Microalbuminuria in adults after prenatal exposure to the Dutch famine

Maternal undernutrition during gestation is associated with an increase in cardiovascular risk factors in the offspring in adult life. The effect of famine exposure during different stages of gestation on adult microalbuminuria (MA) was studied. MA was measured in 724 people, aged 48 to 53, who were born as term singletons in a university hospital in Amsterdam, the Netherlands, around the time of the Dutch famine 1944 to 1945. Twelve percent of people who were exposed to famine in mid gestation had MA (defined as albumin/creatinine ratio >/=2.5) compared with 7% of those who were not prenatally exposed to famine (odds ratio 2.1; 95% confidence interval 1.0 to 4.3). Correcting for BP, diabetes, and other influences that affect MA did not attenuate this association (adjusted odds ratio 3.2; 95% confidence interval 1.4 to 7.7). The effect of famine was independent of size at birth. Midgestation is a period of rapid increase in nephron number, which is critical in determining nephron endowment at birth. Fetal undernutrition may lead to lower nephron endowment with consequent MA in adult life.     

Atopy, immunological changes, and respiratory function in bronchiectasis

Cystic fibrosis has been reported to be associated with an increased prevalence of atopy and reversible airways obstruction. To determine whether such features can also result from other chronic suppurative lung infections, we studied 23 patients with proved bronchiectasis, and 23 age and sex matched normal controls. A personal or family history of atopy was reported with equal frequency in the two groups. Although the groups displayed a similar prevalence of positive immediate hypersensitivity skinprick test responses, the positive patients reacted to more antigens (p less than 0.05) and had larger weal diameters (p less than 0.01) than the positive controls. Other indices, such as blood eosinophil counts and serum IgE, did not differ significantly. Serum concentrations of immunoglobulins G, A, and M and of the four IgG subclasses tended to be higher in patients than controls, but only in the case of IgA (p less than 0.01) was this difference significant. No case of IgG subclass deficiency was noted. The patients displayed significant airflow obstruction, the mean basal one second forced expiratory volume (FEV1), forced vital capacity (FVC), and peak expiratory flow rate (PEFR) being 67%, 77%, and 67% of their predicted values. There was evidence of a significant reversible obstructive component in that FEV1 or PEFR or both increased by 15% or more in nine of the 23 patients after inhalation of fenoterol, the mean increases in FEV1, FVC, and PEFR for the whole group being 9.5%, 11%, and 16.9%. These results indicate that while bronchiectasis provokes a hyperimmune response it differs from cystic fibrosis in that there is no significant increase in the prevalence of atopy. The finding of reversible airways obstruction, however, suggests that bronchodilators may be useful adjuncts to treatment.     

Absence of relationship between tuberculin reactivity and atopy in BCG vaccinated young adults

BACKGROUND: An inverse association between tuberculin responses and atopy has been observed in Japanese children, indicating that BCG immunisation, subclinical exposure to Mycobacterium tuberculosis without clinical disease, or host characteristics may influence the T helper (Th) lymphocyte balance with decreased atopy as a result. This study was undertaken to determine whether tuberculin reactivity is inversely related to atopy in young adults vaccinated with BCG at the age of 14. METHODS: Men and women aged 20-44 years were tested using the adrenaline-Pirquet test with Norwegian produced synthetic medium tuberculin (n = 891). In addition, their serum total and specific IgE antibodies against mite, cat, timothy grass, mould and birch were measured. RESULTS: Of the 574 subjects with complete examinations, 64% had a positive adrenaline-Pirquet tuberculin test (> or =4 mm) and 27% exhibited IgE antibodies (> or =0.35 kU/l) to one or more of the five specific allergens. The geometric mean of total serum IgE in the population was 30.2 kU/l. Tuberculin reactivity and log IgE were not correlated (r = 0.043, p = 0.30). The mean tuberculin reactivity was 4.6 mm, 4.9 mm, and 5.0 mm in the lower, middle and upper tertile of IgE distribution (<14 kU/l, 14-61 kU/l, >61 kU/l). The prevalence of atopy, as assessed by either the presence of any of the five specific IgE antibodies or by each specific IgE antibody separately, did not differ between subjects with a positive and those with a negative tuberculin test. These results persisted after adjustment for age, sex, and smoking status in multivariate logistic regression analyses. CONCLUSIONS: In this young adult population, BCG vaccinated at the age of 14, no significant relationship between a positive tuberculin reaction and atopy was observed. If a true relationship had been found, our study suggests that it may be limited to populations immunised in early childhood when a substantial modulation of the immune system can occur.     

Prevalence of obstructive lung disease in a general population: relation to occupational title and exposure to some airborne agents.

BACKGROUND: The importance of occupational exposure to airborne agents in the development of obstructive disease is uncertain. Studying the relation in a community population has the benefit of reducing the healthy worker effect seen in studies of working populations. METHODS: The prevalence of obstructive lung disease was examined in a Norwegian general population aged 18-73 in a two phased cross sectional survey. In the second phase a stratified sample (n = 1512) of those responding in the first phase was invited for clinical and spirometric examination (attendance rate 84%). Attenders were asked to state all jobs lasting greater than 6 months since leaving school and to say whether they had been exposed to any of seven specific agents and work processes potentially harmful to the lungs. RESULTS: The prevalence of asthma and chronic obstructive lung disease was 2.4% and 5.4%, respectively; spirometric airflow limitation (FEV1/FVC less than 0.7 and FEV1 less than 80% of predicted values) was observed in 4.5% of the population. All jobs were categorised into three groups according to the degree of potential airborne exposure. Having a job with a high degree of airborne exposure increased the sex, age, and smoking adjusted odds ratio for obstructive lung disease (asthma and chronic obstructive lung disease) by 3.6 (95% confidence interval 1.3 to 9.9) compared with having a job without airborne exposure; the association with spirometric airflow limitation was 1.4 (0.3 to 5.2). Occupational exposures to quartz, metal gases, aluminium production and processing, and welding were significantly associated with obstructive lung disease after adjusting for sex, age, and smoking habit, the adjusted odds ratios varying between 2.3 and 2.7. Occupational exposure to quartz and asbestos was significantly related to spirometric airflow limitation in people older than 50. CONCLUSION: Occupational title and exposure to specific agents and work processes may be independent markers of obstructive lung disease in the general population.     

Early allergen exposure, skin prick responses, and atopic wheeze at age 5 in English children: a cohort study

BACKGROUND: For many years it has been assumed that the risk of childhood respiratory allergies is related to allergen exposures in early life. There are, however, few prospective data in support. We aimed to examine this relationship in a representative cohort of children born in Ashford, Kent (UK). METHODS: 625 children (94% of those eligible) were followed from birth to the age of 5.5 years at which time 552 underwent skin prick testing to extracts of house dust mite and cat fur allergens. Maternal reports of wheeze in the last year were collected by interview. These outcomes were related to individual domestic concentrations of Der p 1 and Fel d I allergens estimated from dust collection at the age of 8 weeks. RESULTS: 10% of children were sensitised to house dust mite or cat at age 5.5 years; 7% had atopic wheeze. No significant relationships between allergen exposure and either sensitisation or wheeze were found but, on examination, the exposure-response relationships for both allergens and for each outcome rose steeply at low levels of exposure and were attenuated at high levels of exposure. These patterns were modified by paternal atopy and by birth order. CONCLUSIONS: There are no linear relationships between early allergen exposure and the induction of childhood respiratory allergy; rather, the risks of IgE sensitisation and asthma rise at very low levels of exposure and are attenuated thereafter. These patterns are influenced by parental atopy and birth order. These findings suggest important gene-environment interactions in the development of atopy and asthma and imply that reductions in domestic allergen exposure alone are unlikely to have a major impact in decreasing the incidence of these diseases in childhood.     

Respiratory symptoms, asthma, exercise test spirometry, and atopy in schoolchildren from a Lima shanty town

BACKGROUND: Little is known about the associations between symptoms of asthma, pulmonary function tests, and atopy in developing countries. While asthma in children is often associated with atopy, some studies of wheezing illness have found little or no association, leading to suggestions that there are subgroups of wheezing illness. The ISAAC study recently reported that the prevalence of reported asthma symptoms in Lima, Peru was among the highest in the world, but did not report on the atopic status of the subjects. METHODS: A cross sectional survey was conducted of children aged 8-10 years who had previously participated in a cohort study of respiratory and diarrhoeal illnesses in infancy. Questionnaires were administered asking about respiratory symptoms and asthma diagnoses, pulmonary function tests were performed before and after exercise on a treadmill, and atopy was determined from skin prick tests and specific serum IgE levels. RESULTS: A total of 793 children participated in the survey. The prevalence of asthma related symptoms in the last 12 months was 23.2%, but only 3.8% of children reported a recent asthma attack. The mean differences in pretest percentage predicted forced expiratory volume in one second (FEV(1)) were 8.1% (95% CI 2.4 to 13.8) between children who did and did not report an asthma attack in the last 12 months, and 5.3% (95% CI 2.8 to 7.9) in children who did and did not report respiratory symptoms. The corresponding differences in mean percentage fall in FEV(1) after exercise were 3.1% (95% CI -1 to 7.1) and 5.1% (95% CI 3.4 to 6.8). Recent asthma or respiratory symptoms were not associated with atopy in this population (odds ratios 1.29 (95% CI 0.56 to 2.97) and 0.91 (95% CI 0.61 to 1.37), respectively). CONCLUSIONS: Most asthma in these children was unrecognised and mild. Asthma and asthma symptoms in this population do not seem to be related to atopy.     

An improved murine model of asthma: selective airway inflammation, epithelial lesions and increased methacholine responsiveness following chronic exposure to aerosolised allergen

BACKGROUND: Existing murine models of asthma lack many of the inflammatory and epithelial changes that are typical of the human disease. Moreover, these models are frequently complicated by allergic alveolitis. METHODS: High IgE responder BALB/c mice were systemically sensitised to ovalbumin and chronically challenged with low particle mass concentrations of aerosolised ovalbumin. Titres of antiovalbumin IgE in serum were measured at two weekly intervals by enzyme immunoassay, accumulation of inflammatory cells and histopathological abnormalities of the epithelium were quantified morphometrically in the trachea and the lungs, and airway reactivity was assessed by measuring bronchoconstriction following intravenous administration of methacholine. RESULTS: Mice sensitised by two intraperitoneal injections of ovalbumin developed high titres of IgE antibodies to ovalbumin. Following exposure to low concentrations of aerosolised antigen for up to eight weeks these animals developed a progressive inflammatory response in the airways, characterised by the presence of intraepithelial eosinophils and by infiltration of the lamina propria with lymphoid/mononuclear cells, without associated alveolitis. Goblet cell hyperplasia/metaplasia was induced in the intrapulmonary airways, while epithelial thickening and subepithelial fibrosis were evident following chronic exposure. In parallel, the mice developed increased sensitivity to induction of bronchospasm, as well as increased maximal reactivity. Non-immunised mice exposed to aerosolised ovalbumin had low or absent antiovalbumin IgE and did not exhibit inflammatory or epithelial changes, but developed airway hyperreactivity. CONCLUSIONS: This experimental model replicates many of the features of human asthma and should facilitate studies of pathogenetic mechanisms and of potential therapeutic agents.     

Trends in lung cancer, chronic obstructive lung disease, and emphysema death rates for England and Wales 1941-85 and their relation to trends in cigarette smoking

Trends in smoking associated respiratory diseases in England and Wales during 1941-85 have been studied, with careful attention to problems caused by changes in classification of cause of death. Three diseases were selected for analysis: lung cancer, emphysema, and chronic obstructive lung disease. During 1971-85 deaths that would previously have been certified under chronic bronchitis have increasingly tended to be classified under chronic airways obstruction. The definition of chronic obstructive lung disease that was used includes both terms to avoid the artificial decline caused by consideration of chronic bronchitis in isolation. Age specific rates for all three diseases show a pronounced cohort (period of birth) pattern, rates for men rising up to the rates for those born shortly after the turn of the century and then declining, and rates for women peaking in the cohort born 20-25 years later. For chronic obstructive lung disease, but not for lung cancer and emphysema, the cohort peak is superimposed on a sharply declining downward trend. In both sexes cohort patterns of cumulative cigarette consumption peak at a time broadly similar to those seen for the three diseases. Trends in cigarette consumption, however, cannot explain the underlying steeply declining rate of chronic obstructive lung disease. Nor can they fully explain the declining trends in lung cancer and emphysema rates in younger men and women.     

Spina bifida as an independent risk factor for sensitization to latex.

PURPOSE: Patients with spina bifida are at a high risk for having an immediate type allergy to latex products. The number of surgical interventions, atopy and catheterization are well known responsible factors, whereas the condition of spina bifida per se has not been established as an independent risk factor. MATERIALS AND METHODS: A total of 131 patients with a shunted hydrocephalus (48 with spina bifida and 83 of other origin) were investigated for sensitization to latex by skin prick tests and determination of specific IgE. We hypothesized that the diagnosis of spina bifida will increase the risk for latex sensitization while considering potential confounding factors. Thus, we performed a multiple logistic regression analysis to determine independent risk factors. RESULTS: Whereas 56.3% (27/48) of children with spina bifida proved sensitized against latex, this result was the case in only 16.9% (14/83) with another cause of hydrocephalus (p <0.001). The mean number of surgical interventions was 6.2 for patients with no latex sensitization and 9.3 for those with sensitization (p = 0.02). Of patient sensitized to latex 43.9% had a history of atopy compared to 15.5% of those not sensitized (p = 0.02). Sensitized and nonsensitized patients were comparable regarding gender and catheterization. In a multiple logistic regression analysis the cause of the hydrocephalus (odds ratio 6.76 for spina bifida), atopy (odds ratio 3.37) and the number of surgical interventions (odds ratio 1.14 per operation) were identified as independent risk factors. CONCLUSIONS: The increased risk of latex sensitization in patients with spina bifida seems to be disease associated. Possible explanations for this finding may be genetic, antigen mediated, early latex exposure and immunological reasons.     

Maternal age at menarche and atopy among offspring at the age of 31 years

BACKGROUND: Influences of female hormones on the occurrence of allergic disorders have been suggested. Age at menarche may be a marker of endogenous oestrogen levels. Data from a Finnish birth cohort followed to adulthood were analysed to determine whether there is any association between maternal age at menarche and the occurrence of atopy among offspring. METHODS: The study was conducted in 5188 subjects born in northern Finland for whom data collections were started during pregnancy and a follow up examination was completed at the age of 31 years. Atopy was determined by skin prick tests with cat, birch, grass, and mite extracts, and doctor diagnosed asthma was ascertained by questionnaire at follow up. Maternal age at menarche was obtained from perinatal data. Logistic regression models were used to adjust for maternal age, parity, smoking, season of birth, parental allergy, and measures of adiposity and socioeconomic status. RESULTS: The prevalence of atopy at the age of 31 years was lower in children whose mothers reached menarche at a later age, especially after age 15. Compared with children whose mothers started menarche at the age of 16 or over, the adjusted odds ratios of being atopic for children whose mothers started menarche younger than or at 12, 13, 14 and 15 years were 1.43 (95% CI 1.12 to 1.83), 1.29 (95% CI 1.03 to 1.60), 1. 15 (95% CI 0.93 to 1.42), and 1.19 (95% CI 0.95 to 1.48), respectively. Among girls, the offspring's own age at menarche was not significantly associated with atopy. CONCLUSION: Our results encourage further evaluation of the potential effect of maternal age at menarche on the later development of atopy and possible biological mechanisms.     

Relationship between fetal growth and the development of asthma and atopy in childhood

BACKGROUND: A study was undertaken to investigate the relationship between birth anthropometric measures and the subsequent development of asthma, airway hyperresponsiveness, and atopy in later childhood. METHODS: A longitudinal study was performed on 734 subjects (71%) from a cohort of children born in Dunedin, New Zealand in 1972-73. The birth anthropometric measures were available from hospital records and the main outcome measures of reported asthma, skin prick tests, and methacholine hyperresponsiveness were measured at the age of 13 years, while the serum total IgE was measured at 11 years. RESULTS: After adjustment for other factors, infants with a larger head circumference at birth tended to have higher serum total IgE at 11 years of age (p = 0.02) but IgE was not associated significantly with birth length or birth weight. The adjusted odds ratio for raised serum IgE (>150 IU/ml) in infants with a head circumference of 37 cm or more was 3.4 (95% CI 1.4 to 7.9). In contrast, recent asthma symptoms were positively associated with birth length (p = 0. 04) but not with head circumference. The adjusted odds ratio for asthma in the previous two years in infants with a birth length of 56 cm or more was 6.4 (95% CI 2.0 to 19.8). Infants with a birth weight of less than 3.0 kg had an odds ratio for reported asthma of 0.2 (95% CI 0.0-0.6). There were no significant associations of any of the birth parameters with skin prick positivity, reported hay fever, or eczema. CONCLUSIONS: These results suggest that increased fetal growth is related to an increased risk of asthma and atopy in childhood. The precision of the findings is limited by the small numbers in the extreme categories of each birth parameter, but the results are consistent with intrauterine programming of the developing respiratory and immune systems.     

Atopy phenotype in subjects with variants of the beta subunit of the high affinity IgE receptor

BACKGROUND: Fc epsilon RI plays a central role in atopy, thus genetic variants of Fc epsilon RI-beta may alter receptor function to enhance atopic responses and may manifest as a more severe atopic phenotype and more symptomatic atopic disease. The immunological and clinical features of atopy in children with and without the Leu 181 variant of Fc epsilon RI-beta were compared. METHODS: Sixty British nuclear families, including 10 families with the Fc epsilon RI-beta variant Leu 181, recruited via a young proband with atopic asthma were analysed for atopic parameters including total IgE, specific IgE, and clinical atopic disorder. RESULTS: Compared with other children (combined atopic and non-atopic subjects), maternally inherited Leu 181 was associated with increased levels of total IgE (odds ratio (OR) 4.82, 95% confidence interval (CI) 1.02 to 27.66, p < 0.01) and a positive IgE response to grass pollen allergen (OR 7.45, 95% CI 1.56 to 35.52, p < 0.005) but not wheeze (OR 1.97, 95% CI 0.56 to 7.69), asthma (OR 2.25, 95% CI 0.65 to 7.85), or required medications (OR 0.95, 95% CI 0.29 to 3.14). There were trends for each atopic parameter to be more marked in atopic children with maternally inherited Leu 181 than in atopic children without Leu 181. Children with maternal Leu 181 had significantly raised eosinophils but there was no difference in basophil levels compared with other atopic children. CONCLUSIONS: The Leu 181 variant of Fc epsilon RI-beta, or another identified variant in linkage disequilibrium, may promote the development of atopy.




     

Prevalence, concordance, and heritability of Scheuermann kyphosis based on a study of twins

BACKGROUND: The purpose of this study was to establish a cohort of symptomatic twins with Scheuermann kyphosis to provide estimates of prevalence, concordance, odds ratio, and heritability. These estimates indicate to what extent genetic factors contribute to the etiology of this disease. METHODS: The Odense-based Danish Twin Registry is unique in that it contains data on all 73,000 twin pairs born in Denmark over the last 130 years. For the present study, all 46,418 twins born from 1931 through 1982 received a seventeen-page questionnaire, in which one question was "Have you been diagnosed with Scheuermann disease by a doctor"? The prevalence of self-reported Scheuermann disease was calculated, with the total number of answers used as the general population. Pairwise and probandwise concordance, odds ratio, tetrachoric correlations, and heritability were calculated. RESULTS: We found that the overall prevalence of Scheuermann disease was 2.8%, with a prevalence of 2.1% among women and 3.6% among men (p < 0.0001). The pairwise concordance for monozygotic twins was 0.19 compared with 0.07 for dizygotic twins. The probandwise concordance was 0.31 for monozygotic twins and 0.13 for dizygotic twins. The odds ratios were 32.92 and 6.25 in the monozygotic and dizygotic twins, respectively. These differences were significant (p < 0.01). Heritability was 74%. CONCLUSIONS: In a large cohort of twins that included almost 35,000 individuals, the self-reported overall prevalence of Scheuermann disease was 2.8% and the male-to-female ratio was close to 2:1. Because the pairwise and probandwise concordance and the odds ratio were two to three times higher in monozygotic than in dizygotic twins and the heritability was high, we concluded that there is a major genetic contribution to the etiology of Scheuermann disease.     

Screening older patients for obstructive airways disease in a semi-rural practice

BACKGROUND: Obstructive airways disease in older patients is reported to be not only common, but frequently overlooked and untreated by general practitioners. This study examines the value of screening elderly patients in a large semi-rural general practice for potentially treatable asthma and chronic obstructive pulmonary disease (COPD). METHODS: A random sample of 353 patients aged 60-75 years attended a nurse run screening clinic for pulmonary function testing, serial peak flow recording, and completion of a symptom questionnaire. Patients with a low forced expiratory volume in one second (below the fifth centile of their predicted value) or >15% mean diurnal variation in peak flow were referred to a doctor's clinic for further diagnostic assessment and/or to discuss possible treatment where appropriate. RESULTS: Fifty eight patients (16.4%) had obstructive airways disease, the prevalence of asthma being 6.5% and that of COPD 9.9%. Of these, 30 had no previous diagnosis of airways disease and were not on treatment; eight of them had significant airways reversibility and 10 were current smokers. No newly diagnosed patients had severe disease as measured by pulmonary function or quality of life assessment, and six patients accepted treatment. CONCLUSION: Few older patients benefited from a screening programme for obstructive airways disease in a semi-rural general practice.     

No increase in the prevalence of asthma, allergies, and atopic sensitisation among children in Germany: 1992-2001

BACKGROUND: From 1970 to 1990 increasing rates of asthma and allergic sensitisation were observed in several countries. The aim of this study was to investigate time trends in the prevalence of asthma and allergic sensitisation among school children in Germany between 1992 and 2001. METHODS: Parental reports of asthma, hay fever, and wheezing and measurements of specific serum IgE antibodies were investigated in six serial cross sectional surveys of 9-11 year old school children in three study areas in south west Germany. RESULTS: A total of 6762 school children of mean age 10 years (mean participation rate 77.9%) took part in the investigation in the three study areas. Over the 9 year study period no increase in the prevalence of current wheezing and asthma was observed. In addition, the prevalence of atopic sensitisation remained unchanged during the observation period. CONCLUSIONS: These data, using parental reports and objective measures of allergy, suggest that there has been no further increase in the prevalence of asthma and atopy since 1992. The epidemic may thus have reached a plateau.     

Beta 2 adrenergic receptor gene restriction fragment length polymorphism and bronchial asthma.

BACKGROUND--Beta 2 adrenergic dysfunction may be one of the underlying mechanisms responsible for atopy and bronchial asthma. The gene encoding the human beta 2 adrenergic receptor (beta 2ADR) has recently been isolated and sequenced. In addition, a two allele polymorphism of this receptor gene has been identified in white people. A study was carried out to determine whether this polymorphism is functionally important and has any relation to airways responsiveness, atopy, or asthma. METHODS--The subjects studied were 58 family members of four patients with atopic asthma. Restriction fragment length polymorphism (RFLP) with Ban-I digestion of the beta 2ADR gene was detected by a specific DNA probe with Southern blot analysis. Airways responses to inhaled methacholine and the beta 2 agonist salbutamol, the skin prick test, and serum IgE levels were also examined and correlated to the beta 2ADR gene RFLP. In addition, measurements of cAMP responses to isoproterenol in peripheral mononuclear cells were performed in 22 healthy subjects whose genotype for beta 2ADR was known. RESULTS--A two allele polymorphism (2.3 kb and 2.1 kb) of the beta 2ADR gene was detected in the Japanese population. Family members without allele 2.3 kb (homozygote of allele 2.1 kb) had lower airways responses to inhaled salbutamol than those with allele 2.3 kb. The incidence of asthma was higher in those without allele 2.3 kb than in those with allele 2.3 kb. The beta 2ADR gene RFLP had no relation to airways responses to methacholine and atopic status. cAMP responses in peripheral mononuclear cells of the subjects without allele 2.3 kb tended to be lower than those of the subjects with allele 2.3 kb. CONCLUSIONS--These results suggest that Ban-I RFLP of the beta 2ADR gene may have some association with the airways responses to beta 2 agonists and the incidence of bronchial asthma.     

Relationship between socioeconomic status and asthma: a longitudinal cohort study

BACKGROUND: There is conflicting information about the relationship between asthma and socioeconomic status, with different studies reporting no, positive, or inverse associations. Most of these studies have been cross sectional in design and have relied on subjective markers of asthma such as symptoms of wheeze. Many have been unable to control adequately for potential confounding factors. METHODS: We report a prospective cohort study of approximately 1000 individuals born in Dunedin, New Zealand in 1972-3. This sample has been assessed regularly throughout childhood and into adulthood, with detailed information collected on asthma symptoms, lung function, airway responsiveness, and atopy. The prevalence of these in relation to measures of socioeconomic status were analysed with and without controls for potential confounding influences including parental history of asthma, smoking, breast feeding, and birth order using cross sectional time series models. RESULTS: No consistent association was found between childhood or adult socioeconomic status and asthma prevalence, lung function, or airway responsiveness at any age. Having asthma made no difference to educational attainment or socioeconomic status by age 26. There were trends to increased atopy in children from higher socioeconomic status families consistent with previous reports. CONCLUSIONS: Socioeconomic status in childhood had no significant impact on the prevalence of asthma in this New Zealand born cohort. Generalisation of these results to other societies should be done with caution, but our results suggest that the previously reported associations may be due to confounding.     

Prevalence of atopy, asthma symptoms and diagnosis, and the management of asthma: comparison of an affluent and a non-affluent country

BACKGROUND: The prevalence of childhood asthma and of atopy varies widely between countries. However, few studies have compared the pattern of diagnosis and management of asthma, or the role of atopy in predisposing to asthma between a less affluent country and a more affluent country. The aim of this study was to compare the prevalence of symptoms, diagnosis, and management of asthma, and the prevalence of atopy as measured by skin prick tests in Nigeria and Australia using a standardised methodology. METHODS: Respiratory history was collected using a validated questionnaire administered to parents, and atopy was measured with skin prick tests in 654 Australian and 566 Nigerian children aged 8-11 years (70% consent rate in Australia, 60% in Nigeria). RESULTS: Wheeze and persistent cough were less prevalent in Nigeria (10.2% and 5.1%, respectively) than in Australia (21.9% and 9.6%, respectively), caused less morbidity, and were less likely to be labelled or treated as asthma than in Australia. There was no significant difference in the overall prevalence of atopy between the two countries (Australia 32. 5%, Nigeria 28.2%). Atopy was a strong risk for wheeze in both countries (odds ratio (OR) 3.4 (95% CI 2.3 to 5.1) in Australia, 1.8 (95% CI 1.0 to 3.3) in Nigeria), especially atopy to house dust mites (OR 3.1 (95% CI 2.1 to 4.7) in Australia, 2.4 (95% CI 1.3 to 4. 3) in Nigeria). CONCLUSION: Although there was a similar prevalence of atopy in both countries, Australian children had a higher prevalence of asthma symptoms. Further studies are needed to determine why atopic children in Australia are more at risk of developing asthma. Such studies will have important implications for the prevention of asthma.     

Early exposure to children in family and day care as related to adult asthma and hay fever: results from the European Community Respiratory Health Survey

BACKGROUND: The literature indicates that early exposure to children in the family and to day care permanently influences the development of allergic disease. A study was undertaken to examine the associations of family size and day care with adult asthma and hay fever and to determine whether these associations are mediated through specific IgE production and whether they vary with allergic predisposition. METHODS: 18,530 subjects aged 20-44 years from 36 areas predominantly in the market economies participated in the European Community Respiratory Health Survey and provided information through interviewer-led questionnaires. 13,932 subjects gave blood samples for measurement of specific IgE. RESULTS: Hay fever was less common in subjects with many siblings (OR=0.92; 95% CI 0.90 to 0.95 per sib). There was a U-shaped relationship between asthma and number of siblings (quadratic effect of siblings, pwheeze=0.014, pFEV(1)=0.016). In subjects without siblings but exposed to children in day care, hay fever was less common (OR=0.76; 95% CI 0.60 to 0.98) and asthma symptoms were more common (ORwheeze=1.48; 95% CI 1.12 to 1.95). Adjustment for specific IgEs did not alter these associations. The inverse association of hay fever with siblings was found in sensitised subjects (OR=0.89; 95% CI 0.84 to 0.94) and in those with parental allergy (OR=0.91; 95% CI 0.85 to 0.97), but not in subjects without such a predisposition (OR=1.02; 95% CI 0.97 to 1.09). CONCLUSION: Subjects exposed to many children at home or in day care experienced less hay fever and more asthma in adulthood. Microbial challenge through children may contribute to a non-allergic immunological development giving less hay fever but more airways infections predisposing to asthma. These effects were not mediated through production of specific IgE. The protective effect of siblings on hay fever was particularly strong in those with an allergic predisposition.     

Occupational asthma caused by a plastics blowing agent, azodicarbonamide.

A prevalence study of occupational asthma was carried out by questionnaire in 1980 among a group of 151 workers who had been exposed to azodicarbonamide dust in the process of its manufacture. Twenty-eight (18.5%) people without previous asthma gave a history of episodes of late onset asthma after exposure to azodicarbonamide. Re-exposure caused repetition and worsening of symptoms. Immediate removal from further exposure resulted in rapid cessation of symptoms without further recurrence. Seven of 13 sensitised individuals who were still exposed three months after the onset of disease developed prolonged airways hyperreactivity to common environmental irritants. Azodicarbonamide should be excluded as a causative agent in plastics and rubber industry workers complaining of occupational asthma.