Cigarette smoking and allergic sensitization: A 32-year population-based cohort study

Prevalence and risk factors for allergic sensitization: 3 cross-sectional studies among schoolchildren from 1996 to 2017

Background

The prevalence of allergic sensitization and allergic diseases has increased for decades in Northern Europe, but recent studies are lacking.

Objective

We sought to study the prevalence trends of allergic sensitization, associated risk factors, and the association with asthma and allergic rhinitis (AR) among children in Northern Sweden.

Methods

Three cohorts of children aged 7 to 8 years participated in a skin prick test (SPT) with 10 airborne allergens in 1996, 2006, and 2017, with 2148, 1693, and 1762 participants tested, respectively, representing 87% to 90% of schoolchildren in the catchment communities. Adjusted Poisson regression was used to identify risk factors for allergic sensitization and the association with asthma and AR.

Results

The prevalence of any positive SPT response increased from 21% in 1996 to 30% in 2006 and remained at 30% in 2017 (P < .001). Sensitization to cat was the most common for all the years. The risk factor pattern for a positive SPT response was similar in all examinations, with positive and significant associations with a family history of allergy (risk ratio, 1.4-1.5) and negative and significant associations with having a cat at home (risk ratio, 0.7-0.8). The prevalence of physician-diagnosed asthma increased, but the association with allergic sensitization weakened. The opposite trends were found for AR-decreasing prevalence and strengthened association with allergic sensitization.

Conclusions

The prevalence of allergic sensitization increased from 1996 to 2006 but plateaued in the next decade, whereas the risk factor pattern remained stable. The diverging trends of associations between allergic sensitization and asthma and AR suggest secular trends in the clinical management of allergic diseases.

The Effect of Passive Exposure to Tobacco Smoke on the Immune Response in Children with Asthma

Introduction: There are a few publications about the impact of tobacco smoke on the children's immune system. Material and Methods: The study group consisted of 43 children with asthma. The control group consisted of 37 healthy children. The exposure to tobacco smoke was assessed by the presence of the cotinine in the urine (metabolit of nicotine). Results: The group of children with asthma exposed to tobacco smoke had significantly higher levels of the IL-1 and lower levels IL-4 than children not exposed to the passive smoking. The children from the control group exposed to tobacco smoke had a significantly higher concentration of IL-4 than unexposed children. In the whole analyzed population, there was a significant positive correlation between cotinine-IL1 and cotinine-CRP. Conclusion: In this study we found that the passive exposure to tobacco smoke has the immunomodulatory effects on the immune system.

"Effects of Tobacco Smoke on Aeroallergen Sensitization and Clinical Severity among University Students and Staff with Allergic Rhinitis"

Allergic diseases, affecting a variety of organs, have continuously increased both in developed and developing countries. Tobacco smoke exposure increases prevalence of allergic rhinitis (AR) and may affect allergic sensitization. This study was designed to compare indoor-aeroallergen sensitization between those not exposed and exposed to tobacco smoke in university students and staff with allergic rhinitis. A cross-sectional descriptive study among university students and staff with allergic rhinitis was performed from February 1, 2018, to March 31, 2019. Questionnaires regarding demography, clinical symptoms, and tobacco smoke exposure were implemented. A current smoker was defined as using, at least, 1 cigarette per day for, at least, 1 month. A secondhand smoker was defined as the one who never smoked, but lived with a current smoker, at least, for 1 month. A skin prick test for eight common indoor aeroallergens, Dermatophagoides pteronyssinus, Dermatophagoides farinae, Periplaneta americana, cat dander, dog dander, para grass, careless weed, and Cladosporium spp., was performed. Sensitization was defined as positivity to, at least, 1 aeroallergen. One hundred and twenty-eight adult patients were eligible participants for the study, and 68 cases (53.10%) were classified as having tobacco smoke exposure. Among these, most of them were secondhand smokers (50 cases, 73.50%). There was no statistically significant difference between exposure and nonexposure to tobacco smoke and indoor aeroallergen sensitization, except for the Periplaneta americana antigen (p=0.013). Most of those in the nonexposure group (34 cases, 56.70%) were classified as having intermittent allergic rhinitis, whereas the tobacco exposure group had significantly more prevalence of severe clinical symptoms. In conclusion, tobacco smoke exposure did not appear to have much influence on aeroallergen sensitization for 7 of the 8 antigens examined. However, for the Periplaneta americana antigen, there was a highly significant correlation with patients experiencing worsened allergic rhinitis symptoms. Overall, it was observed that allergic rhinitis patients exposed to tobacco smoke had more severe clinical symptoms. Future studies should look for other potential antigens of interest, such as mould. Implementation of public health practices reducing exposure to tobacco smoke could have benefits in allergic rhinitis patients.

Trends of Sensitization to Inhalant Allergens in Korean Children Over the Last 10 Years

PURPOSE

Climate and lifestyle changes increase an individual's susceptibility to various allergens and also the incidence of allergic diseases. We aimed to examine the changes in sensitization rate for aeroallergens over a 10-year period in Korean children.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of 4493 children who visited the allergy clinic at a tertiary hospital in Korea for allergic rhinitis or asthma from January 2009 to December 2018. The serum specific immunoglobulin E (IgE) levels were measured to confirm the sensitization against Dermatophagoides farinae (D. farinae), Alternaria, weed and tree pollen mixtures, as well as cat and dog dander through ImmunoCAP test.

RESULTS

D. farinae was the most common sensitizing aeroallergen (45.9%) during the 10-year span. The sensitization rate for tree pollen mixture (p for trend <0.001), weed pollen mixtures (p for trend <0.001), dog dander (p for trend=0.025), and cat dander (p for trend=0.003) showed ascending trends during the 10-year study period. Furthermore, the sensitization rate for multiple allergens (≥2) in 2018 increased significantly compared to that in 2009 (p for trend=0.013). Compared with children without sensitization to D. farinae, those with sensitization to D. farinae showed higher sensitization rates to other aeroallergens (p for interaction <0.001).

CONCLUSION

Children's sensitization rate to cat and dog dander and weed and tree pollen mixtures significantly increased during the 10-year period in Korea. Children with sensitization to D. farinae are likely to be sensitized to other aeroallergens as well.

Male sex is strongly associated with IgE-sensitization to airborne but not food allergens: results up to age 24 years from the BAMSE birth cohort

Background

Up to half of the population in high-income countries has allergen-specific IgE antibodies. However, data regarding sex differences of IgE-sensitization from childhood to adulthood is limited.

Objective

To explore IgE-sensitization to common foods and airborne allergens in relation to sex over time in a population-based cohort followed up to young adulthood.

Methods

The Swedish population-based birth cohort BAMSE includes 4089 subjects who have been followed regularly with questionnaires and clinical investigations. A recent 24-year follow-up included 3069 participants (75%). Sera collected at 4, 8, 16 and 24 years were analyzed for IgE-antibodies to 14 common foods and airborne allergens.

Results

At 24 years sensitization to foods had decreased compared to previous follow-ups affecting 8.4%, while sensitization to airborne allergens was more common, affecting 42.2%. Male sex was associated with IgE-sensitization to airborne allergens at all ages (overall OR: 1.68, 95% CI 1.46–1.94) while there was no statistically significant association between sex and sensitization to food allergens (overall OR: 1.10, 95% CI 0.93–1.32). Levels of allergen-specific IgE did not differ significantly between males and females for any of the tested foods or airborne allergens at any age, following adjustment for multiple comparisons.

Conclusion

IgE-sensitization to airborne allergens increases with age up to young adulthood, whereas sensitization to food allergens seems to level off. Male sex is strongly associated with IgE-sensitization to airborne allergens from early childhood up to young adulthood. In contrast, there is little evidence for associations between sex and IgE-sensitization to foods.

Early Intervention is Important to Prevent Sensitization to New Allergens

We review current management for allergic rhinitis and possible new treatments for this condition. Management of allergic rhinitis includes promotion of protective factors, avoidance of allergens, and possibly immunotherapy. In recent years, the incidence of allergic rhinitis has increased in many countries. Early intervention at different stages is an important part of management. Allergic disease in infants has been described as the allergic march, commencing with atopic dermatitis accompanied by infantile asthma and progressing to perennial allergic rhinitis induced by house dust mite allergy. In order to prevent polysensitization, allergen-specific immunotherapy should probably be initiated at an earlier age, especially in children with rhinitis who show monosensitization to house dust mite antigens.

Associations between blood eosinophils and decline in lung function among adults with and without asthma

Eosinophilic inflammation and airway remodelling are characteristic features of asthma, but the association between them is unclear. We assessed associations between blood eosinophils and lung function decline in a population-based cohort of young adults.We used linear mixed models to analyse associations between blood eosinophils and spirometry at 21, 26, 32 and 38 years adjusting for sex, smoking, asthma and spirometry at age 18 years. We further analysed associations between mean eosinophil counts and changes in spirometry from ages 21 to 38 years.Higher eosinophils were associated with lower forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) ratios and lower FEV₁ % predicted values for both pre- and post-bronchodilator spirometry (all p-values ≤0.048). Although eosinophil counts were higher in participants with asthma, the associations between eosinophils and spirometry were similar among participants without asthma or wheeze. Participants with mean eosinophil counts >0.4×10⁹ cells·L^-1 between 21 and 38 years had greater declines in FEV₁/FVC ratios (difference 1.8%, 95% CI 0.7-2.9%; p=0.001) and FEV₁ values (difference 3.4% pred, 95% CI 1.5-5.4% pred); p=0.001) than those with lower counts.Blood eosinophils are associated with airflow obstruction and enhanced decline in lung function, independently of asthma and smoking. Eosinophilia is a risk factor for airflow obstruction even in those without symptoms.

Smoking, environmental tobacco smoke and occupational irritants increase the risk of chronic rhinitis

Background

Allergic and non-allergic rhinitis cause a lot of symptoms in everyday life. To decrease the burden more information of the preventable risk factors is needed. We assessed prevalence and risk factors for chronic nasal symptoms, exploring the effects of smoking, environmental tobacco smoke, exposure to occupational irritants, and their combinations.

Methods

In 2016, a postal survey was conducted among a random population sample of 8000 adults in Helsinki, Finland with a 50.5% response rate.

Results

Smoking was associated with a significant increase in occurrence of chronic rhinitis (longstanding nasal congestion or runny nose), but not with self-reported or physician diagnosed allergic rhinitis. The highest prevalence estimates of nasal symptoms, 55.1% for chronic rhinitis, 49.1% for nasal congestion, and 40.7% for runny nose, were found among smokers with occupational exposure to gases, fumes or dusts.Besides active smoking, also exposure to environmental tobacco smoke combined with occupational exposure increased the risk of nasal symptoms.

Conclusions

Smoking, environmental tobacco smoke, and occupational irritants are significant risk factors for nasal symptoms with an additive pattern. The findings suggest that these factors should be systematically inquired in patients with nasal symptoms for appropriate preventive measures. (192 words).

Cholinergic Modulation of Type 2 Immune Responses

In recent years, the bidirectional relationship between the nervous and immune system has become increasingly clear, and its role in both homeostasis and inflammation has been well documented over the years. Since the introduction of the cholinergic anti-inflammatory pathway, there has been an increased interest in parasympathetic regulation of both innate and adaptive immune responses, including T helper 2 responses. Increasing evidence has been emerging suggesting a role for the parasympathetic nervous system in the pathophysiology of allergic diseases, including allergic rhinitis, asthma, food allergy, and atopic dermatitis. In this review, we will highlight the role of cholinergic modulation by both nicotinic and muscarinic receptors in several key aspects of the allergic inflammatory response, including barrier function, innate and adaptive immune responses, and effector cells responses. A better understanding of these cholinergic processes mediating key aspects of type 2 immune disorders might lead to novel therapeutic approaches to treat allergic diseases.

Predicting the atopic march: Results from the Canadian Healthy Infant Longitudinal Development Study

BACKGROUND

The atopic march describes the progression from atopic dermatitis during infancy to asthma and allergic rhinitis in later childhood. In a Canadian birth cohort we investigated whether concomitant allergic sensitization enhances subsequent development of these allergic diseases at age 3 years.

METHODS

Children completed skin prick testing at age 1 year. Children were considered sensitized if they produced a wheal 2 mm or larger than that elicited by the negative control to any of 10 inhalant or food allergens. Children were also assessed for atopic dermatitis by using the diagnostic criteria of the UK Working Party. At age 3 years, children were assessed for asthma, allergic rhinitis, food allergy, and atopic dermatitis. Data from 2311 children were available.

RESULTS

Atopic dermatitis without allergic sensitization was not associated with an increased risk of asthma at age 3 years after adjusting for common confounders (relative risk [RR], 0.46; 95% CI, 0.11-1.93). Conversely, atopic dermatitis with allergic sensitization increased the risk of asthma more than 7-fold (RR, 7.04; 95% CI, 4.13-11.99). Atopic dermatitis and allergic sensitization had significant interactions on both the additive (relative excess risk due to interaction, 5.06; 95% CI, 1.33-11.04) and multiplicative (ratio of RRs, 5.80; 95% CI, 1.20-27.83) scales in association with asthma risk. There was also a positive additive interaction between atopic dermatitis and allergic sensitization in their effects on food allergy risk (relative excess risk due to interaction, 15.11; 95% CI, 4.19-35.36).

CONCLUSIONS

Atopic dermatitis without concomitant allergic sensitization was not associated with an increased risk of asthma. In combination, atopic dermatitis and allergic sensitization had strong interactive effects on both asthma and food allergy risk at age 3 years.

Atopic dermatitis is associated with active and passive cigarette smoking in adolescents

Objective

The relationship between passive smoking and atopic dermatitis has previously been reported, but few studies have simultaneously evaluated the association of atopic dermatitis with active and passive smoking.

Methods

The relationships between atopic dermatitis and active and passive smoking were evaluated in Korean adolescents. We used a large, representative, population-based survey (The Korea Youth Risk Behavior Web-based Survey) conducted in 2011 and 2012. Active smoking was classified into 3 groups (0 days, 1–19 days, and ≥ 20 days/month). Passive smoking was categorized into 3 groups (0 days, 1–4 days, and ≥ 5 days/week). Atopic dermatitis diagnosed by a medical doctor either during the past 1 month or during the participant’s lifetime was surveyed. Age, sex, obesity status, region of residence, economic level, and parental educational level of the participants were adjusted as confounders. Adjusted odds ratios (AORs) and 95% confidence intervals (CI) were calculated using multiple logistic regression analysis with complex sampling.

Results

A total of 6.8% (10,020/135,682) of the participants reported atopic dermatitis during the last 12 months. Active smoking was significantly associated with atopic dermatitis (previous 12 months) (AOR [95% CI] of smoking ≥ 20 days/month = 1.18 [1.07–1.29]; 1–19 days/month = 1.11 [0.99–1.23], P = 0.002). Passive smoking was also related to atopic dermatitis (previous 12 months) (AOR [95% CI] of smoking ≥ 5 days/week = 1.12 [1.05–1.20]; 1–4 days/week = 1.08 [1.03–1.13], P < 0.001).

Conclusion

Atopic dermatitis was significantly associated with active and passive smoking in Korean adolescents.

The Association between Tobacco Smoke and Serum Immunoglobulin E Levels in Korean Adults

Objective Smoking is common in patients with allergic diseases. The aim of this study was to evaluate the cross-sectional association between the current smoking status and total and specific Immunoglobulin E (IgE) levels in Korean adults. Methods Data were obtained from the 2010 Korean National Health and Nutrition Examination Survey, a national cross-sectional study. We analyzed the data of subjects whose smoking status and serum IgE levels were of acceptable quality. Results A total of 1,963 subjects (1,118 never smokers, 340 ex-smokers, and 505 current smokers) were included. The total IgE levels and specific IgE levels to house dust mite Dermatophagoides farinae (Df), cockroach, and dog allergens in never smokers were significantly (p<0.0001) lower than in ex-smokers or current smokers. After adjusting for other variables, current smokers independently had significantly higher levels of total IgE and cockroach-specific IgE than ex-smokers or never smokers. The proportions of subjects with total IgE ≥150 kU/L and specific IgE ≥0.35 kU/L to Df-specific IgE were significantly (p value for trend <0.05) increased in ex-smokers and current smokers. The total IgE levels and IgE levels specific to Df, cockroaches, and dogs significantly (p value for trend <0.05) and proportionally increased with increasing numbers of cigarettes smoked daily. Conclusion Smoking was associated with elevated total IgE levels and IgE levels specific to Df, cockroach, and dog allergens in a cumulative, dose-dependent manner. Furthermore, current smoking status was an independent risk factor for elevated total IgE levels and IgE levels specific to cockroach allergen.

The Effect of Cigarette Smoking on Lung Function in Young Adults with Asthma

RATIONALE

Life-course persistent asthma and tobacco smoking are risk factors for irreversible airflow obstruction. It is often assumed that smoking and asthma have additive or multiplicative effects on the risk for airflow obstruction, but this has not been demonstrated in prospective studies of children with persistent asthma.

OBJECTIVES

To investigate the effects of smoking and asthma on the development of airflow obstruction in a population-based birth cohort followed to age 38 years.

METHODS

Reports of childhood asthma from ages 9, 11, and 13 and self-reports of adult asthma at ages 32 and 38 years were used to define childhood-onset persistent asthma (n = 91), late-onset asthma (n = 93), asthma in remission (n = 85), and nonasthmatic (n = 572) phenotypes. Cumulative tobacco smoking histories and spirometry were obtained at ages 18, 21, 26, 32, and 38 years. Analyses were by generalized estimating equations adjusting for childhood spirometry, body mass index, age, and sex.

MEASUREMENTS AND MAIN RESULTS

Smoking history and childhood-onset persistent asthma were both associated with lower FEV1/FVC ratios. Associations between smoking and FEV1/FVC ratios were different between asthma phenotypes (interaction P < 0.001). Smoking was associated with lower prebronchodilator and post-bronchodilator FEV1/FVC ratios among subjects without asthma and those with late-onset or remittent asthma, but smoking was not associated with lower FEV1/FVC ratios among those with childhood-onset persistent asthma.

CONCLUSIONS

Childhood-onset persistent asthma is associated with airflow obstruction by mid-adult life, but this does not seem to be made worse by tobacco smoking. We found no evidence that smoking and childhood-persistent asthma have additive or multiplicative effects on airflow obstruction.

High incidence and persistence of airborne allergen sensitization up to age 19 years

BACKGROUND

Longitudinal population-based studies about the natural history of allergic sensitization are rare. The aim was to study incidence and persistence of airborne allergen sensitization up to young adulthood and risk factors for early and late onset of sensitization.

METHODS

All children aged 7-8 years in two municipalities in Northern Sweden were invited to a parental questionnaire and skin prick tests (SPTs) to ten airborne allergens, and 2148 (88%) participated. The protocol was repeated at age 11-12 and 19 years, and 1516 participated in all three examinations.

RESULTS

Prevalence of any positive SPT increased from 20.6% at age 7-8 years to 30.6% at 11-12 years, and 42.1% at 19 years. Animals were the primary sensitizers at age 7-8 years, 16.3%, followed by pollen, 12.4%. Mite and mold sensitization was low. Mean annual incidence of any positive SPT varied between 2.8 and 3.4/100 per year, decreased by age for animal, and was stable for pollen. Sensitization before age 7-8 years was independently associated with family history of allergy, OR 2.1 (95% CI 1.6-2.8), urban living, OR 1.9 (95% CI 1.2-2.9), and male sex, OR 1.3 (95% CI 1.0-1.7), and negatively associated with birth order, OR 0.8 (95% CI 0.7-1.0), and furry animals at home, OR 0.7 (95% CI 0.7-0.9). Incidence after age 11-12 years was associated only with family history of allergy. Multisensitization at age 19 years was significantly associated with early age at sensitization. Remission of sensitization was uncommon.

CONCLUSION

The increasing prevalence of allergic sensitization by age was explained by high incidence and persistence. After age 11-12 years, the factors urban living, number of siblings, and male sex lost their importance.

Janus-faced Acrolein prevents allergy but accelerates tumor growth by promoting immunoregulatory Foxp3+ cells: Mouse model for passive respiratory exposure

Acrolein, a highly reactive unsaturated aldehyde, is generated in large amounts during smoking and is best known for its genotoxic capacity. Here, we aimed to assess whether acrolein at concentrations relevant for smokers may also exert immunomodulatory effects that could be relevant in allergy or cancer. In a BALB/c allergy model repeated nasal exposure to acrolein abrogated allergen-specific antibody and cytokine formation, and led to a relative accumulation of regulatory T cells in the lungs. Only the acrolein-treated mice were protected from bronchial hyperreactivity as well as from anaphylactic reactions upon challenge with the specific allergen. Moreover, grafted D2F2 tumor cells grew faster and intratumoral Foxp3+ cell accumulation was observed in these mice compared to sham-treated controls. Results from reporter cell lines suggested that acrolein acts via the aryl-hydrocarbon receptor which could be inhibited by resveratrol and 3′-methoxy-4′-nitroflavone Acrolein- stimulation of human PBMCs increased Foxp3+ expression by T cells which could be antagonized by resveratrol. Our mouse and human data thus revealed that acrolein exerts systemic immunosuppression by promoting Foxp3+ regulatory cells. This provides a novel explanation why smokers have a lower allergy, but higher cancer risk.

The Danish urban-rural gradient of allergic sensitization and disease in adults

BACKGROUND

The reported prevalence of allergic sensitization among children is lower in rural areas than in urban areas of the world. The aim was to investigate the urban-rural differences of allergic sensitization to inhalant allergens in adults depending on childhood exposure living in an industrialized country as Denmark.

METHODS

A total of 1236 male participants of 30-40 years of age recruited from two epidemiological studies were divided into four groups with regard to place of upbringing; city, town, rural area and farm. Allergic sensitization was assessed by skin prick tests (SPTs) to 10 inhalant allergens and measurements of serum specific IgE (sIgE) to four inhalant allergens (grass, birch, cat and house dust mite).

RESULTS

The prevalence of allergic sensitization to inhalant allergens decreased with decreasing degree of urbanized childhood. The risk of being sensitized to one or more allergens also decreased with decreasing degree of urbanized upbringing measured by sIgE to 4 common allergens as odds ratio with 95% confidence intervals with city as reference; town 0.60 (0.39-0.92), rural area 0.34 (0.22-0.52) and farm 0.31 (0.21-0.46). Furthermore, it was measured by SPT to 10 common allergens; town 0.52 (0.33-0.84), rural area 0.34 (0.21-0.53) and farm 0.29 (0.19-0.45). This urban-rural association was also seen for the risk of sensitization to specific allergens, rhinitis and allergic asthma.

CONCLUSION

This is the first study to show an urban-rural gradient of overall allergic sensitization and specific allergen sensitization in adults depending on their childhood exposure. In this highly homogenous western population, exposure to a less urbanized childhood was associated with lower risk of allergic sensitization and disease as an adult.

Thumb-Sucking, Nail-Biting, and Atopic Sensitization, Asthma, and Hay Fever

BACKGROUND

The hygiene hypothesis suggests that early-life exposure to microbial organisms reduces the risk of developing allergies. Thumb-sucking and nail-biting are common childhood habits that may increase microbial exposures. We tested the hypothesis that children who suck their thumbs or bite their nails have a lower risk of developing atopy, asthma, and hay fever in a population-based birth cohort followed to adulthood.

METHODS

Parents reported children's thumb-sucking and nail-biting habits when their children were ages 5, 7, 9, and 11 years. Atopic sensitization was defined as a positive skin-prick test (≥2-mm weal) to ≥1 common allergen at 13 and 32 years. Associations between thumb-sucking and nail-biting in childhood, and atopic sensitization, asthma, and hay fever at these ages were assessed by using logistic regression with adjustments for sex and other potential confounding factors: parental atopy, breastfeeding, pet ownership, household crowding, socioeconomic status, and parental smoking.

RESULTS

Thirty-one percent of children were frequent thumb-suckers or nail-biters at ≥1 of the ages. These children had a lower risk of atopic sensitization at age 13 years (odds ratio 0.67, 95% confidence interval 0.48-0.92, P = .013) and age 32 years (odds ratio 0.61, 95% confidence interval 0.46-0.81, P = .001). These associations persisted when adjusted for multiple confounding factors. Children who had both habits had a lower risk of atopic sensitization than those who had only 1. No associations were found for nail-biting, thumb-sucking, and asthma or hay fever at either age.

CONCLUSIONS

Children who suck their thumbs or bite their nails are less likely to have atopic sensitization in childhood and adulthood.

Prevalence of Atopic Dermatitis in Chinese Children aged 1-7 ys

Prevalence of atopic dermatitis (AD) is increasing worldwide. Up to date, there has been no face-to-face nation-wide study in China. We aim to explore the prevalence of clinical diagnosed AD in children aged 1-7 ys in China. Twelve metropolises were chosen from different areas of China. In each region, we selected 4-10 kindergartens and 2-5 vaccination clinics randomly. A complete history-taking and skin examination were performed by dermatologists. The definite diagnosis of AD and the severity were determined by two or three dermatologists. All criteria concerned in UK diagnosis criteria, characteristic presentation of AD and atypical manifestations were recorded in detail. A total of 13998 children from 84 kindergartens and 40 vaccination clinics were included. The prevalence of AD was 12.94% by clinical diagnosis of dermatologists overall, with 74.6% of mild AD. Comparatively, prevalence of AD based on UK diagnostic criteria was 4.76%. This is the first face-to-face nation-wide study in Chinese children aged 1-7 ys, revealing that the prevalence of AD in children is closer to that of wealthier nations.

Parental smoking and development of allergic sensitization from birth to adolescence

Background

The relation between secondhand tobacco smoke (SHS) exposure and the development of allergic sensitization in children is unclear. The aim of this study was to determine whether maternal smoking during pregnancy and postnatal SHS exposure contributes to the development of allergic sensitization in children and adolescents up to 16 years of age.

Methods

We included 3316 children from a birth cohort followed up for 16 years. SHS exposure and symptoms of allergic disease were assessed using repeated parental questionnaires. Serum immunoglobulin E against eight common inhalant and six food allergens was assessed at ages 4, 8, and 16 years with ImmunoCAP. The association between SHS exposure and sensitization was explored using logistic regression and generalized estimating equations.

Results

Exposure to SHS in infancy without prior exposure in utero was associated with an excess risk of food sensitization at age 4 years (OR 1.47, 95% CI 1.08–2.00), with comparable ORs at ages 8 and 16 years. In longitudinal analyses, an overall association was indicated between SHS in infancy and food sensitization up to age 16 years (OR 1.24, 95% CI 0.98–1.56). Maternal smoking during pregnancy was unrelated to sensitization up to 16 years of age. When sensitization was combined with concurrent symptoms of allergic disease, SHS in infancy was associated with an overall elevated risk of eczema with sensitization (OR 1.62, 95% CI 1.20–2.18).

Conclusions

SHS exposure in infancy appears to increase the risk of sensitization to food allergens up to age 16 years, as well as eczema in combination with sensitization.

Inhibitory effects of nicotine derived from cigarette smoke on thymic stromal lymphopoietin production in epidermal keratinocytes

Thymic stromal lymphopoietin (TSLP) is regarded as the main factor responsible for the pathogenesis of atopic dermatitis (AD). Cigarette smoke is an aggravating factor for allergies, but has been reported to decrease the risk of AD. In the present study, we evaluated the role of nicotine, the main constituent in cigarette smoke extract, and its underlying mechanism of action in the regulation of TSLP expression. We found that nicotine significantly inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced TSLP expression in BALB/c mice and the mouse keratinocyte cell line PAM212. Nicotine inhibition of TSLP production was abolished by pretreatments with α7 nicotinic acetylcholine receptor (α7 nAChR) antagonists, AMP-activated protein kinase (AMPK) inhibitor, and phosphoinositide 3-kinase (PI3K) inhibitors. The same inhibitors abolished inhibition of nuclear factor-κB (NF-κB) activation by nicotine. These results suggest that nicotine inhibits the expression of TSLP by suppressing the activation of NF-κB through the α7 nAChR-PI3K-AMPK signaling pathway.

Tobacco smoke exposure and multiplexed immunoglobulin E sensitization in children: a population-based study

BACKGROUND

Although there is evidence that exposure to tobacco smoke is harmful to children's respiratory health, the effects of tobacco smoke exposure on the regulation of immunoglobulin E (IgE)-mediated immune responses to specific allergens remain unclear. This study aimed to investigate the relationship between objectively assessed tobacco smoke exposure and specific IgE profiles for a broad spectrum of allergens in a population setting.

METHODS

Children aged 5-18 years (N = 1315) were assessed using serum cotinine measurement and microarray-based multiplexed detection of specific IgE against 40 allergens.

RESULTS

Serum cotinine levels were positively associated with sensitization to foods (adjusted odds ratio [AOR] = 4.95; 95% CI: 1.59-15.34), cockroaches (AOR = 3.77; 95% CI: 1.49-9.51), and pollen (AOR = 2.84; 95% CI: 1.20-6.73) while the association was borderline significant for animals (AOR = 2.53; 95% CI: 0.92-6.93). No associations were found for sensitization against mites, mold, and latex. When considering the degree of allergic sensitization, serum cotinine levels were positively correlated to the number of sensitization to cockroaches (P = 0.004), pollen (P = 0.006), and foods (P < 0.001), with statistically significant positive dose-response relationships (all P < 0.01). Similar results were observed when summing up specific IgE concentrations for the aforementioned allergen categories.

CONCLUSIONS

The association between tobacco smoke exposure and IgE sensitization to environmental allergens varies for different allergens among children. This study demonstrates that elevated serum cotinine levels are significantly associated with IgE sensitization to cockroaches, grass pollen, and certain foods, with potential dose-dependent relationships.

Patterns of Sensitization to Inhalant Allergens in Japanese Lower-Grade Schoolchildren and Related Factors

OBJECTIVE

This study clarified sensitization patterns to house dust mite (HDM) and Japanese cedar pollen (JCP) in Japanese lower-grade schoolchildren. We also explored factors associated with allergic sensitization.

METHODS

This cross-sectional study used a database from the Study on Respiratory Disease and Automobile Exhaust (SORA), a Japanese health study project. The subjects comprised 8,815 pupils aged 6-9 years. We obtained the distribution of HDM- and JCP-specific IgE, respectively, as a marker of sensitization. To determine factors associated with sensitization, we used logistic regression and calculated adjusted odds ratios (AORs) for the relative prevalence of sensitization. The cut-off point for specific IgE levels was 0.35 kU/l.

RESULTS

Sensitization to HDM and JCP was detected in 51 and 39% of subjects, respectively, occurring more often in boys and at older ages. In addition, AORs of sensitization to HDM/JCP were higher in subjects with a history of bronchitis, parental asthma, parental atopic eczema and parental pollinosis. In contrast, AORs for sensitization were lower in those subjected to maternal passive smoking as well as among boys with pets. AORs of sensitization to JCP alone were lower in those with a history of otitis media, those who had been bottle milk fed, and those who were not the firstborn and who lived near a busy road.

CONCLUSION

Sensitization to HDM and JCP was detected in 51 and 39% of lower-grade schoolchildren, respectively.

Early risk factors for pubertal asthma

BACKGROUND

Early life risk factors are previously described for childhood asthma, but less is known related to asthma in adolescence. We aimed to investigate early risk factors (before 2 years) for pubertal asthma and secondarily for pubertal asthma phenotypes based upon allergic comorbidities.

METHODS

Based on data from 550 adolescents in the prospective birth cohort 'Environment and Childhood Asthma' study, subjects were categorized by recurrent bronchial obstruction (rBO) 0-2 years, asthma 2-10 years, and pubertal asthma from 10 to 16 years including incident asthma in puberty and asthma in remission from 10 to 16 years or as never rBO/asthma 0-16 years. Asthma in puberty was further classified based on the comorbidities atopic dermatitis and allergic rhinitis (AR) from 10 to 16 years. Twenty-three common asthma risk factors identified by 2 years of age, including frequency and persistence of bronchial obstruction (severity score), were analysed by weighted logistic regression for each phenotype.

RESULTS

In adjusted models, the risk of pubertal asthma increased significantly with higher severity score, parental rhinitis, being the firstborn child, and familial stress around birth. Pubertal asthma in remission was significantly associated with severity score and number of lower respiratory tract infections and inversely associated with breastfeeding beyond 4 months. Pubertal incident asthma was more common among firstborn children. All asthma phenotypes with allergic diseases were significantly associated with severity score, whereas familial perinatal stress increased the risk of asthma only. Asthma combined with AR was associated with parental asthma and being firstborn, whereas the risk of asthma with both atopic dermatitis and AR increased with higher paternal education, atopic dermatitis, being firstborn, and familial perinatal stress.

CONCLUSION AND CLINICAL RELEVANCE

Important early risk factors for pubertal asthma were early airways obstruction, parental rhinitis, being the firstborn child, and perinatal familial stress.

Allergic Sensitization, Rhinitis and Tobacco Smoke Exposure in US Adults

INTRODUCTION

Tobacco exposure has been linked with sinonasal pathology and may be associated with allergic sensitization. This study evaluates the association between exposure to active smoking or secondhand smoke (SHS) and the prevalence of rhinitis and allergic sensitization in the US adult population.

METHODS

Cross-sectional study in 4,339 adults aged 20-85 in the National Health and Nutrition Examination Survey, 2005-2006. Never smoking was defined as reported lifetime smoking less than 100 cigarettes and serum cotinine levels <10ng/ml, while active smoking was defined as self-reported smoking or serum cotinine concentrations > 10 ng/mL. Self-reported rhinitis was based on symptoms during the past 12 months, and allergen sensitization was defined as a positive response to any of the 19 specific IgE antigens tested.

RESULTS

Almost half of the population (43%) had detectable levels of IgE specific to at least one inhaled allergen and 32% reported a history of rhinitis. After multivariate adjustment, there was a statistically significant association between the highest serum cotinine tertile and rhinitis in active smokers (OR 1.42; 95%CI 1.00-2.00). The association between active smoking and rhinitis was stronger in individuals without allergic sensitization (OR 2.47; 95%CI 1.44-4.23). There was a statistically significant association between increasing cotinine tertiles and decreased odds of inhaled allergen sensitization (p-trend <.01).

CONCLUSION

Tobacco smoke exposure was associated with increased prevalence of rhinitis symptoms, but not with allergic sensitization. The results indicate that the relationship between tobacco smoke exposure and sinonasal pathology in adults may be independent of allergic sensitization.

The mediating effect of body mass index on the relationship between cigarette smoking and atopic sensitization in Chinese adults

BACKGROUND

It is unclear whether the relationship between cigarette smoking and atopy is mediated by body fat mass, such as the Body Mass Index (BMI). We assessed the mediating role of BMI on the relationship between smoking and atopy in Chinese adults.

METHODS

A hospital-based case-control study of 786 atopic cases and 2771 controls was conducted in adults aged 18 years or older from March 2010 to September 2014 in Harbin, China. Mediation models were used to estimate the indirect effects of smoking on atopic sensitization through BMI.

RESULTS

Compared to non-smokers, light smokers and moderate smokers had a lower risk of inhalant allergen sensitization. The indirect effect of smoking and sensitization to aeroallergens were only observed in light smokers (point estimate, -0.026; 95% CI, -0.062 to -0.004). The mediating roles of BMI on the relationships between smoking and other types of allergic sensitization were not statistically significant.

CONCLUSION

BMI appeared to partially mediate the effect of light smoking on sensitization to aeroallergens. However, considering the other harmful health effects of cigarette smoking, the effective method to lower the incidence of atopy would be to decrease body fat mass by physical exercise and employing other more healthy ways of living rather than smoking.

The effects of alcohol consumption and smoking on allergy risk in Korean adults

BACKGROUND

The immune-modulating effects of alcohol and smoking are well known through a great body of research. Furthermore, many studies have been performed on the influence of alcohol and smoking on the development of allergic disease. However, previous studies have reported conflicting results with associations between alcohol intake or smoking and risk of allergy. The purpose of this study was to evaluate the effects of alcohol consumption and smoking on total serum immunoglobulin E (TIgE) and prevalence of sensitization to Dermatophagoides farinae in a representative sample of Korean adults.

METHODS

TIgE levels and IgE levels specific to D. farinae were measured. Alcohol, smoking habit, and other influencing variables were obtained from the 2010 Korean National Health and Nutrition Examination.

RESULTS

Smoking (smoked five packs or more in lifetime) was independently associated with increased risk of sensitization to D. farinae (odds ratio [OR], 1.439; 95% CI, 1.075-1.927). Frequent alcohol drinking (more than four times a week) also showed similar association when compared with subjects who drank less than once per month (OR, 2.052; 95% CI, 1.257-3.350). TIgE levels were also increased along with increased frequency of alcohol drinking. However, smoking habit was not related to TIgE levels.

CONCLUSION

These findings suggest that history of smoking and frequent alcohol consumption are significantly associated with increased prevalence of sensitization to D. farinae. In addition, frequency of alcohol drinking was also related to a moderate increase in TIgE levels in Korean adults.

Effect modification by gender and smoking status on the association between obesity and atopic sensitization in Chinese adults: a hospital-based case-control study

BACKGROUND

There is an ongoing debate on the potential association between obesity and atopy. However, no previous studies have investigated whether this relationship depends on sex and smoking status in Chinese adults.

METHODS

In this hospital-based, case-control study, we recruited 1150 atopic cases aged 18 years or older and 1245 healthy control participants during April 2009 and December 2012 in Harbin, China. We conducted structured questionnaire interviews, anthropometry measurements and serum allergen-specific immunoglobulin E (IgE) testing. Univariate and multivariate logistic regression models were used to explore the relationship between obesity and atopy risk stratified by sex and smoking status.

RESULTS

There was an association between obesity and an increased risk of atopic sensitization after adjusting for age, educational, family history, smoking and alcohol consumption (OR: 2.61, 3.25; 95% CI: 1.57-4.33,1.91-5.56 in males and females, respectively). The association between BMI and allergic sensitization depended on smoking status. In both genders, the association of obesity with atopic sensitization risk was stronger in non-smokers than in current smokers. In males, ORs of atopic sensitization for obesity were 3.15 (95% CI, 1.46-6.68) for non-smokers and 2.22 (95% CI, 1.10-4.48) for current smokers. The corresponding ORs in females were 3.51 (95% CI, 1.98-6.24) and 2.22 (95% CI, 0.46-10.68) for non-smokers and current smokers, respectively. After excluding those subjects who with pre-existing allergic conditions, the same relationship still remained.

CONCLUSIONS

Obesity is positively and significantly associated with the risk of atopy in both men and women as well in both smokers and non-smokers in China. In addition, the relationship between obesity and atopic sensitization is stronger in non-smokers than in current smokers.

Risk of sensitization and allergy in Ragweed workers - a pilot study

Background

Due to its high allergenic potential Ambrosia artemisiifolia has become a health threat in many European countries during the last few decades. Hence, several cities and communities initiated ragweed eradication campaigns. In Berlin, Germany, so-called Ambrosia scouts are being assigned the task of finding and eliminating this weed.

We sought to evaluate the potential risk of sensitization and allergy in these individuals.

Findings

In order to assess the risk of sensitization and allergy, we followed-up 20 Ambrosia scouts by skin-prick test with inhalant allergens, immunoserological and pulmonary function tests. Additionally, medical conditions were evaluated by a questionnaire especially designed for this study.

Despite close contact to ragweed over a median duration of 13.8 months, none of the participants became sensitized or allergic to ragweed. One individual developed a clinical non-relevant sensitization towards the taxiconomically-related plant mugwort. A decline in relative FEV1 was most probably due to heavy smoking.

Conclusions

Our surprising findings suggest that intensive contact and exposure to high ragweed pollen concentrations do not necessarily result in sensitization and/or allergy, meaning that the allergenic potential of this weed might be lower than hitherto expected. However, it is also conceivable that continuous exposure to high allergen levels induced tolerance in the ragweed workers.

Due to the relatively small number of subjects studied, our results might be biased and therefore investigations on larger study groups are needed.

Prevalence and correlates of a 'knee' pattern on the maximal expiratory flow-volume loop in young adults

BACKGROUND AND OBJECTIVE

Visual inspection of the maximal flow-volume curve is an important step in interpreting spirometry. Many young people have a convex inflection or 'knee' on the expiratory part of the loop. This is thought to be a normal variant, but this view is based on theoretical grounds, and the epidemiology of the knee pattern has never been reported.

METHODS

Flow-volume loops from an unselected birth cohort of 1037 individuals at ages 18, 26, 32 and 38 years were visually inspected for a knee pattern. Associations with asthma diagnoses, smoking history, body mass index (BMI) and spirometry were assessed.

RESULTS

The knee pattern was found in approximately two thirds of men and women at age 18. The prevalence decreased with age, but it was more likely to persist in women. The knee was more common after bronchodilator and was associated with higher forced expiratory volume in 1 s/forced vital capacity ratios and mid-expiratory flow rates. There was no association with smoking, except for an inverse correlation in men at age 18. No association was found with BMI. Women with asthma were less likely to have a knee at both ages 18 and 38, whereas men with asthma showed an inverse association at age 18.

CONCLUSIONS

A knee is a very common pattern on flow-volume loop in young adults. In accordance with theoretical predictions, the prevalence of the knee declines with age, but it is more likely to persist in women. It is associated with less airflow obstruction and is less common in people with asthma.

Rhinitis symptoms and asthma among parents of preschool children in relation to the home environment in Chongqing, China

Risk factors for rhinitis and asthma in the home environment were studied by a questionnaire survey. Parents of 4530 1-8 year old children (one parent per child) from randomly selected kindergartens in Chongqing, China participated. 70.4% were females; 47.1% had rhinitis symptoms in the last three months (current rhinitis, CR); 1.6% reported a history of allergic asthma (AA); 2.7% reported a history of allergic rhinitis (AR); 16.4% were current smokers; 50.8% males and 2.4% females were current smokers. Stuffy odor, unpleasant odor, tobacco smoke odor and dry air were associated with CR (adjustment for gender, current smoking and other perceptions of odor or humidity). Associations between home environment and CR, AR, and AA were studied by multiple logistic regression analyses, adjusting for gender, current smoking and other significant home factors. Living near a main road or highway was a risk factor for both CR (OR(95%CI): 1.31(1.13,1.52)) and AR (OR(95%CI): 2.44(1.48,4.03)). Other risk factors for CR included living in rural areas (OR(95%CI): 1.43(1.10,1.85)), new furniture (OR(95%CI): 1.28(1.11,1.49)), water damage (OR(95%CI): 1.68(1.29,2.18)), cockroaches (OR(95%CI): 1.46(1.23,1.73)), and keeping pets (OR(95%CI): 1.24(1.04,1.49)). Other risk factors for AR included redecoration (OR(95%CI): 2.14(1.34,3.41)), mold spots (OR(95%CI): 2.23(1.06,4.68)), window pane condensation (OR(95%CI): 2.04(1.28,3.26)). Water damage was the only home factor associated with AA (2.56(1.34,4.86)). Frequently put bedding to sunshine was protective for CR (OR(95%CI): 0.79(0.68,0.92); cleaning every day was protective for AR (OR(95%CI): 0.40(0.22,0.71)). In conclusion, parents' CR and AR were related to a number of factors of the home environment.

Prevalence of allergic sensitization in the United States: results from the National Health and Nutrition Examination Survey (NHANES) 2005-2006

BACKGROUND

Allergic sensitization is an important risk factor for the development of atopic disease. The National Health and Nutrition Examination Survey (NHANES) 2005-2006 provides the most comprehensive information on IgE-mediated sensitization in the general US population.

OBJECTIVE

We investigated clustering, sociodemographic, and regional patterns of allergic sensitization and examined risk factors associated with IgE-mediated sensitization.

METHODS

Data for this cross-sectional analysis were obtained from NHANES 2005-2006. Participants aged 1 year or older (n = 9440) were tested for serum specific IgEs (sIgEs) to inhalant and food allergens; participants 6 years or older were tested for 19 sIgEs, and children aged 1 to 5 years were tested for 9 sIgEs. Serum samples were analyzed by using the ImmunoCAP System. Information on demographics and participants' characteristics was collected by means of questionnaire.

RESULTS

Of the study population aged 6 years and older, 44.6% had detectable sIgEs, whereas 36.2% of children aged 1 to 5 years were sensitized to 1 or more allergens. Allergen-specific IgEs clustered into 7 groups that might have largely reflected biological cross-reactivity. Although sensitization to individual allergens and allergen types showed regional variation, the overall prevalence of sensitization did not differ across census regions, except in early childhood. In multivariate modeling young age, male sex, non-Hispanic black race/ethnicity, geographic location (census region), and reported pet avoidance measures were most consistently associated with IgE-mediated sensitization.

CONCLUSIONS

The overall prevalence of allergic sensitization does not vary across US census regions, except in early life, although allergen-specific sensitization differs based on sociodemographic and regional factors. Biological cross-reactivity might be an important but not the sole contributor to the clustering of allergen-specific IgEs.

Prevalence trends in respiratory symptoms and asthma in relation to smoking - two cross-sectional studies ten years apart among adults in northern Sweden

Background

Smoking is considered to be the single most important preventable risk factor for respiratory symptoms. Estimating prevalence of respiratory symptoms is important since they most often precede a diagnosis of an obstructive airway disease, which places a major burden on the society. The aim of this study was to estimate prevalence trends of respiratory symptoms and asthma among Swedish adults, in relation to smoking habits. A further aim was to estimate the proportion of respiratory symptom and asthma prevalence attributable to smoking.

Methods

Data from two large-scale cross-sectional surveys among adults performed in northern Sweden in 1996 and 2006 were analysed. Identical methods and the same questionnaire were used in both surveys. The association between smoking, respiratory symptoms and asthma was analysed with multiple logistic regression analyses. Changes in prevalence of respiratory symptoms and asthma from 1996 to 2006 were expressed as odds ratios. Additionally, the population attributable risks of smoking were estimated.

Results

The prevalence of most respiratory symptoms decreased significantly from 1996 to 2006. Longstanding cough decreased from 12.4 to 10.1%, sputum production from 19.0 to 15.0%, chronic productive cough from 7.3 to 6.2%, and recurrent wheeze from 13.4 to 12.0%. Any wheeze and asthmatic wheeze remained unchanged. This parallels to a decrease in smoking from 27.4 to 19.1%. In contrast, physician-diagnosed asthma increased from 9.4 to 11.6%. The patterns were similar after correction for confounders. All respiratory symptoms were highly associated with smoking, and the proportion of respiratory symptoms in the population attributed to smoking (PAR) ranged from 9.8 to 25.5%. In 2006, PAR of smoking was highest for recurrent wheeze (20.6%).

Conclusions

In conclusion, we found that respiratory symptoms, in particular symptoms common in bronchitis, decreased among adults in northern Sweden, parallel to a decrease in smoking from 1996 to 2006. In contrast, the prevalence of physician-diagnosed asthma increased during the same time-period. Up to one fourth of the respiratory symptom prevalence in the population was attributable to smoking.

Impact of active and passive smoking as risk factors for asthma and COPD in women presenting to primary care in Syria: first report by the WHO-GARD survey group

Background

The burden of chronic respiratory disease (CRD) is alarming. International studies suggest that women with CRD are undersurveyed and underdiagnosed by physicians worldwide. It is unclear what the prevalence of CRD is in the general population of Syria, particularly among women, since there has never been a survey on CRD in this nation. The purpose of this study was to investigate the impact of different patterns of smoking on CRD in women.

Materials and methods

We extracted data on smoking patterns and outcome in women from the Global Alliance Against Chronic Respiratory Diseases survey. Using spirometric measurements before and after the use of inhaled bronchodilators, we tracked the frequency of CRD in females active and passive narghile or cigarette smokers presenting to primary care. We administered the questionnaire to 788 randomly selected females seen during 1 week in the fiscal year 2009–2010 in 22 primary care centers in six different regions of Syria. Inclusion criteria were age >6 years, presenting for any medical complaint. In this cross-sectional study, three groups of female subjects were evaluated: active smokers of cigarettes, active smokers of narghiles, and passive smokers of either cigarettes or narghiles. These three groups were compared to a control group of female subjects not exposed to active or passive smoking.

Results

Exposure to active cigarette smoke but not narghile smoke was associated with doctor-diagnosed chronic obstructive pulmonary disease (COPD). However, neither cigarette nor narghile active smoking was associated with increased incidence of spirometrically diagnosed COPD. Paradoxically, exposure to passive smoking of either cigarettes or narghiles resulted in association with airway obstruction, defined as forced expiratory volume in 1 second (FEV₁)/forced vital capacity (FVC) < 70% according to the Global initiative for chronic Obstructive Lung Disease criteria; association with FEV₁ < 80% predicted, evidencing moderate to severe GOLD spirometric grade, and doctor-diagnosed COPD. Physicians tend to underdiagnose COPD in women who present to primary care clinics. Whereas around 15% of enrolled women had evidence of COPD with FEV₁/FVC < 70% after bronchodilators, only 4.8% were physician-diagnosed. Asthma did not appear to be a significant spirometric finding in these female subjects, although around 11% had physician-diagnosed asthma. One limitation is FEV₁/FVC < 70% could have also resulted from uncontrolled asthma. The same limitation has been reported by the Proyecto Latinoamericano de Investigacion en Obstruccion Pulmonar (PLATINO) study.

Conclusion

Contrary to popular belief in developing countries, women exposed to tobacco smoke, whether active or passive, and whether by cigarettes or narghiles, like men are at increased risk for the development of COPD, although cultural habits and taboos may decrease the risk of active smoking in some women.

Recommendations

These findings will be considered for country and region strategy for noncommunicable diseases, to overcome underdiagnosis of CRD in women, fight widespread female cigarette and narghile smoking, and promote behavioral research in this field.

Forceps birth delivery, allergic sensitisation and asthma: a population-based cohort study

BACKGROUND

Studies indicate an increased risk of allergies among children born by caesarean section, possibly because immune development is altered by avoiding exposure to maternal vaginal flora. It is unknown if other obstetric interventions are associated with allergies.

OBJECTIVE

To assess associations between delivery with forceps assistance and development of atopy and asthma.

METHODS

In a population-based cohort of 1037 individuals born in 1972/73, atopy was assessed by skin-prick tests for common allergens at ages 13 and 32 years. A history of asthma was obtained at the same ages. Associations between birth with forceps assistance, atopy and asthma were assessed with adjustments for sex, head circumference at birth, parental atopy disease, birth order and socio-economic status.

RESULTS

Children born using forceps were more likely to have atopy at ages 13 (53% vs. 44%) and 32 (68% vs 59%). They were also more likely to have asthma (21% vs. 11% and 23% vs. 16% at ages 13 and 32 respectively). Except for asthma at age 13, these associations were not statistically significant after adjustment for multiple confounding factors.

CONCLUSIONS & CLINICAL RELEVANCE

Delivery with forceps assistance is associated with an increased risk of atopy and asthma, but the associations were weaker after adjustment for confounding factors. The previously reported association between caesarean birth and atopic disease may be due to confounding rather than altered exposure to maternal flora, although other factors associated with a difficult labour cannot be ruled out.

Increase in sensitization to common airborne allergens among adults - two population-based studies 15 years apart

BACKGROUND

Studies on time trends of allergic sensitization among adults are rare. The aim of the study was to compare the prevalence of allergic sensitization to common airborne allergens among adults 15 years apart and to identify risk factors for allergic sensitization.

METHODS

Clinical examinations including skin prick test (SPT) and structured interviews were performed in two random population samples in 1994 and 2009. Furthermore, specific IgE was analyzed in 2009. SPT data were available for 483 subjects in 1994 and for 463 subjects in 2009 in ages 20-60 years. Specific IgE was analyzed in 692 subjects in ages 20-79 years.

RESULTS

Sensitization to cat (16% to 26%, p < 0.001), dog (13% to 25%, p < 0.001), birch (13% to 18%, p = 0.031) and timothy (12% to 21%, p < 0.001), based on SPT, increased significantly from 1994 to 2009. Sensitization to any positive SPT increased from 35% to 39%, p = 0.13.The proportion of having ≥3 positive SPT reactions increased from 40% to 56%, p = 0.002. The sensitization pattern yielded similar results based on specific IgE. Risk factors for allergic sensitization were having a family history of allergy (OR 3.1, 95% CI 2.0-4.8 for any positive SPT; OR 2.7, 95% CI 1.8-4.0 for any elevated IgE) and urban living (OR 1.7, 95% CI 1.0-2.7; OR 1.5, 95% CI 1.0-2.4).

CONCLUSIONS

The prevalence of allergic sensitization to major airborne allergens as well as multi-sensitization increased significantly between the study years. Young age, a family history of allergy and urban living were significant risk factors for allergic sensitization.

Relevance of birth cohorts to assessment of asthma persistence

The definition of persistent asthma in longitudinal studies reflects symptoms reported at every assessment with no substantive asymptomatic periods. Early-childhood wheezing may be transient, especially if it is of viral etiology. Longitudinal studies provide greater opportunity to confirm the diagnosis by variability of symptoms, objective measurements, and therapeutic responses. Several clinical phenotypes of childhood asthma have been identified, with general consistency between cohorts. Persistent wheezing is often associated with loss of lung function, which is evident from early-childhood and related to persistent inflammation and airway hyperresponsiveness. Female sex, atopy, airway responsiveness, and personal smoking, but not exposure to environmental tobacco smoke, are risk factors for persistence of childhood asthma into adulthood. The effect of breastfeeding remains controversial, but gene-environment interactions may partly explain outcomes. Understanding the natural history and underlying causes of asthma may lead to development of strategies for primary prevention.

Cigarette smoking is associated with high prevalence of chronic rhinitis and low prevalence of allergic rhinitis in men

BACKGROUND

The harmful effects of tobacco smoke on human health, including respiratory health, are extensive and well documented. Previous data on the effect of smoking on rhinitis and allergic sensitization are inconsistent. We sought to investigate how smoking correlates with prevalence of allergic and chronic rhinitis among adults in Sweden.

METHODS

The study population comprised 27 879 subjects derived from three large randomly selected cross-sectional population surveys conducted in Sweden between 2006 and 2008. The same postal questionnaire on respiratory health was used in the three surveys, containing questions about obstructive respiratory diseases, rhinitis, respiratory symptoms and possible determinants of disease, including smoking habits. A random sample from one of the cohorts underwent a clinical examination including skin prick testing.

RESULTS

Smoking was associated with a high prevalence of chronic rhinitis in both men and women and a low prevalence of allergic rhinitis in men. These associations were dose dependent and remained when adjusted for a number of possible confounders in multiple logistic regression analysis. Prevalence of chronic rhinitis was lowest in nonsmokers and highest in very heavy smokers (18.5% vs 34.5%, P < 0.001). Prevalence of sensitization to common airborne allergens was lower in current smokers (25.9%, P = 0.008) and ex-smokers (28.2%, P = 0.022) than in nonsmokers (38.5%).

CONCLUSION

We found that smoking was associated with a high prevalence of chronic rhinitis in both sexes and a low prevalence of allergic rhinitis in men. The associations were dose dependent and remained when adjusting for several possible confounders.

Tobacco smoke exposure and allergic sensitization in children: a propensity score analysis

BACKGROUND AND OBJECTIVE

There is conflicting evidence of the effect of environmental tobacco smoke (ETS) on the development of allergic diseases in children. Studies have shown that this relationship differs depending on maternal history of the disease. We employed the rigour of propensity score methods to assess this relationship using data from a birth cohort.

METHODS

Using n = 662 children from the Wayne County Health, Environment, Allergy and Asthma Longitudinal Study, we assessed the relationship between early-life ETS and subsequent allergic sensitization via a positive skin prick test (SPT+) or at least one specific immunoglobulin E (IgE) ≥ 0.35 (sIgE+) in children aged 2-3 years. Propensity score estimation followed by full and nearest neighbour matching was compared with standard multivariable regression models.

RESULTS

Among children without a maternal history of allergic disease, ETS was positively associated with allergic sensitization in children with an adjusted odds ratio (aOR) for SPT+ of 2.32 (95% confidence interval (CI): 1.28-4.22) and the aOR for sIgE+ was 2.53 (95% CI: 1.43-4.48). Contrarily, for children with a positive maternal history, the aOR for SPT+ and sIgE+ was 0.56 (95% CI: 0.24-1.32) and 0.43 (95% CI: 0.20-0.91), respectively.

CONCLUSIONS

Using propensity score methods to rigorously control for confounding factors, ETS exposure was found to reduce the risk of allergic sensitization in children with a positive maternal history. There is a strong association between early-life ETS and the development of allergic sensitization for children aged 2-3 years without maternal history.

Occupational airborne exposure, specific sensitization and the atopic status: evidence of a complex interrelationship

Background

We have investigated the relationship between atopic status and long-term occupational exposure to latex proteins or methyl diethyl diisocyanate (MDI) as high and low molecular weight asthma-inducing agents, respectively.

Methods

This study is based on retrospective analyses of two groups of symptomatic outpatients: 184 healthcare workers with latex exposure and 156 workers with isocyanate (MDI) exposure. We analysed atopic and non-atopic subgroups according to exposure duration and the frequencies of specific sensitization.

Results

45% of the healthcare subgroup specifically sensitized to latex were atopic, whereas in the non-sensitized healthcare subgroup only 26% were atopic. On the other hand, subjects specifically sensitized to MDI were rarely atopic (only 15%), whereas in the subgroup non-sensitized to MDI atopy was present in 38%. After prolonged durations of exposure, the proportion of atopics was further elevated in most healthcare subgroups but it decreased in the MDI-exposed subjects.

Conclusions

We hypothesize that latex proteins as sensitizing agents might promote the development of atopy, whereas exposure to the low molecular weight MDI might inhibit the atopic status.

Cigarette smoke suppresses the surface expression of c-kit and FcεRI on mast cells

Chronic obstructive pulmonary disease (COPD) is a multicomponent disease characterized by emphysema and/or chronic bronchitis. COPD is mostly associated with cigarette smoking. Cigarette smoke contains over 4,700 chemical compounds, including free radicals and LPS (a Toll-Like Receptor 4 agonist) at concentrations which may contribute to the pathogenesis of diseases like COPD. We have previously shown that short-term exposure to cigarette smoke medium (CSM) can stimulate several inflammatory cells via TLR4 and that CSM reduces the degranulation of bone-marrow-derived mast cells (BMMCs). In the current study, the effect of CSM on mast cells maturation and function was investigated. Coculturing of BMMC with CSM during the development of bone marrow progenitor cells suppressed the granularity and the surface expression of c-kit and Fc ε RI receptors. Stimulation with IgE/antigen resulted in decreased degranulation and release of Th1 and Th2 cytokines. The effects of CSM exposure could not be mimicked by the addition of LPS to the culture medium. In conclusion, this study shows that CSM may affect mast cell development and subsequent response to allergic activation in a TLR4-independent manner.

Asthma in Mexican school-age children is not associated with passive smoking or obesity

Background

Asthma has increased in various regions of the world. The factors associated with the growth in prevalence are still to be determined.

Objective

To evaluate the degree of association of the prevalence of asthma with passive smoking and obesity in school-children in western Mexico.

Methods

A population-based cross-section analytic study. A stratified random sample of 740 primary school pupils of between 6 and 12 years of age was chosen. Asthma, passive smoking and a background of allergic diseases were identified by means of a standardized questionnaire filled out by the parents of the participants. Obesity was identified by means of the body mass index. Proportional sections of population were estimated and the degree of association between asthma (dependent variable) and the independent variables was evaluated by means of multivariate logistic regression.

Results

The following factors of prevalence were found: asthma 8.1%; obesity 19.9%; background of smoking in the father 6.7% and in the mother 13.3%. There was no significant association to be found with asthma in either passive smoking where one of the parents smoked (p = 0.39) or in obesity (p = 0.09). On the other hand, the background of allergic diseases in the mother showed statistically significant association with asthma in the boys (odds ratio = 3.5, 95% confidence interval 1.4 to 8.59), but not in the girls.

Conclusion

With the exception of the maternal background of allergy, neither obesity nor passive smoking are factors associated with asthma in Mexican children.

Association between proximity to major roads and sputum cell counts

BACKGROUND

Air pollution caused by motor vehicle emissions has been associated with exacerbations of obstructive airway diseases; however, the nature of the resulting bronchitis has not been quantified.

OBJECTIVE

To examine whether proximity to major roads or highways is associated with an increase in sputum neutrophils or eosinophils, and to evaluate the effect of proximity to roads on spirometry and exacerbations in patients with asthma.

METHODS

A retrospective study of 485 sputum cell counts from patients attending a tertiary chest clinic in Hamilton, Ontario, identified eosinophilic or neutrophilic bronchitis. Patients' residences were geocoded to the street network of Hamilton using geographic information system software. Associations among bronchitis, lung function, and proximity to major roads and highways were examined using multinomial logistic and multivariate linear regression analyses adjusted for patient age, smoking status and corticosteroid medications.

RESULTS

Patients living within 1000 m of highways showed an increased risk of bronchitis (OR 3.8 [95% CI 1.0 to 13.7]; P<0.05), particularly neutrophilic bronchitis (OR 4.7 [95% CI 1.2 to 18.7]; P<0.05) as well as an increased risk of an asthma diagnosis (OR 1.9 [95% CI 1.0 to 3.4]; P<0.05). Patients living within 300 m of a major road were at increased risk for an asthma exacerbation (OR 1.9 [95% CI 1.5 to 15.5]; P<0.01) and lower lung function, particularly in women (P=0.036).

CONCLUSION

In patients with airway diseases, living close to a highway or major road was associated with neutrophilic bronchitis, an increased risk of asthma diagnosis, asthma exacerbations and lower lung function.

Mast cells and COPD

The pathogenesis of chronic obstructive pulmonary disease (COPD) is based on the innate and adaptive inflammatory immune response to the inhalation of toxic particles and gases. Although tobacco smoking is the primary cause of this inhalation injury, many other environmental and occupational exposures contribute to the pathology of COPD. The immune inflammatory changes associated with COPD are linked to a tissue-repair and -remodeling process that increases mucus production and causes emphysematous destruction of the gas-exchanging surface of the lung. The common form of emphysema observed in smokers begins in the respiratory bronchioles near the thickened and narrowed small bronchioles that become the major site of obstruction in COPD. The inflamed airways of COPD patients contain several inflammatory cells including neutrophils, macrophages, T lymphocytes, and dendritic cells. The relative contribution of mast cells to airway injury and remodeling is not well documented. In this review, an overview is given on the possible role of mast cells and their mediators in the pathogenesis of COPD. Activation of mast cells and mast cell signaling in response to exposure to cigarette smoke is further discussed.

Geographical variations in the prevalence of atopic sensitization in six study sites across Canada

BACKGROUND

Geographical variations in atopic sensitization in Canada have not been described previously. This study used the standardized protocol of the European Community Respiratory Health Survey-1 (ECRHS-1) to investigate the distribution and predictors of atopic sensitization in six sites across Canada and to compare the results with some ECRHS-1 centers.

METHODS

Adults aged 20-44 years in six study sites across Canada underwent allergy skin testing using 14 allergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae) cat, cockroach, grasses (Timothy grass, Kentucky grass), molds (Cladosporium herbarium, Alternaria alternata, Aspergillus fumigatus, Penicillium), trees (tree mix, birch, Olea europea), and common ragweed.

RESULTS

The overall prevalence of atopy (skin test over 0 mm to any allergen) was 62.7%. There was significant geographical variation in the prevalence of atopy in the six study sites (lowest 55.6% [95% C.I.51.3-59.9] in Prince Edward Island, highest 66.0 [61.7-70.3] in Montreal) and of sensitization to each of the allergens tested even after adjustment for confounders. When the first eight of the nine allergens in the ECRHS were used to estimate the prevalence of atopic sensitization, the prevalence of atopy in Canada was 57% compared with 35.2% overall for centers in the ECRHS. The prevalence of atopy in Vancouver (57% [52.3-61.8]) was close to that of Portland, Oregon (52.1% [46.2-58.0]).

CONCLUSION

There was a significant variation in atopic sensitization among different study sites across Canada. The prevalence of atopic sensitization is relatively high in Canada compared with sites in the ECRHS and this may, in part, account for the high prevalence of asthma and asthma symptoms in Canada.

Asthma: time to confront some inconvenient truths

Despite major advances in the understanding of the pathogenesis of asthma and improvements in management, the accompanying benefits from public health initiatives and clinical practice have arguably been less than expected. For example, there are no effective public health strategies or treatment regimes that reduce the risk of developing asthma or influence its natural history. These represent priority areas for future translational research, which would need to investigate genetic and environmental interactions and vaccine strategies. In terms of asthma management it is tempting to focus on novel drug therapies; however, a case can be made that the priority is to undertake research that leads to improvements in the use of existing treatments through public health and primary care initiatives. Guidelines represent an important component of this approach, with recommendations for asthma imbedded within respiratory guidelines that can be implemented in the developing world where other acute and chronic respiratory disorders are common. This approach offers the best opportunity to close the gap between what is currently achieved in asthma management and that which is potentially achievable.

The role of birth cohorts in studies of adult health: the New York women's birth cohort

Epidemiological studies investigating associations between early life factors and adult health are often limited to studying exposures that can be reliably recalled in adulthood or obtained from existing medical records. There are few US studies with detailed data on the pre- and postnatal environment whose study populations are now in adulthood; one exception is the Collaborative Perinatal Project (CPP). We contacted former female participants of the New York site of the CPP who were born from 1959 to 1963 and were prospectively followed for 7 years to examine whether the pre- and postnatal environment is associated with adult health in women 40 years after birth. The New York CPP cohort is particularly diverse; at enrolment, the race/ethnicity distribution of mothers was approximately 30% White, 40% Black and 30% Puerto Rican. Of the 841 eligible women, we successfully traced 375 women (45%) and enrolled 262 women (70% of those traced). Baseline data were available for all eligible women, and we compared those who participated with the remaining cohort (n = 579). Higher family socio-economic status at age 7, availability of maternal social security number, and White race/ethnicity were statistically significantly associated with a higher probability of tracing. Of those traced, race/ethnicity was associated with participation, with Blacks and Puerto Ricans less likely to participate than Whites (OR = 0.5, 95% CI 0.3, 0.8, and OR = 0.5, 95% CI 0.3, 1.0, respectively). In addition, higher weight at 7 years was associated with lower participation (OR = 0.95, 95% CI 0.92, 0.99), but this association was observed only among the non-White participants. None of the other maternal characteristics, infant or early childhood growth measures was associated with participation or with tracing, either overall or within each racial/ethnic subgroup. Daughters' recall of early life factors such as pre-eclampsia (sensitivity = 24%) and birthweight were generally poor, with the latter varying by category of birthweight with the highest sensitivity for the largest babies (81%) and the lowest sensitivity for the smallest babies (54%). These data reinforce the need to rejuvenate existing birth cohorts with prospective data for life course studies of adult health. Understanding the factors that are associated with tracing and participation in these existing cohorts will help in interpreting the validity and generalisability of the findings from these invaluable cohorts.