Gender differences in asthma prevalence may depend on how asthma is defined

Characteristics of inpatients with atopic asthma in a tertiary center: Do age and gender have an influence?

Background: Several studies have demonstrated gender influence on asthma prevalence, being higher among males during early childhood. Little is known about the impact of gender and age on asthma exacerbation characteristics in pediatrics. This study aimed to determine the differences in acute asthma between males and females in three different age groups regarding perinatal characteristics of asthmatic patients, comorbidities, medication adherence, level of blood eosinophils, and pattern of hospitalization.Methods: The medical records of 130 pediatric patients with asthma, who presented to the emergency department at Jordan University hospital with asthma exacerbations, were retrospectively reviewed. Demographic information and clinical characteristics were collected.Results: The mean age of patients was 10.7±4.7 years. The age at diagnosis and gestational age were significantly higher in older children. Furthermore, younger children were significantly more likely to experience winter exacerbations and more emergency presentations. Male patients were considerably younger than their female counterparts and were diagnosed younger. In addition, male patients were more likely to have eosinophil levels higher than 3% than female patients.Conclusion: Gender plays a role in the development and outcome of asthma exacerbations at different ages of pediatrics. A better understanding of gender-based and age-based differences in asthma dictates a personalized approach to treatment.

Yoga Education Program for Reducing Drug Dependency and Promoting Better Asthma Control for Chronic Asthmatic Children: A Multicity Experiment

This article reports a 1-year long yoga education program (YEP) experiment aimed at reducing drug dependency and promoting better asthma control for chronic asthmatic children. Participants were 450 chronic asthmatic children across 4 cities. Two measures were used: Pediatric Asthma Diary (PAD) and Childhood Asthma Control Test (C-ACT). Results indicated that intervention group children had better asthma control in terms of lower average PAD scores and higher C-ACT scores and reduced drug intake vis-à-vis the control group. Within the intervention cohort, asthma symptoms persistence was lower and control was higher for children from Asian cities, boys, Hindus, middle-class children, those whose mothers were their primary caregivers, who lived in standard family setups, who also attended the optional YEP rounds, and regularly self-practiced. The strongest predictor of lower posttest PAD scores and higher C-ACT scores was self-practice. The YEP can be used as an effective complementary treatment for chronic asthmatic children.

Serum perfluoroalkyl substances (PFAS) and risk of asthma and various allergies in adolescents. The Tromsø study Fit Futures in Northern Norway

BACKGROUND

Exposure to environmental pollutants may contribute to the development of asthma and other allergies. The aim of this study was to investigate possible associations between asthma and other allergies with exposure to perfluoroalkyl substances (PFASs) in adolescents from the Arctic region of Norway.

METHODS

The Tromsø study Fit Futures 1 (TFF1) and 3-year follow-up Fit Futures 2 study (TFF2) included 675 adolescents that completed a questionnaire about health conditions and underwent a clinical examination with blood tests and fractional nitric oxide (FeNO) measurement. Serum concentrations of 18 PFASs were measured by UHPLC-MS/MS method.

RESULTS

Total PFASs (ΣPFAS) serum concentration over 4th quartile was positively associated with asthma in the TFF1 (OR 3.35 (95% CI 1.54-7.29), p = 0.002). Total perfluorooctane sulfonate (ΣPFOS), linear PFOS (linPFOS), linear perfluorohexane sulfonate (linPFHxS) concentrations over 4th quartiles were associated with 2 times higher odds of asthma in the TFF1. The positive associations between ΣPFAS, ΣPFOS, linPFOS and asthma remained statistically significant in the TFF2. ΣPFAS and linPFHxS concentrations over 3rd tertiles were associated with positive marker of eosinophilic airways inflammation FeNO> 25 ppb. Concentrations of ΣPFOS and linPFOS over 3rd quartiles were positively associated with self-reported nickel allergy (OR 2.25 (95% CI 1.17-4.35) p = 0.016 and OR 2.53 (95% CI 1.30-4.90) p = 0.006, respectively). Allergic rhinitis, self-reported pollen allergy, food allergy and atopic eczema were not associated with PFASs concentrations.

CONCLUSIONS

This study of Norwegian adolescents showed a positive association between several PFASs and asthma, as well as between PFOS and nickel allergy.

Age at Menarche and Risk of Respiratory Diseases

Several studies have suggested a relationship between reproductive history and respiratory health. The present study explores the association between the age at menarche and the risk of respiratory diseases during early adulthood. The anthropometrical and questionnaire research was conducted among 1323 female university graduates. In a subsample of 152 non-allergic women spirometry tests were additionally performed. We found that the prevalence of allergic diseases, on average, was slightly higher among females having early menarche than in those with a later onset of menstruation; the difference failed to reach statistical significance. However, the risk of allergic rhinitis was significantly related with early menarche compared with average-time, taken as a reference, or late menarche (OR = 1.61 vs. OR = 1 (Ref.) vs. OR = 1.23, p = 0.020). The difference remained significant after adjusting for adiposity (p = 0.050) and socio-economic status (p = 0.001). There was no significant relationship between the age at menarche and the incidence of respiratory infections. We noticed a tendency for increased spirometry variables with increasing age at menarche. In conclusion, early menarche is a risk factor for allergic rhinitis in early adulthood.

Relationship between physical activity level and psychosocial and socioeconomic factors and issues in children and adolescents with asthma: a scoping review

BACKGROUND

Asthma is a heterogeneous chronic airway disease which may reduce capability for physical activity. In healthy peers, physical activity is influenced by psychosocial and socioeconomic factors. Knowledge about the role of these factors has not been mapped in children and adolescents with asthma.

OBJECTIVE

The main objective of this scoping review was to identify psychosocial and socioeconomic factors associated with physical activity level in children and adolescents with asthma in the literature. The specific objectives were to map the instruments used to measure these factors, report on the construction and validation of these instruments, map psychosocial and socioeconomic issues related to physical activity level reported in qualitative studies, and identify gaps in knowledge about the relationship between psychosocial and socioeconomic factors and physical activity level in children and adolescents with asthma.

INCLUSION CRITERIA TYPES OF PARTICIPANTS

Children and adolescents with asthma aged six to 18 years.

CONCEPT

Psychosocial and socioeconomic factors related to physical activity level and participation.

CONTEXT

All physical activity contexts.

TYPES OF SOURCES

Quantitative and qualitative primary studies in English, with no date limit.

SEARCH STRATEGY

The databases searched included nine major databases for health and sports science, and five databases for unpublished studies. After screening and identification of studies, the reference lists of all identified reports were searched, and forward citation searches were conducted using four databases.

EXTRACTION OF THE RESULTS

The following data were extracted: (a) relevant study characteristics and assessment of physical activity level, (b) instruments used to assess psychosocial and socioeconomic factors, (c) association between physical activity level and these factors, (d) construction and validation of instruments, and (e) psychosocial and socioeconomic issues related to physical activity participation.

PRESENTATION OF THE RESULTS

Twenty-one quantitative and 13 qualitative studies were included. In cross-sectional studies, enjoyment, physical self-concept, self-efficacy, attitudes and beliefs about physical activity and health, psychological distress, health-related quality of life, and social support were more often reported as being correlated with physical activity level. In three studies, the construct validity was assessed by factor analysis and construct reliability tests for the study population. Qualitative studies reported 10 issues related to physical activity participation, and capability and being like peers were most commonly reported. There was no direct evidence that qualitative research informed the development or adjustment of instruments in quantitative studies.

CONCLUSIONS

Seven psychosocial factors correlated with physical activity level; capability and being like peers were the most commonly reported issues. Reports of the construction and validation of instruments were sparse.

Relationship between physical activity level and psychosocial and socioeconomic factors and issues in children and adolescents with asthma: a scoping review protocol

REVIEW QUESTION/OBJECTIVE

The first objective of this scoping review is to identify and map information about instruments used to measure psychosocial and socioeconomic factors associated with level of physical activity (PA) in children and adolescents with asthma that have been reported in quantitative literature, and to report on the construction and validation of these instruments. The second objective is to identify and map psychosocial and socioeconomic issues related to PA level reported in qualitative literature and gaps in the evidence on the relationship between psychosocial and socioeconomic factors and PA level in children and adolescents with asthma.Specifically the review questions are as follows.

Adolescent boys with asthma - a pilot study on embodied gendered habits

Purpose

Asthma is a common chronic disease with gender differences in terms of severity and quality of life. This study aimed to understand the gendered practices of male asthmatic adolescents in terms of living with and managing their chronic disease. The study applied a sociological perspective to identify the gender-related practices of participants and their possible consequences for health and disease.

Patients and methods

The study used a combined ethnomethodology and grounded theory design, which was interpreted using Bourdieu’s theory of practice. We aimed to discover how participants interpreted their social worlds to create a sense of meaning in their everyday lives. The study was based on multistage focus group interviews with five adolescent participants at a specialist center for asthmatic children and youths. We took necessary precautions to protect the participants, according to the principles of the Declaration of Helsinki. The study protocol was approved by the Regional Committee for Medical Research Ethics and the hospital’s research department.

Results

The core concept for asthmatic male adolescents was being men. They were focused on being nonasthmatic, and exhibited ambivalence towards the principles of the health services. Physical activity supported their aim of being men and being nonasthmatic, as well as supported their treatment goals. Being fearless, unconcerned, “cool,” and dependent also supported the aim of being men and being nonasthmatic, but not the health service principle of regular medication. Occasionally, the participants were asthmatic when they were not able to or gained no advantages from being nonasthmatic. Their practice of being men independently of being asthmatic emphasized their deeply gendered habits.

Conclusion

Understanding gender differences in living with and managing asthma is important for health workers. Knowledge of embodied gendered habits and their reproduction in social interactions and clinical work should be exploited as a resource during the supervision of asthmatic adolescent boys.

Prevalence of asthma symptoms based on the European Community Respiratory Health Survey questionnaire and FENO in university students: gender differences in symptoms and FENO

BACKGROUND

The fractional concentration of nitric oxide in exhaled air (FENO) is used as a biomarker of eosinophilic airway inflammation. FENO is increased in patients with asthma. The relationship between subjective asthma symptoms and airway inflammation is an important issue. We expected that the subjective asthma symptoms in women might be different from those in men. Therefore, we investigated the gender differences of asthma symptoms and FENO in a survey of asthma prevalence in university students.

METHODS

The information about asthma symptoms was obtained from answers to the European Community Respiratory Health Survey (ECRHS) questionnaire, and FENO was measured by an offline method in 640 students who were informed of this study and consented to participate.

RESULTS

The prevalence of asthma symptoms on the basis of data obtained from 584 students (266 men and 318 women), ranging in age from 18 to 24 years, was analyzed. Wheeze, chest tightness, an attack of shortness of breath, or an attack of cough within the last year was observed in 13.2% of 584 students. When 38.0 ppb was used as the cut-off value of FENO to make the diagnosis of asthma, the sensitivity was 86.8% and the specificity was 74.0%. FENO was ≥ 38.0 ppb in 32.7% of students. FENO was higher in men than in women. The prevalence of asthma symptoms estimated by considering FENO was 7.2%; the prevalence was greater in men (9.4%) than women (5.3%). A FENO ≥ 38.0 ppb was common in students who reported wheeze, but not in students, especially women, who reported cough attacks.

CONCLUSIONS

The prevalence of asthma symptoms in university students age 18 to 24 years in Japan was estimated to be 7.2% on the basis of FENO levels as well as subjective symptoms. Gender differences were observed in both FENO levels and asthma symptoms reflecting the presence of eosinophilic airway inflammation.

TRIAL REGISTRATION NUMBER

UMIN000003244.

Adolescents with asthma: consequences of transition from paediatric to adult healthcare

PURPOSE

A prospective follow-up of adolescents with asthma designed to identify risk factors for deterioration during and after transfer from paediatric to adult healthcare.

METHODS

Adolescents (n=150) with asthma being transferred from paediatric to adult healthcare were recruited consecutively and those with mild/moderate asthma assigned randomly to primary care or specialized care at an adult asthma clinic. Tests of pulmonary function, bronchial responsiveness and working capacity and skin prick tests were performed at the time of entry into the study and two and/or five years later.

RESULTS

Initially, 88.7% of the subjects demonstrated at least one positive skin prick test. During the five-year follow-up, FEV(1) improved, while FEV(1)/FVC remained unchanged. Bronchial hyperresponsiveness was present in 71% of the subjects at the time of inclusion and 59% five years later, while 20 developed hyperresponsiveness during this period. Poor adherence to treatment, female gender and inhalation of steroids exerted negative impacts on logPD(20). The risk for persistence of bronchial hyperresponsiveness was elevated by poor adherence and attenuated by regular exercise. The decline observed in working capacity demonstrated no correlation to the risk factors examined. Subjects with mild/moderate asthma who received primary or specialized care exhibited similar pulmonary function, responses to a histamine challenge and working capacities.

CONCLUSIONS

During a five-year follow-up of asthmatic adolescents leaving paediatric care, pulmonary function rarely deteriorated, but bronchial hyperresponsiveness persisted. Female gender and poor adherence to treatment exerted negative impact on bronchial hyperresponsiveness. Mild/moderate asthma was managed equally effectively with primary or specialized care.

Similar response in male and female B10.RIII mice in a murine model of allergic airway inflammation

BACKGROUND

Several reports have been published on the gender differences associated with allergies in mice.

GOAL

In the present study we investigate the influence of gender on allergy response using a strain of mice, B10.RIII, which is commonly used in the collagen-induced arthritis murine model.

METHODS

Both male and female B10.RIII young mice were immunized with OVA and challenged four times with OVA intranasally. Samples were taken 24 h after the last challenge, and eosinophils in bronchoalveolar lavage (BAL) and parenchyma, Th-2 cytokines in BAL, total and antigen-specific IgE in sera, and antigen-specific T-cell proliferation were measured.

RESULTS

Immunization in both male and female B10.RIII mice with OVA elicited a classical Th2-type response. Results showed no significant differences among male and female mice. Also a high eosinophilia in BAL fluid and parenchyma was produced in both genders without any significant differences. However, the deviation of both parameters was higher in young males compared to young females.

CONCLUSIONS

Gender differences, classically associated with some strains of mice, are not reproducible in B10.RIII mice. Gender differences in murine models of allergic airway inflammation are probably strain-dependent.

Bronchial hyperresponsiveness in skiers: field test versus methacholine provocation?

INTRODUCTION

Asthma is frequently reported in endurance athletes, particularly in cross-country skiers. It has been reported that an exercise field test performed with the competitive type of exercise is the better for diagnosing asthma and bronchial hyperresponsiveness in athletes than bronchial provocation with methacholine.

OBJECTIVE

The main objective was to compare an exercise field test consisting of a skiing competition with methacholine bronchial provocation in the diagnosis of asthma and bronchial hyperresponsiveness among skiers.

METHODS

Twenty-four elite cross-country skiers from the Norwegian national teams (males/females = 16/8) were included in the study. The cumulative dose of inhaled methacholine causing a 20% fall in forced expiratory volume in 1 s (FEV1) (PD20) was compared with reduction in lung function (FEV1) >or= 10% from before to after an exercise field test consisting of a cross-country skiing competition, 10 km (males) and 7 km (females), respectively.

RESULTS

Nine out of 24 (37.5%) athletes experienced a positive methacholine test (PD20 < 8 micromol) (2 females and 7 males), whereas only 2 of the 24 subjects (8.3%) had reductions in FEV1 >or= 10% after the exercise field test. A significant negative correlation was found between age and bronchial responsiveness, r = -0.47, P = 0.02.

CONCLUSION

The methacholine bronchial provocation test is more sensitive than a sport specific exercise field test for identifying athletes with asthma and/or bronchial hyperresponsiveness.

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.

Cow's milk exposure and asthma in a newborn cohort: repeated ascertainment indicates reverse causation

The effect of cow's milk consumption on childhood asthma has been debated for several years. This study attempts to provide further insight into this association through the use of a longitudinal study design. Newborns from parents with atopic history were recruited from Germany, Austria, and England (n = 696). For five repeated ascertainments, information was collected on cow's milk exposure, incidence of doctor-diagnosed asthma, and confounders. Generalized estimation equations, incorporating different models (concurrent, delayed, combined, and reverse causation), were used to determine this association. No association between cow's milk consumption and childhood asthma was found for the concurrent effects model (OR = 0.81, 95% confidence interval [CI]: 0.55, 1.20). In the delayed effects model, the direction of the association varied with time of follow-up. Thus, we stratified by period, which resulted in a significant protective delayed effect at 36 months (OR = 0.18, 95% CI = 0.06, 0.49). However, reverse causation negated this finding since the presence of asthma in prior months led to a reduction in further exposure to cow's milk (OR = 0.40, 95% CI = 0.16, 0.99). Hence, cow's milk consumption does not protect against childhood asthma. The apparent protection of cow's milk against asthma may result from parents of asthmatic children avoiding cow's milk, rather than actual prophylaxis.

Interactions between breast-feeding, specific parental atopy, and sex on development of asthma and atopy

BACKGROUND

The influence of breast-feeding on the risk of developing atopy and asthma remains controversial.

OBJECTIVE

To examine asthma and atopy outcomes by sex, reported specific parental history of atopy, and breast-feeding.

METHODS

In a birth cohort, we examined childhood asthma and atopy (positive skin prick tests) by sex and breast-feeding in relation to maternal and paternal atopy. Interactions were explored in logistic regression models.

RESULTS

For boys, breast-feeding (odds ratio [OR], 1.63; 95% CI, 0.93-2.87; P = .09) and maternal atopy (OR, 1.95; 95% CI, 0.93-4.08; P = .08) were each associated with atopy at age 13 years. Breast-feeding increased the risk for atopy among boys with paternal atopy (OR, 7.39; 95% CI, 2.21-24.66) compared with non-breast-fed boys with paternal atopy, but did not significantly further increase risk among subjects with maternal atopy. For girls, breast-feeding (OR, 0.74; 95% CI, 0.41-1.31) and maternal and paternal atopy were not independent risk factors for atopy at age 13 years. However, breast-feeding increased the risk for atopy in girls with maternal atopy (OR, 3.13; 95% CI, 1.20-8.14) compared with non-breast-fed girls with maternal atopy. There was no such effect among subjects with paternal atopy. Results for the outcome of asthma followed a similar pattern.

CONCLUSION

The influence of breast-feeding on development of atopy and asthma differs by sex and by maternal and paternal atopy, and is most significant among subjects at lower baseline risk.

CLINICAL IMPLICATIONS

Analyses of environmental risk factors for asthma and atopy should be stratified by specific parental atopy and sex.

Changing trends in sex specific prevalence rates for childhood asthma, eczema, and hay fever

Numerous surveys of school-aged children have shown increasing asthma prevalence with a less publicized but noticeable change in the male to female ratio. We sought to confirm this change in the sex ratio in four questionnaire-based surveys and investigate possible explanations. Identical questionnaire surveys were performed in 1989 (n=3,390), 1994 (n=4,047), 1999 (n=3,540) and 2004 (n=1,920) in school-children aged 9-11 years. Over these 15 years the male to female ratio (M:F) significantly narrowed for wheeze (1.34 to 0.98:1 P < 0.0002), for asthma (1.74 to 1.02:1 P < 0.0001), for eczema (1.42:1 to 0.81:1 P < 0.0001) and for hay fever (1.46 to 0.93:1 P < 0.0001). The diagnosis of asthma in children with wheeze was more commonly made in boys in 1989 relative risk RR 1.32 (1.12, 1.56), even in those with accompanying eczema and/or hay fever RR 1.20 (0.99, 1.45). By 2004 this sex bias in diagnosis was no longer present, RR 1.01 (0.91, 1.12) for wheeze and 1.02 (0.85, 1.21) for those with wheeze and eczema and/or hay fever. From 1989 to 2004 no significant difference in sex distribution changes between older and younger children occurred, making secular trends in the onset of puberty in females an unlikely contributory factor. The disappearance of the bias to diagnose asthma in symptomatic males but not in females may be partly responsible for the narrowing of the sex ratio, but other factors such as those enhancing the expression of asthma and atopy in females may also be implicated.

The therapy of pre-school wheeze: appropriate and fair?

The current study aimed to assess prevalence and distribution of use of asthma medication for wheeze in pre-school children in the community. We sent a postal questionnaire to the parents of a random population-based sample of 4,277 UK children aged 1-5 years; 3,410 participated (children of south Asian decent were deliberately over-represented). During the previous 12 months, 18% of the children were reported to have received bronchodilators, 8% inhaled corticosteroids (ICS) and 3% oral corticosteroids. Among current wheezers these proportions were 55%, 25%, and 12%, respectively. Use of ICS increased with reported severity of wheeze, but did not reach 60% even in the most severe category. In contrast, 42% of children receiving ICS reported no or very infrequent recent wheeze. Among children with the episodic viral wheeze phenotype, 17% received ICS compared with 40% among multiple-trigger wheezers. Use of ICS by current wheezers was less common in children of South Asian ethnicity and in girls. Although a high proportion of pre-school children in the community used asthma inhalers, treatment seemed to be insufficiently adjusted to severity or phenotype of wheeze, with relative under-treatment of severe wheeze with ICS, especially in girls and South Asian children, but apparent over-treatment of mild and episodic viral wheeze and chronic cough.

Diagnosing asthma in young children

PURPOSE OF REVIEW

Asthma is defined by the 1997 National Asthma Education and Prevention Program guideline as a chronic inflammatory disorder of the airways which leads to an increase in bronchial hyperresponsiveness to a variety of stimuli or triggers. Since it is difficult to determine whether an individual patient has the above pathophysiology, particularly in young children, it is essential that clinically useful criteria be identified that can serve as proxies for the presence of asthma.

RECENT FINDINGS

There are three reasons for making a diagnosis: to identify the most effective treatment to alleviate symptoms and prevent mortality; to educate the parent or primary caregiver to manage symptoms and avoid triggers; and to estimate the prognosis. A diagnostic test is a procedure which gives a rapid, convenient and inexpensive indication of whether a patient has a certain disease. The likelihood ratio incorporates both the sensitivity and specificity of the test and provides a direct estimate of how much a test result will change the odds of having a disease.

SUMMARY

By applying the principles of evidence-based medicine to define likelihood ratios for each criterion, it should be possible to define the probability of asthma and to identify the best treatment. Future research should permit accurate correlations to be drawn between the underlying pathophysiology and the clinical condition commonly known as asthma.

Factors influencing gender differences in the diagnosis and treatment of asthma in childhood: the Tucson Children's Respiratory Study

Studies identified gender differences in diagnosed asthma, but the extent to which they can be attributed to differences in symptom experience and frequency rather than factors influencing diagnosis has not been established. We investigated prevalence of, and consultation for, asthma symptoms, as well as diagnosis and treatment in 533 boys and 556 girls enrolled in the Tucson Children's Respiratory Study, a population-based birth-cohort study. Questionnaires regarding respiratory symptoms and diagnoses were obtained at ages 2, 3, 6, 8, 11, 13, 16, and 18 years. Boys were significantly more likely than girls to experience both wheeze and frequent wheeze most years in the first decade of life. However, girls with symptoms were less likely than boys to see a physician (74.1% vs. 83.4%, P < 0.001) and to be labeled as having asthma (43.3% vs. 53.8%, P < 0.009), even after adjusting for symptom frequency. A difference in symptom presentation also appeared to influence diagnosis: nocturnal cough without frequent wheeze was more prevalent among girls, and was associated with reduced diagnosis of asthma. Among subjects who consulted a physician for wheeze, boys were significantly more likely than girls to have taken medication (81.5% vs. 73.5%, P < 0.01). The lag time between age at first wheeze and first use of medication among those consulting a physician for wheeze or asthma was greater for girls, especially among subjects with frequent wheeze (2.8 vs. 1.6 years, P < 0.005). These findings indicate that gender differences in the diagnosis and treatment of asthma cannot be explained completely by differences in symptom prevalence and frequency.

Sex differences in factors associated with childhood- and adolescent-onset wheeze

RATIONALE

Factors predicting the development of wheeze may differ between sexes and between childhood and adolescence.

METHODS

A New Zealand birth cohort of 1,037 children was followed to age 26. For this analysis, those reporting recurrent wheezing at two or more assessments were classified as "wheezers." We examined risk factors for development of wheeze before age 10 (childhood) and subsequently (adolescent-onset) for males and for females separately using Cox regression modeling.

RESULTS

Males more often developed childhood wheeze (p = 0.002) and females adolescent-onset wheeze (p < 0.001). Maternal atopy (asthma or hay fever) was a risk factor for childhood wheeze in both sexes (hazard ratio [HR], 1.48, p < 0.05 for males; HR, 2.37, p < 0.001 for females). Paternal atopy also influenced childhood wheeze, significantly for males (HR, 1.72; p = 0.01), and similarly but not significantly for females (HR, 1.70; p = 0.08). For adolescent-onset wheeze, neither maternal (HR, 1.41; p = 0.19) nor paternal history (HR, 0.73; p = 0.42) was a risk factor in males, but maternal history (HR, 2.08; p < 0.01) was a significant risk factor for females. When both age ranges were combined, providing greater power for analysis, paternal history was a stronger risk factor for wheeze in females (HR, 1.62; p = 0.02) than in males (HR, 1.35; p = 0.12).

CONCLUSION

The influence of parental atopy on the development for wheeze differs between males and females and between childhood- and adolescent-onset wheeze.

Health-related quality of life among adolescents with allergy-like conditions - with emphasis on food hypersensitivity

BACKGROUND

It is known that there is an increase in the prevalence of allergy and that allergic diseases have a negative impact on individuals' health-related quality of life (HRQL). However, research in this field is mainly focused on individuals with verified allergy, i.e. leaving out those with self-reported allergy-like conditions but with no doctor-diagnosis. Furthermore, studies on food hypersensitivity and quality of life are scarce. In order to receive information about the extent to which adolescent females and males experience allergy-like conditions and the impact of these conditions on their everyday life, the present study aimed to investigate the magnitude of self-reported allergy-like conditions in adolescence and to evaluate their HRQL. Special focus was put on food hypersensitivity as a specific allergy-like condition and on gender differences.

METHODS

In connection with lessons completed at the children's school, a study-specific questionnaire and the generic instrument SF-36 were distributed to 1488 adolescents, 13-21 years old (response rate 97%).

RESULTS

Sixty-four per cent of the respondents reported some kind of allergy-like condition: 46% reported hypersensitivity to defined substances and 51% reported allergic diseases (i.e. asthma/wheezing, eczema/rash, rhino-conjunctivitis). A total of 19% reported food hypersensitivity. Females more often reported allergy-like conditions compared with males (p < 0.001). The adolescents with allergy-like conditions reported significantly lower HRQL (p < 0.001) in seven of the eight SF-36 health scales compared with adolescents without such conditions, regardless of whether the condition had been doctor-diagnosed or not. Most adolescents suffered from complex allergy-like conditions.

CONCLUSIONS

The results indicate a need to consider the psychosocial impact of allergy-like conditions during school age. Further research is needed to elucidate the gender differences in this area. A team approach addressing better understanding of how allergy-like conditions impair the HRQL may improve the management of the adolescent's health problems, both in health-care services and in schools.

Airway function in women: bronchial hyperresponsiveness, cough, and vocal cord dysfunction

Bronchial hyperreactivity and cough are common medical problems that occur more frequently in women. Differences in size, hormonal effects, density, and sensitivity to receptors and psychologic factors may all play a role, which results in increased expression of upper and lower airway disease. The reason that VCD occurs more commonly in women is not clear but many of the same explanations regarding bronchial hyperreactivity and cough may apply.

Is there a causative role for tetanus toxoid vaccination in the development of allergy-like symptoms and in the increasing prevalence of atopic diseases?

Allergic diseases are a worldwide health problem. They mainly affect people living in developed countries where an increasing prevalence of allergy symptoms has been recorded in the last 20-30 years. The cause of this increase is still disputed, and, among others, the "hygiene hypothesis" supported the concept that relevant changes in lifestyle could have a relationship with the phenomenon. More recently the recorded parallel increase in autoimmune diseases has suggested to consider the "hygiene hypothesis" as a cause of a more general disregulation of the immune system leading to both allergy and to autoimmunity. Here are reported a series of observations, evidence, and data from the literature leading to a different hypothesis. The key points are: (1) the presence of two subsets of patients having allergy symptoms based on an IgE-mediated mechanism or not; (2) the positive results obtained with the autologous serum skin test in either cutaneous or respiratory affected subjects, mainly in children and adult females; (3) the presence of IgG autoantibodies against the alpha-chain of the high affinity IgE receptor (FcepsilonRIalpha) in non-IgE-mediated urticaria and even in respiratory subjects; (4) the cross-reactivity between epitopes of the tetanus toxoid molecule and the FcepsilonRIalpha detected by means of an alpha-chain affinity purified IgG fraction; (5) the positive skin reactivity obtained using IgG anti-tetanus toxoid preparations in allergic and non-allergic volunteers. The presence of IgG autoantibodies actively generated by the population-based vaccination with tetanus toxoid could induce both mediator release from activated mast cell and Th2 cytokine production early in life. There are epidemiological evidences that tetanus toxoid vaccination could be linked with an increased tendency to have allergy symptoms. The different epidemiological distribution of non-IgE-mediated symptoms, mainly affecting young infants would be in agreement with the present hypothesis. The prevalent mother-to-child relationship in terms of risk for allergy symptoms could be explained with the trans-placenta transfer of IgG. A similar transfer could also take place through the mother milk during breast feeding. It may thus be hypothesized that the increased prevalence of allergic diseases could be caused by the generalized tetanus toxoid immunization procedure, progressively extended to most of the countries worldwide in the last 30-40 years. Both the induction of non-IgE-mediated symptoms caused by the mast cell activation via the anti-FcepsilonRIalpha IgG and the long lasting Th2 inflammation of affected tissues would be the inducing mechanisms. This hypothesis would re-configure part of the allergic diseases as a Th2 phenotypic expression of an autoimmune disease.