Effects of early intake of fruit or vegetables in relation to later asthma and allergic sensitization in school-age children

AIM: To assess the associations between nutrition supplements in infancy and later asthma and allergy in school-age children, and to explore the impact of environmental factors in early life. METHODS: Five hundred and two children underwent clinical examination, skin prick test and a second parentally completed questionnaire within 2 y of a cross-sectional questionnairebased study, including 4585 primary school children (6-16 y old) in 1994 from urban Oslo (37%), the mountainous area of Hallingdal (42%), and the industrial, coastal area of Odda (21%). The children were selected from the 1994 survey on the basis of reported diagnosed asthma (n=166), wheeze in the last 12 mo (n=155) and no asthma/no wheeze (n=181). Questions were related to nutrition and environmental exposure in early life. Possible associations between allergic sensitization or asthma at school age and exposures were estimated by logistic regression analysis, adjusting for potential confounders. RESULTS: Daily intake of fresh fruit or vegetables, but not extra vitamins or cod liver oil supplements, in infancy decreased the risk of asthma (adjusted odds ratio (aOR) 0.57 (95% confidence interval (CI): 0.37-0.88). Early supplements of cod liver oil and extra vitamins were associated with increased allergic sensitization (aOR 1.78 (95% CI: 1.03-3.07) and 1.71 (95% CI: 1.01-2.88), respectively). A significantly higher prevalence of allergic sensitization was found in children living in Hallingdal compared to Odda, while the latter children, on the other hand, had the highest prevalence of house dust mite allergy (p = 0.001 vs Hallingdal and p = 0.04 vs Oslo). CONCLUSION: The present study suggests that the early introduction of daily fresh fruit or vegetables may decrease the risk of asthma after 1 y of life, whereas allergic sensitization at school age seemed to increase with extra vitamin and cod liver oil supplements during infancy. Living area influenced allergic sensitization, with differences between coastal and inland areas.     

Epidemiological studies of the very high prevalence of asthma and related symptoms among school children in Costa Rica from 1989 to 1998

The aim of our study was to determine the prevalence of asthma and related respiratory symptoms in school children from Costa Rica during the last 10 years, from 1989 to 1998. Using nationally representative samples of school children from Costa Rica during the last 10 years we have performed three studies. Altogether 9931 children were investigated. The age groups: study I, 5–17 years (n = 2682), study II, 6–7 years (n = 2944), 13–14 years (n = 3200) and study III, 10 years (n = 1105). The diagnostic criteria for asthma used in these studies was as follows: study I (1989), diagnosis by a doctor in combination with the presence of four kinds of respiratory symptoms; studies II (1995) and III (1998), history of wheeze in the past 12 months. The two latter were part of the International Study of Asthma and Allergies in Childhood (ISAAC). A very high prevalence of a history of wheezing was found in the three studies (46.8%, 42.9%, and 45.1%) as well as a diagnosis of asthma (23.4%, 27.7% and 27.1%). The physician's diagnosis of asthma reported in the first study (23%) increased from 23.1 in study II to 27.7% in study III (p = 0.004). This increment could be a real increase in asthma prevalence, or be due to a better awareness about asthma. In study II the group of 6–7‐year‐olds had respiratory symptoms significantly more often than 13–14‐year‐olds (p < 0.001). Boys more often had a history of wheezing (p = 0.001), wheeze during the previous 12 months (p = 0.01) and an asthma diagnosis at the age of 6–7 years (p = 0.002) than girls, but girls had more respiratory symptoms than boys at the age of 13–14 years (p < 0.005). Wheezing in the past 12 months was more common for those living in urban areas aged 6–7 years (p = 0.04), and there was an increase of wheeze after exercise (p = 0.01). For the 13–14‐year‐olds the risk of wheezing was higher during the previous 12 months if they lived in temperate areas (<20°C) and at a high altitude (>1000 m). Living in a rural area and in a warm region (>20°C), increased the risk of dry cough during the previous 12 months in the group of 13–14‐year‐olds. In conclusion, Costa Rica is located in the tropics with a very high humidity, an enormous variety of flora and fauna and a very high prevalence of mite and cockroach allergens, which provide important risk factors that may explain the high prevalence of asthma and asthma‐related symptoms. Further possible factors, such as the change towards a more Western life style, resulting in fewer infections and parasitic diseases in the first years of life and changes in bedding material, may also be unresolved. Increased environmental pollution may add to the very high prevalence of asthma and related respiratory symptoms. The very extensive exposure to mites and cockroaches in bed material and in homes with poor ventilation may be an important factor, but many asthmatic children behave as non atopic, with a viral respiratory infection as a major precipitating factor.     

Has the prevalence of asthma symptoms increased in Australian children?

Abstract  This paper estimates whether an increase has occurred in the prevalence of asthma symptoms and diagnosed asthma in Australian children over the past two decades. Seventeen population-based studies undertaken in Australia since 1969 were reviewed. Inclusion criteria were studies using population samples of children aged 5–12 years, with standardized questionnaire measurements. Data from serial National Health Surveys were also examined for trends in recent and chronic asthma.
The prevalence of recent (12 month) and cumulative wheeze increased, showing a significant correlation with year of study (r = 0.78 and r = 0.79, respectively). Diagnosed asthma showed a smaller but still significant increase (r = 0.65). The trends observed indicated that diagnosed asthma and reported wheeze have increased by almost 1% per year over the past two decades. Data since 1980 have provided estimates of bronchial hyperreactivity (BHR), but no trend was observed. Substantial increases were noted in the National Health Surveys, with recent asthma prevalence in children aged 5–14 increasing from 3.3% in 1983 to 8.3% in 1989, and chronic asthma prevalence increasing from 4.5% in 1977 to 15.2% in 1989. The findings of this review suggest an increase in the prevalence of asthma symptoms in children, but these observations could also be explained by changes in diagnostic fashion and an increased awareness of asthma symptoms.     

Sex-specific trends in prevalence of childhood asthma over 30 years in Patras, Greece

Aim: According to four surveys conducted during 1978–2003, the prevalence of childhood asthma and wheezing has risen in the city of Patras, Greece, albeit at a decelerating rate. We examined sex‐specific wheeze and asthma prevalence in the same urban environment in 2008. Methods: A cross‐sectional parental questionnaire survey was performed in 2008 among third and fourth grade schoolchildren (8–9 year old), which was identical to previously conducted surveys in 1978 (n = 3003), 1991 (n = 2417), 1998 (n = 3076) and 2003 (n = 2725). Results: The prevalence of current wheeze and asthma in 1978, 1991, 1998, 2003 and 2008 (n = 2688) was 1.5%, 4.6%, 6.0%, 6.9% and 6.9%, respectively (p for trend <0.001). Respective values for lifetime (ever had) wheeze and asthma in the 1991–2008 surveys were 8.0%, 9.6%, 12.4% and 12.6% (p for trend <0.001). The male:female ratio of current and lifetime wheeze and asthma increased during the 30‐year surveillance period (p for trend <0.001). Irrespective of sex, diagnosed asthma declined among current wheezers by 17% (p < 0.001), but not among non‐current ones (6.7%, p = 0.16) during 2003–2008. Conclusions: Childhood wheeze and asthma have reached a plateau in an urban environment in Greece, while the male:female ratio increased. Asthma diagnosis declined among schoolage but not preschool wheezers during 2003–2008.     

Continued increase in the prevalence of asthma and atopy.

AIMS: To describe the change in the prevalence of wheeze, diagnosed asthma, and atopy in Wagga Wagga, NSW, Australia, between 1992 and 1997, and to compare this to the increase in prevalence reported between 1982 and 1992. METHODS: A cross sectional study of the prevalence of respiratory symptoms and atopy in schoolchildren aged 8-11 years (n = 1016, response rate 71%) in 1997 compared with studies of similar design in 1992 (response rate 83%, n = 850) and 1982 (response rate 88%, n = 769). Main outcome measures were respiratory symptoms measured by parent completed questionnaire and atopy measured by skin prick tests. RESULTS: Between 1992 and 1997, the prevalence of wheeze increased by 5.1% (95% CI 1.2 to 9.0), asthma diagnosis by 8.1% (95% CI 3.8 to 12.4), and atopy by 6.7% (95% CI 2.2 to 11.2). Similar increases in prevalence had been found between 1982 and 1992. CONCLUSIONS: The prevalence of wheeze, asthma diagnosis, and atopy in Wagga Wagga has continued to increase.     

Continued increase in the prevalence of asthma and atopy

AIMS—To describe the change in the prevalence of wheeze, diagnosed asthma, and atopy in Wagga Wagga, NSW, Australia, between 1992and 1997, and to compare this to the increase in prevalence reported between 1982 and 1992.METHODS—A cross sectional study of the prevalence of respiratory symptoms and atopy in schoolchildren aged 8-11 years (n = 1016, response rate 71%) in 1997 compared with studies of similar design in 1992(response rate 83%, n = 850) and 1982 (response rate 88%, n = 769). Main outcome measures were respiratory symptoms measured by parent completed questionnaire and atopy measured by skin prick tests.RESULTS—Between 1992 and 1997, the prevalence of wheeze increased by 5.1% (95% CI 1.2 to 9.0), asthma diagnosis by 8.1% (95% CI 3.8to 12.4), and atopy by 6.7% (95% CI 2.2 to 11.2). Similar increases in prevalence had been found between 1982 and 1992.CONCLUSIONS—The prevalence of wheeze, asthma diagnosis, and atopy in Wagga Wagga has continued to increase.     

Long-term respiratory symptoms following oesophageal atresia

Background: Oesophageal atresia (OA) is a congenital malformation that can lead to persistent respiratory symptoms in adulthood. Aim: To describe the prevalence of respiratory symptoms in adulthood in a population‐based study of patients with repaired OA and to compare this with the prevalence in the general population. Methods: Of 80 patients operated for OA in Gothenburg in 1968–1983, 79 were located. The patients received a questionnaire on respiratory symptoms. Controls were 4979 gender‐ and age‐matched subjects who answered the same questions. Results: The questionnaire was answered by 73 of 79 (92%) patients. Physician‐diagnosed asthma was reported by 30% in the OA group vs 10% in the control group (OR 4.1; 95% CI 2.4–6.8), and recurrent wheeze in 29% vs 5.5% (OR 6.9; 4.1–11.6). Also wheeze during the last year, asthma medication, a long‐standing cough, cough with sputum production and chronic bronchitis were significantly more common among the patients with OA. In contrast, there was no significant difference regarding risk factors for asthma. The prevalence of respiratory symptoms did not appear to decrease with age. Conclusion: A high prevalence of respiratory symptoms remains among adult patients with repaired OA. Many of the patients had an asthma diagnosis. However, asthma heredity or allergic rhinitis was not overrepresented.     

The prevalence of asthma and allergies in Singapore; data from two ISAAC surveys seven years apart.

BACKGROUND AND AIMS: Over the past few decades, the prevalence of asthma has been increasing in the industrialised world. Despite the suggestion of a similar increase in Singapore, the 12 month prevalence of wheeze among schoolchildren in 1994 was 2.5-fold less than that reported in western populations. It was hypothesised that with increasing affluence in Singapore, the asthma prevalence would further increase and approach Western figures. A second ISAAC survey was carried out seven years later to evaluate this hypothesis. METHODS: The cross-sectional data from two ISAAC questionnaire based surveys conducted in 1994 (n = 6238) and in 2001 (n = 9363) on two groups of schoolchildren aged 6-7 and 12-15 years were compared. The instruments used were identical and the procedures standardised in both surveys. RESULTS: Comparing data from both studies, the change in the prevalence of current wheeze occurred in opposing directions in both age groups--decreasing in the 6-7 year age group (16.6% to 10.2%) but increasing to a small extent in the 12-15 year age group (9.9% to 11.9%). The 12 month prevalence of rhinitis did not change; there was an increase in the current eczema symptoms in both age groups. CONCLUSION: The prevalence of current wheeze, a surrogate measure of asthma prevalence, has decreased significantly in the 6-7 year age group. Eczema was the only allergic disease that showed a modest increase in prevalence in both age groups.     

The prevalence of asthma and allergies in Singapore; data from two ISAAC surveys seven years apart

Background and Aims: Over the past few decades, the prevalence of asthma has been increasing in the industrialised world. Despite the suggestion of a similar increase in Singapore, the 12 month prevalence of wheeze among schoolchildren in 1994 was 2.5-fold less than that reported in western populations. It was hypothesised that with increasing affluence in Singapore, the asthma prevalence would further increase and approach Western figures. A second ISAAC survey was carried out seven years later to evaluate this hypothesis. Methods: The cross-sectional data from two ISAAC questionnaire based surveys conducted in 1994 (n = 6238) and in 2001 (n = 9363) on two groups of schoolchildren aged 6–7 and 12–15 years were compared. The instruments used were identical and the procedures standardised in both surveys. Results: Comparing data from both studies, the change in the prevalence of current wheeze occurred in opposing directions in both age groups—decreasing in the 6–7 year age group (16.6% to 10.2%) but increasing to a small extent in the 12–15 year age group (9.9% to 11.9%). The 12 month prevalence of rhinitis did not change; there was an increase in the current eczema symptoms in both age groups. Conclusion: The prevalence of current wheeze, a surrogate measure of asthma prevalence, has decreased significantly in the 6–7 year age group. Eczema was the only allergic disease that showed a modest increase in prevalence in both age groups.     

Additive effect of eosinophilia and atopy on exhaled nitric oxide levels in children with or without a history of respiratory symptoms

Although atopy and blood eosinophilia both influence exhaled nitric oxide (eNO) measurements, no study has quantified their single or combined effect. We assessed the combined effect of atopy and blood eosinophilia on eNO in unselected schoolchildren. In 356 schoolchildren (boys/girls: 168/188) aged 9.0-11.5 yr, we determined eNO, total serum IgE, blood eosinophil counts and did skin prick tests (SPT) and spirometry. Parents completed a questionnaire on their children's current or past respiratory symptoms. Atopy was defined by a SPT >3 mm and eosinophilia by a blood cell count above the 80th percentile (>310 cells/ml). eNO levels were about twofold higher in atopic-eosinophilic subjects than in atopic subjects with low blood eosinophils [24.3 p.p.b. (parts per billion) vs. 14.1 p.p.b.] and than non-atopic subjects with high or low blood eosinophils (24.3 p.p.b. vs. 12.2 p.p.b. and 10.9 p.p.b.) (p <0.001 for both comparisons). The additive effect of atopy and high eosinophil count on eNO levels remained unchanged when subjects were analyzed separately by sex or by a positive history of wheeze (n=60), respiratory symptoms other than wheeze (n=107) or without respiratory symptoms (n=189). The frequency of sensitization to Dermatophagoides (Dpt or Dpf) was similar in atopic children with and without eosinophilia (66.2% and 67.4%, respectively); eosinophilia significantly increased eNO levels in Dp-sensitized children as well in children sensitized to other allergens. In a multiple linear regression analysis, eNO levels were mainly explained by the sum of positive SPT wheals and a high blood eosinophil count (t=4.8 and 4.3, p=0.000), but also by the presence of respiratory symptoms (especially wheeze) and male sex (t=2.6 and 2.0, p=0.009 and 0.045, respectively). Measuring eNO could be a simple, non-invasive method for identifying subjects at risk of asthma in unselected school populations.     

Filaggrin gene variants and atopic diseases in early childhood assessed longitudinally from birth

Bønnelykke K, Pipper CB, Tavendale R, Palmer CNA, Bisgaard H. Filaggrin gene variants and atopic diseases in early childhood assessed longitudinally from birth.
Pediatr Allergy Immunol 2010: 21: 954–961.
© 2010 John Wiley & Sons A/S Copenhagen Prospective Study on Asthma in Childhood (COPSAC) was one of the discovery cohorts of the association between eczema and variants in the filaggrin coding gene (FLG). Here, we study the FLG‐associated risk of asthma symptoms in early life and describe the temporal relationship in the development of the different FLG‐associated atopic outcomes: asthma, sensitization and eczema, assessed longitudinally from birth. A high‐risk cohort of 411 children was assessed in a prospective clinical study from birth to school‐age. Asthma, acute severe asthma exacerbations, sensitization and eczema were diagnosed prospectively by the investigators. FLG variants R501X and Del4 were determined in 382 Caucasians. Filaggrin variants increased risk of developing recurrent wheeze, asthma and asthma exacerbations (hazard ratio 1.82 [1.06–3.12], p = 0.03), which was expressed within the first 1.5 yr of life. Children with filaggrin variants had a marked and persistent increase in acute severe asthma exacerbations from 1 yr of age (incidence ratio 2.40 [1.19–4.81], p = 0.01) and increased risk of asthma by age 5 (odds ratio 2.62 [1.12–6.11], p = 0.03). FLG variants increased the risk of eczema, manifesting fully in the first year of life (point prevalence ratio for age 0–5 was 1.75 [1.29–2.37]; p‐value = 0.0003) contrasting the increased risk of specific sensitization by age 4 (odds ratio 3.52 [1.72–7.25], p = 0.0007) but not age 1.5. This study describes a FLG‐associated pattern of atopic diseases characterized by the early onset of asthma symptoms and eczema and later development of sensitization. The association of filaggrin variants with asthma suggests skin barrier dysfunction as a novel, and potentially modifiable, mechanism driving early childhood asthma.     

Asthma and allergy among schoolchildren in a mountainous,dry, non‐polluted area in Norway

The aim of this study was to assess prevalence of asthma and allergy in the non‐polluted mountain area of Upper Hallingdal, Norway. All schoolchildren (7–16 years) who in a previous questionnaire survey (n = 1177) reported ‘sometime’ asthma were enrolled in group I (n = 80), the 59 who reported asthma‐like symptoms in the past 12 months formed group II, and 77 of the healthy controls were randomly selected as group III. All 216 children underwent clinical examination, skin prick test, spirometry, bronchial provocation (PD₂₀ metacholine) and treadmill exercise test. Subsequently they were reclassified as (1) healthy, never had asthma or symptoms, (2) symptoms not confirmed as asthma, (3) previous asthma, now healthy, (4) current asthma. Lifetime asthma prevalence was 10.2%. Based upon clinical examination, the specificity and sensitivity of the questionnaire for asthma diagnosis were 0.88 and 0.74, respectively. Forced vital capacity was significantly higher among the asthmatics (group 4 versus 1), whereas forced expiratory volume in one second (FEV₁) and forced expiratory flow at 50% of vital capacity were similar in all groups. More than 10% reduction in FEV₁ following treadmill‐run was found in 20% of children. Children with current asthma compared to controls had significantly; lower mean values of PD₂₀ (9.1 versus 16.5 µmol), higher eosinophil cationic protein (13.4 versus 7.7 µmol) and more frequent sensitization to animal dander (56% versus 10%). In conclusion, despite a favorable climate, little mite sensitization and low outdoor pollution, asthma prevalence was surprisingly high in Upper Hallingdal. Sensitization to animal dander was the most important contributing factor for current asthma.     

Prevalence of allergy-related symptoms in Singaporean children in the second year of life

This study describes the cross-sectional prevalence of symptoms associated with eczema (chronic itchy rash), asthma (wheeze), and allergic rhinitis (rhinoconjunctivitis) in 1026 subjects between 18.5 and 23 months old (median age is 21 months) in Singapore. The first 2 yr cumulative prevalence of chronic itchy rash, wheeze, and rhinoconjunctivitis were 22.1% (n=227), 22.9% (n=235), and 8.4% (n=86) respectively. In total, 42.2% (414 of 979) reported ever having any of these symptoms. Eczema, although prevalent, was diagnosed only in 34.4% (n=78) of children with chronic itchy rash. Children with this eczematous rash were also more prone to wheeze (cOR=2.0, 95% CI: 1.2-3.0) and rhinoconjunctivitis (cOR=2.0, 95% CI: 1.4-2.8). Similarly, subjects who reported rhinoconjunctivitis and chronic itchy rash were 2.4 times (95% CI: 1.6-3.6) and 1.4 times (95% CI: 1.0-2.0) more at risk of wheezing respectively. Family history of allergy was a significant risk factor for chronic itchy rash (aOR=1.8, 95% CI: 1.3-2.4) and wheeze (aOR=1.7, 95% CI: 1.3-2.4). Thus, symptoms related to allergy were already prevalent during the second year of life. Significant proportions of these symptoms are likely to be due to true atopy as strong relationship with familial history and comorbidity with other potential allergic symptoms were observed.     

Increasing prevalence of allergic rhinitis but not asthma among children in Hong Kong from 1995 to 2001 (Phase 3 International Study of Asthma and Allergies in Childhood)

There is a worldwide belief that the prevalence of asthma and other allergic diseases is increasing but the measures used in many studies are susceptible to systematic errors. We examined the trend of asthma, allergic rhinitis and eczema prevalence in school children aged 6–7 years in Hong Kong from 1995 to 2001 using standardized ISAAC methodology. There were 4448 and 3618 children participating in 2001 and 1995, respectively. The prevalence of life-time rhinitis (42.4% vs. 38.9%, p < 0.01), current rhinitis (37.4% vs. 35.1%, p < 0.03), current rhinoconjunctivitis (17.2 vs. 13.6%, p < 0.01) and life-time eczema (30.7% vs. 28.1%, p = 0.01) increased significantly. There was no significant change in prevalence of life-time asthma, life-time wheeze and current wheeze albeit a significant increase in severe asthma symptoms. We investigated a number of potential risk factors including sex, family history of atopy, sibship size, birth weight, respiratory tract infections, pet ownership and exposure to tobacco smoke. However, the increases in prevalence of rhinitis and eczema could not be entirely explained by the change of prevalence of these risk factors. The odds ratio OR for the study period remained significantly associated with current rhinitis (OR 1.31, 95% confidence intervals CI 1.17–1.46), current rhinoconjunctivitis (OR 1.63, 95% CI 1.41–1.87) and life-time eczema (OR 1.30, 95% CI 1.16–1.45) after adjustment for these confounding variables using logistic regression model. Further study is warranted to elucidate the factors contributing to the observable change in the prevalence of rhinitis in our population.     

Wheezing in school children is not always asthma

Our objective was to study whether children with reported asthma differed from children with wheeze but without asthma, and from children with neither asthma nor wheeze, regarding lung function, bronchial hyper‐responsiveness (BHR) using methacholine inhalation, exercise‐induced bronchoconstriction (EIB), and skin prick test (SPT) reactivity. School children (n=2188), enrolled in a survey of asthma, were classified into three mutually exclusive groups by parental report of: asthma, wheeze, and no asthma/no wheeze. A random sample of 80 children in each group was tested (n=240). Among asthmatics, 68% (95% confidence interval (CI), 57–79) had a BHR (measured as PD₂₀ forced expiratory volume in 1 s (FEV₁) ≤ 8.16 μmol using methacholine) compared to 31% (CI 20–42%) and 30% (CI 19–40%) in the wheeze and no asthma/no wheeze groups. The dose–response slope (DRS) confirmed the PD₂₀ data and distinguished equally between groups. EIB (≥10% fall in FEV₁) was more frequent (40%, CI 29–52%) among asthmatics than among children with wheeze (12%, CI 4–19%) and no asthma/no wheeze (7%, CI 1–13%). The prevalence of at least one positive SPT was twice as high in the asthma group (58%, 47–69%) than in the wheeze (27%, CI 16–37%) and the no asthma/no wheeze (25%, 15–35%) groups. These results indicate that children with asthma differ from children with wheeze and children with no asthma/no wheeze regarding lung function, BHR, EIB, and SPT reactivity. Children with wheeze are more similar to children with no asthma/no wheeze with respect to these parameters.     

Cross-sectional survey of risk factors for asthma in 6–7-year-old children in New Zealand: International Study of Asthma and Allergy in Childhood Phase Three

Aim:   To identify risk factors for asthma in primary school-aged children in New Zealand.
Methods:   A cross-sectional survey of 10 873 6–7-year-old children in Auckland, Bay of Plenty, Nelson and Christchurch (a response rate of 85.2%). A questionnaire was completed by the parent or care giver.
Results:   22.2% of children wheezed in the last 12 months (current wheeze). Maori children were at greater risk of current wheeze compared with European children (adjusted odds ratio (adjOR) = 1.37; 95% confidence interval = 1.18–1.59). Antibiotics and paracetamol used in the first year of life were associated with an increased risk of current wheeze (adjOR = 1.78 (1.56–2.04) and adjOR = 1.31 (1.06–1.61), respectively). Watching television for 5 or more hours per day was associated with an increased risk of current wheeze (adjOR = 1.44 (1.13–1.83)). Milk and egg consumption in the last 12 months was associated with a reduced risk of current wheeze.
Conclusions:   This study has identified risk factors for asthma in children aged 6–7 years, although causal pathways cannot be established. These associations have important public health implications if causal.     

Prevalence of self-perceived allergic diseases and risk factors in Italian adolescents

The aim of the study was to assess the symptoms prevalence of allergic diseases in a population of 11–15 yr old schoolchildren, to evaluate the associations between asthma and other symptoms and identify risk factors for asthma, rhinitis and eczema syndromes. A sample of 481 students was studied using an International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Prevalence of different kind of self-reported symptoms was calculated. Using a logistic regression approach, we tried to identify risk factors for three syndromes – rhinitis, eczema and asthma. The highest and the lowest prevalence rates of self-reported symptoms were recorded for rhinitis (43.6%) and for eczema (8.1%), respectively. The prevalence of asthma was 15.7%. Univariate analysis showed a mutual association between wheeze and rhinitis symptoms. Multivariate logistic regression model for eczema syndrome revealed female gender as a significant risk factor. The polytomic logistic multivariate regression revealed female gender and family history of allergy as significant risk factors for rhinitis syndrome only, and maternal smoking and familial allergy for rhinitis and asthma together. In particular, familial allergy yields a 400% higher chance of developing asthma and rhinitis together. The synergistic effect of familial allergy on rhinitis and asthma syndromes suggests the implementation of preventive measures in children with family history of these diseases.     

Stability of respiratory symptoms in unlabelled wheezy illness and nocturnal cough.

OBJECTIVE: To assess the natural history of respiratory symptoms not labelled as asthma in primary schoolchildren. DESIGN: Repeat questionnaire survey of subgroups identified from a previous questionnaire survey after a two year delay. SUBJECTS: The original population of 5321 Sheffield children aged 8-9 years yielded 4406 completed questionnaires in 1991(82.8%). After excluding children with a label of asthma, there were 370 children with current wheeze, 129 children with frequent nocturnal cough, and a random sample of 222 children with minor cough symptoms and 124 asymptomatic children. RESULTS: Response rates in the four groups were 233 (63.0%), 77 (59.7%), 160 (72.1%), and 90 (72.6%) respectively. Of those who initially wheezed, 114 (48.9%) had stopped wheezing and 42 (18.0%) had been labelled as having asthma. Those with more frequent wheezing episodes (p < 0.02) and a personal history of hay fever (p < 0.01) in 1991 were more likely to retain their wheezy symptoms. In the children with frequent nocturnal cough in 1991, 20.1% had developed wheezing, 42.9% had a reduced frequency of nocturnal coughing, and 14.2% had stopped coughing altogether two years later. One sixth had been labelled as having asthma. Children with nocturnal cough were more likely to develop wheezing if they had a family history of atopy (p = 0.02). Only 3.8% and 3.3% of those with minimal cough and no symptoms respectively in 1991 had developed wheeze by 1993 (1.9% and 1.0% labelled as asthma). CONCLUSIONS: Most unlabelled recurrent respiratory symptoms in 8-10 year olds tend to improve. Unlabelled children who have persistent symptoms have other features such as frequent wheezing attacks and a family or personal history of atopy. If a screening questionnaire were to be used to identify such children, a combination of questions should be employed.     

Respiratory symptoms and duration of residence in immigrant teenagers living in Melbourne, Australia.

OBJECTIVE: Examination of the relation between respiratory symptoms and time since arrival in Australia in immigrant teenagers living in Melbourne. DESIGN: Two stage, stratified, cross sectional survey. SETTING: High schools (n = 51). SUBJECTS: 9794 people aged 13-19 years. MAIN OUTCOME MEASURES: Prevalence of wheeze during a 12 month period, region of birth, duration of residence in Australia. RESULTS: The estimated population 12 month period prevalence of wheeze was 18.9% (95% confidence interval (CI), 18.0 to 19.9). In subjects born outside Australia, residence for five to nine years in Australia was associated with a 2.1-fold (CI, 1.1 to 4.0) increase in the odds of self reported wheeze; after 10-14 years, this risk increased 3.4-fold (CI, 1.8 to 6.7). There was no difference in severity of wheeze, measured by reported frequency of attacks, between Australian born and non-Australian born subjects. CONCLUSIONS: The notion of a continued secular increase in the prevalence of wheezing is not supported. There is a time dose effect on the prevalence of symptoms in subjects born outside Australia and now living in Melbourne, which is independent of age and country of birth.