PubMed Health⌕ Search

Biomedical subjects

G Pershagen

Publications and source records attributed to G Pershagen.

At least 19 recordsLinked to original sources
PubMed2006

Elevated expression and genetic association links the SOCS3 gene to atopic dermatitis.

In a systematic analysis of global gene-expression patterns, we found that SOCS3 messenger RNA was significantly more highly expressed in skin from patients with atopic dermatitis than in skin from healthy controls, and immunohistochemical analysis confirmed a similar elevation of SOCS3 protein. Furthermore, we found a genetic association between atopic dermatitis and a haplotype in the SOCS3 gene in two independent groups of patients (P<.02 and P<.03). These results strongly suggest that SOCS3, located in a chromosomal region previously linked to the disease (17q25), is a susceptibility gene for atopic dermatitis.

Adult↗
PubMed2006

Interaction between variants in the interleukin-4 receptor alpha and interleukin-9 receptor genes in childhood wheezing: evidence from a birth cohort study.

BACKGROUND: Several polymorphisms in the IL-4 receptor alpha (IL4RA) gene have been associated with asthma and atopy, but with variable success in different populations. Immunologic studies suggest that IL4RA may interact with other cytokines and receptors, and gene-gene interactions have also been observed with respect to asthma. Such interactions have been proposed to explain partly the difficulties in replicating association studies. METHODS: Using the prospective birth cohort BAMSE, we examined eight single nucleotide polymorphisms (SNPs) and corresponding haplotypes in the IL4RA gene in relation to wheezing and sensitization up to age 4. We also evaluated potential interaction effects (departure from a multiplicative interaction model) between the IL4RA SNPs and four SNPs in the IL-9 receptor (IL9R) gene previously associated with childhood wheezing. RESULTS: We found no main effect of the IL4RA SNPs alone and only weak associations to wheezing and sensitization when haplotypes were considered. Gene-gene interactions between several IL4RA and IL9R SNPs with regard to wheezing were observed (P=0.009), especially between IL4RA Q576R (rs1801275) and IL9R rs731476 (P=0.005). An interaction was also seen between IL4RA and IL9R haplotypes. CONCLUSION: Variants in the IL4RA gene alone may not exert any major influence on susceptibility to asthma-related diseases in childhood, but in combination with other genes, such as IL9R, IL4RA may be an important gene for disease susceptibility.

Case-Control Studies↗
PubMed2006

Allergic diseases and atopic sensitization in children related to farming and anthroposophic lifestyle--the PARSIFAL study.

BACKGROUND: The prevalence of allergic diseases has increased rapidly in recent decades, particularly in children. For adequate prevention it is important not only to identify risk factors, but also possible protective factors. The aim of this study was to compare the prevalence of allergic diseases and sensitization between farm children, children in anthroposophic families, and reference children, with the aim to identify factors that may protect against allergic disease. METHODS: The study was of cross-sectional design and included 14,893 children, aged 5-13 years, from farm families, anthroposophic families (recruited from Steiner schools) and reference children in Austria, Germany, The Netherlands, Sweden and Switzerland. A detailed questionnaire was completed and allergen-specific IgE was measured in blood. RESULTS: Growing up on a farm was found to have a protective effect against all outcomes studied, both self-reported, such as rhinoconjunctivitis, wheezing, atopic eczema and asthma and sensitization (allergen specific IgE > or = 0.35 kU/l). The adjusted odds ratio (OR) for current rhinoconjunctivitis symptoms was 0.50 (95% confidence interval (CI) 0.38-0.65) and for atopic sensitization 0.53 (95% CI 0.42-0.67) for the farm children compared to their references. The prevalence of allergic symptoms and sensitization was also lower among Steiner school children compared to reference children, but the difference was less pronounced and not as consistent between countries, adjusted OR for current rhinoconjunctivitis symptoms was 0.69 (95% CI 0.56-0.86) and for atopic sensitization 0.73 (95% CI 0.58-0.92). CONCLUSIONS: This study indicates that growing up on a farm, and to a lesser extent leading an anthroposophic life style may confer protection from both sensitization and allergic diseases in childhood.

Adolescent↗
PubMed2006

Nonlinear relations between house dust mite allergen levels and mite sensitization in farm and nonfarm children.

BACKGROUND: Low sensitization rates to common allergens have been observed in farm children, which might be due to high exposure to microbial agents. It is not known how microbial agents modify the association between specific allergen exposure and sensitization. OBJECTIVE: To examine the relations between house dust mite allergen exposure and mite sensitization in farm and nonfarm children and to assess the effects of microbial agents levels on this association. METHODS: Major mite allergens of Dermatophagoides pteronyssinus (Der p 1) and Dermatophagoides farinae (Der f 1), endotoxin, beta(1,3)-glucans and fungal extracellular polysaccharides were measured in mattress dust of 402 children participating in a cross-sectional study in five European countries. Mite allergen (Der p 1 + Der f 1) levels were divided into tertiles with cut-offs 1.4 and 10.4 microg/g. Sensitization was assessed by measurement of allergen-specific immunoglobulin E against house dust mite. RESULTS: Prevalence ratios of mite sensitization for medium and high when compared with low mite allergen levels were 3.1 [1.7-5.7] and 1.4 [0.7-2.8] respectively. Highest mite sensitization rates at intermediate exposure levels were consistently observed across country (except for Sweden) and in both farm and nonfarm children. The shape of the dose-response curve was similar for above and below median mattress microbial agent levels, but the 'sensitization peak' appeared to be lower for above median levels. CONCLUSIONS: Our data suggest a bell-shaped dose-response relationship between mite allergen exposure and sensitization to mite allergens. In populations with high microbial agent levels and low sensitization rates, the curve is shifted down.

Adolescent↗
PubMed2006

Fish consumption during the first year of life and development of allergic diseases during childhood.

BACKGROUND: Fish consumption during infancy has been regarded as a risk factor for allergic disease but later evidence suggests a protective role. However, methodological limitations in the studies make conclusions uncertain. The aim of this study was to assess the association between fish consumption during the first year of life and development of allergic diseases by age 4. METHODS: A prospective birth cohort of 4089 new-born infants was followed for 4 years using parental questionnaires at ages 2 months, 1, 2 and 4 years to collect information on exposure and health effects. The response rate at 4 years was 90%. A clinical investigation was performed at age 4 years, which included blood sampling for analysis of specific IgE to common food and airborne allergens. RESULTS: Parental allergic disease and onset of eczema or wheeze during the first year of life delayed introduction of fish in the child's diet. After exclusion of such children to avoid disease-related modification of exposure, regular fish consumption during the first year of life was associated with a reduced risk for allergic disease by age 4, OR(adj) 0.76 (95% CI 0.61-0.94) and sensitization, OR(adj) 0.76 (0.58-1.0). The reduced risk appeared most pronounced for multiple disease, OR(adj) 0.56 (0.35-0.89). IgE-sensitization to fish was only present among 18 of the 2614 children. CONCLUSION: Regular fish consumption before age 1 appears to be associated with a reduced risk of allergic disease and sensitization to food and inhalant allergens during the first 4 years of life.

Child, Preschool↗
PubMed2006

Exposure to microbial components and allergens in population studies: a comparison of two house dust collection methods applied by participants and fieldworkers.

Dust collection by study participants instead of fieldworkers would be a practical and cost-effective alternative in large-scale population studies estimating exposure to indoor allergens and microbial agents. We aimed to compare dust weights and biological agent levels in house dust samples taken by study participants with nylon socks, with those in samples taken by fieldworkers using the sampling nozzle of the Allergology Laboratory Copenhagen (ALK). In homes of 216 children, parents and fieldworkers collected house dust within the same year. Dust samples were analyzed for levels of allergens, endotoxin, (1-->3)-beta-D-glucans and fungal extracellular polysaccharides (EPS). Socks appeared to yield less dust from mattresses at relatively low dust amounts and more dust at high dust amounts than ALK samples. Correlations between the methods ranged from 0.47-0.64 for microbial agents and 0.64-0.87 for mite and pet allergens. Cat allergen levels were two-fold lower and endotoxin levels three-fold higher in socks than in ALK samples. Levels of allergens and microbial agents in sock samples taken by study participants are moderately to highly correlated to levels in ALK samples taken by fieldworkers. Absolute levels may differ, probably because of differences in the method rather than in the person who performed the sampling. Practical Implications Dust collection by participants is a reliable and practical option for allergen and microbial agent exposure assessment. Absolute levels of biological agents are not (always) comparable between studies using different dust collection methods, even when expressed per gram dust, because of potential differences in particle-size constitution of the collected dust.

Air Pollutants↗
PubMed2005

Low socioeconomic status as a risk factor for asthma, rhinitis and sensitization at 4 years in a birth cohort.

BACKGROUND: The relation between socioeconomic status and allergic diseases in childhood is controversial. Some studies have proposed childhood asthma to be more common in families with low socioeconomic status, while sensitization to airborne allergens seems to be more frequent in individuals with higher socioeconomic status in childhood. OBJECTIVE: To assess the relation between socioeconomic status and asthma, rhinitis and sensitization in an unselected prospective birth cohort. METHODS: Four thousand and eighty-nine families with children born 1994-1996 in predefined areas of Stockholm answered questionnaires on environmental factors, socioeconomic status (parental occupation), and symptoms of allergic disease at birth, 1, 2 and 4 years of age. Blood samples taken at 4 years from 2614 children were analysed for specific IgE to common airborne and food allergens. Odds ratios (OR) and 95% confidence intervals (CI) for various outcomes in relation to socioeconomic status were estimated with a multiple logistic regression model, adjusting for potential confounders such as heredity for allergic diseases, maternal smoking, short duration of breastfeeding and house construction. RESULTS: There was a decreasing risk of asthma and rhinitis with increasing socioeconomic status. The OR for asthma was 0.33 (95% CI 0.17-0.66) and for rhinitis 0.50 (0.32-0.79) comparing the highest and the lowest socioeconomic groups, with a tendency to stronger effects in those with heredity for allergic disease. The risk of sensitization to food allergens also decreased with increasing socioeconomic status; OR 0.65 (0.41-1.02) in the highest socioeconomic group (Ptrend=0.03), which was not clearly seen for airborne allergens. CONCLUSION: Asthma, rhinitis and sensitization is more common in lower than in higher socioeconomic groups after adjustment for traditional risk factors. This may be related to additional uncontrolled differences in life style and environmental exposures between the groups, and calls for further studies.

Age of Onset↗
PubMed2005

Validation of questions on asthma and wheeze in farming and anthroposophic children.

BACKGROUND: In most epidemiological surveys the estimated prevalence of asthma is based on questionnaire responses, which may depend on the individual's perception as well as medical consulting habits in a given population. Therefore, measurement of bronchial hyper-responsiveness as a key feature of asthma has been suggested as an objective parameter for asthma. OBJECTIVE: The aim of the present study was to validate questionnaire responses on asthma and wheeze against bronchial response to hypertonic saline (HS) (4.5%) in populations previously shown to have a lower prevalence of asthma and allergies: farmers' children and children from anthroposophic families. METHODS: Children whose parents had completed a written questionnaire in the cross-sectional PARSIFAL-study were drawn from the following four subgroups: 'farm children' (n=183), 'farm reference children' (n=173), 'Steiner schoolchildren' (n=243) and 'Steiner reference children' (n=179). Overall, 319 children with wheeze in the last 12 months and 459 children without wheeze in the last 12 months performed an HS challenge. RESULTS: Odds ratios, sensitivity, specificity, likelihood ratios and measures of association did not differ significantly between the four subgroups. The correlation between the bronchial response to HS and wheeze and asthma questions was moderate and similar for farm children, farm reference children, Steiner schoolchildren and Steiner reference children (kappa for 'wheeze': 0.25, 0.33, 0.31, 0.35, respectively, P=0.754, kappa for 'doctor's diagnosis of asthma': 0.33, 0.19, 0.33, 032, respectively, P=0.499). CONCLUSION: The findings from this study suggest that the reliabilitiy of questionnaire responses on asthma and wheeze is comparable between farmers' children, children raised in families with anthroposophic lifestyle and their respective peers.

Adolescent↗
PubMed2005

Bacterial and fungal agents in house dust and wheeze in children: the PARSIFAL study.

BACKGROUND: Growing up on a farm and an anthroposophic lifestyle are associated with a lower prevalence of allergic diseases in childhood. This might be related to increased inhalatory exposure to microbial agents. OBJECTIVE: To assess the association between microbial agents in house dust and atopic wheeze in farm children, Steiner school children and reference children. METHODS: Levels of bacterial endotoxin, fungal beta(1,3)-glucans and fungal extracellular polysaccharides (EPS) in mattress and living room floor dust were measured in a population of 270 atopic (=Phadiatop-positive) children with self-reported wheezing, including 168 current atopic wheezers, and 441 non-atopic, non-symptomatic controls. These children were selected from a cross-sectional study in five European countries. RESULTS: In the study population as a whole, average levels of mattress dust endotoxin, EPS and glucans were slightly (1.1-1.2-fold; P<0.10) higher in control children than in atopic wheezers. Atopic wheeze was related to mattress levels of endotoxin, EPS and glucans in farm and farm-reference children. However, when adjusting for group (farm vs. farm-reference children), the associations became non-significant whereas the group effect remained. No associations between atopic wheeze and microbial agents were observed in Steiner and Steiner-reference children. For current atopic wheeze, the farm effect became non-significant after adjustment for microbial agent levels. CONCLUSION: Not only bacterial endotoxin but also mould components might offer some protection against atopic wheeze in children. However, the protective effect of being raised on a farm was largely unexplained by the mattress microbial agent levels measured in this study.

Adolescent↗
PubMed2005

Immunoglobulin G4-antibodies to rBet v 1 and risk of sensitization and atopic disease in the child.

BACKGROUND: In 1993 extremely high levels of birch-pollen were recorded in Stockholm, Sweden. This provided an opportunity to evaluate the effects of aeroallergen exposure (exp.) on the early immune response. OBJECTIVE: To assess the influence of exp. to birch-pollen during pregnancy and infancy on the allergen-specific IgE- and IgG4-antibody (ab) response and the development of atopic disease in children. METHODS: A total of 970 children with atopic heredity and born in Stockholm 1992, 1993 or 1994 were investigated at age 4.5-5 years. They were divided into five groups; high-dose exp. at 1 year of age, high-dose exp. at 0-3 months, low-dose exp. at 0-3 months, high-dose exp. during pregnancy and low-dose exp. during pregnancy. The children were examined and skin prick tested with inhalant and food allergens. IgE abs (against birch-pollen and recombinant Bet v 1(rBet v1)) and IgG4 abs (against rBet v 1) were analysed in serum. All children were assembled in one group to assess the effects of different ab responses (IgE/IgG4) on the development of atopic disease. RESULTS: Children exposed to high doses of birch-pollen during the first 3 months of life more often had detectable levels of IgG4 abs to rBet v 1 than the children in the other groups (P < 0.001), independent of sensitization to birch. Overall, the risk of allergic rhinoconjunctivitis was increased among children sensitized to birch-pollen and appeared more pronounced in children without detectable levels of IgG4 ab to rBet v 1 (Odds ratio 9.4; 95% Confidence interval: 5.5-16.1). IgE sensitization to birch-pollen seemed to have a stronger influence on the development of atopic disease than the IgG4-ab response. CONCLUSION: Exposure to high doses of inhalant allergens during the early postnatal period is associated with detectable levels of allergen-specific IgG4 ab even at 5 years of age. An immune modulating effect by IgG4 on symptoms of allergic rhinoconjunctivitis is suggested in children sensitized to birch.

Air Pollutants↗
PubMed2005

Bacterial and fungal components in house dust of farm children, Rudolf Steiner school children and reference children--the PARSIFAL Study.

BACKGROUND: Growing up on a farm and an anthroposophic lifestyle are associated with a lower prevalence of allergic diseases in childhood. It has been suggested that the enhanced exposure to endotoxin is an important protective factor of farm environments. Little is known about exposure to other microbial components on farms and exposure in anthroposophic families. OBJECTIVE: To assess the levels and determinants of bacterial endotoxin, mould beta(1,3)-glucans and fungal extracellular polysaccharides (EPS) in house dust of farm children, Steiner school children and reference children. METHODS: Mattress and living room dust was collected in the homes of 229 farm children, 122 Steiner children and 60 and 67 of their respective reference children in five European countries. Stable dust was collected as well. All samples were analysed in one central laboratory. Determinants were assessed by questionnaire. RESULTS: Levels of endotoxin, EPS and glucans per gram of house dust in farm homes were 1.2- to 3.2-fold higher than levels in reference homes. For Steiner children, 1.1- to 1.6-fold higher levels were observed compared with their reference children. These differences were consistently found across countries, although mean levels varied considerably. Differences between groups and between countries were also significant after adjustment for home and family characteristics. CONCLUSION: Farm children are not only consistently exposed to higher levels of endotoxin, but also to higher levels of mould components. Steiner school children may also be exposed to higher levels of microbial agents, but differences with reference children are much less pronounced than for farm children. Further analyses are, however, required to assess the association between exposure to these various microbial agents and allergic and airway diseases in the PARSIFAL population.

Agriculture↗
PubMed2004

Radon in homes and risk of lung cancer: collaborative analysis of individual data from 13 European case-control studies.

OBJECTIVE: To determine the risk of lung cancer associated with exposure at home to the radioactive disintegration products of naturally occurring radon gas. DESIGN: Collaborative analysis of individual data from 13 case-control studies of residential radon and lung cancer. SETTING: Nine European countries. SUBJECTS: 7148 cases of lung cancer and 14,208 controls. MAIN OUTCOME MEASURES: Relative risks of lung cancer and radon gas concentrations in homes inhabited during the previous 5-34 years measured in becquerels (radon disintegrations per second) per cubic metre (Bq/m3) of household air. RESULTS: The mean measured radon concentration in homes of people in the control group was 97 Bq/m3, with 11% measuring > 200 and 4% measuring > 400 Bq/m3. For cases of lung cancer the mean concentration was 104 Bq/m3. The risk of lung cancer increased by 8.4% (95% confidence interval 3.0% to 15.8%) per 100 Bq/m3 increase in measured radon (P = 0.0007). This corresponds to an increase of 16% (5% to 31%) per 100 Bq/m3 increase in usual radon--that is, after correction for the dilution caused by random uncertainties in measuring radon concentrations. The dose-response relation seemed to be linear with no threshold and remained significant (P = 0.04) in analyses limited to individuals from homes with measured radon < 200 Bq/m3. The proportionate excess risk did not differ significantly with study, age, sex, or smoking. In the absence of other causes of death, the absolute risks of lung cancer by age 75 years at usual radon concentrations of 0, 100, and 400 Bq/m3 would be about 0.4%, 0.5%, and 0.7%, respectively, for lifelong non-smokers, and about 25 times greater (10%, 12%, and 16%) for cigarette smokers. CONCLUSIONS: Collectively, though not separately, these studies show appreciable hazards from residential radon, particularly for smokers and recent ex-smokers, and indicate that it is responsible for about 2% of all deaths from cancer in Europe.

Air Pollutants, Radioactive↗
PubMed2004

Building characteristics, indoor air quality and recurrent wheezing in very young children (BAMSE).

This study was conducted to examine the impact of building characteristics and indoor air quality on recurrent wheezing in infants. We followed a birth cohort (BAMSE) comprising 4089 children, born in predefined areas of Stockholm, during their first 2 years of life. Information on exposures was obtained from parental questionnaires when the children were 2 months and on symptoms and diseases when the children were 1 and 2 years old. Children with recurrent wheezing, and two age-matched controls per case, were identified and enrolled in a nested case-control study. The homes were investigated and ventilation rate, humidity, temperature and NO2 measured. We found that living in an apartment erected after 1939, or in a private home with crawl space/concrete slab foundation were associated with an increased risk of recurrent wheezing, odds ratio (OR) 2.5 (1.3-4.8) and 2.5 (1.1-5.4), respectively. The same was true for living in homes with absolute indoor humidity >5.8 g/kg, OR 1.7 (1.0-2.9) and in homes where windowpane condensation was consistently reported over several years, OR 2.2 (1.1-4.5). However, air change rate and type of ventilation system did not seem to affect the risk. In conclusion, relatively new apartment buildings, single-family homes with crawl space/concrete slab foundation, elevated indoor humidity, and reported wintertime windowpane condensation were associated with recurrent wheezing in infants. Thus, improvements of the building quality may have potential to prevent infant wheezing.

Air Pollutants↗
PubMed2004

Influence of male sex and parental allergic disease on childhood wheezing: role of interactions.

BACKGROUND: Boys have been reported to be more susceptible to childhood wheezing, whereas girls are more susceptible later in life. This difference might be related to both genetic and environmental factors. OBJECTIVE: To investigate the influence of male sex and parental allergic disease on the development of childhood wheezing. METHODS: Infants (n=4089) born in Stockholm were recruited in a prospective study, BAMSE. Data on parental allergic diseases were obtained from questionnaires answered at the children's birth and on symptoms of wheezing at 1, 2 and 4 years of age. Sensitization to inhalant allergens and lung function was investigated at the age of 4 years. RESULTS: Children were classified as having recurrent, transient (n=266), early-onset persistent (n=319) and late-onset wheezing (n=195). Boys were over-represented in all groups of wheezing (odds ratio, OR=1.4-1.5) and both maternal and paternal allergic disease was of importance for the wheezing outcomes. A dominating influence from maternal allergic disease was only seen in children with persistent wheezing. An interaction exceeding additivity was found between male sex and parental allergic disease, particularly in children with persistent wheezing (OR=2.9 and 95% confidence interval, CI 95% 2.1-4.0 for boys with any parental history vs. OR=1.4, CI 95% 1.0-2.1 for girls). Interaction between male sex and parental allergic disease was also observed in children who wheezed at the age of 4 years and were sensitized to inhalant allergens. CONCLUSION: Our data suggest an interaction between male sex and parental allergic disease in childhood wheezing, which may represent a sex-specific genetic influence.

Child, Preschool↗
PubMed2004

Indoor exposures and recurrent wheezing in infants: a study in the BAMSE cohort.

AIM: The aim of this study was to examine the relationship between indoor exposures and the home environment, and the development of recurrent wheezing during infancy. METHODS: A birth cohort, comprising 4089 children, was followed. Information on exposures was obtained shortly after birth, and episodes of wheezing were recorded when the infants were 1 and 2 y of age. In a nested case-control study, 181 infants were enrolled, who had three or more reported episodes of wheezing after 3 mo of age combined with either use of inhaled steroids or symptoms of bronchial hyper-reactivity, and 359 age-matched controls. Home inspections were performed during the winter following enrolment, and indoor conditions were measured. RESULTS: Adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated. The OR for recurrent infant wheezing associated with signs of dampness reported prospectively by parents was 1.4 (0.9-2.2), and the OR for observed signs of dampness at home inspections was 1.6 (1.0-2.5). A trend was found in the risk of recurrent wheezing in relation to the number of indicators of dampness: OR 1.3 (0.8-2.2) for one sign of dampness and OR 2.7 (1.3-5.4) for three or more signs of dampness. Newly painted surfaces in the child's bedroom was associated with an increased OR for recurrent wheezing: 1.7 (1.3-2.6). CONCLUSION: Indicators of dampness, as well as recently repainted interior surfaces, appear to be associated with recurrent infant wheezing, with a strengthened effect of combined indoor exposures.

Air Pollution, Indoor↗
PubMed2003

Strategies for preventing wheezing and asthma in small children.

OBJECTIVE: To assess the effects of living in agreement with allergy preventive guidelines on wheezing and asthma at 2 years of age. DESIGN: Prospective birth cohort study (BAMSE). Questionnaires on heredity and environmental factors were answered when the child was 2 months, and detailed questionnaires on symptoms at 1 and 2 years of age. PARTICIPANTS: 4089 children, born during 1994-1996. SETTING: Child Health Centres in central and north-western parts of Stockholm, Sweden. MAIN OUTCOME MEASURES: Wheezing and asthma up to the age of 2. RESULTS: The effects of preventive guidelines regarding breastfeeding, maternal tobacco smoke and home dampness on wheezing and asthma were assessed in multiple logistic regression models. The cumulative incidence of recurrent wheezing at 2 years of age was 12.6% and of asthma 6.8% among those with a lifestyle in agreement with all guidelines and 24.1 and 17.9%, respectively, in families exposed to at least two of the three risk factors. Among children with no heredity, family lifestyle according to the guidelines gave a twofold reduction of asthma (5.3 vs. 10.5%), while the group with heredity had a threefold reduction (9.1 vs. 27.3%). The attributable fraction for asthma associated with the guidelines was 23% in total and 33% among those with heredity. CONCLUSION: In this observational study, family lifestyle according to preventive guidelines is associated with an important reduction of recurrent wheezing and asthma at 2 years of age, especially among children with allergic heredity. A follow-up will determine whether there still a risk reduction of both symptoms and disease.

Asthma↗
PubMed2003

Exposure to high doses of birch pollen during pregnancy, and risk of sensitization and atopic disease in the child.

BACKGROUND: The role of maternal allergen exposure during pregnancy in sensitization and development of atopic disease in the child remains controversial. In the spring of 1993, extremely high levels of birch pollen were recorded in Stockholm, Sweden. In 1994, the corresponding pollen levels were low. The aim of this study was to assess the influence of exposure during pregnancy to high/low doses of birch pollen on the risk of sensitization and development of atopic disease in children. In addition, a comparison was made with children exposed to birch pollen in early infancy. METHODS: Three hundred and eighty-seven children with atopic heredity, born in Stockholm in July-October 1993 or 1994 (mothers exposed during pregnancy), were investigated at age 4.5 years. The children were clinically examined and were skin prick tested (SPT) with inhalant and food allergens. IgE antibodies (RAST) against birch pollen and recombinant birch pollen allergen (rBet v 1) were analysed in serum. A comparison was made with a similar group of children exposed during the same incident, but in the first 3 months of life, in 1993. RESULTS: The children of mothers high-dose exposed during pregnancy in 1993 tended to be more sensitized (SPT > or = 3 mm) to birch pollen than the children with low-dose exposure during the corresponding period in 1994 (7.6 and 4.6%, respectively, OR: 1.7; 95% CI: 0.7-4.1). A similar but weak tendency was seen for positive RAST analyses (> or =0.35 kU/l) against birch pollen and rBet v 1. Children of mothers high-dose exposed during pregnancy were significantly less sensitized to birch pollen than the children high-dose exposed in early infancy (17.9%, OR: 0.4; 95% CI: 0.2-0.7). There was an overall trend towards a slightly increased prevalence of bronchial asthma, allergic rhinoconjunctivitis and atopic dermatitis in the group with mothers high-dose exposed during pregnancy, compared to those with low exposure. CONCLUSION: Exposure of the mother during pregnancy to high levels of birch pollen resulted in a tendency towards increased risk of sensitization to the same allergen and symptoms of atopic disease in children with atopic heredity. Furthermore, our data indicate that exposure of the mother during pregnancy to inhalant allergens is less likely to result in sensitization in the child than exposure of the child in early infancy.

Asthma↗