnea ( 87% ) , difficulty in sputum discharge or throat clearing ( 87% ) , strenuous activity limitation ( 84% ) , and coughing ( 82.4% ) were most frequently complained about by adult asthmatics ( 55 ) .
the airiap study revealed that approximately one - third of all korean asthmatic patients felt restricted in terms of their abilities to perform the routine activities of daily living such as , exercise , social activities , or sleeping ( 12 ) .
this survey also reported that 52% of asthmatic patients had experienced daytime symptoms during 4 weeks prior to completing the questionnaires , and that 41% of patients with asthma had been woken at night by their symptoms ( 12 ) .
another study conducted to assess the quality of life of 189 patients showed that running , walking , and hurried movements appeared to be the most impaired daily activities ( 56 ) .
the characteristics that significantly impaired an individual 's quality of life score were disease severity , level of asthma control and symptom attacks during the previous 3 months ( all p<0.001 ) ( 56 ) .
interestingly , a discrepancy was identified between perceived and actual asthma control in a substantial number of asthma patients . according to airiap data ,
about one - fifth of korean asthmatic patients with severe persistent symptoms considered that their asthma was adequately controlled , despite their current symptoms suggesting otherwise ( 12 ) ( fig .
this is due in part to the fact that some asthmatics have poor symptom perception ( 57 - 59 ) and partly because asthmatics in korea are not adequately educated about the practical and theoretical aspects of asthma management ( 60 , 61 ) .
no national guidelines concerning best management practice of asthma have been issued in korea , although three academic associations have published separate guidelines ( 62 - 64 ) . however , almost half of the physicians ( 43% ) in 325 korean clinics surveyed by the hira either did not use or were unfamiliar with these guidelines ( 65 ) .
therefore , few asthma patients used or were prescribed inhaled corticosteroid by their physicians to prevent symptoms ( 65 ) ( fig .
4 ) . the reasons for this reluctance to prescribing inhaled corticosteroid as cited by physicians in the hira survey were , in decreasing order ; lack of patient education concerning inhaler use , high cost , patient refusal to use , and side effects ( 65 ) .
in addition , according to the airiap survey , 65% of patients with asthma in korea have never undergone a lung function test , and only 32% of patients reported that they had undergone a lung function test during the previous year ( 12 ) .
moreover , although 6% of patients owned a peak flow meter for self - monitoring , only 20% of them used it daily , whereas another 20% used it on a symptomatic basis ( 12 ) .
another survey found that patients who used a nebulizer at home were not properly instructed as to how to use it , and did not follow equipment maintenance procedures ( 66 ) .
however , paradoxically , most korean asthmatics were satisfied with their treatment , although many expressed a need for more information on the disease ( 12 ) .
this ' disconnect ' from the guidelines by physicians has had a major impact on the management of asthma patients .
to reduce this gap , an ' easy asthma management ' study is currently underway in korea .
the purpose of this study may provide a simple stereotyped algorithm using a computer based program to allow clinicians to easily diagnose asthma and implement its correct management . in december 2004
, it was estimated that 11.9 million koreans had access to the world wide web ( www ) and the number of allocated ip addresses allocated in korea ranked eighth worldwide ( 67 ) . nowadays , computer - based educational programs available on the www are believed to be an effective alternative as they overcome the cost and time barriers that prevent implementation of education programs for asthmatics ( 68 ) .
however studies have shown that asthma educational material on the web sites is highly variable in quality and content , lacks detail of the core concepts essential for asthma education , and fails to meet patients needs ( 69 , 70 ) .
this review showed that the prevalence of asthma in korea ranges from 2 to 13% , and that physicians and patients often underestimate its severity .
mortality from chronic lower respiratory diseases including asthma increased from 12.9 to 22.6 deaths per 100,000 of the population between 1992 and 2002 .
disease severity , level of control , and symptom state were all found to negatively impact the quality of life of asthmatics . moreover , although international and korean asthma management guidelines are available , primary care physicians are largely unfamiliar with or fail to implement them .
 a systematic review of english and korean articles published between 1990 and 2004 and a search of database and various online resources was conducted to determine the prevalences , mortality rates , socioeconomic burden , quality of life , and treatment pattern of asthma in korean adults and children . 
 asthma morbidity and mortality in korea are steadily increasing . 
 the prevalence of asthma in korea is estimated to be 3.9% and its severity is often underestimated by both physicians and patients . 
 mortality resulting from chronic lower respiratory diseases including asthma increased from 12.9 to 22.6 deaths per 100,000 of the population between 1992 and 2002 . 
 disease severity , level of control , and symptom state were all found to negatively impact the quality of life of asthmatics . 
 although international and korean asthma management guidelines are available , familiarity with and implementation of these guidelines by primary care physicians remain poor . 