The relationship of sex to asthma prevalence, health care utilization, and medications in a large managed care organization

The Roles of Sex Hormones in the Course of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by T helper 2 cell (Th2)-shifted abnormal immunity, skin barrier impairment, and pruritus. The prevalence of AD in childhood is slightly higher in boys than in girls; after puberty, the sexual difference is reversed. The female preponderance in all generations exists in intrinsic AD with enhanced Th1 activity and nickel allergy, lacking increased serum IgE or filaggrin mutation. AD is often deteriorated before menstruation. We review the effects of sex hormones on immune responses and skin permeability barrier and propose possible hypotheses for the above phenomena. After puberty, the immune responses of patients are remarkably influenced by sex hormones. Estrogen and progesterone enhance the activities of Th2/regulatory T cell (Treg) but suppress Th1/Th17. Androgens suppress Th1/Th2/Th17 and induce Treg. The skin permeability barrier is fortified by estrogen but is impaired by progesterone and androgens. Dehydroepiandrosterone suppresses Th2 but enhances Th1. The amount of steroid sulfatase converting dehydroepiandrosterone sulfate to dehydroepiandrosterone is higher in women than in men, and thus, women might be more susceptible to the influence of dehydroepiandrosterone. The balance of modulatory effects of sex hormones on immune responses and skin barrier might regulate the course of AD.

Asthma control and acute healthcare visits among young adults with asthma-A population-based study

AIMS

To study asthma control and acute healthcare visits among young adults with asthma.

BACKGROUND

Despite the access to effective treatment and nursing interventions, poor asthma control is still common among individuals with asthma. However, studies describing clinical characteristics among young adults with asthma are rare.

DESIGN

A population-based cohort study.

METHODS

In 2015, as a part of the OLIN paediatric cohort I (recruited in 1996 at age 7-8 years), N = 2,291 young adults (27-28 years) completed a postal questionnaire survey including questions on asthma and respiratory symptoms. Of these, N = 280 (12%) were identified as having current asthma and were further studied.

RESULTS

Of those with current asthma, women reported respiratory symptoms and smoking to a greater extent than men. Approximately one-fourth had uncontrolled asthma and acute healthcare visits due to asthma was reported by 15% of women and 8% of men. Uncontrolled asthma was associated with smoking, lower educational level, use of reliever treatment most days, and acute healthcare visits. Acute healthcare visits due to asthma were associated with periodic use of regular controller treatment also after adjustment for uncontrolled asthma.

CONCLUSION

The result indicate poor adherence to asthma treatment which may lead to decreased asthma control and acute healthcare visits.

IMPACT

Most young adults with asthma are diagnosed and treated in primary care, ideally in a team with a nurse. The main findings highlight the need for evidenced-based nursing interventions, contributing to a more efficient asthma management in primary care.

Novel Insights on Sex-Related Differences in Asthma

PURPOSE OF REVIEW

Asthma, a common respiratory disease that affects about 10% of the US population, represents a significant public health issue. In the last decade, cumulative evidence has demonstrated sex disparities in asthma, including significant differences in epidemiology, clinical presentation, response to therapies, and health outcomes. Understanding sex-related differences in asthma enables clinicians to provide personalized asthma care and improve asthma outcome.

RECENT FINDINGS

Recent studies on sex-related differences in asthma inform us on mechanism underlying asthma pathogenesis across all age groups. Sex hormones directly modulate immune pathways crucial in asthma pathogenesis and affect individual's response to environmental triggers and medications, such as leukokotriene inhibitors. Not surprisingly, the use of external sex hormone supplementations appears to modulate asthma risk. Identification of sex-specific asthma risk loci through genome-wide association studies also provides supporting evidence on sex-related differences in asthma. There is an interaction between sex and obesity, an interaction that could place females at higher risk for systemic inflammation and, consequently, asthma. In this article, we review epidemiological and clinical studies on sex-related differences in asthma, with a special focus on the role of sex hormones, including hormonal therapies and the asthma-obesity interaction.

Mechanical Abnormalities of the Airway Wall in Adult Mice After Intrauterine Growth Restriction

Developmental abnormalities of airways may impact susceptibility to asthma in later life. We used a maternal hypoxia-induced mouse model of intrauterine growth restriction (IUGR) to examine changes in mechanical properties of the airway wall. Pregnant BALB/c mice were housed under hypoxic conditions (10.5% O₂) from gestational day (GD) 11 to GD 17.5 (IUGR; term, GD 21). Following hypoxic exposure, mice were returned to a normoxic environment (21% O₂). A control group of pregnant mice were housed under normoxic conditions throughout pregnancy. At 8 weeks postnatal age, offspring were euthanized and a tracheasectomy performed. Tracheal segments were studied in organ baths to measure active airway smooth muscle (ASM) stress to carbachol and assess passive mechanical properties (stiffness) from stress-strain curves. In a separate group of anesthetized offspring, the forced oscillation technique was used to examine airway mechanics from relative changes in airway conductance during slow inflation and deflation between 0 and 20 cmH₂O transrespiratory pressure. From predicted radius-pressure loops, storage and loss moduli and hysteresivity were calculated. IUGR offspring were lighter at birth (p < 0.05) and remained lighter at 8 weeks of age (p < 0.05) compared with Controls. Maximal stress was reduced in male IUGR offspring compared with Controls (p < 0.05), but not in females. Sensitivity to contractile agonist was not affected by IUGR or sex. Compared with the Control group, airways from IUGR animals were stiffer in vitro (p < 0.05). In vivo, airway hysteresivity (p < 0.05) was increased in the IUGR group, but there was no difference in storage or loss moduli between groups. In summary, the effects of IUGR persist to the mature airway wall, where there are clear abnormalities to ASM contractile properties and passive wall mechanics. We propose that mechanical abnormalities of the airway wall acquired through disrupted fetal growth impact susceptibility to disease.

Mechanical Abnormalities of the Airway Wall in Adult Mice After Intrauterine Growth Restriction

Developmental abnormalities of airways may impact susceptibility to asthma in later life. We used a maternal hypoxia-induced mouse model of intrauterine growth restriction (IUGR) to examine changes in mechanical properties of the airway wall. Pregnant BALB/c mice were housed under hypoxic conditions (10.5% O₂) from gestational day (GD) 11 to GD 17.5 (IUGR; term, GD 21). Following hypoxic exposure, mice were returned to a normoxic environment (21% O₂). A control group of pregnant mice were housed under normoxic conditions throughout pregnancy. At 8 weeks postnatal age, offspring were euthanized and a tracheasectomy performed. Tracheal segments were studied in organ baths to measure active airway smooth muscle (ASM) stress to carbachol and assess passive mechanical properties (stiffness) from stress-strain curves. In a separate group of anesthetized offspring, the forced oscillation technique was used to examine airway mechanics from relative changes in airway conductance during slow inflation and deflation between 0 and 20 cmH₂O transrespiratory pressure. From predicted radius-pressure loops, storage and loss moduli and hysteresivity were calculated. IUGR offspring were lighter at birth (p < 0.05) and remained lighter at 8 weeks of age (p < 0.05) compared with Controls. Maximal stress was reduced in male IUGR offspring compared with Controls (p < 0.05), but not in females. Sensitivity to contractile agonist was not affected by IUGR or sex. Compared with the Control group, airways from IUGR animals were stiffer in vitro (p < 0.05). In vivo, airway hysteresivity (p < 0.05) was increased in the IUGR group, but there was no difference in storage or loss moduli between groups. In summary, the effects of IUGR persist to the mature airway wall, where there are clear abnormalities to ASM contractile properties and passive wall mechanics. We propose that mechanical abnormalities of the airway wall acquired through disrupted fetal growth impact susceptibility to disease.

Mechanical Abnormalities of the Airway Wall in Adult Mice After Intrauterine Growth Restriction

Developmental abnormalities of airways may impact susceptibility to asthma in later life. We used a maternal hypoxia-induced mouse model of intrauterine growth restriction (IUGR) to examine changes in mechanical properties of the airway wall. Pregnant BALB/c mice were housed under hypoxic conditions (10.5% O₂) from gestational day (GD) 11 to GD 17.5 (IUGR; term, GD 21). Following hypoxic exposure, mice were returned to a normoxic environment (21% O₂). A control group of pregnant mice were housed under normoxic conditions throughout pregnancy. At 8 weeks postnatal age, offspring were euthanized and a tracheasectomy performed. Tracheal segments were studied in organ baths to measure active airway smooth muscle (ASM) stress to carbachol and assess passive mechanical properties (stiffness) from stress-strain curves. In a separate group of anesthetized offspring, the forced oscillation technique was used to examine airway mechanics from relative changes in airway conductance during slow inflation and deflation between 0 and 20 cmH₂O transrespiratory pressure. From predicted radius-pressure loops, storage and loss moduli and hysteresivity were calculated. IUGR offspring were lighter at birth (p < 0.05) and remained lighter at 8 weeks of age (p < 0.05) compared with Controls. Maximal stress was reduced in male IUGR offspring compared with Controls (p < 0.05), but not in females. Sensitivity to contractile agonist was not affected by IUGR or sex. Compared with the Control group, airways from IUGR animals were stiffer in vitro (p < 0.05). In vivo, airway hysteresivity (p < 0.05) was increased in the IUGR group, but there was no difference in storage or loss moduli between groups. In summary, the effects of IUGR persist to the mature airway wall, where there are clear abnormalities to ASM contractile properties and passive wall mechanics. We propose that mechanical abnormalities of the airway wall acquired through disrupted fetal growth impact susceptibility to disease.

Factors related to changes in the asthma male: female ratio by age in 403 Mexican counties

BACKGROUND

Asthma is more frequent in males during childhood and in females after adolescence, which has been attributed to changes in sexual hormones levels.

OBJECTIVE

We explored changes of the asthma male: female ratio (AMFR) by age group in a large population (nationwide), and its ecological association (at county level) with some medical, geographical, or sociodemographic factors.

METHODS

Registries of the largest medical institution in Mexico (∼37.5 million subjects assigned to a family physician) were analyzed and the AMFR calculated using asthma incidences.

RESULTS

In boys, asthma incidence peaked at 0 to 4 years and progressively decreased, reaching a plateau in adulthood. In girls, asthma incidence showed a bimodal pattern, with maximal rates at 0 to 4 years old, and again at 50 to 54 years old. In the ecological analysis performed in more than 400 counties, the AMFR in adults (≥15 years old) inversely correlated with population density (r = -0.256) and altitude (r = -0.144), and directly correlated with acute respiratory tract infections (ARTI, r = 0.215), diabetes (r = 0.186), marginalization (r = 0.179), pneumonias (r = 0.166), and mean maximal temperature (r = 0.142), all with P < .01. In the multiple linear regression, only population density (P < .001) and ARTI (P = .006) remained statistically significant in the final model.

CONCLUSION

Asthma incidence in males and females did not match the expected sexual hormones variations, and other factors such as population density and ARTI also influenced the AMFR. These findings challenge the traditional belief that sexual hormones are major determinants of the AMFR.

Sex Modifies Acute Ozone-Mediated Airway Physiologic Responses

Sex differences clearly exist in incidence, susceptibility, and severity of airway disease and in pulmonary responses to air pollutants such as ozone (O3). Prior rodent O3 exposure studies demonstrate sex-related differences in the expression of lung inflammatory mediators and signaling. However, whether or not sex modifies O3-induced airway physiologic responses remains less explored. To address this, we exposed 8- to 10-week-old male and female C57BL/6 mice to either 1 or 2 ppm O3 or filtered air (FA) for 3 h. At 12, 24, 48, and 72 h following exposure, we assessed airway hyperresponsiveness to methacholine (MCh), bronchoalveolar lavage fluid cellularity, cytokines and total protein/albumin, serum progesterone, and whole lung immune cells by flow cytometry. Male mice generated consistent airway hyperresponsiveness to MCh at all time points following exposure. Alternatively, females had less consistent airway physiologic responses to MCh, which were more variable between individual experiments and did not correlate with serum progesterone levels. Bronchoalveolar lavage fluid total cells peaked at 12 h and were persistently elevated through 72 h. At 48 h, bronchoalveolar lavage cells were greater in females versus males. Bronchoalveolar lavage fluid cytokines and total protein/albumin increased following O3 exposure without sex differences. Flow cytometry of whole lung tissue identified dynamic O3-induced immune cell changes also independent of sex. Our results indicate sex differences in acute O3-induced airway physiology responses and airspace influx without significant difference in other injury and inflammation measures. This study highlights the importance of considering sex as a biological variable in acute O3-induced airway physiology responses.

Status of serine tyrosine kinase at germline and expressional levels in asthma patients

Asthma is a disease marked by inflammation of airways with an increasing incidence rate worldwide especially among Asian population. Spleen tyrosine kinase (Syk) is known to be involved in regulation of such inflammation response and thereby rendering its inevitable importance among asthma patients. DNA extraction followed by PCR and sequencing was performed for genomic analysis, mRNA analysis was done by RT PCR whereas Western blot and ELISA was used for protein study. Image J and UNAFOLD were also used for Bioinformatics analysis.The mean age of patients and controls were 31.1±9.3 and 30.4±6.1 years respectively. Results of sequencing showed nonsense exonic mutations in exon 3 at g.25710G>A and g.25722G>A positions. Substitution mutations in introns were also found at g.25827G>A (intron 3), g.63425C>T (intron 8) and g.63445T>G (intron 8). Significantly increased levels of IgE and significantly decreased expression of Syk at transcriptional level was found in patients compared to controls. The western blot results of asthmatic samples and healthy controls revealed that Syk has comparatively low expression in diseased individual's PBMCs. SYK has been found to be altered in DNA, mRNA and protein expression in asthma patients among Pakistani population therefore patients should be treated according to their Syk status for more effective recovery.

Changing prevalence of current asthma and inhaled corticosteroid treatment in the UK: population-based cohort 2006-2016

Asthma is the most common respiratory disorder in the UK, yet we have incomplete knowledge on the prevalence of current disease, treatment and exacerbations.We used UK electronic healthcare records, 2006-2016, to estimate the prevalence of current asthma by year, sex and age (<5, 5-11, 12-17, 18-24, 25-54 and ≥55 years), and the proportion prescribed inhaled corticosteroids (ICS) and additional asthma therapy, treated for exacerbations and other asthma care markers.Overall current asthma prevalence was 6.5% in 2016 (7.2% in 2006). Prevalence fell in those aged <45 years. The lowest prevalence and largest absolute decrease was in children aged <5 years. In 2016, 80% of current asthma patients were managed on ICS (65% in 2006); this increase occurred in all age groups, primarily due to an increase in low-dose ICS. During this time there was an increase in all age groups in the proportion prescribed additional asthma therapy, treated for an exacerbation within primary care and given an annual asthma review or management plan. Hospitalised exacerbations showed minimal change over time.Asthma remains highly prevalent and a significant healthcare burden. In those with a diagnosis, there was an increase in ICS prescriptions and treatment of exacerbations across all age groups. This may reflect a trend towards more aggressive asthma management within primary care. An apparent decline in prevalence was observed in those aged <45 years, particularly in children aged <5 years.

Can early intervention in pediatric asthma improve long-term outcomes? A question that needs an answer

OBJECTIVE

Although many children with asthma do not experience persistence into adulthood, recent studies have suggested that poorly controlled asthma in childhood may be associated with significant airflow obstruction in adulthood. However, data regarding disease progression are lacking, and clinicians are not yet able to predict the course of a child's asthma. The goal of this article was to assess the current understanding of childhood asthma treatment and progression and to highlight gaps in information that remain.

DATA SOURCES

Nonsystematic PubMed literature search and authors' expertise.

STUDY SELECTION

Articles were selected at the authors' discretion based on areas of interest in childhood asthma treatment and progression into adulthood.

RESULTS

Uncontrolled asthma in early childhood can potentially have lasting effects on lung development, but it is unclear whether traditional interventions in very young children preserve lung function. Although not all children respond to standard interventions, certain asthma phenotypes have been identified that can help to understand which children may respond to a particular treatment.

CONCLUSION

Clinicians should monitor children's asthma control and pulmonary function over time to assess the long-term impact of an intervention and to minimize the effect of uncontrolled asthma, especially exacerbations, on lung development. New biologic therapies have shown promise in treating adults with severe, uncontrolled asthma, and some of these therapies are approved in the United States for children as young as age 6. However, knowledge gaps regarding the efficacy and safety of these treatments in younger children hamper our understanding of their effect on long-term outcomes.

Asthma over the Adult Life Course: Gender and Hormonal Influences

Asthma is a common disorder that affects genders differently across the life span. Earlier in life, it is more common in boys. At puberty, asthma becomes more common and often more severe in girls and women. The effect of sex hormones on asthma incidence and its severity is difficult to differentiate from other asthma severity risk factors, such as racial background, socioeconomic factors, obesity, atopy, environmental exposure, and, in particular, lung aging. Recognizing gender-associated and age-associated differences is important to understanding the pathobiology of asthma and to providing effective education and personalized care for patients with asthma across the life course.

Sex Bias in Asthma Prevalence and Pathogenesis

Sex-related differences in asthma prevalence are well established and change through the reproductive phases of life. As children, boys have increased prevalence of asthma compared to girls. However, as adults, women have increased prevalence of asthma compared to men. Many factors, including genetics, environment, immunological responses, and sex hormones, affect the sex disparity associated with the development and control of asthma and other allergic diseases. Fluctuations of hormones during puberty, menstruation, pregnancy, and menopause, alter asthma symptoms and severity. In this article, we review clinical and epidemiological studies that examined the sex disparity in asthma and other allergic diseases as well as the role of sex hormones on asthma pathogenesis.

Endocrine regulation of lung disease and inflammation

IMPACT STATEMENT

Sex-differences in the incidence and severity of inflammatory lung diseases have been recognized for years. Women of reproductive age are more likely to suffer from chronic lung disease, with higher mortality rates than men. Physiological changes in hormone levels such as those occurring during the menstrual cycle, pregnancy, and menopause have been associated with lung function changes and asthma symptoms. Despite this, the roles of sex hormones in the mechanisms associated with lung diseases have not been fully elucidated. This review summarizes basic and clinical studies of sex hormones as potential modulators of lung function and inflammation. The information obtained from sex-specific research on lung physiology and pathology will potentially help in the development of sex-specific therapeutics for inflammatory lung disease that may account for the hormonal status of the patient.

Role of estrogen receptors α and β in the development of allergic airway inflammation in mice: A possible involvement of interleukin 33 and eosinophils

Recent studies have shown that the estrogen receptor α (ERα), but not ERβ, is involved in the proinflammatory and propruritic responses in cutaneous allergy. In addition, results from our recent study showed that while oral administration of the rather ERβ-selective agonist bisphenol A exacerbated the respiratory allergic inflammation, the potential inflammatory reaction in the skin was decreased after administration of bisphenol A. This study aimed to elucidate whether ERα and ERβ are involved in the progression of an allergic airway inflammation. We performed an in vivo experiment using an animal model of allergic airway inflammation using male BALB/c mice to confirm an increase in the proinflammatory response induced by propylpyrazoletriol (PPT), an ERα agonist, and diarylpropionitrile (DPN), an ERβ agonist. Oral administration of PPT or DPN showed a significant increase in the inflammation of the lung and infiltration of eosinophils. While the expression of Th2 cytokines such as interleukin 4 (IL-4) and IL-13 was not affected by exposure to PPT or DPN, administration of these agonists significantly increased the expression of IL-33. The mechanism underlying the development of such allergic inflammatory responses was determined by an in vitro study using the human bronchial epithelial cell line (BEAS-2B) and the human eosinophilic leukemia cell line (EoL-1). Activated cells were exposed to PPT or DPN for 24 h, and the cytokine levels were measured. The IL-33 levels in BEAS-2B cells increased significantly after exposure to PPT or DPN. In addition, pretreatment with PPT or DPN increased the expression of IL-8 in activated EoL-1 cells. Our findings indicate that ERα and ERβ are involved in the proinflammatory response in respiratory allergy, and their effects may be mediated by an increase in the expression of IL-33 and infiltration of eosinophils.

Nationwide use of inhaled corticosteroids by South Korean asthma patients: an examination of the Health Insurance Review and Service database

BACKGROUND

Previous studies have found that the prescription rates of inhaled corticosteroid (ICS) were considerably low although it is recommended as the optimal asthma treatment. The aim of this study was to analyze the current status of ICS prescription for asthma patients in the South Korea.

METHODS

We evaluated quality assessment data based on nationwide Health Insurance Review and Service (HIRA) database from July 2013 to June 2014. ICS prescription rates in asthma patients were analyzed by types and specialty of medical institutions. Also, we graded medical institutions by their ICS prescription rate. In addition, ICS prescription rates were calculated by patient gender, age, and insurance type.

RESULTS

This study included 831,613 patients and 16,804 institutions in the analysis. The overall mean ICS prescription rate was 22.58%. Tertiary hospitals had the highest mean prescription rate (84.16%) whereas primary healthcare clinics had the lowest (20.71%). By specialty, internal medicine physicians prescribed ICS more frequently compared to other specialists. Of all, 47.17% of medical institutions prescribed ICS to <10% of asthma patients, while less than 6% of institutions prescribed ICS to >80% of asthma patients. Also, we found that female and patients with age >90 or <20 years exhibited lower ICS prescription rate.

CONCLUSIONS

The ICS prescription rate was found to be inadequate, given the importance of ICS as an asthma treatment. The prescription rates were especially low in primary healthcare clinics, and by specialists in fields other than internal medicine.

Asthma control, lung function, nutritional status, and health-related quality of life: differences between adult males and females with asthma

OBJECTIVE

To evaluate health-related quality of life in asthma patients treated at a referral center in southern Brazil, identifying differences between male and female patients, as well as to evaluate differences between the males and females in terms of asthma control, lung function, and nutritional status.

METHODS

This was a cross-sectional study involving patients ≥ 18 years of age treated at an asthma outpatient clinic. We evaluated clinical parameters, lung function, nutritional status, and quality of life.

RESULTS

A total of 198 patients completed the study. The mean age was 56.2 ± 14.8 years, and 81.8% were female. The proportion of patients with uncontrolled asthma was higher among females than among males (63.0% vs. 44.4%; p = 0.041). The body mass index (BMI) and percentage of body fat were higher in females than in males (30.2 ± 5.8 kg/m2 vs. 26.9 ± 4.5 kg/m2 and 37.4 ± 6.4% vs. 26.5 ± 7.4%; p = 0.002 and p < 0.001, respectively). Quality of life was lower in females than in males in the following domains: symptoms (3.8 ± 1.5 vs. 4.6 ± 1.7; p = 0.006); activity limitation (3.6 ± 1.3 vs. 4.4 ± 1.5; p = 0.001); emotional function (3.6 ± 1.9 vs. 4.5 ± 1.7; p = 0.014); and environmental stimuli (3.2 ± 1.6 vs. 4.3 ± 1.9; p = 0.001).

CONCLUSIONS

Male asthma patients appear to fare better than do female asthma patients in terms of health-related quality of life, asthma control, BMI, percentage of body fat, and comorbidities.

The relationship of health literacy to diabetes status differs by sex in older adults

OBJECTIVE

Lower health literacy is associated with higher rates of mortality and chronic disease. It remains unclear whether health literacy is associated with diabetes and/or hyperglycemia in older adults, and if this relationship differs by sex.

RESEARCH DESIGN AND METHODS

We performed a cross-sectional analysis of 2510 older adults in the Health, Aging and Body Composition (Health ABC) Study who had both a Rapid Estimate of Adult Literacy in Medicine (REALM) measurement and diabetes status available. Sex-stratified logistic regression models were used to analyze the relationship of health literacy categories (low, medium, and high) to diabetes status, adjusting for key covariates. Secondary analyses examined the relationship of health literacy to glycemic markers (A1C, fasting blood glucose).

RESULTS

Among participants in the Health ABC cohort, 429 had diabetes. Mean age was 76years old and 45% were female. Men with diabetes more commonly had low health literacy levels than men without diabetes (10.1% versus 9.3%, p=0.02). Similar results were seen among women (14.7% versus 6.1%, p<0.01). In a model adjusting for age, race, income, education, BMI, smoking, and alcohol use, women with low versus high health literacy had a two-fold higher likelihood of diabetes (OR=2.2; 95% CI 1.1-4.3). No significant relationship was observed in men. Progressively lower categories of health literacy were associated with higher age-adjusted mean A1C and fasting blood glucose levels in women (both p for trend <0.01) but not men.

CONCLUSIONS

In this large, ethnically diverse sample of community-dwelling older adults, lower health literacy level is related to a greater likelihood of diabetes and higher A1C and fasting blood glucose levels in women-but not in men-after adjusting for age, race, and other demographic and lifestyle factors. Future studies are needed to assess mechanisms underlying this relationship and if interventions to improve health literacy are effective in reducing the burden of diabetes, particularly in women.

Hormones, sex, and asthma

OBJECTIVE

To summarize the current literature on the sex disparity in asthma and the role of sex hormone signaling in allergic and neutrophilic airway inflammation.

DATA SOURCES

PubMed and Centers for Disease Control and Prevention health surveys were searched.

STUDY SELECTIONS

Clinical and epidemiologic studies in children and adults as well as animal models of asthma were included in this review.

RESULTS

Compared with males, females have an increase in asthma prevalence starting around puberty, and fluctuations in hormones during menstruation, pregnancy, and menopause are associated with changes in asthma symptoms. Animal studies using genetic deletions of estrogen receptors or androgen receptors have shown that estrogen signaling promotes and androgen signaling attenuates allergen-mediated type 2 airway inflammation. Furthermore, animal studies have found that ovarian hormones are important for interleukin 17A-mediated airway inflammation.

CONCLUSION

Sex hormones are important in regulating asthma pathogenesis. However, additional studies need to be conducted to further elucidate how sex hormones are initiating and driving the inflammatory response(s) in asthma. Determining these pathways will provide the foundation necessary for the development of treatment strategies and potentially new therapeutics for patients, in particular females, with asthma.

Foetal growth restriction in mice modifies postnatal airway responsiveness in an age and sex-dependent manner

Epidemiological studies demonstrate an association between intrauterine growth restriction (IUGR) and asthma; however the underlying mechanism is unknown. We investigated the impact of maternal hypoxia-induced IUGR on airway responsiveness in male and female mice during juvenility and adulthood. Pregnant BALB/c mice were housed under hypoxic conditions for gestational days 11-17.5 and then returned to normoxic conditions for the remainder of pregnancy. A control group was housed under normoxic conditions throughout pregnancy. Offspring were studied at 2 weeks (juveniles) and 8 weeks (adults), where lung volume was assessed by plethysmography, airway responsiveness to methacholine determined by the forced oscillation technique and lungs fixed for morphometry. IUGR offspring were lighter at birth, exhibited "catch-up growth" by 2 weeks, but were again lighter in adulthood. IUGR males were "hyper-responsive" at 2 weeks and "hypo-responsive" as adults, in contrast with IUGR females who were hyper-responsive in adulthood. IUGR males had increased inner and total wall thickness at 2 weeks which resolved by adulthood, while airways in IUGR females were structurally normal throughout life. There were no differences in lung volume between Control and IUGR offspring at any age. Our data demonstrate changes in airway responsiveness as a result of IUGR that could influence susceptibility to asthma development and contribute to sexual dimorphism in asthma prevalence which switches from a male dominated disease in early life to a female dominated disease in adulthood.

Exacerbation risk and characterisation of the UK's asthma population from infants to old age

BACKGROUND

Few studies have examined the characteristics of a general asthma population; most have focused on more severe patients or severe exacerbations.

METHODS

This population-based cohort study, from April 2007 to September 2015, used linked primary and secondary care electronic healthcare records (Clinical Practice Research Datalink, Hospital Episode Statistics). Characteristics of four age cohorts, 'Under 5s', '5 to 17s', '18 to 54s', '55+', were described. Exacerbation risk factors, including asthma severity (measured by the British Thoracic Society (BTS) stepwise approach), were assessed using Poisson regression.

RESULTS

424 326 patients with current asthma were eligible (n, median follow-up: 'Under 5s'=17 320, 1 year; '5 to 17s'=82 707, 3.3 years; '18 to 54s'=210 724, 4 years; '55+'=113 575, 5.1 years). Over 60% of the total study population had mild asthma (BTS steps 1/2). There were differences between the cohort's characteristics, including by gender, disease severity and exacerbation pattern. The rate of exacerbations was highest in the oldest cohort and lowest in the '5 to 17s' cohort (rate per 10 person-years (95% CI), 'Under 5s'=4.27 (4.18 to 4.38), '5 to 17s'=1.48 (1.47 to 1.50), '18 to 54s'=3.22 (3.21 to 3.24), '55+'=9.40 (9.37 to 9.42)). In all cohorts, exacerbation rates increased with increasing asthma severity, after adjusting for confounders including gender, socioeconomic status, smoking, body mass index, atopy, rhinitis, gastro-oesophageal reflux, anxiety, depression and COPD.

CONCLUSION

The majority of UK patients with asthma had mild asthma and did not experience an exacerbation during follow-up. Patients aged ≥55 years had the lowest proportion with mild asthma and highest rate of exacerbations; the opposite was found in patients aged between 5 and 18 years.

Sex differences in outcomes after discharge from Alberta emergency departments for asthma: A large population-based study

OBJECTIVE

Asthma exacerbations frequently result in emergency department (ED) visits. While sex differences have been identified in some asthma studies, there is a paucity of literature on sex differences in the ED setting, especially population-based ones. This study examines sex differences in important outcomes of patients discharged from EDs for acute asthma in Alberta, Canada.

METHODS

Alberta residents aged from 2 to 55 years discharged from EDs with a primary diagnosis of asthma during 1999-2011 were identified from administrative databases from a single-payer health care system for the entire geographic region of Alberta. Multivariable Cox regression models analyzed time to first follow-up physician or specialist visit, and logistic regression models analyzed the binary outcome of ED return within 30 days for asthma.

RESULTS

There were 115,853 discharged patients analyzed (40.4% and 59.1% female in pediatric and adult groups, respectively). Approximately 26% of patients revisited the ED during 1999-2011 and 5.1% did so within 30 days. Women had higher odds of a 30-day ED return after ED discharge than men (unadjusted odds ratio [uOR] = 1.26; 95% confidence interval [CI] 1.17-1.36). Time to first non-ED physician follow-up was shorter for girls (unadjusted hazard ratio [uHR] = 1.05; 95%CI 1.03-1.07) and women (uHR = 1.62; 95%CI 1.59-1.64) than for boys and men, respectively. Significant interactions between sex and age, socio-economic status, area of residence, and comorbidities were identified and changed the effect of sex on outcomes.

CONCLUSIONS

In conclusion, women return to EDs within 30 days of discharge for acute asthma more often than men. Time to first non-ED physician follow-up for children and adults differed by sex. Multiple factors likely contribute to these differences; however, identifying these differences is critical to understand the influence of sex on health behaviors and outcomes.

Postpartum airway responsiveness and exacerbation of asthma during pregnancy - a pilot study

Background

Airway responsiveness and inflammation are associated with the clinical manifestations of asthma and the response to pharmacological therapy.

Objective

To investigate if airway responsiveness and inflammatory characteristics are related to asthma exacerbations during pregnancy.

Materials and methods

In women with asthma who were prescribed controller medication and monitored closely during pregnancy, the risk of exacerbations was analyzed in relation to postpartum measures of fractional exhaled nitric oxide (F_ENO), skin prick test reactivity, static and dynamic lung volumes, diffusing capacity for carbon monoxide, bronchial responsiveness to inhaled mannitol, and inflammatory characteristics in induced sputum. Obtained data were analyzed in relation to exacerbation status during pregnancy. The PD₁₅ is defined as the cumulative administered dose causing a 15% decline in forced expiratory volume in the first second (FEV₁).

Results

Fifty women (mean age ± standard deviation of 32±5 years) were enrolled over an 11-month period and examined on average 4 months postpartum. During pregnancy, 13 women had a total of 16 exacerbations (8 mild and 8 severe). Women with asthma exacerbation during pregnancy had more pronounced airway responsiveness to inhaled mannitol (geometric mean PD₁₅ 82 vs 171 mg, p=0.04) and were less likely to be atopic (62% vs 86%, respectively; p=0.04) than the non-exacerbators. No statistically significant difference was found between the 2 groups of women with regard to type of airway inflammation in sputum and fractional exhaled nitric oxide (F_ENO).

Conclusion

More pronounced airway hyperresponsiveness together with nonatopic status appears to characterize women at high risk of exacerbation of asthma during pregnancy.

High prevalence of severe asthma in a large random population study

BACKGROUND

The prevalence of asthma severity is not well described at a population level.

OBJECTIVE

We sought to determine the prevalence of phenotypic signs of asthma severity among asthmatic patients in a general population and to describe risk factors for asthma severity.

METHODS

We performed an epidemiologic study conducted between 2008 and 2012 (West Sweden Asthma Study). A postal questionnaire was sent to a random population (n = 30,000) in west Sweden, with 18,087 responses. A total of 2,006 subjects were carefully phenotyped. Only subjects with "active asthma" (symptoms or medication in the last year, n = 744) were analyzed in this study to determine the degree of severity of the disease within an asthma cohort. Phenotypes of severity were calculated based on (1) multiple symptoms during the day despite ongoing use of asthma medications, (2) FEV₁ of less than 70% of predicted value, (3) daily or almost daily use of rescue medications, (4) nighttime symptoms once a week or more, and (5) oral corticosteroid use/emergency department visits. Asthmatic patients were grouped as having nonsevere disease, 1 sign of severity, or 2 or more signs of severity.

RESULTS

A total of 36.2% of asthmatic patients expressed at least 1 sign of asthma severity, and 13.2% had 2 or more signs. The group with 2 or more signs was older in age and had higher body mass index, a higher rate of tobacco smoking, and lower lung function. Bronchial hyperreactivity, airway inflammation, and sensitization were significantly different among the 3 groups. At a population level, the prevalence of asthma severity was 3.1% for 1 sign and 1.3% for at least 2 signs.

CONCLUSION

More than 1 in 3 asthmatic patients show at least 1 sign of asthma severity. The phenotypes of asthma severity are highly diverse, which is important to consider when implementing personalized medicine in asthmatic patients.

Sex differences in asthma in swimmers and tennis players

BACKGROUND

Elite athletes, independent of sport, have increased risk of developing asthma, but little is known about sex difference among adolescent athletes.

OBJECTIVE

To investigate and compare sex-related differences according to symptoms and treatment of asthma, allergy, and health among elite athletes and a reference group.

METHODS

Adolescent elite swimmers (n = 101), tennis players (n = 86), and a reference group (n = 1,628) responded to a questionnaire about respiratory symptoms, allergy, health behavior, psychosomatic symptoms, self- esteem, and well-being. The athletes performed a mannitol provocation and a sport-specific exercise provocation. Atopy was assessed by skin prick tests, and fractional exhaled nitric oxide was measured.

RESULTS

The females reported more asthma symptoms than the males in both the reference group (29.1% vs 22.3%) and the athlete group (56.4% vs 40.2%). However, no significant differences were found in physician-diagnosed asthma or treatment with inhaled corticosteroids. More female athletes had a positive mannitol provocation result (48.7% vs 35.8% in male athletes), and more female swimmers had a positive exercise provocation result (15.1% vs 7.7% in male swimmers). The females in all groups had more psychosomatic symptoms compared with the respective males, and the males in the reference group reported higher self-esteem and felt more well-being compared with the reference group females.

CONCLUSION

Overall, we found a higher prevalence of asthma symptoms in the females. However, the frequency of physician-diagnosed asthma and the prescription of inhaled corticosteroids were the same in both sexes. This finding demonstrates an insufficient diagnosis of asthma in females.

Sex-specific risk factors for childhood wheeze and longitudinal phenotypes of wheeze

BACKGROUND

Although sexual dimorphism in wheeze and asthma prevalence are well documented, sex-specific risk factors for wheeze and longitudinal wheeze phenotypes have not been well elucidated.

OBJECTIVE

By using a large prebirth cohort, this study aimed to identify sex-specific risk factors for wheeze from birth through midchildhood and identify distinct longitudinal wheeze phenotypes and the sex-specific risk factors associated with these phenotypes.

METHODS

Mothers reported child wheeze symptoms over the past year approximately yearly on 9 occasions starting at age 1 year. We identified sex-specific predictors of wheeze, wheeze phenotypes, and sex-specific predictors of these phenotypes by using generalized estimating equations, latent class mixed models, and multinomial logistic analysis, respectively.

RESULTS

A total of 1623 children had information on wheeze at 1 or more time points. Paternal asthma was a stronger predictor of ever wheezing in boys (odds ratio [OR], 2.15; 95% CI, 1.74-2.66) than in girls (OR, 1.53; 95% CI, 1.19-1.96; P for sex by paternal asthma interaction = .03), whereas being black or Hispanic, birth weight for gestational age z score, and breast-feeding duration had stronger associations among girls. We identified 3 longitudinal wheeze phenotypes: never/infrequent wheeze (74.1%), early transient wheeze (12.7%), and persistent wheeze (13.1%). Compared with never/infrequent wheeze, maternal asthma, infant bronchiolitis, and atopic dermatitis were associated with persistent wheeze in both sexes, but paternal asthma was associated with persistent wheeze in boys only (OR, 4.27; 95% CI, 2.33-7.83; P for sex by paternal asthma interaction = .02), whereas being black or Hispanic was a predictor for girls only.

CONCLUSION

We identified sex-specific predictors of wheeze and longitudinal wheeze patterns, which might have important prognostic value and allow for a more personalized approach to wheeze and asthma treatment.

Asthma as a disruption in iron homeostasis

Over several decades, asthma has evolved from being recognized as a single disease to include a diverse group of phenotypes with dissimilar natural histories, pathophysiologies, responses to treatment, and distinctive molecular pathways. With the application of Occam's razor to asthma, it is proposed that there is one cause underlying the numerous phenotypes of this disease and that the responsible molecular pathway is a deficiency of iron in the lung tissues. This deficiency can be either absolute (e.g. asthma in the neonate and during both pregnancy and menstruation) or functional (e.g. asthma associated with infections, smoking, and obesity). Comparable associations between asthma co-morbidity (e.g. eczema, urticaria, restless leg syndrome, and pulmonary hypertension) with iron deficiency support such a shared mechanistic pathway. Therapies directed at asthma demonstrate a capacity to impact iron homeostasis, further strengthening the relationship. Finally, pathophysiologic events producing asthma, including inflammation, increases in Th2 cells, and muscle contraction, can correlate with iron availability. Recognition of a potential association between asthma and an absolute and/or functional iron deficiency suggests specific therapeutic interventions including inhaled iron.

Sex Differences in the Relationship between Fitness and Obesity on Risk for Asthma in Adolescents

OBJECTIVE

To evaluate the relationship of fitness and obesity on asthma risk in adolescent girls and boys.

STUDY DESIGN

A cross-sectional assessment of participants 12-19 years of age was conducted by the use of data from the 1999-2004 National Health and Nutrition Examination Survey. Participants completed cardiorespiratory fitness testing, body composition measurements, and respiratory questionnaires.

RESULTS

A total of 4828 participants were included. Overweight/obesity was associated with increased odds of history of asthma (aOR 1.63, 95% CI 1.16-2.30), current asthma (aOR 1.73, 95% CI 1.13, 2.64), and wheezing (aOR 1.40, 95% CI 1.03-1.91) in girls. Overweight/obesity also was associated with increased odds of asthma attacks (aOR 2.67, 95% CI 1.56-4.65) and wheezing related to exercise (aOR 1.60, 95% CI 1.07-2.38) in girls. High fitness was associated with lower odds of asthma-related visits to the emergency department (aOR 0.24, 95% CI 0.07-0.89), wheezing-related medical visits (aOR 0.31, 95% CI 0.13-0.75), wheezing-related missed days (aOR 0.14, 95% CI 0.06-0.33), and wheezing related to exercise (aOR 0.43, 95% CI 0.24-0.76) in boys.

CONCLUSION

Overweight/obesity is associated with increased asthma prevalence and morbidity in girls but not in boys, independent of fitness. High fitness is associated with decreased rates of asthma morbidity in boys but not in girls, independent of weight status. Obesity and fitness may each influence asthma onset and severity in different ways for girls compared with boys.

Asthma and rhinitis have different genetic profiles for IL13, IL17A and GSTP1 polymorphisms

BACKGROUND

Asthma and rhinitis have a complex etiology, depending on multiple genetic and environmental risk factors. An increasing number of susceptibility genes are currently being identified, but the majority of reported associations have not been consistently replicated across populations of different genetic backgrounds.

PURPOSE

To evaluate whether polymorphisms of IL4R (rs1805015), IL13 (rs20541), IL17A (rs2275913) and GSTP1 (rs1695) genes are associated with rhinitis and/or asthma in adults of Portuguese ancestry.

METHODS

192 unrelated healthy individuals and 232 patients, 83 with rhinitis and 149 with asthma, were studied. All polymorphisms were detected by real time polymerase chain reaction (PCR) using TaqMan assays.

RESULTS

Comparing to controls, significant association with asthma was observed for GSTP1 rs1695 AA genotype (odds ratio (OR) - 1.96; 95% CI - 1.18 to 3.25; p=0.010). The association sustains for allergic asthma (OR - 2.17; 95% CI - 1.23 to 3.80; p=0.007). IL13 rs20541 GG genotype was associated with less susceptibility to asthma (OR - 0.55, 95% CI - 0.33 to 0.94, p=0.028). Among patients, IL17A rs2275913 AA genotype was less associated with asthma than with rhinitis (OR - 0.20; 95% CI of 0.07 to 0.56; p=0.002). A similar association was found for IL13 rs20541 GG genotype (OR - 0.48; 95% CI of 0.25 to 0.93; p=0.031). There were no significant differences in the distribution of allelic and genotypic frequencies between patients and controls for the IL4R polymorphism' analyzed.

CONCLUSION

These results support the existence of a significant association between GSTP1 rs1695 and IL13 rs20541 SNPs, with susceptibility to asthma, in the population studied. Different genotype profiles of IL17A and IL13 genes seem to influence the clinical pattern of disease expression mainly confined to the upper airways, as rhinitis, or including the lower airways, as asthma.

Factors associated with increased healthcare utilization among adults with asthma

OBJECTIVE

To evaluate determinants of increased emergency room (ER) visit and hospitalization among adults with asthma, with emphasis on the role of psychological distress, self-efficacy, and obesity.

METHODS

For analysis 2009, 2011/2012 California Health Interview Survey was used. Adults who reported lifetime asthma were selected. Association between ER and overnight hospital stay with population characteristics were conducted using chi-square analysis. Multivariable binary logistic regression models, taking into account control variables, were utilized to assess the relationship between ER visit or overnight hospital stay with that of psychological distress, self-efficacy, and obesity.

RESULTS

Odds of ER visits were higher among those with mild-to-moderate psychological distress (adjusted odds ratio [aOR] = 1.94, 95% CI: 1.28, 2.94), and among those with serious psychological distress (aOR = 2.62, 95% CI: 1.65, 4.16). Mild-to-moderate distress was associated with two-fold increase in hospital overnight stay (aOR = 2.05, 95% CI: 1.29, 3.25). Adults with asthma who reported low self-efficacy had increased ER visits (aOR = 6.21, 95% CI: 3.63, 10.65) and hospitalization (aOR = 4.13, 95% CI: 2.63, 6.49). Finally, adults who had asthma and were obese had higher odds of ER visits (aOR = 1.60, 95% CI: 1.20, 2.13).

CONCLUSIONS

Healthcare utilization is higher among asthma patients with psychological distress, low self-efficacy, and obesity. Interventions, such as incorporation of integrated care models, are critical to ensure early screening of mental health status among such patients. In addition, there is a need for patient education and improved weight management among adults with asthma.

Different risk factor patterns for adult asthma, rhinitis and eczema: results from West Sweden Asthma Study

BACKGROUND

Atopic diseases including asthma, rhinitis and eczema have increased in the second half of the past century. This has been well studied among children and adolescents but with the exception of asthma to a much lesser extent in adults. The adult risk factor pattern of atopic diseases, in particular of eczema, and their relation to allergic sensitization are yet to be fully elucidated. Studies among adults that have compared the risk factor pattern for these conditions in the same material are very few. The objective of this study was to compare the risk factor patterns for asthma, rhinitis and eczema in a randomly selected adult population.

METHODS

A questionnaire survey on atopic diseases was dispatched by mail to 30,000 randomly selected individuals in West Sweden aged 16-75 years and 62 % participated. A subgroup of 2000 individuals was selected for clinical examinations including blood sampling for specific serum Immunoglobulin E to common airborne allergens and 1172 attended.

RESULTS

The prevalence of current asthma was 11.8 %, current rhinitis 42.8 %, current eczema 13.5 and 2.3 % had all three conditions while 13.9 % had at least two conditions. No mutual risk factor was identified for all three conditions. Allergic sensitization was a strong risk factor for current asthma (OR 4.1 CI 2.7-6.3) and current rhinitis (OR 5.1 CI 3.8-6.9) but not so for current eczema. Obesity was a risk factor for current asthma and current rhinitis, while farm childhood decreased the risk for current asthma and current rhinitis. Occupational exposure to gas dust or fumes and female sex was associated with an increased risk of current asthma and current eczema.

CONCLUSIONS

There are different risk factor patterns for asthma, rhinitis and eczema in adults but some risk factors are overlapping between some of the conditions. The effect of mutable risk factors should be assessed further in longitudinal studies.

Roads Less Traveled: Sexual Dimorphism and Mast Cell Contributions to Migraine Pathology

Migraine is a common, little understood, and debilitating disease. It is much more prominent in women than in men (~2/3 are women) but the reasons for female preponderance are not clear. Migraineurs frequently experience severe comorbidities, such as allergies, depression, irritable bowel syndrome, and others; many of the comorbidities are more common in females. Current treatments for migraine are not gender specific, and rarely are migraine and its comorbidities considered and treated by the same specialist. Thus, migraine treatments represent a huge unmet medical need, which will only be addressed with greater understanding of its underlying pathophysiology. We discuss the current knowledge about sex differences in migraine and its comorbidities, and focus on the potential role of mast cells (MCs) in both. Sex-based differences in pain recognition and drug responses, fluid balance, and the blood–brain barrier are recognized but their impact on migraine is not well studied. Furthermore, MCs are well recognized for their prominent role in allergies but much less is known about their contributions to pain pathways in general and migraine specifically. MC-neuron bidirectional communication uniquely positions these cells as potential initiators and/or perpetuators of pain. MCs can secrete nociceptor sensitizing and activating agents, such as serotonin, prostaglandins, histamine, and proteolytic enzymes that can also activate the pain-mediating transient receptor potential vanilloid channels. MCs express receptors for both estrogen and progesterone that induce degranulation upon binding. Furthermore, environmental estrogens, such as Bisphenol A, activate MCs in preclinical models but their impact on pain pathways or migraine is understudied. We hope that this discussion will encourage scientists and physicians alike to bridge the knowledge gaps linking sex, MCs, and migraine to develop better, more comprehensive treatments for migraine patients.

Doublesex and mab-3 related transcription factor 1 (DMRT1) is a sex-specific genetic determinant of childhood-onset asthma and is expressed in testis and macrophages

BACKGROUND

Asthma is a disease affecting more boys than girls in childhood and more women than men in adulthood. The mechanisms behind these sex-specific differences are not yet understood.

OBJECTIVE

We analyzed whether and how genetic factors contribute to sex-specific predisposition to childhood-onset asthma.

METHODS

Interactions between sex and polymorphisms on childhood asthma risk were evaluated in the Multicentre Asthma Genetics in Childhood Study (MAGICS)/Phase II International Study of Asthma and Allergies in Childhood (ISAAC II) population on a genome-wide level, and findings were validated in independent populations. Genetic fine mapping of sex-specific asthma association signals was performed, and putatively causal polymorphisms were characterized in vitro by using electrophoretic mobility shift and luciferase activity assays. Gene and protein expression of the identified gene doublesex and mab-3 related transcription factor 1 (DMRT1) were measured in different human tissues by using quantitative real-time PCR and immunohistochemistry.

RESULTS

Polymorphisms in the testis-associated gene DMRT1 displayed interactions with sex on asthma status in a population of primarily clinically defined asthmatic children and nonasthmatic control subjects (lowest P = 5.21 × 10(-6)). Replication of this interaction was successful in 2 childhood populations clinically assessed for asthma but showed heterogeneous results in other population-based samples. Polymorphism rs3812523 located in the putative DMRT1 promoter was associated with allele-specific changes in transcription factor binding and promoter activity in vitro. DMRT1 expression was observed not only in the testis but also in lung macrophages.

CONCLUSION

DMRT1 might influence sex-specific patterns of childhood asthma, and its expression in testis tissue and lung macrophages suggests a potential involvement in hormone or immune cell regulation.

Asthma and Wheeze Prevalence among Nursing Professionals in Western Japan: A Cross-Sectional Study

Although adult asthma is attributable to occupational factors, few reports are available on asthma prevalence among health care workers in Japan. The objective of this study was to estimate the prevalence of asthma and wheeze among Japanese nursing professionals. A cross-sectional study was conducted by postal survey using a translated version of the European Community Respiratory Health Survey questionnaire from April to June 2013. The analysis included 4634 nursing professionals (257 men and 4377 women) and the overall response rate was 84.8%. The prevalence of current asthma and wheeze were 10.7% (95% confidence interval (CI), 9.9%-11.7%) and 15.6% (95% CI, 14.5%-16.6%), respectively. More than one year of work experience as a nursing professional and more than one year of experience with bed-making tasks were associated with odds ratios (ORs) of 1.95 (95% CI, 1.12-3.39) and 1.64 (95% CI, 1.15-2.23) for wheeze, respectively. Current smoking was significantly associated with the presence of wheeze, with ORs of 2.27 for men (95% CI, 1.11-4.64) and 2.01 for women (95% CI, 1.54-2.64). Among female nurses, latex allergy was associated with wheeze (OR, 1.87; 95% CI, 1.56-2.23), as was body mass index ≥30 (OR, 2.76; 95% CI, 1.65-4.62). This study has provided the prevalence of asthma and wheeze among Japanese nursing professionals. Employment period, bed-making tasks, latex allergy, obesity, and smoking may be risk factors for prevalent wheeze among nursing professionals.

Asthma is Different in Women

Gender differences in asthma incidence, prevalence and severity have been reported worldwide. After puberty, asthma becomes more prevalent and severe in women, and is highest in women with early menarche or with multiple gestations, suggesting a role for sex hormones in asthma genesis. However, the impact of sex hormones on the pathophysiology of asthma is confounded by and difficult to differentiate from age, obesity, atopy, and other gender associated environmental exposures. There are also gender discrepancies in the perception of asthma symptoms. Understanding gender differences in asthma is important to provide effective education and personalized management plans for asthmatics across the lifecourse.

Phenotypes, Risk Factors, and Mechanisms of Adult-Onset Asthma

Asthma is a heterogeneous disease with many phenotypes, and age at disease onset is an important factor in separating the phenotypes. Genetic factors, atopy, and early respiratory tract infections are well-recognized factors predisposing to childhood-onset asthma. Adult-onset asthma is more often associated with obesity, smoking, depression, or other life-style or environmental factors, even though genetic factors and respiratory tract infections may also play a role in adult-onset disease. Adult-onset asthma is characterized by absence of atopy and is often severe requiring treatment with high dose of inhaled and/or oral steroids. Variety of risk factors and nonatopic nature of adult-onset disease suggest that variety of mechanisms is involved in the disease pathogenesis and that these mechanisms differ from the pathobiology of childhood-onset asthma with prevailing Th2 airway inflammation. Recognition of the mechanisms and mediators that drive the adult-onset disease helps to develop novel strategies for the treatment. The aim of this review was to summarize the current knowledge on the pathogenesis of adult-onset asthma and to concentrate on the mechanisms and mediators involved in establishing adult-onset asthma in response to specific risk factors. We also discuss the involvement of these mechanisms in the currently recognized phenotypes of adult-onset asthma.

Gender- and age-specific risk factors for wheeze from birth through adolescence

BACKGROUND AND OBJECTIVE

Cross-sectional gender differences in wheeze are well documented, but few studies have examined the gender-specific risk factors for wheeze longitudinally. This study aims to identify gender- and age-specific risk factors for wheeze from birth through adolescence.

METHODS

The incidence of wheeze was ascertained every 6 months through age 14 years in a birth cohort consisting of 499 children with a parental history of atopy. Gender- and age-specific risk factors were identified through generalized estimating equations.

RESULTS

A total of 454 (91.0%) and 351 (70.3%) children were followed past age 7 and 13 years, respectively. Maternal asthma was a risk factor for wheeze in girls (OR = 2.05, 95% CI 1.44-2.91, P < 0.0001) and boys (OR = 1.79, 1.29-2.48, P = 0.0004) and had a similar effect on wheeze throughout the ages. Paternal asthma (OR = 1.83, 1.38-2.57, P = 0.0005) and infant bronchiolitis (OR = 2.15, 1.47-3.14, P < 0.0001) were risk factors for boys only, with similar effects throughout the ages.

CONCLUSION

Using a prospective cohort, we identified gender- and age-specific risk factors for wheeze. The identification of gender-specific early life risk factors may allow for timely interventions and a more personalized approach to the treatment of asthma.

Fine particulate matter (PM2.5 ) exposure during a prolonged wildfire period and emergency department visits for asthma

BACKGROUND AND OBJECTIVE

The 2006-2007 wildfire period was one of the most extensive and long lasting fires in Australian history with high levels of fine particulate matter (PM2.5 ). Large populations were exposed to smoke for over 2 months. The study aimed to investigate the association between wildfire-related PM2.5 exposure and emergency department (ED) visits for asthma.

METHODS

A time-stratified case-crossover design was used to investigate associations between daily average PM2.5 and ED attendances for asthma from December 2006 to January 2007. ED data were obtained from the Victorian Emergency Minimum Dataset. Smoke dispersion during the wildfire event was modelled using a validated chemical transport model. Exposure data (daily average PM2.5 , temperature and relative humidity) were modelled for the study period. Various lag periods were investigated.

RESULTS

There were 2047 ED attendances for asthma during the study period. After adjusting for temperature and relative humidity, an interquartile range increase in PM2.5 levels of 8.6 μg/m(3) was associated with an increase in ED attendances for asthma by 1.96% (95%CI: 0.02, 3.94) on the day of exposure. Lag periods up to 2 days prior did not show any association. A strong association was observed among women 20 years and older (5.08% 95%CI: 1.76, 8.51).

CONCLUSIONS

Wildfire-related PM2.5 was associated with increased risk of ED attendance for asthma during the wildfire event. It is important to understand the role of wildfire PM2.5 as a trigger for asthma presentations.

Asthma Is More Severe in Older Adults

Background

Severe asthma occurs more often in older adult patients. We hypothesized that the greater risk for severe asthma in older individuals is due to aging, and is independent of asthma duration.

Methods

This is a cross-sectional study of prospectively collected data from adult participants (N=1130; 454 with severe asthma) enrolled from 2002 – 2011 in the Severe Asthma Research Program.

Results

The association between age and the probability of severe asthma, which was performed by applying a Locally Weighted Scatterplot Smoother, revealed an inflection point at age 45 for risk of severe asthma. The probability of severe asthma increased with each year of life until 45 years and thereafter increased at a much slower rate. Asthma duration also increased the probability of severe asthma but had less effect than aging. After adjustment for most comorbidities of aging and for asthma duration using logistic regression, asthmatics older than 45 maintained the greater probability of severe asthma [OR: 2.73 (95 CI: 1.96; 3.81)]. After 45, the age-related risk of severe asthma continued to increase in men, but not in women.

Conclusions

Overall, the impact of age and asthma duration on risk for asthma severity in men and women is greatest over times of 18-45 years of age; age has a greater effect than asthma duration on risk of severe asthma.

Sex-related clinical aspects in insect venom anaphylaxis

Experimental studies, epidemiological data, and clinical observations suggest that the gender factor is involved in the development and manifestation of IgE-dependent allergic diseases. We intend to answer the question if sex-related factors may play a role in Hymenoptera venom allergy (HVA). In the majority of recent studies the frequency of HVA symptoms with respect to both LL and SYS reactions is similar for men and women, while proven sensitization to insect venom is less frequent in women. Studies assessing clinical reactivity in HVA indicate that male sex and vespid venom allergy are factors increasing the risk of severe allergic reactions. Regarding the risk of adverse events associated with gender in the course of venom immunotherapy (VIT), the results of two large EAACI multicenter studies are discordant. In the first study, women showed increased risk of VIT adverse events. In the latter, systemic allergic side effects were not associated with gender. Despite theoretical premises and certain clinical observations indicating an important role of estrogens in allergic diseases, their influence on stinging insects' venom hypersensitivity is not unequivocal and remains still open. Further studies on the safety of VIT in females seem to be advisable.

Prospective Study on the Relationship of Obesity to Asthma Impairment and Risk

BACKGROUND

Although studies consistently show an association between obesity and increased asthma incidence, the role of obesity in asthma control is less clear.

OBJECTIVE

The objective of this study was to evaluate the association between baseline body mass index (BMI) and measures of subsequent asthma control in a large real-world cohort of adults with persistent asthma.

METHODS

In Kaiser Permanente Southern California (KPSC), a large managed care organization, we identified adults with persistent asthma in 2006, continuous health plan enrollment in 2007 and 2008, and a BMI measurement in 2006 or 2007. Each patient's last BMI measure in 2006 or 2007 was categorized into a BMI group: normal (<25 kg/m(2)), overweight (25-29.9 kg/m(2)), or obese (≥30 kg/m(2)). Asthma control outcomes in 2008 included asthma hospitalizations or emergency department visits (EDHO), oral corticosteroid dispensings linked to an asthma encounter (OCS), and dispensing of ≥7 short-acting beta-agonist canisters (SABA7). Multivariable analyses were conducted to assess the relationships of BMI categories with the risk of the asthma control outcomes after controlling for potential confounders.

RESULTS

In the 10,233 eligible adults-after adjusting for potential demographic, comorbidity, and prior utilization confounders-we found an increased relative risk (RR) of EDHO in overweight and obese (RR 1.40, 95% CI 1.10-1.78) individuals. Only obesity was associated in adjusted analyses with a significant increased relative risk of SABA7 (RR 1.27, 95% CI 1.15-1.40).

CONCLUSIONS

Elevated BMI, particularly obesity, is associated with subsequent poor asthma control, especially in the risk domain (exacerbations). These findings further support the importance of facilitating weight loss in overweight and obese adults with asthma.

Natural progression of childhood asthma symptoms and strong influence of sex and puberty

RATIONALE

Asthma prevalence, onset, remission and relapse, and healthcare use have been intensively studied. However, asthma symptom progression through childhood and adolescence has not been well studied, in part due to the challenges in obtaining consistent and robust long-term follow-up data on a large series of subjects with asthma.

OBJECTIVES

To use the asthma diary symptom data of the Childhood Asthma Management Program placebo group (5 yr, 418 subjects, and total 564,518 records) to establish sex-specific high-resolution time courses of the natural progression of asthma symptoms through childhood and adolescence.

METHODS

We used the asthma diary symptom code as a measure of daily disease severity. Annual records of Tanner stage were used to determine the influence of puberty on severity. A data alignment technique was used to derive 13-year time courses of mean symptoms and mean Tanner stage.

MEASUREMENTS AND MAIN RESULTS

Data analyses showed three age- and sex-related phases of asthma symptom progression: Phase 1 (ages 5 and 6 yr)-greater severity in boys; Phase 2 (ages 7 to 9 yr)-no sex difference in severity; and Phase 3 (age 10-17 yr)-greater severity in girls. The continuous decline of symptoms in both sexes stops abruptly at the onset of puberty.

CONCLUSIONS

The severity of asthma symptoms varies through childhood and adolescence, and patterns differ by sex. Puberty has a strong influence on symptom progression in both sexes. Progression of symptoms is a distinct aspect of asthma epidemiology.

Sex steroid signaling: implications for lung diseases

There is increasing recognition that sex hormones (estrogen, progesterone, and testosterone) have biological and pathophysiological actions in peripheral, non-reproductive organs, including the lung. Clinically, sex differences in the incidence, morbidity and mortality of lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, lung cancer and pulmonary hypertension have been noted, although intrinsic sex differences vs. the roles of sex steroids are still not well-understood. Accordingly, it becomes important to ask the following questions: 1) Which sex steroids are involved? 2) How do they affect different components of the lung under normal circumstances? 3) How does sex steroid signaling change in or contribute to lung disease, and in this regard, are sex steroids detrimental or beneficial? As our understanding of sex steroid signaling in the lung improves, it is important to consider whether such information can be used to develop new therapeutic strategies to target lung diseases, perhaps in both sexes or in a sex-specific manner. In this review, we focus on the basics of sex steroid signaling, and the current state of knowledge regarding how they influence structure and function of specific lung components across the life span and in the context of some important lung diseases. We then summarize the potential for sex steroids as useful biomarkers and therapeutic targets in these lung diseases as a basis for future translational research in the area of gender and individualized medicine.

Low prevalence of asthma in sub Saharan Africa: a cross sectional community survey in a suburban Nigerian town

BACKGROUND

Asthma remains an important cause of morbidity and mortality, especially in developing countries but the prevalence in Nigeria is not well described.

METHODS

Using the European Community Respiratory Health Survey (ECRHS) standard screening questionnaire and asthma criteria, we recruited a representative sample of adults resident in a suburban community in Nigeria through a stratified three-stage cluster sampling technique.

RESULTS

Out of a total of 3590 individuals contacted, 2310 responded and provided completed data (62.8% female). The prevalence of respiratory symptoms ranged from 0.4% (95% CI: 0.1-0.6) to 9.1% (95% CI: 7.6-10.6). Apart from nasal allergies, the most frequently reported symptoms were 'woken up by an attack of breathlessness at any time in the last 12 months' (2.4%, 95% CI: 1.8-3.0) and 'woken up by an attack of cough at any time in the last 12 months' (2.9%, 95% CI: 2.0-3.7). The combined proportion of respondents reporting previous asthma attack or currently taking asthma medication within the preceding 12 months (diagnosed asthma) was 1.5%, 95% CI: 1.0-2.0. The proportion with 'probable asthma' based on ECRHS criteria of any three symptoms of asthma (woken up by an attack of breathlessness or previous asthma attack or currently taking asthma medication within the preceding 12 months) was 3.1%, 95% CI: 2.0-4.3 for men and 3.3%, 95% CI: 2.4-4.2 for women.

CONCLUSION

The prevalence of asthma in this suburban Nigerian population is low. Determinants of adult asthma distribution in low-income setting need further clarification.

Gender differences in work-related asthma: surveillance data from California, Massachusetts, Michigan, and New Jersey, 1993-2008

OBJECTIVE

To characterize work-related asthma by gender.

METHODS

We analyzed state-based sentinel surveillance data on confirmed work-related asthma cases collected from California, Massachusetts, Michigan, and New Jersey during 1993-2008. We used Chi-square and Fisher's Exact Test statistics to compare select characteristics between females and males.

RESULTS

Of the 8239 confirmed work-related asthma cases, 60% were female. When compared to males with work-related asthma, females with work-related asthma were more likely to be identified through workers' compensation (14.8% versus 10.6%) and less likely to be identified through hospital data (14.2% versus 16.9%). Moreover, when compared to males, females were more likely to have work-aggravated asthma (24.4% versus 13.5%) and less likely to have new-onset asthma (48.0% versus 56.5%). Females were also more likely than males with work-related asthma to work in healthcare and social assistance (28.7% versus 5.2%), educational services (11.8% versus 4.2%), and retail trade (5.0% versus 3.9%) industries and in office and administrative support (20.0% versus 4.0%), healthcare practitioners and technical (13.4% versus 1.6%), and education training and library (6.2% versus 1.3%) occupations. Agent groups most frequently associated with work-related asthma were miscellaneous chemicals (20.3%), cleaning materials (15.3%), and indoor air pollutants (14.9%) in females and miscellaneous chemicals (15.7%), mineral and inorganic dusts (13.2%), and pyrolysis products (12.7%) in males.

CONCLUSIONS

Among adults with work-related asthma, males and females differ in terms of workplace exposures, occupations, and industries. Physicians should consider these gender differences when diagnosing and treating asthma in working adults.