Prevalence Of Doctor-diagnosed Asthma Research Articles

Early-Life Exposure to Malnutrition From the Chinese Famine on Risk of Asthma and Chronic Obstructive Pulmonary Disease in Adulthood.

ObjectivesIntrauterine malnutrition has a long-term effect on respiratory and lung function. However, few studies have explored the association between early-life exposure to famine with asthma and chronic obstructive pulmonary disease (COPD) in adulthood. Therefore, we aimed to investigate the association of early-life exposure to the Chinese famine of 1959–1962 with asthma and COPD later in life.MethodsThis national population-based study included 6,771 participants from the baseline survey of the China Health and Retirement Longitudinal Study (CHARLS) who were born around the time of the Chinese famine. The famine exposure groups were determined according to the participants' birth year as non-exposed (1964–1967), fetal-exposed (1959–1962), preschool-exposed (1954–1957), and school-age exposed (1950–1953). Information about the demographic characteristics, self-reported doctor-diagnosed asthma and COPD, behavior and lifestyles, and indoor pollution were collected using validated questionnaires. In addition, peak expiratory flow (PEF) was measured to assess pulmonary function. Multivariable logistic regression and generalized linear mixed models were performed to explore the risk of adult asthma and COPD, PEF changes during various famine exposure periods compared with the non-exposed group. Stratified and sensitivity analyses were conducted to examine the modification and robustness of the association.ResultsThe prevalence of doctor-diagnosed asthma and COPD was 2.8 and 8.1%, respectively. Compared with the non-exposed group, the risk was significantly higher in the fetal-exposed group for asthma [adjusted odds ratio, (aOR) = 1.87, 95% confidence interval (CI):1.14–3.07] and the school-age exposed group [1.30 (1.00–1.69)] for COPD after controlling for confounders. Furthermore, we observed that fetal exposure to famine was significantly associated with a decrement of PEF in adulthood [β = −11.38 (−22.75 to −0.02)] compared with the non-exposed group. Stratified analyses showed that the association of asthma was stronger in men, who resided in severely famine-affected areas, smoked, and used solid fuels for cooking. No clearly consistent association was observed for subsequent COPD.ConclusionsOur results suggest that fetal exposure to the Chinese famine is significantly associated with the increased risk of asthma in adulthood. Future prospective studies are warranted to examine the association and mechanisms.

Work-related allergy and asthma associated with cleaning agents in health workers in Southern African tertiary hospitals.

Health workers (HWs) are exposed to diverse cleaning agents in large hospitals. This study determined the prevalence of work-related symptoms, allergic sensitization, and lung function abnormalities in HWs of two tertiary hospitals in Southern Africa. A cross-sectional study of 699 HWs (South Africa: SAH, n = 346; Tanzania: TAH, n = 353) was conducted. Health outcomes were assessed using a standardized ECRHS questionnaire, immunological tests (specific IgE antibody to common aero-allergens and to occupational allergens: natural rubber latex [NRL] Hev b5 and Hev b6.02, chlorhexidine, and ortho-phthalaldehyde [OPA]), spirometry [pre-and post- bronchodilator], methacholine challenge, and fractional exhaled nitric oxide (FeNO). A large proportion of participants (78%) were women. Median age was 42 years, with 76% nurses, 12% cleaners, and 5% administrative workers. Current smoking was more common in SAHWs (12%) than TAHWs (1%). The overall prevalence of doctor-diagnosed asthma was 7%. Atopy was present in 43% of HWs, while 4% were sensitized to OPA, 2% to NRL, and 1% to chlorhexidine. Prevalence of work-related ocular-nasal symptoms (16%) was higher than skin (12%) and chest (7%) symptoms. TAHWs had significantly lower mean lung volumes, higher degrees of significant airflow obstruction and impaired lung function. The prevalence of bronchial hyperresponsiveness in SAHWs (14%) was high. Overall, 23% of HWs had abnormal FeNO; 6% having high (>50 ppb) levels. FeNO was positively associated with sensitization to occupational allergens, primarily OPA and NRL. HWs from both hospitals had similar prevalence of work-related respiratory symptoms. Sensitization to OPA and NRL appears to be contributing to allergic airway inflammation in these HWs.

Asthma and Dietary Intake of Fish, Seaweeds, and Fatty Acids in Korean Adults.

The dietary intake of fish and fatty acid may influence the risk of asthma, yet epidemiological research remains controversial and inconclusive. We examined the association between asthma and the dietary intake of fish, seaweeds, and fat in a Korean population, aged 19 to 64 years, using the data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2013–2016 (n = 13,038). The prevalence of doctor-diagnosed asthma and medication prescribed asthma were 2.5% and 1.0%, respectively. The subjects with medication prescribed asthma had significantly lower consumption of seaweeds (p = 0.0110) and lower n3/n6 polyunsaturated fatty acid (PUFA) (p = 0.0275) as compared to subjects without medication prescribed asthma. Multiple logistic regression analysis showed that the odds ratio (OR) (95% confidence interval, CI) of doctor-diagnosed asthma in the highest quartile were 0.63 (0.41–0.97) and 0.66 (0.44–1.00) for fish and seaweeds respectively, compared to the lowest quartile after adjusting confounding factors. Furthermore, there were significant inverse associations between medication prescribed asthma and seaweeds [OR (95% CI) = 0.37 (0.19–0.70)], n-3 PUFA [OR (95% CI) = 0.43 (0.21–0.89)] and n3/n6 [OR (95% CI) = 0.47 (0.22–0.99)] intake after adjusting for confounding factors. These results suggest, that the higher consumption of fish and seaweed and the high ratio of n-3 to n-6 PUFA may be associated with a lower prevalence of asthma.

Asthma-related outcomes associated with indoor air pollutants among schoolchildren from four informal settlements in two municipalities in the Western Cape Province of South Africa.

The health impact of indoor air pollution in informal settlement households has not been extensively studied in South Africa. This cross-sectional study investigated the association between asthma and common indoor exposures among schoolchildren from four informal settlements located in two municipalities in the Western Cape Province. A total of 590 children, aged 9-11years, were recruited. The International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was administered to caregivers. Pulmonary function assessment included spirometry and fractional exhaled nitric oxide (FeNO). Phadiatop test for atopy was done. The prevalence of doctor-diagnosed asthma was 3.4% (n=20) among whom only 50% were on treatment. The prevalence of current wheeze was 12.9%, and 17.6% had airway obstruction (FEV1 <lower limit of normal), while 10.2% had airway inflammation (FeNO>35ppb). In adjusted logistic regression models, dampness, visible mold growth, paraffin use for cooking, and passive smoking were associated with a twofold to threefold increased risk in upper and lower airway outcomes. The strongest association was that of visible mold growth with rhinitis (adjusted odds ratio-aOR 3.37, 95% CI: 1.69-6.71). Thus, there is a need for improved diagnosis of childhood asthma and Indoor Air Quality in informal settlement households.

Asthma-Related Outcomes Associated with Indoor Air Pollutants from a Survey of School Children Residing in Informal Settlement Households of the Western Cape Province of South Africa

The health impact of indoor air pollution in informal settlement households has not been extensively studied in South Africa. This study investigated the association between asthma and common indoor exposures in a survey of school children residing in the Western Cape Province. A total of 590 children, aged 9 &amp;#8211; 11 years, were recruited from four informal settlements in the province. The International Study of Asthma and Allergies in Children (ISAAC) questionnaire, was administered to caregivers. Pulmonary function assessment included spirometry and fractional-exhaled nitric oxide (FeNO). Phadiatop test for atopy was done. The prevalence of doctor-diagnosed asthma was 3.4% (n&amp;#61;20) among whom only 50% were on treatment. The prevalence of asthma symptoms (wheezing in the past 12 months) was 12.9% and 17.6% had airway obstruction (FEV1 &amp;lt; lower limit of normal) while 10.2% had airway inflammation (FeNO &amp;gt; 35 ppb). In adjusted logistic regression models, dampness, visible mould growth, paraffin-use for cooking, and passive smoking were associated with a two-fold increased risk in upper and lower airway outcomes. The strongest association was for rhinitis (adjusted odds-ratio &amp;#8211; aOR 3.01, 95%CI: 1.45 &amp;#8211; 6.15). There is a need for improved diagnosis of childhood asthma and indoor air quality in informal settlement households.

Relationship between Pesticide Metabolites, Cytokine Patterns, and Asthma-Related Outcomes in Rural Women Workers.

The objective of this study was to investigate the relationship between exposure to organophosphate (OP) and pyrethroid (PYR) pesticides with serum cytokine patterns and asthma-related outcomes among rural women workers. A cross-sectional study was conducted among rural women (n = 211), including those working and living on farms and nearby town dwellers. Pesticide exposure was assessed using urinary metabolite concentrations of OP and PYR pesticides. Health outcome assessment was ascertained through the European Community Respiratory Health Survey (ECRHS) questionnaire, fractional exhaled nitric oxide (FeNO), and serum cytokines associated with asthma. The prevalence of doctor-diagnosed asthma was 11%, adult-onset asthma 9%, and current asthma 6%. In this population, the proportion of T helper type 2 (Th2) cytokines (interleukin (IL)-4, IL-5, and IL-13) detectable in subjects was between 18% and 40%, while the proportion of non-Th2 cytokines (IL-6, IL-8, IL-10, IL-17, and interferon gamma) was between 35% and 71%. Most Th2 and non-Th2 cytokines were positively associated with either OP or PYR metabolites. Non-Th2 cytokines showed much stronger associations with OP metabolites (Dimethyl phosphate OR = 4.23; 95% CI: 1.54–11.65) than Th2 cytokines (Dimethyl phosphate OR = 1.69; 95% CI: 0.83–3.46). This study suggests that exposure to most OP and some PYR pesticides may be associated with asthma-related cytokines, with non-Th2 cytokines demonstrating consistently stronger relationships.

Early polysensitization is associated with allergic multimorbidity in PARIS birth cohort infants.

Profiles of allergic sensitization are poorly documented in infancy. Relations between early sensitization and allergic morbidity need to be clarified. This study dealt with children involved in the Pollution and Asthma Risk: an Infant Study (PARIS), a population-based prospective birth cohort. Allergic sensitization to twelve food and four inhalant allergens was assessed at 18months and defined by a specific immunoglobulin E (IgE) level ≥0.35kUA /l. Health data were collected by standardized questionnaires at 2 and 6years. Early allergic profiles were identified by an unsupervised cluster analysis based on health data at 2years and IgE measurements. Profiles were compared with regard to allergic morbidity and multimorbidity at 6years. Sensitization to any allergen concerned 13.6% of infants. By cluster analysis, 1525 infants were grouped into three profiles: 89.2% not or rarely sensitized (only 3.7% of sensitized), 9.2% mainly sensitized to one or few allergens (45.2% of monosensitized and 45.9% of paucisensitized) and 1.6% all polysensitized. The prevalence of doctor-diagnosed asthma, rhinitis, eczema, food allergy and multimorbidity at 2years increased from profile one to profile three (p-trend <0.001). At 6years, symptoms of current asthma, rhinitis, eczema and multimorbidity were significantly more frequent in the last two profiles. This study highlights, as early as 18months of age, three profiles of increasing severity with regard to allergic sensitization and diseases. These profiles also differ in terms of allergic morbidity at 6years. Early sensitization can predict allergic multimorbidity in childhood, and in the case of early polysensitization, multimorbidity is more frequent as soon as infancy.

Sous-diagnostic de l’asthme chez les enfants en classe de CE2

Undiagnosed asthma has been poorly studied before adolescence since it can go unnoticed by parents and doctors. Moreover, it is unusual to look for undiagnosed asthma by directly questioning children on the presence of current respiratory symptoms. Epidemiologic studies show that more adolescents quote symptoms suggestive of asthma than the prevalence of doctor-diagnosed asthma, but respiratory symptoms compatible with asthma remain undetected by parents of younger children more frequently than doctors diagnose asthma in their children. We attempted to evaluate the relevance of a questionnaire used since 2011 by school doctors in Paris to detect asthma. In this questionnaire, the family history of atopy and asthma were completed by the parents when they met the school doctor (last year of preschool) and questions on current respiratory symptoms were answered by third-grade children seen alone by the school doctor. One hundred and thirty-one children out of 1135 children questioned had a positive questionnaire for suspected asthma. In three-quarters of the cases, questionnaires were positive based on the children's answers on their respiratory symptoms (without a positive answer on personal or family history being necessary). The outcome of 41 children screened by the questionnaire was known. Twenty (49%) children had received a final diagnosis of asthma, of whom 12 were put on asthma controllers. Among these 20 children, two children underwent lung function testing and two others underwent tests for allergy. In eight children, tests had been requested by the child's GP, but no final diagnosis was reported by the parents. None of the 13 children in whom asthma was ruled out had any test performed. It was concluded that it is possible to detect undiagnosed asthma in children as young as 8 years by directly asking them about their respiratory symptoms. The knowledge of personal and family history can improve screening for asthma in these children. A more thorough evaluation of all children with a positive questionnaire is necessary to better understand the properties of the questionnaire. Finally, the best way to implement this screening program remains to be established (school health, GPs).

PD05 ‐ Asthma and allergy from infancy into school age – the allergic march revisited

Background The allergic march describes a proposed natural course of allergic disease during childhood. However, different patterns of allergic morbidity have been suggested. The aim of this study was to describe the prevalence of doctordiagnosed asthma and allergic manifestations from infancy into school age and the relationship between early manifestations and the prevalence of asthma at school age.

Prevalence of asthma and respiratory symptoms in children in a low socio-economic status area of Nigeria.

Warri and environs in the Niger Delta, in the Southern region of Nigeria. To investigate the burden of respiratory illness in children in the Niger Delta. A cross-sectional survey of 1397 schoolchildren aged 7-14 years in areas of low socio-economic status (SES), using written questionnaires in English based on the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire, with explanation of symptoms. The prevalence of doctor-diagnosed asthma was 0.9% (95%CI 0.4-1.3), and wheeze in the last 12 months was 5.4% (95%CI 4.3-6.6). The prevalence of other respiratory symptoms was high, in particular night cough 23.3% (95%CI 21.1-25.5), rhinitis 19.2% (95%CI 17.1-21.3) and phlegm production 16.6% (95%CI 14.7-18.6). Risk of wheeze in the younger age groups was twice (OR 2.09, 95%CI 1.29-3.39) that of older ages after controlling for sex and geographical area. Risk of asthma in urban children was reduced (OR 0.15, 95%CI 0.05-0.50) compared to rural children after controlling for age and sex. Urban children also had a lower risk of rhinitis, exercise limitations and absenteeism due to respiratory illness than rural children. The prevalence of symptoms of allergic disease was lower than in the African centres in the ISAAC surveys conducted in urban centres. Doctor-diagnosed asthma is likely to be a poor indicator of asthma in low SES areas of developing countries due to health care access issues.

Pet-keeping and its impact on asthma and allergies among preschool children in Shanghai, China

Whether early pet-keeping is a risk factor for children’s asthma and allergies remains controversial. To investigate associations between asthma, allergies and airway symptoms among children and the indoor environment, a cross-sectional study was conducted in 5 districts of Shanghai. A number of 13335 questionnaires (response rate: 85.3%) of 4-6 year old children were analyzed. Families in urban areas have more pets except for dogs than families in suburbs. Fish are the most common pets in urban districts. The prevalence of doctor-diagnosed asthma was 10.3%, wheeze (ever) 28.3%, rhinitis (ever) 54.1%, doctor-diagnosed hay fever 12.6% and eczema (ever) 22.9%. In logistic regression analyses, early furred pet-keeping was positively associated with most of the symptoms and significantly with rhinitis (ever, adjusted OR=1.41, 95% CI=1.14–1.76) and doctor-diagnosed hay fever (1.38, 1.02–1.88). Current furred pet-keeping was significantly negatively associated with doctor-diagnosed asthma (0.57, 0.39–0.83). Persistent furred pet-keeping was significantly positively associated with rhinitis on pet or pollen exposure. However, current pet-keeping is not randomly distributed in the population. Children in families with “allergy” or with “pet avoidance behavior” (due to allergies in the family) have more symptoms, but have avoided cats and dogs, leading to the conclusion that such animals are “protective”, namely the “Healthy Pet-Keeping” effect. Moreover, rodents and birds are risks for children’s health. Fish-keeping is also seemingly a risk. This study indicates that early pet-keeping is a risk factor for asthma and allergies in families with a history of allergies, and part of residents in Shanghai have pet-avoidance behavior.

Toll-like receptor 2 and 4 genes influence susceptibility to adverse effects of traffic-related air pollution on childhood asthma

BackgroundEpidemiological studies have reported adverse effects of ambient air pollution on the prevalence of asthma. Laboratory studies have suggested that innate immune responses are involved.ObjectiveA study was undertaken to determine...

Changes in the prevalence of asthma in adults since 1966: the Busselton health study

Asthma prevalence has increased worldwide; although less so in developed countries recently. This study assessed changes in the prevalence of asthma and related symptoms in the Busselton community since 1966. Cross-sectional respiratory health surveys of Busselton adults were conducted in 1966, 1969, 1972, 1975, 1981, 1990 and 2005-2007. Logistic regression models were used to estimate prevalence rates of asthma, respiratory symptoms, smoking, airway hyperresponsiveness (AHR) and atopy and to make comparisons in 2005-2007 and previous survey years. Asthma was defined as ever having doctor-diagnosed asthma (DDA). The prevalence of DDA was around 6% from 1966 to 1975, 8% in 1981 and rose to 19% in 2005-2007. From 1981 to 2005-2007, smoking prevalence declined and obesity and atopy increased but changes in these variables explained only a small part of the increase in DDA. Wheeze and cough/phlegm increased but AHR, breathlessness and doctor-diagnosed bronchitis remained relatively stable over the same period. These observations indicate that the increase in DDA is partly explained by increased symptoms and atopy. The lack of changes in AHR and doctor-diagnosed bronchitis suggests that factors such as diagnostic transfer and increased awareness of asthma have also contributed to the rise in prevalence of DDA.

Domestic Fuels, Indoor Air Pollution, and Children's Health

Reliance on solid biomass fuel for cooking and heating exposes many children of developing countries to high levels of indoor air pollution. This study investigates the association between household use of biomass fuels for cooking and prevalence of respiratory symptoms and diseases among children in rural India. The air-quality parameters (CO, CO(2), NO, NO(2), SO(2), O(3), suspended particulate matter (SPM), including temperature and relative humidity) were investigated using a YES-Plus multigas air-quality monitor for gaseous and Kimoto handy samplers (HS-7) for TSPM. Seven hundred fifty households and 1505 children were selected for this study. A questionnaire developed on the pattern of the the International Study of Asthma and Allergies in Childhood (ISAAC) and the International Union Against Tuberculosis and Lung Disease (IUATLD) with some modifications were used for evaluation of respiratory health. The lung function parameters, namely, PEF, FVC, FEV(1), FEF, and SVC were examined on an electronic Spiro Meter (Maestro Medline Ltd.). Logistic regression was used to estimate the odds of suffering from respiratory infections among children from households using biomass fuels relative to children from households using liquified petroleum gas (LPG), after controlling for potentially confounding factors. The study suggests that exposure to cooking smoke from biomass combustion is significantly associated with decline in lung function and prevalence of doctor-diagnosed asthma (OR = 2.20; 95% CI: 1.16, 4.19) and other respiratory diseases.

Environmental Noise and Asthma in Children: Sex-Specific Differences

Objective. There is evidence that stress increases the risk of asthma. Chronic noise exposure is known to act as an unspecific stressor, but little is known about its effect on the risk of asthma in children. The aim of this study was to compare subjectively reported noise annoyance in 12-year-old asthmatic and non-asthmatic children with special regard to sex-specific differences. Subjects and methods. In a German multi-center birth cohort study we assessed the annoyance by different sources of environmental noise, doctor-diagnosed asthma, and potential confounders by questionnaire. The comparisons between asthmatic and non-asthmatic children were stratified by sex. Results. A total of 336 boys and 316 girls were included in the analysis. Prevalence of doctor-diagnosed asthma was 13% in boys and 5% in girls; 73% of the boys and 74% of the girls reported at least some degree of noise annoyance during the day and night time. In girls, asthma was associated with a significantly increased total noise annoyance at night (adjusted odds ratio aOR 1.5, 95%CI 1.1;2.1), for noise within the home/apartment (aOR 3.5, 95%CI 1.5;8.0), and in or around the house (aOR 3.3, 95%CI 1.7;6.3). No statistical significant effects were seen in boys. Conclusions. Noise annoyance, particularly at night or caused by domestic sources, is associated with increased asthma prevalence in girls but not boys. Further research is needed to identify underlying mechanisms of these sex-specific differences.

Exposure to Alternaria alternata in US homes is associated with asthma symptoms

Exposure to the fungus Alternaria alternata is a risk factor for asthma. Few studies have examined Alternaria exposures in indoor environments. We examined whether exposure to A alternata in US homes was associated with asthma-related outcomes. The data for this study were collected as part of the National Survey of Lead and Allergens in Housing. This cross-sectional study surveyed a nationally representative sample of 831 housing units inhabited by 2456 individuals in 75 different locations throughout the United States. An interviewer-administered questionnaire obtained information on demographics, household characteristics, and occupants' health status. Exposure to A alternata was assessed by measuring concentrations of A alternata antigens in vacuumed dust samples using a polyclonal anti-A alternata antibody assay. Dust samples were collected from a bed, a sofa, or a chair, and from bedroom, living room, and kitchen floors. Lifetime prevalence of doctor-diagnosed asthma was 11.2%, and 6.9% of the study subjects reported active asthma symptoms in the past 12 months. The prevalence of current symptomatic asthma increased with increasing Alternaria concentrations in US homes; higher levels of A alternata antigens increased the odds of having asthma symptoms in the past year (relative to the lowest tertile, adjusted odds ratio was 1.52, 95% CI, 0.90-2.55 for the 2nd tertile; and 1.84, 95% CI, 1.18-2.85 for the 3rd tertile). Exposure to A alternata in US homes is associated with active asthma symptoms. Measures that reduce indoor exposure to A alternata may help control asthma exacerbations.

Primary prevention of childhood asthma and allergic disorders

The prevalence of asthma and allergic disorders in childhood is increasing in many parts of the world. This review focuses on recent findings with regard to environmental risk factors and their manipulation in the primary prevention of these diseases in childhood. Recent studies have failed to resolve the controversy on the subject of exposure to indoor aeroallergens and the risk of sensitization and asthma in childhood. Bronchiolitis due to respiratory syncytial virus in infancy is associated with a significant increase in risk of asthma, but not atopy. In the prevention of these diseases, the effects of breastfeeding are controversial, with studies showing a protective effect in children without allergic predisposition, but other studies showing no effect or even the potential for an increased asthma risk. A significant reduction in the prevalence of doctor-diagnosed asthma at 7 years was found in a randomized controlled multifaceted (reduction of inhaled and ingested allergens) intervention study of high-risk infants. Other intervention measures, such as an education program on how to reduce exposure, the use of probiotics, and immunization against infections, all showed some protective effects. More research is required, especially with regard to longer periods of follow-up for all current intervention studies aimed at reducing exposure, the onset and duration of intervention, and other novel intervention measures in the primary prevention of asthma and allergic diseases in childhood.

Parental education and children's respiratory and allergic symptoms in the Pollution and the Young (PATY) study

Inequalities in health between socio-economic groups are a major public health concern. The current authors studied associations between parental socio-economic status (SES) and children's respiratory and allergic symptoms in 13 diverse countries, including the Russian Federation, North America (Canada and the USA), and countries across Eastern and Western Europe. Data of 57,000 children aged 6-12 yrs, originating from eight cross-sectional studies, were analysed. SES was defined by parental education. Respiratory and allergic symptoms were defined by parental questionnaire reports. Multiple logistic regressions showed that low parental education was associated with a decreased risk of inhalant allergy and itchy rash in school children. Furthermore, low parental education was associated with an increased prevalence of wheeze and nocturnal dry cough. No clear association was found between parental education and prevalence of doctor-diagnosed asthma and bronchitis. Part of the difference between socio-economic groups with regard to their children's symptoms was explained by established risk factors, such as parental allergy, smoking during pregnancy, pet ownership, crowding, mould/moisture in the home, use of gas for cooking, and air pollution (particulate matter with a diameter of <10 microm). However, differences remained after adjusting for these variables. Children's health was associated with parental education. The association could not fully be explained by established risk factors.

Asthma symptoms associated with depression and lower quality of life: a population survey.

To identify any association between asthma and depression and quality of life. A face-to-face Health Omnibus Survey of a random and representative sample of the South Australian population in August 1998. 3010 randomly selected participants aged 15 years and over. Prevalence of doctor-diagnosed asthma, and scores for depression (measured by PRIME-MD instrument) and quality of life (measured by SF-36) in affected participants. The prevalence of asthma was 9.9%. The prevalence of major depression was significantly higher for those who experienced dyspnoea, wakening at night with asthma, and morning symptoms of asthma. Quality-of-life scores were also lower for the same groups. Depression is a serious but potentially remediable comorbidity with asthma that may affect appropriate diagnosis and outcome.

Gender differences in asthma prevalence may depend on how asthma is defined

Background: Asthma may be defined either as wheeze within the previous 12 months (current wheeze), doctor-diagnosed asthma (DDA), or current wheeze plus confirmed airway hyperresponsiveness (AHR). Aims: We wanted to estimate asthma prevalence in randomly selected adolescents based on different criteria for asthma diagnosis, study gender differences in reported asthma-like symptoms vs DDA, and relate our findings to measurements of AHR, levels of exhaled nitric oxide (ENO) and total IgE. Methods: As part of the health survey of North-Trøndelag (HUNT), 8571 adolescents aged 13–19 years were investigated with an interview on allergic and respiratory symptoms (phase I study). Of these, 401 subjects who reported wheeze within the previous 12 months (current wheeze) and 213 non-symptomatic controls were randomly selected and investigated with allergy screening, methacholine bronchoprovocation test and measurements of ENO (phase II study). Results : In the phase I study, prevalence of current wheeze was 26% (30% in girls and 23% in boys, P < 0.01). Prevalence of DDA was 10.8% (10.5% in girls and 11% in boys). Among subjects with current wheeze, the likelihood of having DDA was reduced in girls compared to boys, odds ratio (95% CI) 0.82 (0.68-0.98) which was partly explained by a longer history of wheeze among boys. In the phase II study, although more girls than boys with current wheeze had AHR (62% versus 50%, P < 0.02), more boys than girls reported DDA (44% vs . 32%, P < 0.02). Of the objective parameters, increased levels of ENO most strongly increased the risk of having DDA. Conclusions: When asthma is defined as DDA, there is a risk of underestimating the prevalence of asthma, especially among girls.