Prevalence of allergic sensitization, hay fever, eczema, and asthma in a longitudinal birth cohort

Cord blood methylation at TNFRSF17 is associated with early allergic phenotypes

Food allergy and eczema are the earliest allergic phenotypes in childhood. These diseases could be related to either IgE-mediated or non-IgE-mediated reactions to the allergen. TNFRSF17 is a key molecule in B cell maturation and is important in both types of responses.We conducted a study comparing the relative expression and the methylation status at the TNFRSF17 in regard to the child's early atopic sensitisation and allergic phenotypes.In the recruited population of 200 women and 174 children with available clinical data (physical examination by allergist and antigen-specific IgE measurements), 78 cord blood samples were included in the gene expression analysis (relative gene expression with GAPDH as reference by RT-PCR) and 96 samples with microarray DNA methylation data (whole genome methylation profile Infinium MethylationEPIC).The altered TNFRSF17 methylation pattern in the cord blood at both single cg04453550 and mean methylation at upstream of TNFRSF17 was observed in children who developed food allergy and/or eczema in early childhood. The change in methylation profile was mirrored by the relative expression. The profile of IgE sensitisation to food and/or inhalant allergens was not significantly associated with either methylation or expression of TNFRSF17.In conclusion, methylation at the upstream sites at TNFRSF17 in the cord blood at birth is associated with food allergy and eczema early in childhood.

Seasonal variations and social disparities in asthma hospitalizations and outcomes

OBJECTIVE

Exposure to asthma exacerbating triggers may be dependent on the season and an individual's social factors and subsequent means to avoid triggers. We assessed for seasonal variations and differential outcomes based on race and income in admissions for asthma in a United States nationwide assessment.

METHODS

This retrospective study assessed adult hospitalizations for asthma 2016-2019 using the National Inpatient Sample. Hospitalizations were categorized by season: winter (December-February), spring (March-May), summer (June-August), fall (September-November). Multivariable linear and logistic regression were used to assess associations between season, race, income quartile (determined by the median income within a patient's ZIP code), and outcomes.

RESULTS

The study included 423,140 admissions with a mean age of 51 years, and 73% of the cohort being female and 56% non-white. Admissions peaked during winter (124, 145) and were lowest in summer (80,525). Intubation rates were increased in summer compared to winter (2.73 vs 1.93%, aOR = 1.19, 95% CI: 1.04-1.37) as were rates of noninvasive positive pressure ventilation (NIPPV) (7.92 vs 7.06%, aOR = 1.08, 95% CI: 1.00-1.17). Compared to white patients, intubation (2.53 vs 1.87%, absolute difference 0.66%, aOR = 1.14, 95% CI: 1.02-1.29) and NIPPV (9.95 vs 5.45%, absolute difference 4.5%, aOR = 1.69, 95% CI: 1.57-1.82) were increased in Black patients. No significant associations between income and clinical outcomes were found.

CONCLUSIONS

Asthma admission peak during winter, while summer admissions and non-white race are associated with higher rates of NIPPV and intubation. Public health initiatives and strategically timed outpatient visits could combat seasonal variation and social disparities in asthma outcomes.

The impact of maternal anxiety during pregnancy on children's eczema and allergic rhinitis: The Ma'anshan birth cohort study

OBJECTIVE

The objective of this study was to investigate the associations between maternal exposure to anxiety during pregnancy and the susceptibility of offspring to eczema and allergic rhinitis and the possibility of sensitivity periods and cumulative effects.

METHODS

The study's sample consisted of 3160 mother-child pairs from the Ma'anshan Birth Cohort Study. Maternal anxiety was repeatedly measured in the 1st, 2nd, and 3rd trimesters of pregnancy using the Chinese version of the Pregnancy-Related Anxiety Scale. Information regarding children's eczema and allergic rhinitis diagnoses was collected through parental reports at 12, 24, 36 and 48 months of age. Binary logistic regression models were used for statistical analysis and corrected for multiple comparisons using the false discovery rate (FDR) method.

RESULTS

Children whose mothers experienced anxiety throughout pregnancy had the highest odds of developing total eczema (aOR 1.45, 95% CI 1.02-2.07) and total allergic rhinitis (aOR 1.67, 95% CI 1.17-2.37) between the ages of 6 and 48 months. The higher the trajectory of the maternal anxiety scores throughout pregnancy, the higher the odds of total eczema (aOR 1.65, 95% CI 1.14-2.40) and allergic rhinitis (aOR 1.84, 95% CI 1.28-2.66) in their offspring. The association between maternal anxiety and children's eczema was mainly concentrated in the first 24 months, whereas the association with allergic rhinitis was mainly concentrated in the 36-48 months.

CONCLUSION

Maternal anxiety during any trimester of pregnancy, especially with a consistently high trajectory of anxiety scores, was associated with higher odds of children's eczema and allergic rhinitis.

Factors associated with sensitisation to selected aero-allergens in children and adolescents with asthma followed up at Laquintinie Hospital Douala, Cameroon

INTRODUCTION

In spite of the substantial impact of pediatric asthma on healthcare resources, there is a notable dearth of research focusing on allergen sensitization specifically in children and adolescents with asthma in Cameroon, with existing studies primarily concentrating on adult populations. We, therefore, set out to determine factors associated with sensitization to selected aero-allergens in children and adolescents with asthma followed up at Laquintinie Hospital Douala, Cameroon.

METHODOLOGY

We conducted a cross-sectional analytical study on patients aged 2-17 years followed up for pediatric asthma at Laquintinie Hospital Douala for 8 months (January to August 2023). Skin prick tests were performed using selected standardized aeroallergens extracts. Factors associated with sensitization were determined using multivariable logistic regression analysis. The threshold for significance was set at p < .05.

RESULTS

In total, 126 children and adolescents with asthma were recruited, 50.79% of whom were male with an average age of 8.00 ± 3.99 years. Eight out of 10 patients (83.52%) were sensitized to common aero-allergens (20.59% monosensitized and 79.41% polysensitized). The most common aero-allergens found were the dust mites Dermatophagoïdes pteronyssinus (81.37%), Blomia tropicalis (67.64%) and Dermatophagoïdes farinae (52.94%) followed by Blatella species (25.49%). The factors independently associated with sensitization in our population were the personal history of allergic rhinitis in the patient [adjusted odds ratio, aOR: 4.07 (95% confidence interval, CI: 1.41-11.76), b = 0.54, p = .009], chest tightness at rest [aOR: 5.92 (95% CI: 1.08-32.38), b = 0.87, p = .040), and age above 5 years [aOR: 4.65 (95% CI: 1.47-14.69), b = 0.59, p = .009).

CONCLUSION

Sensitization to multiple aeroallergens is common in children and adolescents with asthma, especially for dust mites and cockroaches. Factors associated with sensitization are patients aged >5 years, chest tightness at rest, and a personal history of allergic rhinitis.

Epidemiology of eczema in South-Eastern Australia

BACKGROUND/OBJECTIVES

Eczema is a common chronic debilitating skin condition in childhood. Data on the epidemiology and natural history of eczema across the life course are lacking. This analysis aimed to describe these epidemiological features in Australian children and adults.

METHODS

Data collected on eczema from four Australian cohort studies were analysed: namely HealthNuts, Melbourne Atopic Cohort Study (MACS), Tasmanian Longitudinal Health Study (TAHS) and the Australian arm of the European Community Respiratory Health Survey (ECRHS).

RESULTS

Among children aged under 6 years, 28.8%-35.6% have ever-had eczema, and 16.7%-26.6% had 'current eczema'. Among those aged 6-12 years, 14.6%-24.7% had 'current eczema' with 12.0%-18.5% of those at ages of 6 and 10 years classified as having moderate-to-severe eczema according to the Scoring of Atopic Dermatitis (SCORAD) index. In adults, the prevalence of 'eczema ever' ranged between 13.8% and 48.4%. The 12-month period prevalence of eczema was 15.1% at age 18, while current eczema was 8.5% at an average age of 51, and 8.8% at an average age 53 years. Eczema was more common among young boys, but this difference became non-significant for older children and early adolescents. In contrast, eczema was more common for adult women than men.

CONCLUSIONS

Eczema is common both in children and adults. The proportion of severe eczema in children was substantial.

Development of a Water-Dispersible Supramolecular Complex of Polyphenol with Polypeptides for Attenuation of the Allergic Response using a Mechanochemical Strategy

The prevalence of allergic disorders has increased worldwide in recent decades. Polyphenols, including resveratrol and curcumin, are posited to have potential as therapeutic agents for allergy; however, their use has been limited by poor water solubility. Accordingly, a highly concentrated, water dispersible, supramolecular complexes of polyphenols with polypeptides (poly-L-lysine, poly-γ-glutamic acid) and gelatin using high-speed vibration milling are developed. The complex exhibited resistance to photobleaching and thermal radiation. Treatment of a rat basophilic leukemia cell line (RBL-2H3) with polypeptide complexes containing resveratrol is suppressed allergic responses in vitro. Moreover, aerosolized administration of polypeptide complexes is demonstrated excellent bioavailability and inhibition of immediate hypersensitivity reactions in ear tissue in vivo. Furthermore, the method avoids the use of organic solvent and therefore reduces undesirable biological responses.

Allergic disease, sleep problems and psychological distress in children recruited from the general community

BACKGROUND

It is unclear which allergic disease is most strongly related to which sleep problem and whether sleep problems may mediate the association between allergic disease and psychological distress. There is also a need for more community-based studies using non-referred samples.

OBJECTIVE

To examine the association between individual allergic diseases and sleep problems and test whether the association between allergic disease and psychological distress is mediated through sleep problems.

METHODS

Parents of 1449 Australian children aged 6-10y recruited from the general community completed measures of sleep problems (Pediatric Sleep Survey Instrument), psychological distress (Strengths and Difficulties Questionnaire), and frequency of allergic disease.

RESULTS

Sleep and psychological distress scores were in the normal range. After controlling for co-existing allergic diseases: allergic rhinitis was associated with sleep routine problems, morning tiredness, night arousals, sleep disordered breathing and restless sleep; asthma with sleep routine problems, sleep disordered breathing and restless sleep; and eczema with restless sleep. Path analyses revealed that sleep problems mediated the association between asthma and allergic rhinitis but not eczema with psychological distress.

CONCLUSION

In this non-referred community sample, the frequency of sleep problems and psychological distress was lower than that typically reported in children referred to specialized centres. However, allergic rhinitis was associated with a broad range of sleep problems and to a lesser extent in children with asthma and least in children with eczema. Path analysis revealed that the association between allergic disease and psychological distress was mediated through sleep problems highlighting the importance of assessing sleep health in children with allergic disease.

Heterogeneous associations of polyomaviruses and herpesviruses with allergy-related phenotypes in childhood

BACKGROUND

Evidence suggests a complex interplay between infections and allergic diseases.

OBJECTIVE

To explore the association of 14 common viruses with eczema, asthma, and rhinoconjunctivitis in childhood.

METHODS

We used cross-sectional (n = 686) and prospective (n = 440) data from children participating in the Rhea birth cohort. Immunoglobulin G to polyomaviruses (BK polyomavirus, JC polyomavirus, KI polyomavirus [KIPyV], WU polyomavirus [WUPyV], human polyomavirus 6, human polyomavirus 7, Trichodysplasia spinulosa polyomavirus, Merkel cell polyomavirus, human polyomavirus 9, and human polyomavirus 10) and herpesviruses (Epstein-Barr virus, Cytomegalovirus, Herpes simplex virus-1, Herpes simplex virus-2) were measured at age 4 years by fluorescent bead-based multiplex serology. Definitions of eczema, asthma, and rhinoconjunctivitis at ages 4 and 6 years were based on questionnaires. Mediation of the associations by immune biomarkers was tested.

RESULTS

Less likely to have eczema at age 4 years were KIPyV-seropositive (odds ratio [OR], 0.47; 95% confidence interval [CI], 0.27-0.82) and human polyomavirus 6 (OR, 0.44; 95% CI, 0.26-0.73) compared with their seronegative counterparts. Seropositivity to Epstein-Barr virus was negatively associated with eczema at age 4 years (OR, 0.39; 95% CI, 0.22-0.67) and 6 years (OR, 0.50; 95% CI, 0.25-0.99). Children with a higher burden of herpesviruses or of skin polyomaviruses had the lowest odds of eczema at age 4 years. Higher odds for asthma at age 4 years were found for WUPyV-seropositive children (OR, 3.98; 95% CI, 1.38-11.51), and for children seropositive to both respiratory polyomaviruses (KIPyV and WUPyV) (OR, 7.35; 95% CI, 1.66-32.59) compared with children seronegative to both. No associations were observed for rhinoconjunctivitis. There was no evidence of mediation by immune biomarkers.

CONCLUSION

A heterogeneous pattern of infections and allergic diseases was observed with common infections associated with a decreased eczema risk and an increased asthma risk in children.

A national cross-sectional study of exposure to outdoor nitrogen dioxide and aeroallergen sensitization in Australian children aged 7-11 years

The prevalence of allergic diseases in Australian children is high, but few studies have assessed the potential role of outdoor air pollution in allergic sensitization. We investigated the association between outdoor air pollution and the prevalence of aeroallergen sensitization in a national cross-sectional study of Australian children aged 7-11 years. Children were recruited from 55 participating schools in 12 Australian cities during 2007-2008. Parents completed a detailed (70-item) questionnaire. Outdoor nitrogen dioxide (NO₂), as a proxy for exposure to traffic-related emissions, was estimated using measurements from regulatory monitors near each school and a national land-use regression (LUR) model. Three averaging periods were assessed, using information on duration of residence at the address, including lifetime, previous (lifetime, excluding the last year), and recent (the last year only). The LUR model was used as an additional source of recent exposure estimates at school and home addresses. Skin prick tests (SPTs) were performed to measure sensitization to eight common aeroallergens. Multilevel logistic regression estimated the association between NO₂ and sensitization (by individual allergens, indoor and outdoor allergens, and all allergens combined), after adjustment for individual- and area-level covariates. In total, 2226 children had a completed questionnaire and SPT. The prevalence of sensitization to any allergen was 44.4%. Sensitization to house dust mites (HDMs) was the most common (36.1%), while sensitization to Aspergillus was the least common (3.4%). Measured mean (±s.d.) NO₂ exposure was between 9 (±2.9) ppb and 9.5 (±3.2) ppb, depending on the averaging period. An IQR (4 ppb) increase in measured previous NO₂ exposure was associated with greater odds of sensitization to HDMs (OR: 1.21, 95% CI: 1.01-1.43, P = 0.035). We found evidence of an association between relatively low outdoor NO₂ concentrations and sensitization to HDMs, but not other aeroallergens, in Australian children aged 7-11 years.

Food allergy, airborne allergies, and allergic sensitisation among adolescents living in two disparate socioeconomic regions in Ecuador: A cross-sectional study

Background

Allergic diseases are under-investigated and overlooked health conditions in developing countries. We measured the prevalence of food allergy (FA), airborne allergic disease, and allergic sensitisation among adolescents living in 2 socio-demographically disparate regions in Ecuador. We investigated which risk factors are associated with these conditions.

Methods

A cross-sectional study involved 1338 students (mean age: 13 ± 0.9 years old) living in Cuenca (n = 876) and Santa Isabel (n = 462). History of allergic symptoms (noted by parents or doctor) to food, house dust mites (HDM), pollen, and pets were recorded. Sociodemographic characteristics, environmental exposures, and parental history of allergic disorders data were collected. Sensitisation to 19 food and 20 aeroallergens was measured by skin-prick testing (SPT). FA and airborne allergic diseases (to HDM, pollen, cat, or dog) were defined as a report of allergic symptoms noted by doctor, together with a positive SPT (wheal size ≥3 mm). Logistic regression models were used to identify environmental and parental factors associated with allergic conditions.

Results

FA was prevalent among 0.4% (95% CI 0.2%–0.9%), and food sensitisation among 19.1% of the adolescents. Shrimp was the most frequent food linked with FA and food sensitisation. Risk factors associated with FA could not be evaluated due to the low prevalence. Food sensitisation was higher among adolescents exposed to family smoking (OR 1.63, 95% CI 1.14–2.34, p = 0.008) and those with parental history of allergic disorders (OR 1.68, 95% CI 1.13–2.49, p = 0.01), but less common among adolescents owning dogs (OR 0.59, 95% CI 0.41–0.84, p = 0.003).

Airborne allergic diseases were prevalent amongst 12.0% of the adolescents (95% CI: 10.4–13.9, n = 1321), with HDM as the primary allergen (11.2%). Airborne allergic diseases were less common among adolescents with more siblings (OR 0.79, 95% CI 0.65–0.96, p = 0.02) and those who lived with farm animals in the first year of life (OR 0.47, 95% CI 0.23–0.95, p = 0.04), but, most common among adolescents with a smoking family (OR 1.67, 95% CI 1.04–2.70, p = 0.03) and with a parental history of allergic disorders (OR self-perceived: 2.62, 95% CI 1.46–4.71, p = 0.001; OR diagnosed by a doctor: 4.07, 95% CI 2.44–6.80, p < 0.001).

Conclusions

FA and airborne allergies are less prevalent in Ecuador than in developed regions; there is a great dissociation between the prevalence of allergic disease and allergic sensitisation. Shrimp and HDM were the most prevalent allergens. Risk factors identified in this study to be related to allergic diseases should be considered by physicians, health practitioners, and epidemiologists in Ecuador.

The triad of current asthma, rhinitis and eczema is uncommon among adults: Prevalence, sensitization profiles, and risk factors

BACKGROUND

Coexistence of asthma, rhinitis, and eczema has been studied in children, but data are lacking in adults. As new treatments emerge, epidemiological data on the coexistence are needed.

AIMS

To study the prevalence of concomitant asthma, rhinitis and eczema in the general adult population and among those sensitized to aeroallergens, and to study associations between background characteristics and risks of phenotypes of asthma, rhinitis, and eczema.

METHODS

In the West Sweden Asthma Study, phenotypes and sensitization profiles of 1103 randomly selected adults (16-75 years) were assessed. The methods included measures of serum-IgE and structured interviews on asthma, rhinitis, eczema, their associated symptoms, and relevant risk factors.

RESULTS

Among all participants and in those sensitized, 2% and 6% had concomitant asthma, rhinitis, and eczema, respectively, and the condition did not differ by age or sex. Corresponding figures for asthma and rhinitis, but not eczema, was 8% and 19%, respectively. Determinants of coexistence of the three conditions were family history of asthma/allergy, body mass index, and occupational exposure to gas, dust and fumes. Allergic sensitization in those with asthma, rhinitis and eczema was found in 78%, in those with asthma and rhinitis but not eczema in 65%, in those with asthma and eczema but not rhinitis in 40%, while only 5% were sensitized among those having asthma only.

CONCLUSIONS

In the general adult population about 2% have concomitant asthma, rhinitis, and eczema. Of sensitized adults, about 6% has coexistence of the three conditions.

Impact of allergic rhinitis on the day-to-day lives of children: insights from an Australian cross-sectional study

STUDY DESIGN AND OBJECTIVE

Cross-sectional, observational survey to describe the impact of allergic rhinitis (AR) on Australian children (2 to 15 years).

METHODS

Participants (n=1541), parents of children aged 2 to 15 years, provided information on behalf of themselves and one eligible child in their household using a custom-built online questionnaire. Children were allocated to case (AR) or control (No AR) analysis groups based on a validated screening questionnaire.

STATISTICAL METHODS

The study sample was stratified on age: primary analysis population (6 to 15 years, n=1111; AR=797, No AR=314); exploratory population (2 to 5 years). The primary endpoint, parent-perceived burden, was quantified using a validated measure of health status and analysed via comparison of means.

RESULTS

The majority of AR cases were treated (730/797; 90.3%) and classified as having moderate-severe, intermittent AR (549/797; 68.9%). Half reported adequate symptom control in the prior 2 weeks (389/797; 48.8%; OR=4.04; 95% CI (CI) 2.24 to 7.31). Having AR was associated with worse overall health status (7.4 vs 8.4, mean difference (least squares mean difference (LSMD))=-0.99; 95% CI -1.18 to -0.79), fewer days being happy (22.2 vs 25.9, LSMD=-3.68; 95% CI -4.82 to -2.54) and more days of poor physical (2.82 vs 0.78, LSMD=2.04; 95% CI 1.61 to 2.47) and emotional (2.14 vs 0.67, LSMD=1.47; 95% CI 1.02 to -1.92) health compared with not having AR. All of these outcomes were significantly (p<0.05) worse in children who reported inadequate symptom control. Having AR negatively impacted on schoolwork, sleep and other activities, and increased the likelihood of having comorbidities.

CONCLUSION

The parent-perceived burden of AR in Australian children is high and it impacts many areas of day-to-day living. Inadequate symptom control is a key driver of the extent of this impact. Opportunities to optimise the management of AR in children include the adoption of self-assessment tools to gauge and monitor adequacy of symptom control.

Trajectories of asthma and allergies from 7 years to 53 years and associations with lung function and extrapulmonary comorbidity profiles: a prospective cohort study

BACKGROUND

Longitudinal trajectories of asthma and allergies from childhood to adulthood might be differentially associated with lung function and chronic obstructive pulmonary disease (COPD), but associations with extrapulmonary comorbidities have not been well investigated. We aimed to assess these trajectories and examine their associations with lung function outcomes and profiles of comorbidities.

METHODS

In this prospective cohort study, data for asthma and related allergic conditions (ie, eczema, hay fever, and food allergy) were prospectively collected from the Tasmanian Longitudinal Health Study for participants aged 7-53 years originally recruited in Tasmania, Australia. All surviving individuals in the database with contact details were invited in the most recent follow-up (mean age 53 years). There were no exclusion criteria. With use of latent class analysis, we identified longitudinal trajectories of asthma and allergic conditions from 7-53 years, and profiles of self-reported extrapulmonary conditions recorded at 53 years. The associations between asthma and allergy trajectories and morbidity profiles and lung function at 53 years were investigated with regression models.

FINDINGS

Between Sept 3, 2012, and Nov 8, 2016, of 6128 individuals invited, 3609 (58·9%) individuals were enrolled. We identified five asthma and allergy trajectories: minimal and least asthma and allergies (n= 1767 [49·0%]); late-onset hay fever, no asthma (n=1065 [29·5%]); early-onset remitted asthma and allergies (n=236 [6·5%]); late-onset asthma and allergies (n=317 [8·8%]); and early-onset persistent asthma and allergies (n=224 [6·2%]); and four profiles of extrapulmonary morbidities: minimal or least disease (n=2206 [61·1%]); dominant mental health disorders (n=861 [23·9%]); dominant cardiovascular diseases or risks (n=424 [11·7%]); and multiple disorders (n=117 [3·2%]). The late-onset asthma and allergies trajectory was predominantly associated with the multiple disorders profile (relative risk ratio 3·3 [95% CI 1·9-5·9]), whereas the other asthma and allergy trajectories were associated only with the dominant mental health disorders profile. Both spirometrically defined and clinical COPD were most strongly associated with the early-onset persistent asthma and allergies trajectory (odds ratio [OR] 5·3 [95% CI 3·2-8·6]) and also with the late-onset asthma and allergies trajectory (OR 3·8 [2·4-6·1]).

INTERPRETATION

Distinct longitudinal trajectories of asthma and allergic disease from childhood to 53 years are associated with different profiles of extrapulmonary comorbidities and varying risk of COPD. These findings can inform a personalised approach in clinical guidelines and management focusing on treatable traits. Comorbidity profiles are a new target for early identification and intervention.

FUNDING

National Health and Medical Research Council of Australia, EU's Horizon 2020, The University of Melbourne, Clifford Craig Medical Research Trust of Tasmania, The Victorian, Queensland & Tasmanian Asthma Foundations, The Royal Hobart Hospital, Helen MacPherson Smith Trust, and GlaxoSmithKline.

Eczematous graft-vs-host disease: A report of three cases and review of the literature

Graft-vs-host disease (GVHD) is the most common complication following hematopoietic cell transplantation, which affects skin frequently. Acute and chronic forms of GVHD manifest commonly as maculopapular to morbilliform eruptions and sclerotic or lichen-planus-like lesions, respectively; however, atypical presentations such as eczema-like GVHD may occur at times. We describe three cases of GVHD with diverse and polymorphous cutaneous eruptions including pompholyx-like and vasculitis-like rash as well as erythematous plaques and papulosquamous eruptions, with skin biopsy showing unifying histopathological findings with concurrent changes of spongiotic dermatitis and vacuolar interface reaction with apoptotic keratinocytes. In addition, the clinical and pathological features of previously reported cases of eczema-like GVHD are reviewed. It is emphasized that the course of the disease can be variable and successful management often involves a combination of multiple therapeutic modalities including immunosuppression with or without ultraviolet therapy. These cases highlight the importance of meticulous clinicopathological correlation with careful exclusion of mimicking conditions to arrive at the correct diagnosis.

Beyond Smoking: Environmental Determinants of Asthma Prevalence in Western Nepal

BACKGROUND

Asthma is widely prevalent in Nepal, but the causes are not well known aside from some general associations with ambient air pollution and microbial exposures. Information on the wide-ranging determinants of asthma prevalence among the population at risk can help policy makers to reduce risk.

OBJECTIVE

The present study is a preliminary investigation of the environmental, socioeconomic and behavioral determinants of asthma prevalence in western Nepal.

METHODS

A survey was conducted among 420 randomly selected households in western Nepal. A cross-sectional analytical study design was employed with the primary data using econometric tools of probit and logistic regression.

RESULTS

Environmental variables such as extreme cold winter, deteriorating river water quality and air pollution were associated with an increase in asthma prevalence. However, individual or household characteristics such as advancing age of household head, use of pesticides in the home for the control of pests, piped drinking water with old pipes and lack of participation in awareness programs were associated with an increase in asthma prevalence.

DISCUSSION

Among environmental factors, decreasing river water quality, increasing air pollution, and extremely cold winters are more likely to contribute to asthma prevalence. In light of the effects of environmental factors on the prevalence of asthma in Nepal, the high public and private costs of asthma could further impoverish the rural poor.

CONCLUSIONS

Environmental health policy makers should design adaptation strategies along with additional community programs addressing asthma-instigating factors. Programs to reduce environmental pollution can reduce morbidity due to asthma.

PARTICIPANT CONSENT

Obtained.

ETHICS APPROVAL

This study was approved by the Ethical Committee of the Nepal Health Research Council.

COMPETING INTERESTS

The authors declare no competing financial interests.

[Environmental risk factors for asthma developement]

The prevalence of asthma has increased rapidly since the early 1970s, and only changes in exposure to environmental factors; which go together with changes in lifestyle, are likely to explain such a rapid increase. Exposure to allergens is a risk factor for allergic sensitization, and allergic sensitization is a risk factor for allergic asthma. However, apart from indoor mold exposure as a risk factor for childhood asthma, there is insufficient evidence to conclude that the associations between allergen exposure and asthma development are causal. A new challenge for research is to analyze the huge amount of data derived from the metagenomic characterization of the environmental and human microbiome, to understand the role of interactions between viruses, bacteria and allergens in the development of asthma. It is recognized that prenatal and postnatal exposure to air pollution and maternal smoking increase the risk of developing asthma in children. In adults, the data are scarce and the results remain controversial as regards these exposures and asthma incidence. Further research is needed to appraise the effect of exposure to phenols, phthalates and perfluorinated compounds, which are widespread in the environment and may be associated with asthma, especially in children. Frequent use of chemicals for home cleaning especially in the form of sprays - which is a common practice at the population level - is a risk factor for the development of adult asthma. The domestic use of cleaning products might also be a risk factor for asthma in children exposed at home. The chemicals involved in these relationships are still to be identified. Occupational asthma is a major phenotype of adult asthma. A significant part of these asthma cases might relate to occupational exposure to cleaning products. While there is evidence of associations between diet during pregnancy or during childhood and the risk of developing asthma in children, the data in adults are insufficient. Beyond genetic factors, body composition is influenced by dietary choices and physical activity. Further research is needed to clarify the complex interplay between these nutritional factors and asthma development. The new challenge for research is to decipher the role of all the environmental factors to which the individual is exposed since conception ("exposome") in the development of asthma, using a holistic approach.