Progression of allergy and asthma through childhood to adolescence

Trends in Allergic Sensitization and Diseases in the Korean General Population Over a 9-Year Period

OBJECTIVES

The prevalence of allergic sensitization and diseases varies over time due to changes in climate, environment, and lifestyle. This study analyzed changes in sensitization to house dust mites (HDM) and dogs, as well as the prevalence of allergic diseases in the Korean general population over a 9-year period and identified contributing factors.

METHODS

This cross-sectional study used data from the Korea National Health and Nutrition Examination Survey conducted in 2010 and 2019. Participants were aged ≥10 years, with the analysis stratified by adolescents (10-18 years) and adults (≥19 years). We evaluated the prevalence of allergic sensitization and diseases and examined links to clinicodemographic factors across the two survey years. Multivariate logistic regression was performed to evaluate the association between sensitization and clinicopathological factors.

RESULTS

In total, 4,084 participants (2010: n=2,019, 2019: n=2,065) were enrolled. In 2010, HDM sensitization was 36.9%, declining to 36.6% in 2019. Dog sensitization decreased from 6.1% in 2010 to 5.8% in 2019. There were no significant differences between the two years among total participants; however, dog sensitization increased significantly among adolescents (2010: 8.7% vs. 2019: 15.3%; P=0.027). In 2010, HDM sensitization was negatively associated with urban residence (odds ratio [OR], 0.76; 95% CI, 0.60-0.96) and apartment dwelling (OR, 0.78; 95% CI, 0.64-0.95) but was without significance in 2019. In adolescents, dog sensitization was strongly correlated with urban residence (OR, 8.06; 95% CI, 1.53-42.49) in 2010, whereas HDM sensitization was associated with obesity (OR, 2.02; 95% CI, 1.04-3.91) in 2019. In adults, heavy drinking was linked to dog sensitization (OR, 2.35; 95% CI, 1.20-4.62) in 2010 and HDM sensitization in 2019 (OR, 1.44; 95% CI, 1.03-2.02).

CONCLUSION

The prevalence of HDM sensitization remained stable over 9 years, while dog sensitization increased in adolescents. The factors associated with sensitization differed between age groups and years. Understanding these trends and related factors in the general population can help healthcare providers develop new strategies to reduce allergic sensitization and diseases.

Based on what parameters is safe to discontinuate inhaled corticosteroids in children with asthma?

OBJECTIVE

Remission of childhood asthma has not been widely studied. Patients in clinical remission continue to have some degree of bronchial hyperresponsiveness (BHR). The aim of this study was to investigate whether clinical parameters and lung function test are good parameters for discontinuation of inhaled corticosteroids (ICS) in asthmatic children, including patients with persistent BHR, as measured by the methacholine challenge test (MCT).

METHODS

One year after discontinuation of inhaled corticosteroids (ICS), MCT was performed in a group of 40 asthmatic children to confirm or exclude BHR. In all patients, ICS treatment was discontinued based on the same parameters: symptoms, spirometry, daily PEF, and negative bronchodilator test. After achieving complete asthma control for at least 6 to 12 months, ICS treatment was stepped down and discontinued. Clinical course and spirometry were followed up after ICS discontinuation.

RESULTS

Positive MCT was found in 50% of the patients. There was no statistically significant difference between the positive and negative MCT groups in age at initiation and discontinuation of ICS therapy, duration of ICS therapy, duration of stepping down period, FEV1, and PEF at the time of withdrawal of ICS and one year later. ICS treatment had to be restarted in two patients from the positive MCT group, due to recurrence of asthma symptoms.

CONCLUSION

Clinical parameters, normal spirometry, daily PEF values, and a negative bronchodilator test are good parameters for discontinuing ICS treatment in asthmatic children, even in patients with persistent BHR. Children should continue to be monitored, as symptoms may recur.

A survey of allergic conjunctivitis in children in China

To explore the risk factors for allergic conjunctivitis (AC) in Chinese children. We recruited 176 children who suffered from AC and a control group comprising 131 normal subjects in southern China. Each participant completed a questionnaire and underwent multiple eye examinations and a skin prick test (SPT). The data of the questionnaire, the scores of the symptoms/signs and the results of the SPT were analysed. The rate of parental allergic history in the case group was much higher than that in the control group (P < 0.01). Compared with the control group, the case group was more likely to have other concomitant diseases (P < 0.01). The scores of ocular symptoms/signs had a significant correlation with the clinical duration of AC in the case group (P < 0.01). Children with other concomitant diseases or a parental allergic history were more likely to have AC.

Periconceptional folic acid supplementation and child asthma: a Right From the Start follow-up study

OBJECTIVE

High maternal folic acid exposure has been studied as a risk factor for child asthma with inconclusive results. Folic acid supplementation that begins before pregnancy may propagate high exposures during pregnancy, particularly in regions with fortified food supplies. We investigated whether folic acid supplementation initiated periconceptionally is associated with childhood asthma in a US cohort.

MATERIALS AND METHODS

We re-contacted mother-child dyads previously enrolled in a prospective pregnancy cohort and included children age 4 to 8 years at follow-up (n = 540). Using first trimester interviews, we assessed whether initial folic acid-containing supplement (FACS) use occurred near/before estimated conception ("periconceptional") or after (during the "first trimester"). Follow-up questionnaires were used to determine if a child ever had an asthma diagnosis ("ever asthma") or asthma diagnosis with prevalent symptoms or medication use ("current asthma"). We examined associations between FACS initiation and asthma outcomes using logistic regression, excluding preterm births and adjusting for child age, sex, maternal race, maternal education, and parental asthma.

RESULTS

Approximately half of women initiated FACS use periconceptionally (49%). Nine percent of children had "ever asthma" and 6% had "current asthma." Periconceptional initiation was associated with elevated odds of ever asthma [adjusted odds ratio (95% Confidence Interval): 1.65 (0.87, 3.14)] and current asthma [1.87 (0.88, 4.01)], relative to first trimester initiation.

CONCLUSION

We observed positive, but imprecisely estimated associations between periconceptional FACS initiation and child asthma. Folic acid prevents birth defects and is recommended. However, larger studies of folic acid dosing and timing, with consideration for childhood asthma, are needed.

Evaluation of climate change adaptation measures for childhood asthma: A systematic review of epidemiological evidence

Global climate change (GCC) is widely accepted as the biggest threat to human health of the 21st century. Children are particularly vulnerable to GCC due to developing organ systems, psychological immaturity, nature of daily activities, and higher level of per-body-unit exposure. There is a rising trend in the disease burden of childhood asthma and allergies in many parts of the world. The associations of CC, air pollution and other environmental exposures with childhood asthma are attracting more research attention, but relatively few studies have focused on CC adaptation measures and childhood asthma. This study aimed to bridge this knowledge gap and conducted the first systematic review on CC adaptation measures and childhood asthma. We searched electronic databases including PubMed, Embase, and Web of Science using a set of MeSH terms and related synonyms, and identified 20 eligible studies included for review. We found that there were a number of adaptation measures proposed for childhood asthma in response to GCC, including vulnerability assessment, improving ventilation and heating, enhancing community education, and developing forecast models and early warning systems. Several randomized controlled trials show that improving ventilation and installing heating in the homes appear to be an effective way to relieve childhood asthma symptoms, especially in winter. However, the effectiveness of most adaptation measures, except for improving ventilation and heating, have not been explored and quantified. Given more extreme weather events (e.g., cold spells and heatwaves) may occur as climate change progresses, this finding may have important implications. Evidently, further research is urgently warranted to evaluate the impacts of CC adaptation measures on childhood asthma. These adaptation measures, if proven to be effective, should be integrated in childhood asthma control and prevention programs as GCC continues.

Prescribing patterns and cost-utility analysis of management of childhood asthma in Saudi Arabia: a retrospective cross-sectional study

Objective

This study is based on a retrospective cross-sectional study to assess the prescribing patterns and cost-utility analysis of management of childhood asthma in Saudi Arabia.

Methods

Prescription data were collected for 1 year from electronic records of pharmacy. The unit dose price was retrieved from pharmacy database and compared with daily price based on WHO Defined Daily Dose (DDD) and Saudi Initiative for Asthma (SINA). The cost of each drug is calculated from average prices of each unit dose of each prescription.

Key findings

In male children (57.98%), asthma was more common in comparison to female children (41.02%) at the studied hospital. Salbutamol (44.55%) was the most commonly prescribed medication followed by budesonide (30.97%) and montelukast (12.82%), whereas prednisolone (0.15%) was the least prescribed medication for the management of childhood asthma. It was found that fixed-dose combination of budesonide and formetrol prescribed for the longest duration of therapy (30 days) and imposed highest cost as well [197.10 SR (52.53 USD)] among all the prescribed medicine.

Conclusion

In this study, inhalation route is the most preferred one for management of asthma; this may be due to their fast therapeutic action. Salbutamol was the most popular drug for quick reliever therapy, while budesonide was the most favoured drug for childhood asthma management. Medication prescribed for the management of childhood asthma at the mentioned study centre adhere to SINA guideline.

A nationwide study of asthma correlates among adolescents in Saudi Arabia

Background

Asthma is a chronic airway inflammation disease that is frequently found in children and adolescents with an increasing prevalence. Several studies are linking its presence to many lifestyle and health correlates. The objective of this study was to explore these correlates and find characteristics of self-reported asthmatics among adolescents in Saudi Arabia.

Methods

This is a cross-sectional, school-based study carried out in all 13 regions of Saudi Arabia. Sampling was randomly done from intermediate and secondary school students. Data in our study consisted of demographic characteristics, health conditions and lifestyle patterns and were compared between the two groups: asthmatics versus non-asthmatics. Comparison between the two groups was done by analyzing our data using Statistical Analysis Software SURVEYFREQ procedure (SAS Version 9; SAS Institute, Cary, NC).

Results

Among a sample of 11,348 participants, the prevalence of self-reported asthma was found to be 8.2%. Various characteristics were found significantly different between the 2 groups including the gender, the weight, the family’s education, and dietary patterns. Self –reported asthmatic were more likely to be males, overweight or obese, with a lower father’s level of education and a higher consumption of milk and power drinks.

Conclusion

Asthma disease remains prevalent among adolescents in Saudi Arabia and requires higher awareness and better guidance for its prevention and treatment. Further efforts should focus on health promotion and lifestyle wellness to support preventive efforts of this chronic disease condition.

Gestational age at birth and wheezing trajectories at 3-11 years

OBJECTIVE

Children born preterm have an increased risk of asthma in early childhood. We examined whether this persists at 7 and 11 years, and whether wheezing trajectories across childhood are associated with preterm birth.

DESIGN

Data were from the UK Millennium Cohort Study, which recruited children at 9 months, with follow-up at 3, 5, 7 and 11 years.

OUTCOMES

Adjusted ORs (aOR) were estimated for recent wheeze and asthma medication use for children born <32, 32-33, 34-36 and 37-38 weeks' gestation, compared with children born at full term (39-41 weeks) at 7 (n=12 198) and 11 years (n=11 690). aORs were also calculated for having 'early-remittent' (wheezing at ages 3 and/or 5 years but not after), 'late' (wheezing at ages 7 and/or 11 years but not before) or 'persistent/relapsing' (wheezing at ages 3 and/or 5 and 7 and/or 11 years) wheeze.

RESULTS

Birth <32 weeks, and to a lesser extent at 32-33 weeks, were associated with an increased risk of wheeze and asthma medication use at ages 7 and 11, and all three wheezing trajectories. The aOR for 'persistent/relapsing wheeze' at <32 weeks was 4.30 (95% CI 2.33 to 7.91) and was 2.06 (95% CI 1.16 to 2.69) at 32-33 weeks. Birth at 34-36 weeks was not associated with asthma medication use at 7 or 11, nor late wheeze, but was associated with the other wheezing trajectories. Birth at 37-38 weeks was not associated with wheeze nor asthma medication use.

CONCLUSIONS

Birth <37 weeks is a risk factor for wheezing characterised as 'early-remittent' or 'persistent/relapsing' wheeze.

The Prevalence of Ocular Allergy and Comorbidities in Chinese School Children in Shanghai

Objective

To investigate the prevalence and features of ocular allergy (OA) and comorbidities among school children in Shanghai, China.

Methods

This was a population-based cross-sectional study. Each participant completed an ISAAC-based questionnaire. The prevalence of OA symptoms, allergic rhinitis (AR) asthma, atopic dermatitis (AD), and sensitization to mites, pollen, and food was analyzed.

Results

A total of 724 and 942 completed questionnaires from the 7–9-year-old (young group) and the 12–14-year-old (teen group) groups were analyzed, respectively. The overall prevalence of OA symptoms was 28%. However, more young students (10.6%) reported mild to severe daily life interference caused by OA than the teens (5.7%). The young group had higher prevalence of diagnosed allergic conjunctivitis (10.2%). The overall prevalence of AR symptom, diagnosed asthma, and diagnosed AD was 40.4%, 11.6%, and 16.7%, respectively. Young children had higher prevalence of diagnosed AR and AD than the teens. There were gender associated differences in the prevalence of AR and asthma among young children, but not among the teens. The comorbidities associated with OA was also analyzed. Sensitization to mites, food, and pollen was associated with higher prevalence of allergic conditions.

Conclusions

OA together with other allergic conditions affected a significant number of children in Shanghai.

Establishing a birth cohort to investigate the course and aetiology of asthma and allergies across three generations - rationale, design, and methods of the ACROSSOLAR study

Background

Atopic diseases are a major burden of disease on a global scale. Regarding their aetiology, the early years of life are assumed to play a crucial role. In addition, there is growing evidence that elucidating the impact of cross-generational effects and epigenetic mechanisms such as DNA methylation can substantially widen the scientific knowledge of the occurrence and progression of these diseases. We are thus aiming at following the course of asthma, allergies, and potential risk factors for their occurrence across three generations by establishing a birth cohort in the offspring of an existing population-based cohort.

Methods/Design

2051 young adults who have been recruited in 1995 for Phase II of the International Study of Asthma and Allergies in Childhood (ISAAC) and who have subsequently been followed-up by the Study on Occupational Allergy Risks (SOLAR) are asked bi-annually since 2009 if they conceived a child in the meantime. If parenthood is reported, parents are invited to enrol along with their children in the ACROSSOLAR cohort. Participation involves completing a questionnaire assessing general and health-related information about the course of the pregnancy and the first year of life of their children. Subsequently, the children are followed up until primary school age when asthma and allergies can be diagnosed reliably. In addition, DNA for epigenetic analysis will be collected and analysed. Longitudinal data analysis techniques will then be used to assess potential associations between early-life exposures and onset of childhood asthma and allergies taking into account epigenetics.

Discussion

Birth cohorts are especially suited to elucidate the impact of genetic predisposition, epigenetics, exposures during the first years of life, and gene-environment interactions on the occurrence and progression of asthma and allergies. By building upon an existing cohort, ACROSSOLAR offers a unique and cost-effective opportunity to investigate the aetiology of atopic disease in a prospective and cross-generational way.

Time-trend analysis of prevalence, incidence and traditional Chinese medicine use among children with asthma: a population-based study

BACKGROUND

This study determined annual prevalence and incidence trends of asthma among children in Taiwan from 2002 to 2008. Risk factors and traditional Chinese medicine (TCM) use were examined.

METHODS

A random sample was selected for a population-based study with a selection probability of 0.5 from all 3-18 years insurants. The annual prevalence and incidence of asthma were estimated according to age, sex, insurance premium and degree of urbanization.

RESULTS

The prevalence of asthma increased from 12.99% in 2002 to 16.86% in 2008. The increase was greatest in 2008, among boys, 11-15 years, ≥medium insurance premium, and high- and medium-density urban area. TCM use in asthma-prevalent children decreased from 1.16% in 2002 to 0.59% in 2008. The incidence fluctuated, ranging from 1.01% in 2002 to 1.49% in 2005. The highest was in 2005, among boys, 3-5 years, ≥medium insurance premium and high-density urban area. TCM use in asthma-incident children decreased from 3.59% in 2002 to 1.69% in 2008.

CONCLUSION

This study demonstrated a substantial increase in annual prevalence of asthma among children in Taiwan from 2002 to 2008. The incidence fluctuated. The TCM use showed a decreasing linear trend and was higher in incident than in prevalent cases.

Ambient ozone exposure and children's acute asthma in New York City: a case-crossover analysis

BACKGROUND

Childhood asthma morbidity has been associated with ambient ozone in case-crossover studies. Varying effects of ozone by child age and sex, however, have been less explored.

METHODS

This study evaluates associations between ozone exposure and asthma emergency department visits and hospitalizations among boys and girls aged 5-17 years in New York City for the 2005-2011 warm season period. Time-stratified case-crossover analysis was conducted and, for comparison, time-series analysis controlling for season, day-of-week, same-day and delayed effects of temperature and relative humidity were also performed.

RESULTS

We found associations between ambient ozone levels and childhood asthma emergency department visits and hospitalizations in New York City, although the relationships varied among boys and girls and by age group. For an increase of interquartile range (0.013 ppm) in ozone, there was a 2.9-8.4% increased risk for boys and 5.4-6.5% for girls in asthma emergency department visits; and 8.2% increased risk for girls in hospitalizations. Among girls, we observed stronger associations among older children (10-13 and 14-17 year age groups). We did not observe significant modification by age for boys. Boys exhibited a more prompt response (lag day 1) to ozone than did girls (lag day 3), but significant associations for girls were retained longer, through lag day 6.

CONCLUSIONS

Our study indicates significant variance in associations between short-term ozone concentrations and asthma events by child sex and age. Differences in ozone response for boys and girls, before and after puberty, may point towards both social (gendered) and biological (sex-linked) sources of effect modification.

Impact of diurnal temperature range on human health: a systematic review

Increasing epidemiological studies have shown that a rapid temperature change within 1 day is an independent risk factor for human health. This paper aimed to systematically review the epidemiological evidence on the relationship between diurnal temperature range (DTR) and human health and to propose future research directions. A literature search was conducted in October 2013 using the databases including PubMed, ScienceDirect, and EBSCO. Empirical studies regarding the relationship between DTR and mortality and morbidity were included. Twenty-five relevant studies were identified, among which, 11 investigated the relationship between DTR and mortality and 14 examined the impact of DTR on morbidity. The majority of existing studies reported that DTR was significantly associated with mortality and morbidity, particularly for cardiovascular and respiratory diseases. Notably, compared with adults, the elderly and children were more vulnerable to DTR effects. However, there were some inconsistencies regarding the susceptible groups, lag time, and threshold of DTR. The impact of DTR on human health may be confounded or modified by season, socioeconomic, and educational status. Further research is needed to further confirm the adverse effects of DTR in different geographical locations; examine the effects of DTR on the health of children aged one or under; explore extreme DTR effects on human health; analyze the difference of DTR effects on human health in different locations and the modified effects of potential confounding factors; and develop detailed preventive measures against large DTR, particularly for susceptible groups.

Diurnal temperature range and childhood asthma: a time-series study

BACKGROUND

Hot and cold temperatures have been associated with childhood asthma. However, the relationship between daily temperature variation and childhood asthma is not well understood. This study aimed to examine the relationship between diurnal temperature range (DTR) and childhood asthma.

METHODS

A Poisson generalized linear model combined with a distributed lag non-linear model was used to examine the relationship between DTR and emergency department admissions for childhood asthma in Brisbane, from January 1st 2003 to December 31st 2009.

RESULTS

There was a statistically significant relationship between DTR and childhood asthma. The DTR effect on childhood asthma increased above a DTR of 10°C. The effect of DTR on childhood asthma was the greatest for lag 0-9 days, with a 31% (95% confidence interval: 11% - 58%) increase of emergency department admissions per 5°C increment of DTR. Male children and children aged 5-9 years appeared to be more vulnerable to the DTR effect than others.

CONCLUSIONS

Large DTR may trigger childhood asthma. Future measures to control and prevent childhood asthma should include taking temperature variability into account. More protective measures should be taken after a day of DTR above 10°C.

Maternal bereavement and childhood asthma-analyses in two large samples of Swedish children

BACKGROUND

Prenatal factors such as prenatal psychological stress might influence the development of childhood asthma.

METHODOLOGY AND PRINCIPAL FINDINGS

We assessed the association between maternal bereavement shortly before and during pregnancy, as a proxy for prenatal stress, and the risk of childhood asthma in the offspring, based on two samples of children 1-4 (n = 426,334) and 7-12 (n = 493,813) years assembled from the Swedish Medical Birth Register. Exposure was maternal bereavement of a close relative from one year before pregnancy to child birth. Asthma event was defined by a hospital contact for asthma or at least two dispenses of inhaled corticosteroids or montelukast. In the younger sample we calculated hazards ratios (HRs) of a first-ever asthma event using Cox models and in the older sample odds ratio (ORs) of an asthma attack during 12 months using logistic regression. Compared to unexposed boys, exposed boys seemed to have a weakly higher risk of first-ever asthma event at 1-4 years (HR: 1.09; 95% confidence interval [CI]: 0.98, 1.22) as well as an asthma attack during 12 months at 7-12 years (OR: 1.10; 95% CI: 0.96, 1.24). No association was suggested for girls. Boys exposed during the second trimester had a significantly higher risk of asthma event at 1-4 years (HR: 1.55; 95% CI: 1.19, 2.02) and asthma attack at 7-12 years if the bereavement was an older child (OR: 1.58; 95% CI: 1.11, 2.25). The associations tended to be stronger if the bereavement was due to a traumatic death compared to natural death, but the difference was not statistically significant.

CONCLUSIONS/SIGNIFICANCE

Our results showed some evidence for a positive association between prenatal stress and childhood asthma among boys but not girls.

Training improves physical fitness and decreases CRP also in asthmatic conscripts

To study the respiratory and physical health of young men, 224 asthmatic and 668 non-asthmatic military conscripts were recruited from the intake groups of July 2004 and January 2005 in Kajaani, Finland. Factors affecting respiratory health were elicited by a questionnaire at the beginning of the service, and results of high sensitive C-reactive protein (hsCRP) determination, peak expiratory flow (PEF), and 12-minute running test were collected at the beginning and the end of the service. Respiratory infections were diagnosed by a study physician. Upon entering military service, asthmatics had frequent exercise- and cold-related asthma symptoms (69.6% and 76.3%), and 48% of them had no medication for asthma. At the beginning, 25.8% of asthmatics and 19.1% of non-asthmatics had a poor result of less than 2,200 m (p = 0.05) in the 12-minute running test, and after 180 to 362 days of service, the corresponding percentages were 11.7% and 9.7% (p = 0.434). The levels of hsCRP, a marker of low-grade systemic inflammation, decreased significantly among both asthmatics, 1.5 (p = 0.001), and non-asthmatics, 1.6 mg/L (p < 0.001). Asthmatic men had 0.2 and non-asthmatics 0.1 respiratory infections per month (p < 0.001). In summary, asthmatic conscripts can enhance their physical fitness by training similarly to non-asthmatic ones. Their levels of hsCRP also decrease.

Impact of gender on asthma in childhood and adolescence: a GA2LEN review

A number of studies have shown gender differences in the prevalence of wheeze and asthma. The aim of this review was to examine published results on gender differences in childhood and adolescent asthma incidence and prevalence, define current concepts and to identify new research needs. A Medline search was performed with the search words (gender OR sex) AND (child OR childhood OR adolescence) AND (asthma). Articles that reported on absence or presence of gender differences in asthma were included and reviewed, and cross-references were checked. Boys are consistently reported to have more prevalent wheeze and asthma than girls. In adolescence, the pattern changes and onset of wheeze is more prevalent in females than males. Asthma, after childhood, is more severe in females than in males, and is underdiagnosed and undertreated in female adolescents. Possible explanations for this switch around puberty in the gender susceptibility to develop asthma include hormonal changes and gender-specific differences in environmental exposures. This aspect needs consideration of the doctors and allergists who diagnose and treat asthmatic individuals. In conclusion, sex hormones are likely to play an important role in the development and outcome of the allergic immune response and asthma in particular. By obtaining functional data from appropriate models, the exact underlying mechanisms can be unravelled. To examine the effect of gender-specific differences in environmental exposures and changes of asthma prevalence and severity in puberty, larger populations may need to be investigated.

The challenge of asthma in adolescence

The adolescents with asthma are a distinct group of patients with different problems and needs compared to children and adults. Specific issues of asthma in adolescence are the variability of the clinical spectrum, the presence of particular risk factors for the persistence of symptoms, underdiagnosis and undertreatment of the disease. Refusal of the sick role, denial of symptoms, carelessness about dangerous inhalation exposure, erratic self-medication, overexertion without taking precautions against exercise-induced asthma, and a poor relationship between patients, their families, and often doctors are the main obstacles to successful management of asthma in this critical age. There are also major problems of compliance for these patients. The goal of optimal quality of life will be achieved only if the physician thoroughly understands the adolescent's needs and provides optimal care.

Do risk factors for childhood infections and malnutrition protect against asthma? A study of Brazilian male adolescents

OBJECTIVES

We studied the association between early life conditions and asthma in adolescence.

METHODS

We conducted a population-based birth cohort study involving 2250 male 18-year-olds residing in Brazil.

RESULTS

Approximately 18% of the adolescents reported having asthma. Several childhood factors were found to be significantly associated with increased asthma risk: being of high socioeconomic status, living in an uncrowded household, and children being breastfed for 9 months or longer.

CONCLUSIONS

The present results are consistent with the "hygiene hypothesis," according to which early exposure to infections provides protection against asthma. The policy implications of our findings are unclear given that risk factors for asthma protect against serious childhood diseases in developing countries.

Atopic symptoms among California veterinarians

BACKGROUND

The prevalence of allergic symptoms among veterinarians has not been studied adequately.

METHODS

A questionnaire was sent to 2,000 California veterinarians; the return rate was 73% (N=1416).

RESULTS

A history of either asthma, allergic rhinitis (AR), or atopic dermatitis (AD) was reported by 66% of respondents. AR was reported by 62%, asthma by 16%, and AD by 11%. Forty percent of the veterinarians reported animal related respiratory and/or skin symptoms. The most commonly reported causes of symptoms were cats and dogs. In multivariate logistic analysis, the significant risk factors for having adult asthma were the history of AR with the history of AD (OR 13.9), AR alone (OR 6.3), and asthma in childhood (OR 6.4).

CONCLUSIONS

The prevalence of asthma and other atopic symptoms was high in the studied population. Most veterinarians with respiratory or skin symptoms reported the symptoms as being related to specific animal contact.

Bronchial hyperresponsiveness and airway inflammation in adolescents with asymptomatic childhood asthma

BACKGROUND

About 70% of childhood asthmatics become free of asthma-related symptoms during adolescence. Little is known about bronchial hyperresponsiveness (BHR) and airway inflammation in young adults with "outgrown" childhood asthma.

METHODS

We studied 61 nonsmoking medical students (18 intermittent mild asthmatics, 23 students with outgrown childhood asthma but free of asthma-related symptoms for 10 years (asymptomatic asthmatics) and 20 healthy students). BHR and lung function were measured, and induced sputum samples analyzed for eosinophil count, eosinophilic cationic protein (ECP), granulocyte-macrophage colony stimulating factor (GM-CSF), and tumor necrosis factor-alpha (TNF-alpha).

RESULTS

BHR was still present in most asymptomatic asthmatics, but it was milder compared with healthy students. Only three subjects with previous asthma had no BHR and no signs of airway inflammation. Percentages of eosinophil, and ECP, TNF-alpha and GM-CSF concentrations in induced sputum of mild asthmatics and asymptomatic asthma groups were higher than in the healthy group. In asymptomatic asthmatics group, the duration of asthma, sputum eosinophil percentage, and the level of TNF-alpha in sputum correlated significantly with BHR.

CONCLUSIONS

Only a few subjects with longstanding asymptomatic asthma could be considered as cured; most asymptomatic asthmatics continued to exhibit BHR and signs of airway inflammation. The outcome of childhood asthma and BHR was associated with the degree of airway inflammation and the duration of childhood asthma.

Effect of short-term exposure to gaseous pollution on asthma hospitalisation in children: a bi-directional case-crossover analysis

STUDY OBJECTIVE

Assess associations between short-term exposure to gaseous pollutants and asthma hospitalisation among boys and girls 6 to12 years of age.

DESIGN

A bi-directional case-crossover analysis was used. Conditional logistic regression models were fitted to the data for boys and girls separately. Exposures averaged over periods ranging from one to seven days were used to assess the effects of gaseous pollutants on asthma hospitalisation. Estimated relative risks for asthma hospitalisation were calculated for an incremental exposure corresponding to the interquartile range in pollutant levels, adjusted for daily weather conditions and concomitant exposure to particulate matter.

SETTING

Toronto, Ontario, Canada.

PARTICIPANTS

A total of 7319 asthma hospitalisations for children 6 to 12 years of age (4629 for boys and 2690 for girls) in Toronto between 1981 and 1993.

MAIN RESULTS

A significant acute effect of carbon monoxide on asthma hospitalisation was found in boys, and sulphur dioxide showed significant effects of prolonged exposure in girls. Nitrogen dioxide was positively associated with asthma admissions in both sexes. The lag time for certain gaseous pollutant effects seemed to be shorter in boys (around two to three days for carbon monoxide and nitrogen dioxide), as compared with girls (about six to seven days for sulphur dioxide and nitrogen dioxide). The effects of gaseous pollutants on asthma hospitalisation remained after adjustment of particulate matter. The data showed no association between ozone and asthma hospitalisation in children.

CONCLUSIONS

The study showed positive relations between gaseous pollutants (carbon monoxide, sulphur dioxide, and nitrogen dioxide) at comparatively low levels and asthma hospitalisation in children, using bi-directional case-crossover analyses. Though, the effects of certain specific gaseous pollutants were found to vary in boys and girls.

Skin-prick test findings in atopic asthmatic children: a follow-up study from childhood to puberty

In a prospective cohort study we investigated the course of allergic sensitization from childhood to puberty in a group of children with atopic asthma. An attempt was made to correlate the findings with the persistence of asthma. A total of 150 children with atopic asthma established at 7 years of age were evaluated when 8-10 years of age. A battery of skin-prick tests (SPTs) to common environmental allergens, a detailed clinical history for asthma severity classification, and spirometric analyses, were performed. In 127 of these children a re-evaluation was performed at puberty. A variety of statistical methods were used to analyze the results regarding changes in skin test reactivity to individual aeroallergens and atopic index (degree of atopy), as well as to determine any correlation between these changes and the persistence of asthma in puberty. A wide spectrum of modification in skin reactivity to common environmental allergens was observed, including the complete loss of sensitization to some allergens or the development of a new one to others. Specifically, 34% of asthmatic children sensitive to Dermatophagoides pteronyssinus and 52.7% sensitive to cat lost their sensitivity in puberty, while only 7.5% and 11.1%, respectively, became sensitized (p = 0.03 and p = 0.001, respectively). In contrast, regarding pollen sensitivity, 30.2% and 24% of asthmatic children became sensitive in puberty to olive pollen and grasses mix, respectively, and only 11.7% and 12.5%, respectively, lost their sensitivity to these allergens (p = 0.04). No correlation was shown between the skin test reactivity changes to individual allergens and the persistence of asthma, but a significant correlation was found between atopic index to indoor allergens in childhood and the persistence of asthma at puberty (p = 0.04). Interestingly, multi-sensitivity to allergens (>/= 4 allergens) in childhood was also found to correlate with the persistence of asthma at puberty [p = 0.05, odds ratio (OR) = 2.65, 95% confidence interval (CI) 1.2-7.2]. Our findings indicate that significant modification of skin reactivity to common environmental allergens in atopic children with asthma in puberty can occur. However, no association between these changes and the persistence of asthma could be demonstrated, although children with indoor allergic sensitization and multi-reactivity were found to have a higher probability of maintaining their asthma in puberty.

The prevalence of environmental exposure to perceived asthma triggers in children with mild-to-moderate asthma: data from the Childhood Asthma Management Program (CAMP)

BACKGROUND

The Childhood Asthma Management Program, a 5-year randomized clinical trial of treatments for childhood asthma, has enrolled and characterized a cohort of 1041 children with mild-to-moderate asthma.

OBJECTIVE

We sought to describe self-reported sensitivities and environmental exposures and investigate the relationships between self-report of these exposures as asthma triggers and their prevalence in the home.

METHODS

Self-reports of sensitivities and home exposures were obtained by interview with the child or parent. Sensitivities were further assessed by using allergy skin testing (prick or puncture) against a core battery of allergens. Home exposures were further assessed by using analysis of a home dust sample.

RESULTS

Environmental exposures were surprisingly common despite self-reported sensitivities to environmental factors. Of patients reporting that cigarette smoking frequently causes asthma symptoms, 26% reported having at least one parent who smokes cigarettes. Thirty-nine percent of patients reporting that exposure to animals frequently causes asthma symptoms live with a furry pet in their home. We found a smaller proportion of homes with a high level of cat allergen (P <.001) among the children who reported that animals frequently or always trigger asthma symptoms compared with those who reported that animals never or occasionally trigger asthma symptoms, suggesting modification of the home environment. No such results were seen for dog exposure. However, clinical symptoms did not reduce exposure to parental cigarette smoking (P =.15), house dust (P =.31), or damp and musty areas (P =.51).

CONCLUSION

These data suggest that children with mild-to-moderate asthma are frequently symptomatic and exposed to a wide variety of environmental exposures that are perceived to trigger symptoms by means of self-report. Although environmental modification of asthmatic homes may occur, many children remain exposed to agents that are known to trigger their asthma.

Marker antibody expression stratifies Crohn's disease into immunologically homogeneous subgroups with distinct clinical characteristics

BACKGROUND

Perinuclear antineutrophil cytoplasmic antibodies (pANCA) have been detected in a clinically distinct Crohn's disease subpopulation. Antibodies to Saccharomyces cerevisiae (ASCA) have been demonstrated in the majority of patients with Crohn's disease.

AIMS

To examine the relationship between selective marker antibody expression in Crohn's disease and disease onset, location, and clinical behaviour patterns.

METHODS

Sera from 156 consecutive patients with established Crohn's disease were evaluated in a blinded fashion for the presence of ASCA and ANCA. Clinical profiles were generated by investigators blinded to immune marker status.

RESULTS

Using multiple regression analyses, higher ASCA levels were shown to be independently associated with early age of disease onset as well as both fibrostenosing and internal penetrating disease behaviours. Higher ANCA levels were associated with later age of onset and ulcerative colitis-like behaviour. Substratification of the Crohn's disease population using selective ANCA and ASCA expression (high levels of a single marker antibody): (1) distinguished homogeneous subgroups that manifested similar disease location and behaviours; and (2) identified patients with more aggressive small bowel disease.

CONCLUSIONS

The findings suggest that by taking into account the magnitude of the host immune response, Crohn's disease can now be stratified on an immunological basis into more homogeneous clinically distinct subgroups, characterised by greater uniformity among anatomical distribution of disease and disease behaviour.

Problems and possibilities in understanding the natural history of asthma

In early life, asthma symptoms can occur intermittently or may not be severe enough to limit normal activities, which makes it difficult for the clinician to make reliable predictions and administer therapy with some precision. In the case of pediatric asthma, the identification of children who will experience the development of a clinically important illness that will impair their quality of life can be a complex process. The usual methods for describing this information include the prognostic statistics of sensitivity, specificity, likelihood ratio, and positive predictive value. The sensitivity, specificity, and likelihood ratio of various early markers of asthma have been calculated from several cohort studies.

Childhood asthma: causes, epidemiological factors and complications

Asthma is common in children and its prevalence in this age group is increasing. While the reasons for this reported increase, and indeed the true magnitude of the increase, remain unclear, there can be no doubt that asthma is now a major health problem in children worldwide. Fortunately, our knowledge of the pathophysiology of asthma is also increasing. It is now known that asthma is a chronic inflammatory disease regulated by a variety of mediators, of which perhaps the leukotrienes are among the most important. This new understanding of the pathophysiology of the disease has spurred the development of the antileukotriene agents, which can be expected to play an increasingly important role in the management of childhood asthma.

The role of allergy in the development of asthma

Recent studies have shown that initial sensitization to airborne environmental allergens occurs typically in early childhood, but subsequent progression to persistent atopic asthma, which may not manifest for several years, is restricted to only a subset of atopics. The key to establishing the link between atopy and asthma lies in the development of persistent inflammation in the airway wall, resulting in structural and functional changes in local tissues which are responsible for the symptoms of the disease. This review summarizes recent findings on the nature of the cellular and molecular mechanisms underlying this process, and addresses the issue of why the intensity and duration of these tissue-damaging responses in the airway wall apparently exceeds the critical threshold required for development of persistent asthma in only a minority of allergy sufferers.

Respiratory symptoms and duration of residence in immigrant teenagers living in Melbourne, Australia

OBJECTIVE

Examination of the relation between respiratory symptoms and time since arrival in Australia in immigrant teenagers living in Melbourne.

DESIGN

Two stage, stratified, cross sectional survey.

SETTING

High schools (n = 51).

SUBJECTS

9794 people aged 13-19 years.

MAIN OUTCOME MEASURES

Prevalence of wheeze during a 12 month period, region of birth, duration of residence in Australia.

RESULTS

The estimated population 12 month period prevalence of wheeze was 18.9% (95% confidence interval (CI), 18.0 to 19.9). In subjects born outside Australia, residence for five to nine years in Australia was associated with a 2.1-fold (CI, 1.1 to 4.0) increase in the odds of self reported wheeze; after 10-14 years, this risk increased 3.4-fold (CI, 1.8 to 6.7). There was no difference in severity of wheeze, measured by reported frequency of attacks, between Australian born and non-Australian born subjects.

CONCLUSIONS

The notion of a continued secular increase in the prevalence of wheezing is not supported. There is a time dose effect on the prevalence of symptoms in subjects born outside Australia and now living in Melbourne, which is independent of age and country of birth.

Atopy and allergic disorders among adults in Tartu, Estonia compared with Uppsala, Sweden

BACKGROUND

Recent studies in children and adults indicate that the prevalence of atopy and allergic disorders is lower in previously socialist countries in Eastern Europe compared with countries with a market economy while revealed risk factors are similar.

OBJECTIVES

To estimate the prevalence of atopy among adults in Tartu, Estonia and to compare the prevalence of risk factors for atopy and allergic respiratory diseases in Estonia and Sweden.

METHODS

As a part of cross-sectional study-European Community Respiratory Health Survey-random samples of 20-44 year olds (n = 351 in Tartu and n = 470 in Uppsala) and persons of the same age with asthma like symptoms or on current asthma medication according to a postal questionnaire (n = 95 in Tartu and n = 201 in Uppsala) were interviewed and circulating IgE antibodies were measured.

RESULTS

The prevalence of atopy was 19% in Tartu and 32% in Uppsala (P < 0.001). The prevalence of sensitization to pollen was twice lower (11.5 vs 23.2; P<0.001) and the prevalence of pollen associated asthma symptoms was four times lower (1.7 vs 6.8; P<0.001) in Tartu than in Uppsala while sensitization to pollen was an equally large risk factor for asthma in both centres. Age was inversely related to cat and pollen associated symptoms of rhinoconjunctivitis in Uppsala (OR 0.6 and 0.7, respectively, P < 0.05) but not in Tartu.

CONCLUSIONS

The prevalence of atopy was lower in Tartu, Estonia than in Uppsala Sweden. Perception of allergic disorders seemed to be lower in Tartu than in Uppsala. Age did not influence the prevalence of atopy nor allergic disorders in Tartu, while in Uppsala age was inversely related to clinical allergy. This could suggest a cohort effect underlying the increasing prevalence of allergy in Western Europe.