Atopic sensitization among children in an Arctic environment

BACKGROUND: Asthma has been reported to be rare among Inuits, but so far total and specific IgE levels have never been determined in arctic populations. OBJECTIVE: To determine the prevalence of atopy in children living in an arctic environment, and to examine whether atopy and total IgE levels were associated with parental place of birth, as a measure of ethnicity, and travel history. MATERIAL AND METHODS: All schoolchildren in Sisimiut, a community on the West coast of Greenland, were screened for atopy. Blood samples were analysed for total IgE and for specific IgE against inhalant and food allergens. Information on place of birth of children and their parents was obtained from national registries. Information on travel history was obtained from self-administered questionnaires. RESULTS: A total of 1031 schoolchildren aged 5 to 18 years had a blood sample drawn (85% of available children for the study). Of these, 151 (14.6%) children were sensitized to at least one inhalant allergen and 42 (4.1%) to at least one food allergen. Sensitization to grass was most common, whereas sensitization to mugwort, birch, animal-dander and house-dust mite was infrequent. Children whose parents were both born abroad had a higher risk of sensitization to inhalant allergens compared with children born of Greenlandic parents (OR = 8.6, 95% CI 2.8-27.1). Furthermore, children who had been abroad had a higher risk of sensitization towards pollen (OR = 1.6, 95% CI 1.0-2.5) and animal-dander (OR = 2.1, 95% CI 1.0-4.6) after adjustment for confounders. Both atopic and non-atopic children demonstrated high levels of total IgE (medians of 251 and 58 kU/L). CONCLUSIONS: Compared with European findings Greenlandic children have high levels of total IgE but a low prevalence of allergic sensitization towards inhalant allergens. This may be due to a low genetic susceptibility to atopy and less allergen exposure, as well as to living conditions in an arctic environment.     

Atopic sensitization and atopic dermatitis in Estonian and Swedish infants

BACKGROUND: Early life events seem to have a major impact on the development of tolerance or sensitization. OBJECTIVE: The aim of the study was to compare the prevalence of sensitization and atopic dermatitis (AD) during the first 2 years of life in Estonia and in Sweden. METHODS: Two groups comprising 110 Estonian and 123 Swedish infants were followed from birth up to 2 years of age. Data about symptoms of allergy, infections and use of antibiotics were obtained by questionnaires. Clinical examinations, skin prick tests (SPTs) with food and inhalant allergens, and blood sampling for IgE analyses were carried out at 3, 6, 12 and 24 months. RESULTS: The cumulative incidence of AD and positive SPTs were lower in the Estonian than the Swedish infants (14% vs. 24%; P = 0.06 and 13% vs. 24%; P = 0.03), while circulating IgE antibodies were more common (39% vs. 27%; P = 0.06) and often present without any clinical significance in Estonian children. Estonian infants had respiratory illnesses more often and they had received antibiotics more frequently. Use of antibiotics increased the risk for positive SPT in the Estonian (odds ratio = 1.7, 95% confidence interval = 1.1-2.5), but not in the Swedish infants. This may be explained by the use of broad-spectrum antibiotics in Estonia, while in Sweden mostly penicillin was prescribed. CONCLUSIONS: The prevalence of AD and positive SPTs was lower in the Estonian than the Swedish infants, while circulating IgE antibodies were more common and often present without any clinical significance. These differences cannot simply be explained by infections, or use of broad-spectrum antibiotics in the two countries, although more the natural lifestyle in Estonia may be contributing factor.     

The prevalence of asthmatic respiratory symptoms among adults in Estonian and Swedish university cities

The prevalence of atopy and related diseases is lower among children in Eastern European countries than in countries with a market economy. Such comparisons have not been made in adults. The European Community Respiratory Health Survey (ECRHS) postal questionnaire was mailed to random samples of 3000 inhabitants in Tartu, Estonia, and 3600 in Uppsala, Sweden, between the ages of 20 and 44 years. Asthmatic symptoms (wheeze with breathlessness occurring in the absence of colds) were less prevalent in Tartu (4.6% vs 6.8%, P<0.001), as were attacks of asthma (1.9% vs 3.3%, P<0.01), current asthma medication (0.7% vs 4.9%), and allergic rhinitis (17.8% vs 22.2%, P<0.001). Age was inversely related to allergic rhinitis in Uppsala (P<0.05), but not in Tartu. Nocturnal respiratory symptoms (wakening with chest tightness or being woken by an attack of breathlessness or an attack of cough) were more prevalent in Tartu (P<0.001), and their prevalence increased with age (P<0.05) in Tartu, but not in Uppsala. Symptoms of asthma and hay fever were less common but other respiratory problems more common in Tartu than in Uppsala. The difference in the prevalence of hay fever diminished with age, supporting the notion that the increasing prevalence of allergy among children and young adults in Western Europe is caused by a cohort effect.     

Predictors of persistence of remission of the respiratory symptoms in school children

The evolution of the respiratory symptoms in school children hampers the interpretation of epidemiologic findings concerning potential risk factors. It is thus important to identify prognostic factors that predict symptoms' persistence or remission. A seven-year follow-up of 663 children showed that half of them experience the remission of cough, chest wheeze and attacks of dyspnea. The results of multivariate analysis showed that the persistence of cough is more likely to occur in children with a history of spastic bronchitis (logOR = 3.1; 95% CI: 1.3-7.1) and the presence of coal-stove in kitchen (logOR = 3.1: 95% CI: 1.4-6.9). The probability of persistence of wheeze depends on history of bronchitis (logOR = 3.9; 95% CI: 1.4-11.4), history of parental asthma(logOR = 4.8; 95% CI: 1.1-25.2) and diagnosis of pollen sensitivity (logOR = 3.9; 95% CI = 1.2-12.9). On the other hand the persistence of attack of dyspnea was associated with a shortness of breath on exertion(logOR = 4.7; 95% CI: 1.5-16.8). The results of the study confirm an important role of medical history in the assessment of prognosis of the respiratory health status in children.     

Allergic disease and sensitization in Steiner school children

BACKGROUND: The anthroposophic lifestyle has several features of interest in relation to allergy: for example, a restrictive use of antibiotics and certain vaccinations. In a previous Swedish study, Steiner school children (who often have an anthroposophic lifestyle) showed a reduced risk of atopy, but specific protective factors could not be identified. OBJECTIVE: To investigate factors that may contribute to the lower risk of allergy among Steiner school children. METHODS: Cross-sectional multicenter study including 6630 children age 5 to 13 years (4606 from Steiner schools and 2024 from reference schools) in 5 European countries. RESULTS: The prevalence of several studied outcomes was lower in Steiner school children than in the reference group. Overall, there were statistically significant reduced risks for rhinoconjunctivitis, atopic eczema, and atopic sensitization (allergen-specific IgE > or =0.35 kU/L), with some heterogeneity between the countries. Focusing on doctor-diagnosed disease, use of antibiotics during first year of life was associated with increased risks of rhinoconjunctivitis (odds ratio [OR], 1.97; 95% CI, 1.26-3.08), asthma (OR, 2.79; 95% CI, 2.03-3.83), and atopic eczema (OR, 1.63; 95% CI, 1.22-2.17). Early use of antipyretics was related to an increased risk of asthma (OR, 1.54; 95% CI, 1.11-2.13) and atopic eczema (OR, 1.32; 95% CI, 1.02-1.71). Children having received measles, mumps, and rubella vaccination showed an increased risk of rhinoconjunctivitis, whereas measles infection was associated with a lower risk of IgE-mediated eczema. CONCLUSION: Certain features of the anthroposophic lifestyle, such as restrictive use of antibiotics and antipyretics, are associated with a reduced risk of allergic disease in children.     

Total serum IgE and its association with asthma symptoms and allergic sensitization among children.

BACKGROUND: Asthma and wheezing during childhood are associated with elevated total serum IgE and with allergic sensitization to local aeroallergens. However, little is known about the longitudinal relationship between total serum IgE and the development of wheezing and allergic sensitization during childhood. OBJECTIVE: The purpose of our investigation was to determine the relationship between total serum IgE and the development of wheezing and allergic sensitization in childhood. METHODS: Our study subjects were participants in the Tucson Children's Respiratory Study who underwent an IgE measurement in at least 1 of 3 surveys (at years 1, 6, and 11) and complete allergy skin tests during the latter 2 surveys. The children's phenotypes were categorized on the basis of skin test response (never, early, and late) and wheezing status (never, early, late, and persistent). Repeated-measures analyses were used, allowing subjects to be included who had unequal numbers of IgE observations (a total of 263 boys and 277 girls). RESULTS: We found that total serum IgE levels track with age: subjects with high serum IgE levels less than 1 year old continued to have high IgE levels at ages 6 and 11 years. Both persistent wheezing and early sensitization were associated with high serum IgE levels at all ages. Boys who had late or persistent wheezing or who were sensitized early or late had high serum IgE levels as early as age 9 months, whereas only girls with persistent wheezing and early sensitization had elevated IgE levels at that age. Children who wheezed only in the first years of life and not after (ie, those with early wheezing) had serum IgE levels that were not different from those of nonwheezing children. CONCLUSION: On the basis of these findings we conclude that although total serum IgE tracks with age, children who are predisposed to persistent wheezing and early sensitization to local aeroallergens already have high levels of IgE at age 9 months. This suggests that the predisposition to respond to environmental stimuli through high levels of IgE precede early allergic sensitization, indicating that there may be a common defect in the development of the immune system involving IgE production and early allergic sensitization.     

On early sensitization to allergens and development of respiratory symptoms

BACKGROUND: Various studies have suggested that a sequence of events occurring in childhood may affect the development of asthma in susceptible individuals. We have investigated whether early childhood sensitization to aeroallergens is an important risk factor in the later development of asthma symptoms. OBJECTIVE AND METHODS: In this study we examine this issue in children enrolled in the Tucson epidemiology study of obstructive airways disease, who had at least two allergen skin tests, one before and one after 8 years of age. Respiratory symptom data were available from 12 survey questionnaires, spanning a period of 20 years. During the first, sixth, seventh and eleventh surveys, skin tests were performed with commercially available allergens. CONCLUSION: As compared with children who were sensitized after 8 years of age, children over 8 years who were sensitized to any allergen before age 8 years were significantly more likely to report shortness of breath with wheeze (SOBWZ), wheeze apart from colds or wheeze most days (OR = 4.1 SOBWZ; OR = 3.88 WZ apart from colds; and OR = 2.83 WZ most days). Children who were sensitized after 8 years were no more likely to have the symptoms described above than children who were never found to be sensitized. Based on these results we conclude that early allergic sensitization is a significant risk factor for later development of wheezy symptoms, where as late sensitization is not.     

Exhaled nitric oxide: relation to sensitization and respiratory symptoms

BACKGROUND: Conflicting data have been presented as to whether nitric oxide (NO) in exhaled air is merely reflecting atopy rather than airway inflammation. OBJECTIVE: To investigate the relationship between exhaled NO (eNO) and nasal NO (nNO), respiratory symptoms, and atopy, in the context of a cross-sectional study of the respiratory health of bleachery workers. METHODS: Two hundred and forty-six non-smoking bleachery and paper-mill workers answered a questionnaire and were examined by measurements of eNO and nNO and spirometry, outside the pollen season. Blood samples were collected and analysed for specific IgE against common aeroallergens (birch, timothy, cat and house dust mite). Atopy was defined as a positive Phadiatop trade mark test. RESULTS: The atopic and the non-atopic subjects without asthma or rhinitis had similar levels of eNO. Subjects reporting asthma or rhinitis who were also sensitized to perennial allergens had higher levels of eNO, whereas those sensitized to only seasonal allergens had similar eNO levels as non-atopic subjects with asthma or rhinitis. In multiple linear regression models adjusted for nNO, eNO was associated with asthma and sensitization to perennial allergens. CONCLUSION: The results indicate that only atopic subjects who have recently been exposed to the relevant allergen have elevated levels of eNO. Atopic subjects who are not being exposed to a relevant allergen or have never experienced symptoms of asthma or rhinitis show normal eNO. These data indicate that eNO relates to airway inflammation in atopic subjects.     

Factors associated with increased respiratory symptoms among asthmatic children in Singapore

Asthma is a common cause of childhood morbidity. The objective of the present study was to evaluate the factors associated with increased asthma morbidity among asthmatic children in Singapore. A cohort of primary school children (n = 6,404, aged 6-13 years) were evaluated using the American Thoracic Society and the Division of Lung Diseases of the National Heart, Lung and Blood Institute, USA (ATS-DLD) respiratory questionnaire. A total of 2,222 of 6,404 children (34.8%) was found to have reported symptoms of wheezing. Of these, 899/2,222 (40.5%) reported symptoms of "increased asthma morbidity". This was associated with the younger age group, male sex and higher socio-economic status. In addition, concurrent or past allergies were strongly associated with increased asthma morbidity, while premature birth and a history of prior childhood respiratory illnesses and Infections were predictive of greater asthma morbidity. No association was found between increased morbidity and presence of domestic pets, parental smoking, childcare attendance, and the season of birth.     

IgE-sensitization to predatory mites and respiratory symptoms in Swedish greenhouse workers

BACKGROUND: Predatory mites are used as biological pesticides worldwide for control of spider mites and other pests in greenhouses. The aim of this study was to evaluate the impact of occupational exposure to Phytoseiulus persimilis and Hypoaspis miles on IgE sensitization among a large group of Swedish greenhouse workers and to examine the relationship between exposure and allergic asthma and rhinoconjunctivitis. METHODS: A total of 96 greenhouse workers from the southern part of Sweden, who were using the predatory mites for control of pests, were investigated with a questionnaire and a medical examination including lung function test. Blood samples were taken to test for allergen-specific IgE antibodies to Phytoseiulus persimilis and Hypoaspis miles as well as to Tetranychus urticae, Dermatophagoides pteronyssinus/farinae and Tyrophagus putrescentiae. RESULTS: Seventeen of the 96 workers were positive in ImmunoCAP to predatory mites: 17 to P. persimilis (17.7%) and 14 to H. miles (14.6%). Subjects sensitized to predatory mites were significantly more often atopic (13/17), defined as a positive Phadiatop, than those who lacked IgE against these mite species (17/79) (P <0.01). IgE antibodies to the red spider mite T. urticae were present among 23 subjects. Thirty-five of the investigated subjects displayed a positive ImmunoCAP to at least one of the investigated mite species. Furthermore, sensitization to any of the mites tested was significantly associated with asthma (OR=9.3) and rhinoconjunctivitis (OR=4.3). CONCLUSIONS: IgE sensitization to predatory mites, P. persimilis and H. miles, is common among greenhouse workers. The findings stress the importance of improved allergen avoidance in greenhouse environments.     

Somatic symptoms, peer and school stress, and family and community violence exposure among urban elementary school children

Somatic symptoms are a common physical response to stress and illness in childhood. This study assessed 409, primarily African American (85.6 %), urban elementary school children to examine the association between: (1) somatic symptoms and potential external stressors (school and peer stress, family conflict, and community violence) and (2) parent and child agreement on children’s self-report of somatic symptoms. The odds of self-report of somatic complaints were significantly associated with family conflict, school and peer stress, and community violence exposure (OR = 1.26, 95 % CI: 1.05–1.50; OR = 1.18, 95 % CI 1.08–1.28; and OR = 1.02, 95 % CI: 1.00–1.05, respectively). Identifying the associations between social, family, and community based stress and somatic symptoms may improve the quality of life for children living in urban environments through early identification and treatment.     

Early, current and past pet ownership: associations with sensitization, bronchial responsiveness and allergic symptoms in school children

BACKGROUND: Studies have suggested that early contact with pets may prevent the development of allergy and asthma. OBJECTIVE: To study the association between early, current and past pet ownership and sensitization, bronchial responsiveness and allergic symptoms in school children. METHODS: A population of almost 3000 primary school children was investigated using protocols of the International Study on Asthma and Allergies in Childhood (ISAAC). Allergic symptoms were measured using the parent-completed ISAAC questionnaire. Sensitization to common allergens was measured using skin prick tests (SPT)s and/or serum immunoglobulin (Ig)E determinations. Bronchial responsiveness was tested using a hypertonic saline challenge. Pet ownership was investigated by questionnaire. Current, past and early exposure to pets was documented separately for cats, dogs, rodents and birds. The data on current, past and early pet exposure were then related to allergic symptoms, sensitization and bronchial responsiveness. RESULTS: Among children currently exposed to pets, there was significantly less sensitization to cat (odds ratio (OR) = 0.69) and dog (OR = 0.63) allergens, indoor allergens in general (OR = 0.64), and outdoor allergens (OR = 0.60) compared to children who never had pets in the home. There was also less hayfever (OR = 0.66) and rhinitis (OR = 0.76). In contrast, wheeze, asthma and bronchial responsiveness were not associated with current pet ownership. Odds ratios associated with past pet ownership were generally above unity, and significant for asthma in the adjusted analysis (OR = 1.85), suggesting selective avoidance in families with sensitized and/or symptomatic children. Pet ownership in the first two years of life only showed an inverse association with sensitization to pollen: OR = 0.71 for having had furry or feathery pets in general in the first two years of life, and OR = 0.73 for having had cats and/or dogs in the first two years of life, compared to not having had pets in the first two years of life. CONCLUSION: These results suggest that the inverse association between current pet ownership and sensitization and hayfever symptoms was partly due to the removal of pets in families with sensitized and/or symptomatic children. Pet ownership in the first two years of life only seemed to offer some protection against sensitization to pollen.     

"Early" cat ownership and the risk of sensitization and allergic rhinitis in Ligurian children with respiratory symptoms.

BACKGROUND: Studies on the role of cat ownership in the development of allergy have lead to conflicting results, probably owing to heterogeneity of the populations evaluated. OBJECTIVE: To evaluate the possible effect of cat ownership on the frequency of sensitization and asthma or rhinitis in children living in Liguria, Italy, who attended a pediatric clinic for respiratory symptoms. METHODS: We enrolled 269 consecutive school-aged children in 12 months. Sensitization to aeroallergens by skin prick testing and the presence of respiratory symptoms (ie, asthma and rhinitis) were evaluated. To analyze the role of different independent variables in association with respiratory symptoms and sensitization, a multiple logistic regression analysis was performed. RESULTS: Of 269 children, 81 were exposed to cats at home in the first 2 years of life ("early" cat owners), 65 after the first 2 years of life ("late" cat owners), and 123 never ("never" cat owners). Early cat ownership was significantly associated with a lower risk of cat sensitization compared with never cat ownership (adjusted odds ratio [ORadj], 0.32; 95% confidence interval [CI], 0.14-0.74; P = .01). Early cat ownership was also associated with a significantly lower risk of allergic rhinitis than late cat ownership (ORadj, 0.43; 95% CI, 0.22-0.85) or never cat ownership (ORadj, 0.51; 95% CI, 0.28-0.92). No differences in the frequency of asthma were found among the 3 groups (P = .74) CONCLUSIONS: Cat ownership in early childhood can play an important role in preventing sensitization to cat and in lowering the frequency of allergic rhinitis, at least in children with the characteristics of the population studied.     

Aeroallergen sensitization rates in military children with rhinitis symptoms.

BACKGROUND: Childhood sensitization rates for many aeroallergens are underreported. OBJECTIVES: To examine aeroallergen sensitization rates in military children undergoing skin testing for rhinitis and investigate the timing of atopic development for perennial and seasonal allergens. METHODS: A skin testing database was retrospectively analyzed. Children 18 years and younger referred for rhinitis underwent skin prick testing to either a screening panel of 8 tests or a standard panel of 51 allergens. RESULTS: A total of 209 patients underwent skin testing to the 8-test panel. Of these patients, 35.4% had at least 1 positive result. Atopy increased with age, from 6.3% in those younger than 1 year to 58.8% in those 5 years old. The most common allergens were mold mix (16.3%), cat (13.2%), dust mite mix (11.4%), tree mix (9.4%), and grass mix (9.4%). Only 4.0% were sensitized to seasonal aeroallergens before the age of 3 years. A total of 345 children underwent testing to a 51-allergen panel. A total of 80.3% had at least 1 positive test result, and the average number of positive test results was 11.4. Both the percentage of atopy and the average number of positive skin test results increased with age. The most common allergens were grasses, Alternaria, and cottonwood. Thirty-two of 51 allergens were positive in 20% or more children. Rates for many underreported allergens are presented. CONCLUSIONS: In children, aeroallergen sensitization rates are high and increase with age. Perennial allergens predominate up to the age of 3 years. Rates for many underreported allergens are presented. Although performed in a military population, these results should be applicable to many practices.     

Infant temperament and anxious symptoms in school age children

A group of 164 children from different infant temperament categories were seen at 7 years of age for a laboratory battery that included behavioral and physiological measurements. The major results indicated that children who had been classified as high reactive infants at 4 months of age, compared with infants classified as low reactive, (a) were more vulnerable to the development of anxious symptoms at age 7 years, (b) were more subdued in their interactions with a female examiner, (c) made fewer errors on a task requiring inhibition of a reflex, and (d) were more reflective. Further, the high reactives who developed anxious symptoms differed from the high reactives without anxious symptoms with respect to fearful behavior in the second year and, at age 7 years, higher diastolic blood pressure, a narrower facial skeleton, and greater magnitude of cooling of the temperature of the fingertips to cognitive challenge. Finally, variation in magnitude of interference to fearful or aggressive pictures on a modified Stroop procedure failed to differentiate anxious from nonanxious or high from low reactive children.     

IgE-mediated allergy to wood dusts probably does not explain the high prevalence of respiratory symptoms among Swedish woodwork teachers

A previous study revealed an increased occurrence of work-related respiratory complaints among Swedish woodwork teachers. For determination of whether an IgE-mediated mechanism was the cause of the symptoms, 127 woodwork teachers and 111 reference subjects (other school personnel) in Stockholm gave serum for analysis of total IgE, Phadiatop, and RAST to extract of sawdust from five commonly used Scandinavian woods (pine, birch, juniper, alder, and linden). The total serum-IgE level was similar in the woodwork teachers (geometric mean 35, range <2–1700 kU/l) and the reference group (34, <2–860 kU/l), and the frequency of positive Phadiatop was equal (29.9% and 31.5%, respectively). RAST was positive only in three cases, two reference subjects (birch and pine) and one woodwork teacher (alder). Hence, no correlation between exposure and sensitization to wood dust was found, and the results do not support the assumption that the complaints related to exposure to dusts from the examined Scandinavian woods are IgE mediated.     

Heights and weights of Swedish school children born in 1955 and 1967

Samples of Swedish school children born in 1955 and 1967 were compared regarding average heights and weights from 10-15 years. The main findings were that both boys and girls had been gaining more weight than height, especially around the ages at which peak velocity generally occurs. Since the advantage in height of children born in 1967 gradually diminishes after age at peak height velocity, it seems that the height difference during puberty mainly reflects an earlier maturation of these children, compared to the children born in 1955.