Latitude, birth date, and allergy

Being born in autumn or winter is associated with asthma and allergic rhinitis in Finland

BACKGROUND

Our population-based study has previously shown that being born in winter or spring was associated with adult-onset asthma. The aim was to study if season of birth (SOB) is associated with airway allergy and related diseases: NSAID exacerbated respiratory disease (N-ERD), asthma, allergic rhinitis (AR), nonallergic rhinitis (NAR), chronic rhinosinusitis with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP) in Finland.

METHODS

A randomly sampled retrospective registry-based follow-up data (n = 74,868) of patients visiting Hospital District of Helsinki and Uusimaa (HUS) in Finland was used. The birth date, sex, visit date and comorbidities were collected from electronic health record data during visits from 2005 to 2019.

RESULTS

The mean (SD, range) age of the sample was 34.53 (25.47, 0-102) years, with 48.7 % being men. We divided the whole population in four groups based on the season they were born (SOB-groups). When observing these four SOB-groups, the proportion of those having asthma was 43.1%, 42.1%, 41.1%, 42.7%, in winter, spring, summer, and autumn SOB-groups, respectively. The proportion of those having AR was 12.6%, 12.0%, 10.7%, 12.1%, respectively. When having summer as a reference, being born in any other time of year was significantly associated with AR and, being born in autumn or winter was associated with asthma. No significant association was observed in CRS or N-ERD or NAR groups in adjusted models.

CONCLUSIONS

The study suggests that early life immunological events may have a role a role in pathogenesis of asthma and AR. As no association was observed between SOB and CRSsNP, CRSwNP, N-ERD or NAR, further studies on this are warranted.

Being overweight and born in the spring are associated with an increased risk for rhinitis

AIM

To explore the relationship between the season of birth and the prevalence of recurrent or chronic rhinitis (rhinitis).

METHODS

The medical records of consecutive 17-year-old conscripts to the Israeli army were reviewed. We compared the prevalence of rhinitis between children born during different seasons. Multivariate analysis was performed with additional variables.

RESULTS

The prevalence of rhinitis among the 1.1 million recruits was 7.1% in males and 5.3% in females. The association between birth season and the prevalence of rhinitis was highly significant (p < 0.001 for both genders). Spring was the birth season with the highest prevalence of rhinitis (7.4% in males and 5.5% in females). Males born in the winter and females born in the autumn had the lowest prevalence of rhinitis (6.7%, and 5.2% respectively). There was an increased odds ratio for rhinitis among those with a body mass index above 25, higher cognitive score and maternal birth country out of Israel or Africa.

CONCLUSIONS

There was an increased risk of rhinitis among young Israeli adults who were born in the spring, were overweight and had a higher cognitive-score. Family planning to avoid a spring birth and preventing overweight may reduce the risk of chronic rhinitis.

Hosts, microbiomes, and the evolution of critical windows

The absence of microbial exposure early in life leaves individuals vulnerable to immune overreaction later in life, manifesting as immunopathology, autoimmunity, or allergies. A key factor is thought to be a "critical window" during which the host's immune system can "learn" tolerance, and beyond which learning is no longer possible. Animal models indicate that many mechanisms have evolved to enable critical windows, and that their time limits are distinct and consistent. Such a variety of mechanisms, and precision in their manifestation suggest the outcome of strong evolutionary selection. To strengthen our understanding of critical windows, we explore their underlying evolutionary ecology using models encompassing demographic and epidemiological transitions, identifying the length of the critical window that would maximize fitness in different environments. We characterize how direct effects of microbes on host mortality, but also indirect effects via microbial ecology, will drive the optimal length of the critical window. We find that indirect effects such as magnitude of transmission, duration of infection, rates of reinfection, vertical transmission, host demography, and seasonality in transmission all have the effect of redistributing the timing and/or likelihood of encounters with microbial taxa across age, and thus increasing or decreasing the optimal length of the critical window. Declining microbial population abundance and diversity are predicted to result in increases in immune dysfunction later in life. We also make predictions for the length of the critical window across different taxa and environments. Overall, our modeling efforts demonstrate how critical windows will be impacted over evolution as a function of both host-microbiome/pathogen interactions and dispersal, raising central questions about potential mismatches between these evolved systems and the current loss of microbial diversity and/or increases in infectious disease.

Pollen allergy: Developing multi-sectorial strategies for its prevention and control in lower and middle-income countries

Pollen allergy is considered a major public health problem that causes morbidity and subsequently affects a patient's quality of life. Pollen due to their large size cannot enter the thoracic regions of the respiratory tract but can affect the nasopharyngeal mucous membrane. At the same time, the submicronic-pollen particles can act as respirable particles reaching deeper into the upper airways leading to exacerbation of asthma, chronic obstructive pulmonary disease (COPD) and other allergic reactions. Based on the existing literature, expanding evidence shows that climate change and air pollutants could affect the pollen number, morphology, season, allergen content, and distribution pattern. Hence, this will influence the prevalence and occurrence of allergies linked to pollen exposure. Being a part of biogenic pollutants, pollen allergens are not expected to diminish in the foreseeable future. Therefore, it is imperative that steps need to be strengthened to improve and optimize preventive/adaptive strategies. This paper aims to review the major causes of widespread allergy, identify the major gaps, and suggest key preventive/adaptive measures to address the onset and exacerbation of pollen-related allergic diseases with a major focus on lower and middle-income countries. The study also discusses how-to implement the prevention and control measures at the individual, health care communities and organizations, Local Governments, National/International Governments levels to decrease the risk of illnesses associated with pollen allergy.

Turkish Guideline for Diagnosis and Treatment of Allergic Rhinitis (ART)

OBJECT

To prepare a national guideline for Otorhinolaryngologist who treat allergic rhinitis patients.

METHODS

The study was conducted by three authors, namely the writing support team. The support team made the study plan, determined the writing instructions, chose the subgroups including the advisory committee, the advisors for authors and the authors. A workshop was organized at the very beginning to explain the details of the study to the team. Advisors took the chance to meet their coworkers in their subgroups and determined the main headings and subheadings of the guideline, together with the authors. After key words were determined by the authors, literature search was done in various databases. The authors keep in touch with the advisors and the advisors with the advisory committee and the support group at every stage of the study. National and International published articles as well as the abstracts of unpublished studies, imperatively presented in National Congresses, were included in this guideline. Only Guideline and meta-analyses published in last seven years (2013-2017) and randomized controlled studies published in last two years (2015-2017) were included. After all work was completed by the subgroups, support team brought all work together and edited the article.

RESULTS

A detailed guideline about all aspects of allergic rhinitis was created.

CONCLUSION

The authors believe that this guideline will enable a compact and up-to-date information on allergic rhinitis to healthcare professionals. This guideline is the first in the field of Otolaryngology in Turkey. It should be updated at regular intervals.

Inflammatory Bowel Diseases: Review of Known Environmental Protective and Risk Factors Involved

Inflammatory bowel diseases consisting of Crohn's disease and ulcerative colitis are chronic inflammatory diseases of the gastrointestinal tract. In addition to genetic susceptibility and disturbances of the microbiome, environmental exposures forming the exposome play an important role. Starting at birth, the cumulative effect of different environmental exposures combined with a predetermined genetic susceptibility is thought to cause inflammatory bowel disease. All these environmental factors are part of a Western lifestyle, suiting the high incidence rates in Europe and the United States. Whereas receiving breastfeeding, evidence of a Helicobacter pylori infection and vitamin D are important protective factors in Crohn's disease as well as ulcerative colitis, increased hygiene, experiencing a bacterial gastroenteritis in the past, urban living surroundings, air pollution, the use of antibiotics, nonsteroidal anti-inflammatory drugs, and oral contraceptives are likely to be the most important risk factors for both diseases. Current cigarette smoking yields a divergent effect by protecting against ulcerative colitis but increasing risk of Crohn's disease, whereas former smoking increases chances of both diseases. This review gives a clear overview of the current state of knowledge concerning the exposome. Future studies should focus on measuring this exposome yielding the possibility of combining all involved factors to one exposome risk score and our knowledge on genetic susceptibility.

Association of season of birth with DNA methylation and allergic disease

BACKGROUND

Season of birth influences allergy risk; however, the biological mechanisms underlying this observation are unclear. The environment affects DNA methylation, with potentially long-lasting effects on gene expression and disease. This study examined whether DNA methylation could underlie the association between season of birth and allergy.

METHODS

In a subset of 18-year-old participants from the Isle of Wight (IoW) birth cohort (n = 367), the risks of birth season on allergic outcomes were estimated. Whole blood epigenome-wide DNA methylation was measured, and season-associated CpGs detected using a training-and-testing-based technique. Validation method examined the 8-year-old Prevention and Incidence of Asthma and Mite Allergy (PIAMA) cohort. The relationships between DNA methylation, season of birth and allergy were examined. CpGs were analysed in IoW third-generation cohort newborns.

RESULTS

Autumn birth increased risk of eczema, relative to spring birth. Methylation at 92 CpGs showed association with season of birth in the epigenome-wide association study. In validation, significantly more CpGs had the same directionality than expected by chance, and four were statistically significant. Season-associated methylation was enriched among networks relating to development, the cell cycle and apoptosis. Twenty CpGs were nominally associated with allergic outcomes. Two CpGs were marginally on the causal pathway to allergy. Season-associated methylation was largely absent in newborns, suggesting it arises post-natally.

CONCLUSIONS

This study demonstrates that DNA methylation in adulthood is associated with season of birth, supporting the hypothesis that DNA methylation could mechanistically underlie the effect of season of birth on allergy, although other mechanisms are also likely to be involved.

Spring season birth is associated with higher emergency department admission for acute allergic reactions

BACKGROUND

Acute allergic reactions are important causes of emergency department (ED) admission, imposing a significant clinical and organizational burden. Since the season of birth is linked with early exposure to allergens, this study was aimed to establish whether an association exists between season of birth and incidence and severity of acute allergic reactions in the ED.

METHODS

The electronic hospital database was searched to identify all consecutive adult patients who were admitted to the ED for acute allergic reactions (acute urticaria, acute angioedema, urticaria-angioedema and anaphylaxis) during a 1-year period.

RESULTS

The final study population consisted in 588 patients (328 women and 260 men; mean age 43 ± 18 years, range 16-96 years). Increased frequency of ED admission was observed for patients born in spring, whereas the lowest frequency was found for those born in autumn. Patients born in spring exhibited 1.19 and 1.12 higher risk of ED admission for acute allergic reactions compared to those born in autumn and in all other seasons, respectively. This difference remained significant in patients with allergic reaction attributable to drugs and in those with unknown triggers, whereas no pattern of seasonality was observed in patients with allergic reactions attributable to aliments, hymenoptera, chemicals or inhalants. Patients born in spring also exhibited 1.86 and 1.52 higher risk of being admitted to the ED for severe acute allergic reactions compared to those born in autumn and in all other seasons, respectively.

CONCLUSIONS

Patients born in spring appear particularly vulnerable to allergic reactions requiring ED visit.

Fractional exhaled nitric oxide (FeNO) among office workers in an academic institution, Malaysia--associations with asthma, allergies and office environment

OBJECTIVE

There are few studies on fractional exhaled nitric oxide (FeNO) and respiratory symptoms among adults in tropical areas. The aim was to study associations between FeNO and selected personal factors, respiratory symptoms, allergies, office characteristics and indoor office exposures among office workers (n = 460) from a university in Malaysia.

METHODS

Information on health was collected by a questionnaire, skin prick test and FeNO measurement. Temperature, relative air humidity, carbon monoxide and carbon dioxide were measured in the offices. Settled dust was vacuumed in the offices and analyzed for endotoxin, (1,3)-β-glucan and house dust mites allergens, namely Dermatophagoides pteronyssinus (Der p 1) and Dermatophagoides farinae (Der f 1). Two-level linear mixed models and multiple logistic regression were used to analyze the associations.

RESULTS

One-fourth (25.9%) of the office workers had elevated FeNO level (≥ 25 ppb) and 61.5% had HDM, cat, seafood or pollen allergy. Male gender (p < 0.001), current smoking (p = 0.037), height (p < 0.001) and atopy (p < 0.001) were associated with FeNO. The amount of vacuumed dust was associated with FeNO among atopic subjects (p = 0.009). Asthma and rhinitis symptoms were associated with FeNO (p < 0.05), especially among atopic subjects. In particular, a combination of atopy and elevated FeNO were associated with doctor-diagnosed asthma (p < 0.001), rhinitis (p < 0.001) and airway symptoms last 12 months (p < 0.001).

CONCLUSION

Gender, smoking, height and atopy are important risk factors for elevated FeNO levels. A combination of allergy testing and FeNO measurement could be useful in respiratory illness epidemiology studies and patient investigations in tropical areas.

Food allergy diagnosis and therapy: where are we now?

Food allergy is a growing worldwide epidemic that adversely effects up to 10% of the population. Causes and risk factors remain unclear and diagnostic methods are imprecise. There is currently no accepted treatment for food allergy. Therefore, there is an imminent need for greater understanding of food allergies, revised diagnostics and development of safe, effective therapies. Oral immunotherapy provides a particularly promising avenue, but is still highly experimental and not ready for clinical use.

The influence of sun exposure in childhood and adolescence on atopic disease at adolescence

BACKGROUND

It has been postulated that ultraviolet ray exposure in childhood might influence the development of allergic disease. We examined whether reported sun exposure during childhood or in adolescence is related to the occurrence of atopy or allergic disease.

METHODS

Population-based longitudinal cohort study with sixteen-year follow-up (N = 415). Subjects were recruited at birth as part of an infant health study. The reported daily duration of sun exposure in the summer months was recorded at 8 and 16 yrs of age. Allergen sensitization and the presence of eczema, asthma, and rye grass positive rhinitis were recorded at age 16.

RESULTS

Reported sun exposures of more than 4 h per day during summer holidays in adolescence were associated with reduced eczema and rhinitis but not inhalant allergen sensitization or asthma risk. Thus, higher sun exposure during summer holidays and summer weekends in adolescence was associated with significantly reduced eczema (test of trend p-value = 0.001 summer holidays; test of trend p-value = 0.003 summer weekends) and rye grass positive rhinitis (test of trend p-value = 0.03 summer holidays; test of trend p-value = 0.02 summer weekends). Sun exposure at adolescence or age 8 was not related to inhalant allergen sensitization. There was no association between serum 25(OH)D levels at adolescence with either inhalant allergen sensitization or allergic disease and adjustment for serum 25(OH)D levels did not alter these findings.

CONCLUSIONS

Increased sun exposure during summer holidays in adolescence was associated with reduced eczema and rhinitis risk, independently of measured vitamin D levels but no difference in inhalant allergen sensitization or asthma. The beneficial effects of sun exposure on allergic disease may operate independently from vitamin D or an effect on allergen sensitization.

Within-mother analysis of seasonal patterns in health at birth

A large literature describes relationships between month of birth, birth weight, and gestation. These relationships are hypothesized to reflect the causal impact of seasonal environmental factors. However, recent work casts doubt on this interpretation by showing that mothers with lower socioeconomic status are more likely to give birth in months that are associated with poorer birth outcomes. Seasonality in the numbers of conceptions in different months can also induce a mechanical correlation between preterm birth and month of birth. This paper analyzes the seasonality of health at birth using a large sample of 647,050 groups of US siblings representing 1,435,213 children. By following the same mother over time, we eliminate differences in fixed maternal characteristics as an explanation for seasonal differences in health at birth. We find a sharp trough in gestation length among babies conceived in May, which corresponds to an increase in prematurity of more than 10%. Birth weight conditional on gestation length, however, is found to be strongly hump-shaped over the year, with 8-9 additional g for summer conceptions. We examine several potential mechanisms for explaining seasonality in birth outcomes that have generally been dismissed in the literature on seasonality in rich countries, notably disease prevalence and nutrition. The May trough in gestation length coincides with a higher influenza prevalence in January and February, when these babies are nearing full term, whereas the hump shape in birth weight is associated with a similar pattern in pregnancy weight gain.

Can temperature explain the latitudinal gradient of ulcerative colitis? Cohort of Norway

Background

Incidence and prevalence of ulcerative colitis follow a north–south (latitudinal) gradient and increases northwards at the northern hemisphere or southwards at the southern hemisphere. The disease has increased during the last decades. The temporal trend has been explained by the hygiene hypothesis, but few parallel explanations exist for the spatial variability. Many factors are linked to latitude such as climate. Our purpose was to investigate the association between variables governing the climate and prospectively identified patients.

Methods

In this study, we used a subset of the population-based Cohort of Norway (n = 80412) where 370 prevalent cases of ulcerative colitis were identified through self-reported medication. The meteorological and climatic variables temperature, precipitation, and altitude were recorded from weather stations of the Norwegian Meteorological Institute. Summer temperature was used to capture environmental temperature.

Results

Summer temperature was significantly related to the prevalence of ulcerative colitis. For each one-degree increase in temperature the odds for ulcerative colitis decreased with about 9% (95% CI: 3%-15%). None of the other climatic factors were significantly associated to the risk of ulcerative colitis. Contextual variables did not change the association to the prevalence of ulcerative colitis.

Conclusions

The present results show that the prevalence of ulcerative colitis is associated to summer temperature. Our speculation is that summer temperature works as an instrumental variable for the effect of microbial species richness on the development of ulcerative colitis. Environmental temperature is one of the main forces governing microbial species richness and the microbial composition of the commensal gut flora is known to be an important part in the process leading to ulcerative colitis.

The relationship of season of birth to asthma and allergy in urban African American children from 10 to 13 years of age

OBJECTIVES

To assess the relationship between season of birth and presence of asthma and allergy in preteen, low-income, African American children.

METHODS

The study consisted of a self-administered survey followed by telephone interviews of parents of children attending 19 middle schools in Detroit, Michigan. Out of 4194 children, 1292 were identified with asthma and 962 parents of these children provided informed consent and took part in telephone interviews.

RESULTS

No statistically significant relationships were observed between season of birth and diagnosis of asthma (p > .05) or with diagnosis adjusting for income, age, gender, parent's education, or parent being a smoker (p > .05). No statistically significant association was evident between season of birth and presence of allergy (p > .05) or with allergy adjusting for the above variables (p > .05).

CONCLUSIONS

Identifying children vulnerable to problems with asthma and allergy, especially in populations exhibiting high prevalence of the conditions and significant disparities in outcomes, requires use of all possible means. Season of birth does not appear to be a useful indicator in identification of such children. The findings from this study do not support the proposition that season of birth, associated with early exposure to viruses as evident in the winter and to seasonal allergens, contributes to more asthma and/or allergy.

Association between latitude and allergic diseases: a longitudinal study from childhood to middle-age

BACKGROUND

Worldwide variations in allergy prevalence suggest that geographic factors may contribute to asthma. Ecologic studies have suggested that latitude, a marker of UV-B exposure and allergen exposures, may be related to clinical allergies.

OBJECTIVE

To examine the relationship between latitude or UV-B based on self-reported geolocation and allergic sensitization and disease prevalence in Australia.

METHODS

The Tasmanian Longitudinal Health Study is a population-based study of respiratory disease spanning childhood to adulthood. The most recent follow-up included a postal survey of 5,729 participants and a clinical substudy of 1,396 participants. Participants' residential addresses were coded for latitude and linked with the UV-B data from satellite-based observations of atmospheric ozone. Multivariable logistic regression analyses were performed to estimate the associations between latitude or UV-B and allergic diseases.

RESULTS

Most northerly latitude, that is, latitude closest to the Equator, and high current UV-B exposure were associated with increased odds of hay fever, food allergy, and skin sensitization to house dust mites and molds. More northerly latitude and higher UV-B exposure were associated with increased odds of current asthma among atopic individuals contrasting with a reduced odds of current asthma among nonatopic individuals.

CONCLUSION

This is the first study, to our knowledge, to demonstrate a differential effect of atopic status on the relationship between latitude and current asthma. Our study demonstrates in a genetically and culturally similar group of individuals that geographic factors may a play role in the development of allergic disease.

Latitude, sunlight, vitamin D, and childhood food allergy/anaphylaxis

Vitamin D is widely known for its role in bone metabolism, but this sterol hormone also has important immunomodulatory properties. Vitamin D is produced by the conversion of D3 in the skin following UVB exposure, or after ingestion of D2 or D3. At the extremes of latitude, there is insufficient UVB intensity in the autumn and winter months for adequate synthesis of vitamin D to occur. Growing evidence implicates vitamin D deficiency in early life in the pathogenesis of nonskeletal disorders (e. g., type 1 diabetes and multiple sclerosis) and, more recently, atopic disorders. Several studies have reported higher rates of food allergy/anaphylaxis or proxy measures at higher absolute latitudes. Although causality remains to be determined, these studies suggest a possible role for sunlight and/or vitamin D in the pathogenesis of food allergy/anaphylaxis.

Early life precursors, epigenetics, and the development of food allergy

Food allergy (FA), a major clinical and public health concern worldwide, is caused by a complex interplay of environmental exposures, genetic variants, gene-environment interactions, and epigenetic alterations. This review summarizes recent advances surrounding these key factors, with a particular focus on the potential role of epigenetics in the development of FA. Epidemiologic studies have reported a number of nongenetic factors that may influence the risk of FA, such as timing of food introduction and feeding pattern, diet/nutrition, exposure to environmental tobacco smoking, prematurity and low birth weight, microbial exposure, and race/ethnicity. Current studies on the genetics of FA are mainly conducted using candidate gene approaches, which have linked more than 10 genes to the genetic susceptibility of FA. Studies on gene-environment interactions of FA are very limited. Epigenetic alteration has been proposed as one of the mechanisms to mediate the influence of early life environmental exposures and gene-environment interactions on the development of diseases later in life. The role of epigenetics in the regulation of the immune system and the epigenetic effects of some FA-associated environmental exposures are discussed in this review. There is a particular lack of large-scale prospective birth cohort studies that simultaneously assess the interrelationships of early life exposures, genetic susceptibility, epigenomic alterations, and the development of FA. The identification of these key factors and their independent and joint contributions to FA will allow us to gain important insight into the biological mechanisms by which environmental exposures and genetic susceptibility affect the risk of FA and will provide essential information to develop more effective new paradigms in the diagnosis, prevention, and management of FA.

Season of birth and childhood food allergy in Australia

BACKGROUND

Recent studies suggest a possible role for low ultraviolet radiation exposure and low vitamin D status as a risk factor for food allergy. We hypothesized that children born in autumn/winter months (less sun exposure) might have higher food allergy rates than those born in spring/summer.

METHODS

We compared IgE-mediated food allergy rates by season of birth in 835 children aged 0-4 yr assessed 1995-2009 in a specialist referral clinic, using population births as controls. To address potential concerns about generalizability, we also examined national prescriptions for adrenaline autoinjectors (2007) and infant hypoallergenic formula (2006-2007).

RESULTS

Although live births in the general ACT population showed no seasonal pattern (50% autumn/winter vs. 50% spring/summer), autumn/winter births were more common than spring/summer births among food allergy patients (57% vs. 43%; p < 0.001). The same seasonal pattern was observed with peanut (60% vs. 40%; p < 0.001) and egg (58% vs. 42%; p = 0.003). Regional UVR intensity was correlated with relative rate of overall food allergy (β, -1.83; p = 0.05) and peanut allergy (β, -3.27; p = 0.01). National data showed that autumn/winter births also were more common among children prescribed EpiPens (54% vs. 46%; p < 0.001) and infant hypoallergenic formula (54% vs. 46%; p < 0.001).

CONCLUSIONS

The significantly higher rates of food allergy in children born autumn/winter (compared to spring/summer), the relationship between relative food allergy rates and monthly UVR, combined with national adrenaline autoinjector and infant hypoallergenic formula prescription data, suggest that ultraviolet light exposure/vitamin D status may be one of many potential factors contributing to childhood food allergy pathogenesis.

The role of latitude, ultraviolet radiation exposure and vitamin D in childhood asthma and hayfever: an Australian multicenter study

Observations of increasing allergy prevalence with decreasing distance from the Equator and positive associations with ambient ultraviolet radiation have contributed to a growing interest in the possible role of vitamin D in the etiology of allergy. The aims of this study were to describe any latitudinal variation in the prevalence of childhood allergy in Australia and to evaluate, in parallel, the individual associations between ultraviolet radiation (UVR)- and vitamin D-related measures and hayfever asthma and both conditions. Participants were population-based controls who took part in a multicenter case-control study, aged 18-61 yr and resident in one of four study regions ranging in latitude from 27°S to 43°S. Data were derived from a self-administered questionnaire, interview and examination by a research officer and biologic sampling. Latitude and longitude coordinates were geocoded from participants' residential locations and climatic data were linked to postcodes of current residence. Stored serum was analyzed for 25-hydroxyvitamin D concentrations and silicone rubber casts of the skin were used as an objective measure of cumulative actinic damage. There was an inverse latitude gradient for asthma (a 9% decrease per increasing degree of latitude); however, this pattern did not persist after adjusting for average daily temperature. There was no association between any of the UVR- or vitamin D-related measures and childhood asthma, but greater time in the sun in winter between the ages 6-15 yr was associated with an increase in the odds of having hayfever [adjusted odds ratios (OR) 1.29; 95% CI 1.01-1.63]. Oral supplementation with cod liver oil in childhood increased the odds of a history of having both asthma and hayfever (2.87; 1.00-8.32). Further investigation of the possible role of early vitamin D supplementation in the development of allergy is warranted. Our results also suggest that solar exposure during childhood may be important in allergic sensitization. Plausible explanations, including biologic mechanisms, exist for both observations.

Epidemiology of allergy

Atopic disease represents a spectrum of disorders characterized by abnormal sensitivity mediated by IgE; approximately 20% of Americans suffer from some form of allergic disease. The sequelae of inhalant and food allergies may present in many organ systems. Manifestations of allergic disease in one site are often associated with symptoms from another site. It is important for clinicians to understand the epidemiology of atopic disease and its causes to facilitate implementation of effective treatment and prevention strategies. This review focuses on the epidemiology of inhalant allergies causing allergic rhinitis and asthma and on IgE-mediated food allergies.

Projections of the effects of climate change on allergic asthma: the contribution of aerobiology

Climate change is unequivocal and represents a possible threat for patients affected by allergic conditions. It has already had an impact on living organisms, including plants and fungi with current scenarios projecting further effects by the end of the century. Over the last three decades, studies have shown changes in production, dispersion and allergen content of pollen and spores, which may be region- and species-specific. In addition, these changes may have been influenced by urban air pollutants interacting directly with pollen. Data suggest an increasing effect of aeroallergens on allergic patients over this period, which may also imply a greater likelihood of the development of an allergic respiratory disease in sensitized subjects and exacerbation of symptomatic patients. There are a number of limitations that make predictions uncertain, and further and specifically designed studies are needed to clarify current effects and future scenarios. We recommend: More stress on pollen/spore exposure in the diagnosis and treatment guidelines of respiratory and allergic diseases; collection of aerobiological data in a structured way at the European level; creation, promotion and support of multidisciplinary research teams in this area; lobbying the European Union and other funders to finance this research.

What has the ECRHS told us about the childhood risks of asthma, allergy and lung function?

Few studies investigate how environmental factors in childhood may influence adult respiratory health. The European Community Respiratory Health Survey (ECRHS) is a longitudinal multi-centre study of Western world adults, including retrospective assessment of early life factors. Analyses of the ECRHS showed both beneficial and harmful long-term effects of childhood factors on adult asthma, allergy and lung function. Childhood pets were associated with less adult atopy and hay fever; beneficial effects were also indicated for growing up on a farm and for early exposure to other children. The findings have contributed to further development of the hygiene hypothesis and further understanding of the mechanisms relating microbial stimulation to allergy; however, the public health consequences may be limited. Harmful effects of early life factors on adult asthma and lung function were indicated for severe respiratory infections early in life, parental smoking and long-term dog keeping. Intervention with regard to parental smoking and vaccination against common lower airways infections may improve respiratory health in the population. Thus, early life environment had permanent beneficial and adverse effects on adult respiratory health. The multi-centre structure of the ECRHS, the large sample size, the extensive information about each participant and follow-up until the age of 56 years, have given the basis for convincing conclusions, and made possible publication of unsuspected findings in spite of the problems related to adult recall of childhood events. The ECRHS have contributed substantially to increased knowledge about the early life origins of allergy and obstructive pulmonary disease, providing a basis for prevention.

Geo-climate effects on asthma and allergic diseases in adults in Turkey: results of PARFAIT study

The aim of the study was to evaluate the role of geo-climatic factors on the prevalence of allergic diseases in the adult population in Turkey. A total of 25,843 questionnaires using data from parents of 25,843 primary schoolchildren from 14 cities were evaluated. Mean annual temperature was significantly associated with the prevalence of asthma and wheezing in both sexes [respectively; OR: 1.008 (95% CI: 1.003-1.011) and OR: 1.012 (1.006-1.018 in males), OR: 1.007 (1.003-1.012) and OR: 1.01 (1.002-1.018) in females]. In addition, it was associated with eczema in females [OR: 1.007 (1.001-1.012)]. Asthma in females was associated with mean annual humidity in the air [OR: 1.001 (1.000-1.002)]. Annual number of days with snow is associated with wheezing in both sexes [respectively, OR: 1.001 (1.000-1.002) in males and OR: 1.002 (1.000-1.003) in females]. Protective measures could come into priority in certain areas of the country. Allergic diseases may increase as a cause of climate change in the future.

Regional variation in epinephrine autoinjector prescriptions in Australia: more evidence for the vitamin D-anaphylaxis hypothesis

BACKGROUND

There is little information on the regional distribution of anaphylaxis in Australia.

OBJECTIVE

To examine the influence of latitude (a marker of sunlight/vitamin D status) as a contributor to anaphylaxis in Australia, with a focus on children from birth to the age of 4 years.

METHODS

Epinephrine autoinjector (EpiPen) prescriptions (2006-2007) in 59 statistical divisions and anaphylaxis hospital admission rates (2002-2007) in 10 regions were used as surrogate markers of anaphylaxis.

RESULTS

EpiPen prescription rates (per 100,000 population per year) were higher in children from birth to the age of 4 years (mean, 951) than in the overall population (mean, 324). In an unadjusted model of children from birth to the age of 4 years, decreasing absolute latitude was associated with a decrease in EpiPen prescription rates, such that rates were higher in southern compared with northern regions of Australia (beta, -44.4; 95% confidence interval, -57.0 to -31.8; P < .001). Adjusting for age, sex, ethnicity, indexes of affluence, education, or access to medical care (general, specialist allergy, or pediatric) did not attenuate the finding (beta, -51.9; 95% confidence interval, -71.0 to -32.9; P < .001). Although statistical power was limited, anaphylaxis admission rates (most prominent in children aged 0-4 years) showed a similar south-north gradient, such that admission rates were higher in southern compared with northern regions of Australia.

CONCLUSIONS

EpiPen prescription rates and anaphylaxis admissions are more common in southern regions of Australia. These data provide additional support for a possible role of vitamin D in the pathogenesis of anaphylaxis.

Introduction of oral vitamin D supplementation and the rise of the allergy pandemic

The history of the allergy pandemic is well documented, enabling us to put the vitamin D hypothesis into its historical context. The purpose of this study is to compare the prevalence of rickets, vitamin D supply, and allergy prevalence at 50-year intervals by means of a retrospective analysis of the literature since 1880. English cities in 1880 were characterized by an extremely high rickets prevalence, the beginning of commercial cod liver oil production, and the near absence of any allergic diseases. By 1930 hay fever prevalence had risen to about 3% in English-speaking countries where cod liver oil was preferentially used for the treatment of rickets. In 1980 vitamin D was used nation-wide in all industrialized countries as supplement to industrial baby food, thus eradicating nearly all cases of rickets. At the same time the allergy prevalence reached an all-time high, affecting about 30% of the population. Time trends are therefore compatible with the vitamin D hypothesis although direct conclusions cannot be drawn. It is interesting, however, to note that there are at least two earlier research papers linking synthesized vitamin D intake and allergy (Reed 1930 and Selye 1962) published prior to the modern vitamin D hypothesis first proposed in 1999.

Inverse relationship between multiple sclerosis and allergic respiratory diseases

Th1 up-regulation seems to favour autoimmunity, while Th2 up-regulation seems to favour humoral immunity. Accordingly, subjects affected by atopic diseases (such as allergic respiratory diseases, ARDs) should be less prone to autoimmune diseases (such as multiple sclerosis, MS), and vice versa. The recent identification of Th17 cells, which seem to favour the development of both autoimmunity and allergy, led to the revision of the classic Th1/Th2 paradigm. We studied 200 MS patients and 200 controls to analyze the relationships between ARDs and MS. MS patients had less probability to suffer from ARDs (OR = 0.30, p < 0.001) and allergic rhinitis (OR = 0.25, p < 0.001), after adjusting for environmental factors. MS tended to be less severe when associated to ARDs. Our findings add some elements for the comprehension of immune mechanisms involved in MS pathogenesis and suggest to analyze other MS cohorts, in order to evaluate if MS patients affected by allergic diseases show particular clinical findings.

Fungi and pollen exposure in the first months of life and risk of early childhood wheezing

BACKGROUND

Many studies have found that the risk of childhood asthma varies by month of birth, but few have examined ambient aeroallergens as an explanatory factor. A study was undertaken to examine whether birth during seasons of elevated ambient fungal spore or pollen concentrations is associated with risk of early wheezing or blood levels of Th1 and Th2 type cells at 24 months of age.

METHODS

514 children were enrolled before birth and followed to 24 months of age. Early wheezing was determined from medical records, and Th1 and Th2 type cells were measured in peripheral blood using flow cytometry. Ambient aeroallergen concentrations were measured throughout the study period and discrete seasons of high spore and pollen concentrations were defined.

RESULTS

A seasonal pattern was observed, with birth in autumn to winter (the spore season) associated with increased odds of early wheezing (adjusted odds ratio 3.1; 95% confidence interval 1.3 to 7.4). Increasing mean daily concentrations of basidiospores and ascospores in the first 3 months of life were associated with increased odds of wheeze, as were increasing mean daily concentrations of total and specific pollen types. Levels of Th1 cells at age 24 months were positively associated with mean spore concentrations and negatively associated with mean pollen concentrations in the first 3 months of life.

CONCLUSIONS

Children with higher exposure to spores and pollen in the first 3 months of life are at increased risk of early wheezing. This association is independent of other seasonal factors including ambient levels of particulate matter of aerodynamic diameter <or=2.5 microm and lower respiratory infections.

[The effects of season at time of birth on asthma and pneumonia in childhood and adulthood in a birth cohort in southern Brazil]

This study evaluated the effects of seasonal weather at time of birth and ambient temperature during the first six months of life on hospitalizations due to asthma and pneumonia in preschool children and on diagnosis of asthma in adulthood among individuals from the 1982 birth cohort in Pelotas, Rio Grande do Sul, Brazil. The cohort included 5,914 live births, of which 77% were followed up until adulthood (23-24 yr). The risk of hospitalization due to pneumonia and asthma among children born from April to June (autumn) was 1.31 (95%CI: 0.99-1.73) to 2.4 (95%CI: 1.11-4.99) times higher than that of children born from January to March (summer). For temperature in the first six months of life, risk of hospitalization was 1.64 (95%CI: 1.26-2.13) to 3.16 (95%CI: 1.63-6.12) times higher for children born in the coldest as compared to the hottest temperature tertile. The effects of seasonality decreased with age, and the association with asthma in adulthood was weak. Hospitalizations in poor children were more frequent, but the effects of seasonality on pneumonia were more evident among the wealthiest.

The prevalence of preterm birth and season of conception

Preterm birth is a major obstetric problem. An exploration of the season of conception in relation to preterm birth may provide direction in the search for risk factors. We conducted a retrospective cohort study of 82 213 singleton livebirths (20-45 weeks' gestation) to 61,630 women at Magee-Womens Hospital, Pittsburgh, PA, from 1995 to 2005. Conception was estimated based on gestational age determined by best obstetric estimate. Fourier series analysis was used to model seasonal trends. Spontaneous preterm birth at <37 weeks was associated with conception season (P < 0.05). The peak prevalence occurred among conceptions in winter and spring (peaking February 23 at 6.9%), with an average trough among late summer/early autumn conceptions (August 25 at 6.2%). The pattern for spontaneous preterm birth <32 weeks was similar (P < 0.05), with the peak on March 13 (1.7%), and nadir on September 12 (1.4%). Results were similar when indicated preterm births were included. These seasonal changes may increase our insight into the role of exposures with seasonal periodicity in the pathophysiology of preterm birth.

On the role of breastfeeding in health promotion and the prevention of allergic diseases

Based on animal models, we specify the major role of different bioactive milk components known to participate significantly in neonatal health promotion and in protection against a large number of infectious diseases and the development of allergies and asthma.

Body height differentiation by season of birth: Girls from Cracow, Poland

Published studies world wide demonstrate that measures of human development and health status vary depending on the month of birth but these patterns are not always consistent and sometimes even conflict. Direct factors related to the birth season that may significantly differentiate morphological and functional traits and mechanisms causing these relations have not been found so far. On the basis of cross-sectional material, gathered in the years 1983 and 2000 by the Department of Anthropology of the Academy of Physical Education in Cracow, two main hypotheses have been verified: (1) average body height differences by month of birth are statistically insignificant, (2) the magnitude of these differences does not change with time. Metric data of 4672 girls aged 5-18 years, born in 1965-1978 and 1982-1995, were used. The total sample was also subdivided into prepubertal (5-9 years) and adolescent (10-18 years) groups. The age of the individuals was calculated to the nearest day and the procedure of standardization on the interpolated values of regional norms was applied. A highly significant relationship between the birth month and average values of height was revealed in preadolescent girls. The results obtained for the entire material proved insignificant. The patterns of the month-of-birth effect on body height for girls born in 60./70. and 80./90. show high similarity, though the effect seems weaker in the latter sample. Winter proved to be the most favorable birth season for later body height.

Clinical characteristics of peanut-allergic children: recent changes

OBJECTIVE

The goal was to determine whether patients seen in a referral clinic are experiencing initial allergic reactions to peanuts earlier, compared with a similar population profiled at a different medical center 10 years ago, and to investigate other changes in clinical characteristics of the patients between the 2 groups.

METHODS

We reviewed the medical charts of peanut-allergic patients seen in the Duke University pediatric allergy and immunology clinic between July 2000 and April 2006.

RESULTS

The median ages of first peanut exposure and reaction were 14 and 18 months, respectively; the respective ages in a similar population profiled between 1995 and 1997 were 22 and 24 months. Within our patient group, those born before 2000 were first exposed to peanuts at a median age of 19 months and reacted at a median age of 21 months, compared with first exposure at 12 months and first reaction at 14 months for those born in or after 2000. Most patients (68%) demonstrated sensitization or clinical allergy to other foods (53% to eggs, 26% to cow's milk, 20% to tree nuts, 11% to fish, 9% to shellfish, 7% to soy, 6% to wheat, and 6% to sesame seeds).

CONCLUSIONS

In the past decade, the ages of first peanut exposure and reaction have declined among peanut-allergic children seen in a referral clinic. Egg allergy is very common in peanut-allergic patients, and sesame seeds should perhaps be considered one of the major food allergens. The decline in the age of first peanut reaction seems to be attributable to earlier exposure.

Fluticasone furoate nasal spray: a single treatment option for the symptoms of seasonal allergic rhinitis

BACKGROUND

Fluticasone furoate (USAN-approved name) is a novel, enhanced-affinity glucocorticoid administered in a unique side-actuated device for the management of seasonal allergic rhinitis (SAR).

OBJECTIVE

We sought to evaluate the efficacy and safety of once-daily fluticasone furoate nasal spray, 110 microg, in patients aged 12 years or older with fall SAR.

METHODS

Patients (n = 299) received fluticasone furoate or placebo for 2 weeks in this double-blind, parallel-group randomized study. Patients evaluated nasal and ocular symptoms using a 4-point categoric scale. Efficacy was assessed on the basis of the mean change from baseline in reflective and instantaneous total nasal symptom scores and reflective total ocular symptom scores.

RESULTS

Fluticasone furoate produced significantly greater improvements than placebo in daily reflective total nasal symptom score (-1.473, P < .001; primary end point), morning predose instantaneous total nasal symptom score (-1.375, P < .001), daily reflective total ocular symptom score (-0.600, P = .004), and patient-rated overall response to therapy (P < .001). The onset of therapeutic effect occurred at 8 hours after initial administration. Fluticasone furoate was well tolerated.

CONCLUSION

Fluticasone furoate, 110 microg once daily, was effective and well tolerated for the treatment of nasal symptoms of SAR in patients aged 12 years and older. Treatment also produced significant improvements in ocular symptoms. Fluticasone furoate was fast acting, as indicated by an 8-hour onset of action, and provided 24-hour symptom control.

CLINICAL IMPLICATIONS

New treatments for the bothersome symptoms of SAR are needed. One such treatment, fluticasone furoate nasal spray, provides effective relief of the symptom profile of SAR.

The vitamin D slant on allergy

Oral vitamin D supplementation has been introduced into modern medicine to prevent rickets without the knowledge that this may have profound immunological consequences. The main vitamin D metabolite calcitriol suppresses dendritic cell maturation and consecutive Th(1) cell development, which has independently described as a key mechanism of allergy development. Animal studies and epidemiological surveys now provide a first link of early vitamin D supplementation and later allergy where several vitamin D regulated genes seem to be involved. A randomized clinical trial of vitamin D supplementation could be a further step to follow up the vitamin hypothesis.

Pre-natal and post-natal exposure to respiratory infection and atopic diseases development: a historical cohort study

Background

According to the hygiene hypothesis, infections in early life protect from allergic diseases. However, in earlier studies surrogate measures of infection rather than clinical infections were associated with decreased frequencies of atopic diseases. Exposure to infection indicating sub-clinical infection rather than clinical infection might protect from atopic diseases.

Objective: to investigate whether exposure to acute respiratory infections within pregnancy and the first year of life is associated with atopic conditions at age 5–14 years and to explore when within pregnancy and the first year of life this exposure is most likely to be protective.

Methods

Historical cohort study: Population level data on acute respiratory infections from the routine reporting system of the former German Democratic Republic were linked with individual data from consecutive surveys on atopic diseases in the same region (n = 4672). Statistical analyses included multivariate logistic regression analysis and polynomial distributed lag models.

Results

High exposure to acute respiratory infection between pregnancy and age one year was associated with overall reduced odds of asthma, eczema, hay fever, atopic sensitization and total IgE. Exposure in the first 9 months of life showed the most pronounced effect. Adjusted odds ratio's for asthma, hay fever, inhalant sensitization and total IgE were statistical significantly reduced up to around half.

Conclusion

Exposure to respiratory infection (most likely indicating sub-clinical infection) within pregnancy and the first year of life may be protective in atopic diseases development. The post-natal period thereby seems to be particularly important.