Changes In Prevalence Of Asthma Research Articles

Longitudinal changes in the prevalence of adult asthma: An epidemiological survey among Japanese salaried employees and their dependents using healthcare insurance claim from 1999 to 2019

BackgroundInformation on changes in asthma prevalence and the treatment status for asthma is used as basic information for taking medical and administrative measures against asthma. However, this information among adults is relatively limited. MethodsTo elucidate changes in the prevalence of asthma and treatment status over time among Japanese adults, health insurance claim data from some health insurance societies covering salaried employees and their dependents were studied longitudinally. Claim data from FY1999 to 2007 were obtained from two health insurance societies, and data from FY 2011 to 2019 were obtained from three different health insurance societies, and changes in standardized asthma prevalence among subjects aged 20–59 years, proportion of asthma patients prescribed ICS, leukotriene receptor antagonist (LTRA), and LABA, and the mean number of acute asthma exacerbations per year were analyzed. ResultsThe prevalence of asthma increased from 1.6% in 1999 to 3.0% in 2007 and 2.9% in 2011 to 4.6% in 2019. Increased trends in asthma prevalence from 2011 to 2019 were more noticeable in subjects in their 50s than those in their 20s for both sexes. The number of emergency visits related to asthma was 1.5 per year in 1999, which decreased to 0.8 per year in 2019. The proportion of people prescribed all anti-asthma medications (ICS, LTRA, and LABA) increased over time. ConclusionsThe prevalence of adult asthma among Japanese salaried employees and their dependents has increased over the last 20 years, suggesting more attention should be paid to the prevention of this disease in adults.

Rising and falling prevalence of asthma symptoms

Asthma is the leading chronic disease in children, affecting 5·1 million children in the USA. 1 Asthma and Allergy Foundation of AmericaAsthma facts and figures. https://www.aafa.org/asthma-factsDate: 2021 Date accessed: July 13, 2021 Google Scholar However, worldwide important variations have been reported in asthma prevalence. In The Lancet, Innes Asher and colleagues report findings from the Global Asthma Network (GAN), assessing global changes in asthma prevalence over the past three decades, with use of similar, standardised methods as the International Study of Asthma and Allergies in Childhood (ISAAC). 2 Asher MI Rutter CE Bissell K et al. Worldwide trends in the burden of asthma symptoms in school-aged children: Global Asthma Network Phase I cross-sectional study. Lancet. 2021; 398: 1569-1580 Google Scholar Using centres that completed GAN Phase I and ISAAC Phase I (1993–95), ISAAC Phase III (2001–03), or both, the authors assessed the global prevalence and the 10-yearly change in prevalence of current wheeze, severe asthma symptoms, asthma ever, exercise wheeze, and night cough (defined by four core questions in a questionnaire). The study included data from questionnaires filled by almost 120 000 adolescents (aged 13–14 years) and school-aged children (aged 6–7 years) from 27 centres in 14 countries. Worldwide trends in the burden of asthma symptoms in school-aged children: Global Asthma Network Phase I cross-sectional studyTrends in prevalence and severity of asthma symptoms over the past three decades varied by age group, country income, region, and centre. The high worldwide burden of severe asthma symptoms would be mitigated by enabling access to effective therapies for asthma. Full-Text PDF Open Access

Association between Temporary Housing Habitation after the 2011 Japan Earthquake and Mite Allergen Sensitization and Asthma Development

Introduction: We previously reported an increased prevalence of asthma in adults who lived in temporary housing after the 2011 Great East Japan Earthquake. The goal of the current study was to investigate changes in asthma prevalence and mite-specific immunoglobulin E (IgE) titers in temporary housing residents during 2014–2019. Methods: By using the Global Initiative for Asthma guidelines, we diagnosed asthma in Ishinomaki city temporary housing residents aged 15 years or older. We then analyzed serum antigen-specific IgE levels to Dermatophagoides farinae (Der f), Dermatophagoides pteronyssinus (Der p), and Aspergillus fumigatus. Results: The prevalence of asthma exceeded 20% across all age-groups throughout the study period. The proportion of study participants with a “positive” antigen-specific IgE titer (i.e., ≥0.35 IU_A/mL) was higher in asthmatics than in nonasthmatics for Der f and Der p but not for Aspergillus fumigatus. Among residents ≥50 years old who were diagnosed with asthma, the percentage with a Der f-specific IgE titer ≥0.10 IU_A/mL was higher than the proportion with ≥0.35 IU_A/mL. Among study participants, asthma onset occurred before the earthquake, during residence in shelters or temporary housing, and (starting in 2016) after moving out of temporary housing. The Der p-specific IgE level was positively correlated with the duration of temporary housing (p < 0.05, r = 0.41) and inversely correlated with the time elapsed since moving out of temporary housing (p < 0.05, r = −0.35). Conclusion: Mite allergen sensitization was found in both asthmatic and nonasthmatic temporary housing residents after the 2011 Japan earthquake and tsunami; asthma developed even after subjects moved out of temporary housing.

Changes in children's asthma prevalence over two decades in Lanzhou: effects of socioeconomic, parental and household factors.

BackgroundThe prevalence of childhood asthma may have changed with rapid economic development. This study aims to ascertain potential changes in asthma prevalence in relation to changes in socioeconomic, parental and household factors, based on a comparison between two periods spanning over 20 years in Lanzhou, a large northwestern city of China.MethodsCross-sectional studies using the same protocols were performed in Lanzhou, China in 1994–1995 (Period I) and in 2017 (Period II). Children of 6–12 years old from elementary schools were selected by a multistage sampling method. Information on the presence of asthma and asthma-related symptoms of children, socioeconomic status, feeding methods, parental illness and behavior patterns, as well as household characteristics, were collected through a questionnaire survey. Logistic regression models were used to estimate odds ratios of asthma prevalence with regard to socioeconomic, parental and household factors, respectively.ResultsSignificant prevalence reductions were observed for paternal smoking, household coal use, and parental asthma, while the prevalence increased significantly for children sleeping in their own rooms or own beds, ventilation use during cooking, and parental occupation and education level after 22 years. In children, the prevalence of ever-diagnosed asthma decreased from 3.2% in period I to 1.5% in Period II (P<0.001); the prevalence of wheeze also decreased from 15.4% to 9.3% (P<0.001). Passive smoking (OR =1.531, 95% CI: 1.032–2.270) and poor household ventilation (OR =1.709, 95% CI: 1.208–2.416) were significantly associated with an increased prevalence of wheeze in Period I, whereas household mold (OR =2.112, 95% CI: 1.203–3.811) was significantly associated with prevalence of wheeze. Parental asthma history was associated with increased prevalence of asthma and asthma-related symptoms. Breastfeeding was significantly associated with reduced risk of asthma in period II children.ConclusionsThe prevalence of asthma and that of asthma-related symptoms were lower in 2017 than in 1994–1995 in school children living in Lanzhou. In 2017 with increased urbanization and industrialization, breastfeeding became a significant protective factor and household mold was a significant risk factor for asthma diagnosis and asthma-related symptoms. Promoting breastfeeding and household mold control is recommended to reduce the risk of childhood asthma in contemporary Lanzhou.

Change in the symptom profile treated as asthma \u2013 two cross-sectional studies twenty years apart

AimsThe aims of the study were to investigate prevalence trends of respiratory symptoms, asthma and asthma treatment among young adults in Estonia and to estimate changes in symptom profile among subjects who self-report asthma attacks or use asthma medications.MethodsTwo similar questionnaires on respiratory health were sent to subjects in Tartu, Estonia, aged between 20 and 44 years; first in 1993/94, and then in 2014/15. To study the impact of different respiratory symptoms on asthma diagnosis and treatment, the log–binomial regression was used to estimate the association between ‘attack of asthma’ (as a proxy for current asthma) and respiratory symptoms as well as asthma treatment and respiratory symptoms, adjusted for age, sex and smoking history.ResultsSelf–reported prevalence of asthma attack, asthma medication use and nasal allergies increased over the twenty years between studies, whereas there was no change in prevalence of asthma–related symptoms, and the prevalence of most respiratory symptoms either decreased, or remained unchanged. For women experiencing asthma attacks, the prevalence of nasal allergies increased and waking with chest tightness decreased. For men using asthma medication, the prevalence of a wheeze without a cold decreased. Women using asthma medication reported decreased prevalence of waking with chest tightness.ConclusionSelf-reported asthma attacks and asthma medication use has increased in last 20 years, while the prevalence of most respiratory symptoms either decreased or did not change. It is likely that changes in asthma symptom profile have had an impact on the prevalence of asthma and asthma treatment.

Can selection explain the protective effects of farming on asthma?

Reduced asthma and allergy risks in farmers have been ascribed to microbial exposures. However, selection may also play a role and this was assessed in two Scandinavian farming populations. Asthma prevalence in 739 Danish farming students was compared to that of 1,105 siblings. 8,482 Norwegian farmers were also compared with 349 early retired farmers. The prevalence of ever-asthma was 5.4% in farming students and 5.2% in siblings (OR 1.1; 95%CI 0.73-1.7). Current asthma in farmers was 3.0% compared to 6.3% in farmers who had retired early (OR 1.8, 95%CI 1.1-2.9). Adjustments for early retirement increased the asthma prevalence by 0.3-0.6%. Farmers who had changed production were more likely to have asthma (OR 9.8, 95% CI 6.0-16). No healthy worker selection into farming was observed and changes in asthma prevalence due to early retirement were small. Selection effects are therefore unlikely to explain the protective effects of farming on asthma.

Atopy and allergic respiratory disease in rural Poland before and after accession to the European Union

In 2003, we recorded a striking difference in the prevalence of atopy between village and small-town populations in southwest Poland. Nine years later, we undertook a second survey of the same area. We sought to assess whether rapid changes in farming practices, driven by accession to the European Union in 2004, were accompanied by an increase in atopy, asthma, and hay fever in these villages. In 2012, we surveyed 1730 inhabitants older than 5 years (response rate, 85%); 560 villagers and 348 town inhabitants who had taken part in the earlier survey. Participants completed a questionnaire on farm-related exposures and symptoms of asthma and hay fever. Atopy was assessed by using skin prick tests. In 2012, far fewer villagers had contact with cows (4% vs 24.3% in 2003) or pigs (14% vs 33.5%), milked cows (2.7% vs 12.7%), or drank unpasteurized milk (9% vs 35%). Among the villagers, there was a significant increase at all ages in the prevalence of atopy between 2003 and 2012 both in the total population (7.3% vs 19.6%, P < .0001) and among those who took part in both surveys (7.9% vs 17.8%, P < .0001). Among the townspeople, the prevalence of atopy did not change substantially (20% vs 19.9% and 21.7% vs 18.5%, respectively). Hay fever increased 2-fold in the villages (3.0% vs 7.7%) but not in the town (7.1% vs 7.2%); there was little or no change in asthma prevalence in the villages (5.0% vs 4.3%) or town (4.3% vs 5.0%). We report a substantial increase in atopy at all ages and in a remarkably short period of time in a Polish population whose farm-related exposures were dramatically reduced after their country's accession to the European Union.

House dust mite sensitization is the main risk factor for the increase in prevalence of wheeze in 13‐ to 14‐year‐old schoolchildren in Guangzhou city, China

Little is known about time trend of prevalence of asthma and the association between the changing prevalence and allergen sensitization in Chinese children. To determine the changes in prevalence of asthma and allergen sensitization in schoolchildren over a period of 15years. A total of 6928 schoolchildren aged 13-14years in 2009 were recruited for the study using the Phase III Protocol of the International Study of Asthma and Allergic disease in Childhood (ISAAC) and 2531 of them underwent skin prick test for seven common aeroallergens. The results were compared with those obtained in the Phase I (1994/95) and III (2001/02) ISAAC studies. The prevalence of asthma ever and current wheeze increased from 3.9% and 3.4% in 1994, to 4.6% and 4.8% in 2001 (P<0.001), and to 6.9% and 6.1% in 2009 (P≤0.008). The prevalence of higher degree of skin response to house dust mites (HDMs) and cat, and atopic index increased significantly in all children in 2010 when compared with those in 2002 (P<0.001). Prevalence of wheeze remained unchanged in subjects without sensitization to any tested allergen including HDMs (P>0.05). Sensitization to HDMs, especially Dermatophagoides Pteronyssinus was associated with increase in prevalence of wheeze. The prevalence of wheeze and sensitization to common aeroallergens in secondary schoolchildren in Guangzhou China has increased significantly since 1994. Sensitization to HDMs is an important risk factor associated with the increase in prevalence of wheeze in this group of population in Guangzhou city.

Lessons Learned from the Prevalence of Childhood Asthma in Korea

Asthma is a chronic disease in childhood that affects virtually every facet of a patient's life and school activities, and every member of the family. It imposes a substantial socio-economic burden and demands many special considerations. Despite frequent updates on the current concepts of asthma management and its natural history, the prevalence of childhood asthma has increased worldwide in recent decades. More recently, however, comparable data on the prevalence of childhood asthma showed little change or a plateau in the incidence in some countries, including Korea. For example, the prevalence of asthma symptoms in the past 12 months in 13- to 14-year-old school children was 8.7% in Korea, compared with 8.8% in the entire Asia-Pacific region.1 As part of collaborative international studies in 1995, 2000, and 2005, national and regional cross-sectional surveys of asthma were performed using the Korean versions of the International Study of Asthma and Allergies in Childhood (ISAAC) written and video questionnaires. The ISAAC involves epidemiological studies enthusiastically carried out by the contributing members of the Korean Academy of Pediatric Allergy and Respiratory Diseases. There is little doubt regarding the prevalence of asthma determined by the ISAAC using the Korean versions of the written and video questionnaires.2,3 The lifetime prevalence of wheezing fell from 19.3% in 1995 to 14.4% in 2000 in Korea, whereas the number of affected children increased during this period in other countries.4 In addition, the prevalence of wheezing in the previous 12 months decreased from 10.5% in 1995 to 5.2% in 2000 in Korea.4 In contrast to the increased prevalence of asthma in 13- to 14-year-old children in Japan, the prevalence decreased in Korea. This decrease was partially attributable to a greater awareness of symptoms, early diagnosis, and proper management of childhood asthma by caregivers and physicians, following a successful Nationwide Asthma Campaign. In this issue, Kwon et al.5 showed that there was little change in asthma prevalence between 2005 Lessons Learned from the Prevalence of Childhood Asthma in Korea Ha-Baik Lee Department of Pediatrics, Hanyang University College of Medicine, Seoul, Korea (13.0%) and 2008 (11.7%) based on the results of an epidemiological study conducted in metropolitan Seoul in 2008, using the same methodologies. A comparison of asthma prevalence among sequential phases of the ISAAC revealed similar trends. The rate for any diagnosis of asthma ever was 8.7% in 1995, 9.4% in 2000, 7.6% in 2005, and 7.9% in 2008. The prevalence of asthma treatments during the previous 12 months was 3.5% in 1995, 3.3% in 2000, 3.0% in 2005, and 2.7% in 2008. Several risk factors are important in the development of asthma in children, and although some childhood asthmatics 'outgrow' the disease, asthma more commonly persists throughout adulthood. Both genetic susceptibility and environmental factors contribute to the development and persistence of asthma symptoms in children.6 Arruda et al.7 reported that risk factors for asthma include early sensitization to airborne allergens, a history of atopic dermatitis or allergic rhinitis, maternal smoking during pregnancy, passive smoking, lower respiratory infections, air pollution, and various genetic polymorphisms. The risk factors for asthma symptoms in Korean children are similar to those identified in Phase Three of the ISAAC; these include body mass index, passive smoking, and pets.8 In this paper, striking risk factors for asthma development were male gender; a history of atopic dermatitis, allergic rhinitis, or viral bronchiolitis; parental asthma; use of antibiotics during infancy; exposure to molds in the house during infancy; and moving to a new house, especially in genetically susceptible individuals.5 These results offer an opportunity to better understand asthma development. In general, medical research has made progress in many human diseases, and advances in asthma research have reduced the toll of the disease. Nevertheless, much work remains. One common goal is to refocus attention on the prevalence and risk factors based on epidemiological studies of childhood asthma. However, efforts must still be directed toward better prevention and management of the disease, with a goal of minimizing the potential deterioration of lung function. It is important to educate the public and the medical community regarding more effective preventive measures and therapies for asthma.

Asthma and Allergic Diseases in School Children from 1992 to 2007 with Incidence Data

Background. Information about change in the prevalence of asthma and allergic diseases and factors related with these diseases would be beneficial in decreasing the burden of these diseases. Objective.To assess (i) change in prevalence of asthma and allergic diseases; (ii) factors associated with asthma and wheeze; and (iii) incidence of asthma and wheeze. Methods. A questionnaire was administered to children aged 7–12 years in first five grades in the same primary school in 1992 (n: 1036), 1997 (n: 738), 2002 (n: 621), and 2007 (n: 422) and filled by the parents. A second survey in 2007 (n: 474, in eight grades) was conducted in the same schoolchildren, 6 months apart, to assess the incidence of asthma and wheeze and the associated factors. Results. Comparison of 1992, 1997, 2002, and 2007 surveys revealed that prevalence of asthma (8.3%, 9.8%, 6.4%, 3.3%, respectively), wheeze (11.9%, 13.3%, 6.4%, 3.1%, respectively), hay fever (15.4%, 14.1%, 7.2%, 3.1%, respectively), and eczema (4.0%, 4.3%, 1.8%, 1.2%, respectively) were significantly lower in 2002 and 2007 compared with that in 1992. Percentage of passive smoking decreased after 1992 (74.0%, 64.0%, 64.1%, and 65.5%, respectively). Incidence of asthma and wheeze in 2007 surveys were 0.9/100 and 1.1/100, respectively. After the adjustment for age and gender, infection in the past, family atopy, and presence of atopic disease (eczema or hay fever) were associated with asthma and wheeze. Maternal smoking and lack of breast feeding were associated with asthma. Male gender, pet ownership in the past, lack of health insurance coverage, snoring, and wood or coal used as fuel were associated with wheeze. Conclusions. Decreased prevalence of asthma and allergic diseases in the last 10 years could be related to decreased rate of passive smoking. Lower socioeconomic status and lack of breast feeding could increase the risk of asthma in children.

Changes in the prevalence of asthma, eczema and hay fever in pre‐pubertal children: a 40‐year perspective

Surveys of primary schools children in Aberdeen carried out in 1964, 1989, 1994 and 1999 suggested a slowing of the increase in parent-reported wheeze between 1994 and 1999. To assess whether this pattern had continued, questionnaires were distributed to 5712 children aged 7-12 years in the same schools in 2004. A total of 3271 (57.3%) completed questionnaires were returned. As in earlier surveys the results were divided into those for younger children (school years 3-4; age 7-9 years) and older children (school years 5-7; age 9-12 years). Compared with 1999, the 2004 results showed a decrease in the proportion of children with wheeze in the last 3 years from 30.1% to 23.3% (P < 0.001) in the younger group and from 27.6% to 25.1% (P = 0.052) in the older group. There was no significant change in the lifetime prevalence of asthma in either the younger or the older group, but the lifetime prevalence of eczema and hay fever increased by around 10% in both the younger and older groups (all P < 0.001). The differences in the time trends for the different conditions suggest that the causal factors for wheeze and asthma differ from those for other allergic diseases of childhood.

Changes in asthma prevalence among school children during a 6 -year period: Influence of socioeconomic status

Asthma prevalence is increasing worldwide, especially in developing countries. To determine the prevalence of asthma diagnosis and related symptoms in children, its changes during a 6-year period and the influence exerted by socioeconomic status. Cross-sectional study conducted among school children of Santiago. A sample of 4,561 children aged 6-7 and 13-14 years attending public schools (central district, medium-low and low socioeconomic status) and private schools (eastern districts, high socioecomic status) were surveyed. Dependent variables were asthma diagnosis (AD), wheezing during the last 12 months (WHE12) and frequency of episodes of wheezing (FEW). Prevalence odds ratios were calculated using regression models, adjusted for several confounding variables. AD prevalence for the group as a whole was higher in boys than in girls (13.2% and 10.8%, respectively p =0.016). Prevalence rate of AD was also higher for children aged 13-14 than 6-7 years (13.8% and 10.1%, respectively p <0.01). An inverse association was found between SES and WHE12. Higher maternal education level was associated with lower prevalence of WHE12 in both age groups and with lower prevalence of FEW in 6-7 year-old children. Paternal education level was positively associated with AD among younger children. At the central district, increasing trends of WHE12 and FEW prevalence were observed during 1994-2000 among 6-7 years children. A significant association was observed between socioeconomic status, asthma diagnosis and symptoms in school children living in Santiago. Data support an increasing trend of asthma prevalence and severity among 6-7 year-old children during the period 1994-2000.

Asthma during the primary school ages – prevalence, remission and the impact of allergic sensitization

Childhood is the most important time for asthma development. The aims of this study were to study changes in prevalence of asthma and wheeze, remission of asthma and changes in risk factor pattern from age 7-8 to age 11-12 in a cohort of school children. In 1996, 3525 children aged 7-8 years in northern Sweden were invited to participate in a parental expanded ISAAC questionnaire survey. The cohort has been followed prospectively with yearly follow-ups to age 11-12, with a 97% yearly response rate. Skin prick tests were conducted at age 7-8 and 11-12. The prevalence of physician-diagnosed asthma increased from 5.7% at age 7-8 to 7.7% at age 11-12. Life-time prevalence of wheeze was 34.7% at age 11-12. The remission of asthma was 10% yearly and inversely related to allergic sensitization. Relapses were common, and remission persisting throughout the observation period was 5% yearly. Allergic sensitization was associated with current asthma at age 7-8 [adjusted odds ratio (OR) 4.9 (95% confidence interval (CI) 3.3-7.3)] and when the children were 4 years older [OR 5.6 (3.9-8.2)]. A family history of asthma was associated with current asthma at age 7-8 [OR 3.0 (2.1-4.5)] and 11-12 (OR 2.8 [2.0-3.9]). Ever having lived with a cat was significantly negatively associated with current asthma. The prevalence of asthma increased continuously during the primary school ages. Among several significant risk factors, allergic sensitization and a family history of asthma were the most important. With increasing age many known risk factors lost significance. Remission was inversely related to allergic sensitization.

Trends in asthma prevalence and population changes in South Australia, 1990–2003

To examine changes in asthma prevalence in the context of other population changes between 1990 and 2003, for specific age and sex groups. Cross-sectional survey based on household interviews, repeated annually. Representative samples of the South Australian population between 1990 and 2003 (around 3000 people per year). Current prevalence of doctor-diagnosed asthma and other health and demographic variables potentially associated with asthma, and asthma management. Response rate was over 71%. Between 1990 and 2003, asthma prevalence increased significantly, doubling in females (from 7.3% in 1990 to 14.6% in 2003), with a smaller increase in males (from 7.8% to 9.4%). Asthma also increased in all age groups, but the largest relative increases occurred in people aged 55 years and older. Logistic regression analyses showed that obesity was a major predictive variable for every age group studied. The prevalence of asthma morbidity (waking at night and days lost from usual activities because of asthma) among those with asthma showed no significant changes between 1990 and 2003. Asthma action plans (introduced on a population basis in 1992) peaked in their distribution at 42% in 1994, and then declined to half that percentage in 2003. The increase in asthma prevalence occurred at the same time as increases in population prevalence of obesity (10.3% to 18.7%) and diabetes (3.1% to 6.9%), and decline in recent vigorous exercise (42.4% to 32.7%). The increase in asthma prevalence over a decade was large, but concentrated among specific sex and age groups. The increase accompanied population increases in obesity and diabetes and a decline in vigorous exercise.

Changes in Prevalence of Asthma and Allergies Among Children and Adolescents in Italy: 1994–2002

Several studies conducted during the 1990s indicated an increase in the prevalence of symptoms of asthma; more recent investigations suggest that the trend is stabilizing or may even be reversing. We compared 2 cross-sectional surveys conducted in 1994 and 2002 in 8 areas in northern and central Italy, to evaluate prevalence changes for asthma, allergic rhinitis, and eczema. The International Study of Asthma and Allergies in Childhood methods and questionnaires were used to investigate 6- to 7-year-old children (16,115 and 11,287 questionnaires completed by parents in 1994-1995 and 2002, respectively) and 13- to 14-year-old adolescents (19,723 and 10,267 questionnaires completed by adolescents in 1994-1995 and 2002, respectively). In each phase, the overall response rate was >90%. Prevalence changes were calculated as the absolute difference between the prevalence recorded on the 2 occasions. The prevalence of wheeze (past 12 months) increased slightly among children (change: 0.8%; 95% confidence interval [CI]: 0.0% to 1.6%) and was rather stable among adolescents. Symptoms of allergic rhinitis (children: change: 5.2%; 95% CI: 4.0% to 6.4%; adolescents: change: 4.1%; 95% CI: 1.9% to 6.3%) and symptoms of atopic eczema (children: change: 4.4%; 95% CI: 3.6% to 5.2%; adolescents: change: 2.1%; 95% CI: 1.2% to 3.0%) increased clearly in both age groups. There was some heterogeneity across the centers among adolescents, especially for allergic rhinitis, with larger increases seen in the 3 metropolitan areas. The changes observed paralleled profound family changes, ie, better parental education, higher rates of maternal employment, and lower rates of exposure to parental smoke. These factors, however, do not explain all of the observed changes in prevalence. The results indicate that the epidemiologic features of asthma and allergies in Italy are changing rapidly, although the causes are still uncertain.

Changes in asthma prevalence and impact on health and function in Seattle middle-school children: 1995 vs 2003

The prevalence of asthma has increased during the past several decades but may have stabilized during the last 5 years. It is not known whether the functional and health impact of asthma has decreased during the past decade. To evaluate changes during a recent 8-year period in the prevalence and health and functional impact of current asthma symptoms in young teenagers. In 1995 and 2003, 2,330 and 2,397 middle-school students from Seattle, WA, respectively (median age, 13 years), completed written surveys and answered questions pertaining to 4 wheezing or asthma video scenarios. Children were categorized as having physician-diagnosed current asthma (wheeze in the past year and a physician diagnosis of asthma), undiagnosed current asthma symptoms (wheeze in the past year without a physician diagnosis), or no asthma. Outcome measures were the prevalence of asthma and undiagnosed asthma symptoms and the differences between years in respiratory-associated functional impairment (exercise limitation, missed school, disrupted sleep) and health impact (physician visits, wheeze-limited speech). The prevalence of physician-diagnosed current asthma increased from 1995 to 2003 (3.0% to 6.2%), whereas that for undiagnosed current asthma symptoms decreased (12.0% to 6.2%). The degree of functional and health impairment was similar between the 2 study periods for each subgroup and was highest in the children with physician-diagnosed current asthma. The prevalence of current asthma symptoms in middle-school children from Seattle decreased slightly between 1995 and 2003, whereas the diagnosis of asthma increased. However, the health and functional impact of asthma did not diminish. Asthma is being diagnosed more often, but many children with asthma are still not achieving good asthma control.

Gene-Environment Interaction Effects on the Development of Immune Responses in the 1st Year of Life

Asthma is a common disease that results from both genetic and environmental risk factors. Children attending day care in the 1st year of life have lower risks for developing asthma, although the mechanism for this "day care" effect is largely unknown. We investigated the interactions between day care exposure in the 1st 6 mo of life and genotypes for 72 polymorphisms at 45 candidate loci and their effects on cytokine response profiles and on the development of atopic phenotypes in the 1st year of life in the Childhood Onset of Asthma (COAST) cohort of children. Six interactions (at four polymorphisms in three loci) with "day care" that had an effect on early-life immune phenotypes were significant at P<.001. The estimated false-discovery rate was 33%, indicating that an estimated four P values correspond to true associations. Moreover, the "day care" effect at some loci was accounted for by the increased number of viral infections among COAST children attending day care, whereas interactions at other loci were independent of the number of viral infections, indicating the presence of additional risk factors associated with day care environment. This study identified significant gene-environment interactions influencing the early patterning of the immune system and the subsequent development of asthma and highlights the importance of considering environmental risk factors in genetic analyses.

Changing prevalence of asthma in Taiwanese adolescents: two surveys 6 years apart

This study compared the prevalence of asthma among Taiwanese adolescents with individual-level risk factors and municipal-level air pollution and meteorology data to determine whether changes in these factors could explain the observed change in prevalence. We conducted two national surveys of respiratory illness and symptoms in Taiwanese middle-school students in 1995-96 and 2001. The effects of personal and environmental factors were assessed and temporal changes of outdoor monitoring data were also compared with asthma prevalence difference. A total of 44,104 children from the 1995-96 survey and 11,048 children from the 2001 survey attended schools located within 1 km of 22 monitoring stations. Lifetime prevalences of physician-diagnosed and questionnaire-determined asthma increased during this period. After adjustment for potential risk factors, the prevalence differences were statistically unchanged. Although parental education level contributed most, changes in investigated personal and environmental factors might not explain the observed changes in asthma prevalence. Municipalities with higher temperature increase were significantly associated with prevalence difference in questionnaire-determined asthma. We concluded that correlates of the investigated individual-level factors, which have changed over time, still underlie changes in asthma prevalence. Increasing temperature might be the main reason for the rising trends of asthma in Taiwanese adolescents.

Change in prevalence of asthma in Danish children and adolescents

There is evidence suggesting that the prevalence of asthma has increased, especially in industrialized countries. To investigate whether the prevalence of asthma in Danish children and adolescents has changed during the past 15 years. Serial cross-sectional studies of 2 different random population samples of children aged 7 to 17 years, living in urban Copenhagen, Denmark, were performed 15 years apart. The first cohort was investigated in 1986 (n = 527) and the second in 2001 (n = 480). The same methods were applied at both occasions. Skin test reactivity was measured using standard techniques. Asthma was defined on the basis of questionnaire responses and was regarded as nonatopic (intrinsic) if no positive reactions were observed on the skin test and as atopic (extrinsic) if at least 1 positive reaction was noted. Current asthma was defined as symptoms within the preceding 12 months. The prevalence of current asthma increased from 5.3% in 1986 to 11.7% in 2001. This was primarily due to an increase in intrinsic asthma, which was 4.2-fold (1.5% to 6.4%), compared with extrinsic asthma, which increased only 1.4-fold (3.8% to 5.5%). The changes were more pronounced in girls. The prevalence of asthma has increased substantially during the past 15 years. The observed striking increase in intrinsic asthma suggests the possibility of a more heterogeneous disorder, involving more important factors than atopy. Furthermore, our findings suggest that asthma might be shifting toward female predominance in childhood.

Asthma prevalence in Melbourne schoolchildren: have we reached the peak?

To determine the change in prevalence of asthma, eczema and allergic rhinitis in Australian schoolchildren between 1993 and 2002. Questionnaire based survey, using the protocol of the International Study of Asthma and Allergy in Childhood. Metropolitan Melbourne primary schools within a 20 km radius of the GPO in 1993 and 2002. All children in school years 1 and 2 (ages 6 and 7) attending a random sample of 84 schools in 1993 and 63 schools in 2002. Parent-reported symptoms of atopic disease; treatment for asthma; country of birth. There was a 26% reduction in the 12-month period prevalence of reported wheeze, from 27.2% in 1993 to 20.0% in 2002. The magnitude of reduction was similar for boys (27%) and girls (25%). The 12-month period prevalence of reported eczema increased from 11.1% in 1993 to 17.2% in 2002, and rhinitis increased from 9.7% to 12.7%. There were reductions in the proportion of children attending an emergency department for asthma in the previous year (3.6% to 2.3%), the proportion admitted to hospital (1.7% to 1.1%) and the proportion taking asthma medication (18.5% to 13.4%). Of those who reported frequent wheeze, there was an increase in the proportion taking regular inhaled steroids (34.5% to 40.9%). There has been a significant reduction in the prevalence of reported asthma in Melbourne schoolchildren, whereas the prevalence of eczema and allergic rhinitis has continued to increase.