Sex differences among children 2-13 years of age presenting at the emergency department with acute asthma

Sex differences in sociodemographic, clinical, and laboratory variables in childhood asthma: A birth cohort study

BACKGROUND

There are marked sex differences in the prevalence and severity of asthma, both during childhood and adulthood. There is a relative lack of comprehensive studies exploring sexdifferences in pediatric asthma cohorts.

OBJECTIVE

To identify the most relevant sex differences in sociodemographic, clinical, and laboratory variables in a well-characterized large pediatric asthma cohort.

METHODS

We performed a cross-sectional analysis of the Mayo Clinic Olmsted County Birth Cohort. In the full birth cohort, we used a natural language-processing algorithm based on the Predetermined Asthma Criteria for asthma ascertainment. In a stratified random sample of 300 children, we obtained additional pulmonary function tests and laboratory data. We identified the significant sex differences among available sociodemographic, clinical, and laboratory variables.

RESULTS

Boys were more frequently diagnosed with having asthma than girls and were younger at the time of asthma diagnosis. There were no sex differences in relation to socioeconomic status. We identified a male predominance in the presence of a tympanostomy tube and a female predominance in the history of pneumonia. A higher percentage of boys had a forced expiratory volume in 1 second/forced vital capacity ratio less than 0.85. Blood eosinophilia and atopic sensitization were also more common in boys. Finally, boys had higher levels of serum periostin than girls.

CONCLUSION

This study described significant sex differences in a large pediatric asthma cohort. Overall, boys had earlier and more severe asthma than girls. Differences in blood eosinophilia and serum periostin provide insights into possible mechanisms of the sex bias in childhood asthma.

Effectiveness of a Vendor Predictive Model for the Risk of Pediatric Asthma Exacerbation: A Difference-in-Differences Analysis

BACKGROUND

Asthma is a common cause of morbidity and mortality in children. Predictive models may help providers tailor asthma therapies to an individual's exacerbation risk. The effectiveness of asthma risk scores on provider behavior and pediatric asthma outcomes remains unknown.

OBJECTIVE

Determine the impact of an electronic health record (EHR) vendor-released model on outcomes for children with asthma.

METHODS

The Epic Systems Risk of Pediatric Asthma Exacerbation model was implemented on February 24, 2021, for volunteer pediatric allergy and pulmonology providers as a noninterruptive risk score visible in the patient schedule view. Asthma hospitalizations, emergency department (ED) visits, or oral steroid courses within 90 days of the index visit were compared from February 24, 2019, to February 23, 2022, using a difference-in-differences design with a control group of visits to providers in the same departments. Volunteer providers were interviewed to identify barriers and facilitators to model use.

RESULTS

In the intervention group, asthma hospitalizations within 90 days decreased from 1.4% (54/3,842) to 0.7% (14/2,165) after implementation with no significant change in the control group (0.9% [171/19,865] preimplementation to 1.0% [105/10,743] post). ED visits in the intervention group decreased from 5.8% (222/3,842) to 5.5% (118/2,164) but increased from 5.5% (1,099/19,865) to 6.8% (727/10,743) in the control group. The adjusted difference-in-differences estimators for hospitalization, ED visit, and oral steroid outcomes were -0.9% (95% confidence interval [CI]: -1.6 to -0.3), -2.4% (-3.9 to -0.8), and -1.9% (-4.3 to 0.5). In qualitative analysis, providers understood the purpose of the model and felt it was useful to flag high exacerbation risk. Trust in the model was calibrated against providers' own clinical judgement.

CONCLUSION

This EHR vendor model implementation was associated with a significant decrease in asthma hospitalization and ED visits within 90 days of pediatric allergy and pulmonology clinic visits, but not oral steroid courses.

Roles of Genetic Predisposition in the Sex Bias of Pulmonary Pathophysiology, as a Function of Estrogens : Sex Matters in the Prevalence of Lung Diseases

In addition to studies focused on estrogen mediation of sex-different regulation of systemic circulations, there is now increasing clinical relevance and research interests in the pulmonary circulation, in terms of sex differences in the morbidity and mortality of lung diseases such as inherent-, allergic- and inflammatory-based events. Thus, female predisposition to pulmonary artery hypertension (PAH) is an inevitable topic. To better understand the nature of sexual differentiation in the pulmonary circulation, and how heritable factors, in vivo- and/or in vitro-altered estrogen circumstances and changes in the live environment work in concert to discern the sex bias, this chapter reviews pulmonary events characterized by sex-different features, concomitant with exploration of how alterations of genetic expression and estrogen metabolisms trigger the female-predominant pathological signaling. We address the following: PAH (Sect.7.2) is characterized as an estrogenic promotion of its incidence (Sect. 7.2.2), as a function of specific germline mutations, and as an estrogen-elicited protection of its prognosis (Sect.7.2.1). More detail is provided to introduce a less recognized gene of Ephx2 that encodes soluble epoxide hydrolase (sEH) to degrade epoxyeicosatrienic acids (EETs). As a susceptible target of estrogen, Ephx2/sEH expression is downregulated by an estrogen-dependent epigenetic mechanism. Increases in pulmonary EETs then evoke a potentiation of PAH generation, but mitigation of its progression, a phenomenon similar to the estrogen-paradox regulation of PAH. Additionally, the female susceptibility to chronic obstructive pulmonary diseases (Sect. 7.3) and asthma (Sect.7.4), but less preference to COVID-19 (Sect. 7.5), and roles of estrogen in their pathogeneses are briefly discussed.

Sex-specific differences in children attending the emergency department: prospective observational study

OBJECTIVE

To assess the role of sex in the presentation and management of children attending the emergency department (ED).

DESIGN

The TrIAGE project (TRiage Improvements Across General Emergency departments), a prospective observational study based on curated electronic health record data.

SETTING

Five diverse European hospitals in four countries (Austria, The Netherlands, Portugal, UK).

PARTICIPANTS

All consecutive paediatric ED visits of children under the age of 16 during the study period (8-36 months between 2012 and 2015).

MAIN OUTCOME MEASURES

The association between sex (male of female) and diagnostic tests and disease management in general paediatric ED visits and in subgroups presenting with trauma or musculoskeletal, gastrointestinal and respiratory problems and fever. Results from the different hospitals were pooled in a random effects meta-analysis.

RESULTS

116 172 ED visits were included of which 63 042 (54%) by boys and 53 715 (46%) by girls. Boys accounted for the majority of ED visits in childhood, and girls in adolescence. After adjusting for age, triage urgency and clinical presentation, girls had more laboratory tests compared with boys (pooled OR 1.10, 95% CI 1.05 to 1.15). Additionally, girls had more laboratory tests in ED visits for respiratory problems (pooled OR 1.15, 95% CI 1.04 to 1.26) and more imaging in visits for trauma or musculoskeletal problems (pooled OR 1.10, 95% CI 1.01 to 1.20) and respiratory conditions (pooled OR 1.14, 95% CI 1.05 to 1.24). Girls with respiratory problems were less often treated with inhalation medication (pooled OR 0.76, 95% CI 0.70 to 0.83). There was no difference in hospital admission between the sexes (pooled OR 0.99, 95% CI 0.95 to 1.04).

CONCLUSION

In childhood, boys represent the majority of ED visits and they receive more inhalation medication. Unexpectedly, girls receive more diagnostic tests compared with boys. Further research is needed to investigate whether this is due to pathophysiological differences and differences in disease course, whether girls present signs and symptoms differently, or whether sociocultural factors are responsible.

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.

The frequency of asthma exacerbations and healthcare utilization in patients with asthma from the UK and USA

BACKGROUND

Asthma exacerbations are frequent in patients with severe disease. This report describes results from two retrospective cohort studies describing exacerbation frequency and risk, emergency department (ED)/hospital re-admissions, and asthma-related costs by asthma severity in the US and UK.

METHODS

Patients with asthma in the US-based Clinformatics™ DataMart Multiplan IMPACT (2010-2011; WEUSKOP7048) and the UK-based Clinical Practice Research Datalink (2009-2011; WEUSKOP7092) databases were categorized by disease severity (Global Initiative for Asthma [GINA]; Step and exacerbation history) during the 12 months pre-asthma medical code (index date). Outcomes included: frequency of exacerbations (asthma-related ED visit, hospitalization, or oral corticosteroid use with an asthma medical code recorded within ±2 weeks) 12 months post-index, asthma-related ED visits/hospitalization, and asthma-related costs 30 days post-index. Risk of a subsequent exacerbation was determined by proportional hazard model.

RESULTS

Of the 222,817 and 211,807 patients with asthma included from the US and UK databases, respectively, 12.5 and 8.4% experienced ≥1 exacerbation during the follow-up period. Exacerbation frequency increased with disease severity. Among the 5,167 and 2,904 patients with an asthma-related ED visit/hospitalization in the US and UK databases, respectively, 9.2 and 4.7% had asthma-related re-admissions within 30 days. Asthma-related re-admission rates and costs increased with disease severity, approximately doubling between GINA Step 1 and 5 and in patients with ≥2 versus <2 exacerbations in the previous year. Risk of a subsequent exacerbation increased 32-35% for an exacerbation requiring ED visit/hospitalization versus oral corticosteroids.

CONCLUSION

Increased disease severity was associated with higher exacerbation frequency, ED/hospitalization re-admission, costs and risk of subsequent exacerbation, indicating that these patients require high-intensity post-exacerbation management.

Exercise-induced bronchoconstriction update-2016

The first practice parameter on exercise-induced bronchoconstriction (EIB) was published in 2010. This updated practice parameter was prepared 5 years later. In the ensuing years, there has been increased understanding of the pathogenesis of EIB and improved diagnosis of this disorder by using objective testing. At the time of this publication, observations included the following: dry powder mannitol for inhalation as a bronchial provocation test is FDA approved however not currently available in the United States; if baseline pulmonary function test results are normal to near normal (before and after bronchodilator) in a person with suspected EIB, then further testing should be performed by using standardized exercise challenge or eucapnic voluntary hyperpnea (EVH); and the efficacy of nonpharmaceutical interventions (omega-3 fatty acids) has been challenged. The workgroup preparing this practice parameter updated contemporary practice guidelines based on a current systematic literature review. The group obtained supplementary literature and consensus expert opinions when the published literature was insufficient. A search of the medical literature on PubMed was conducted, and search terms included pathogenesis, diagnosis, differential diagnosis, and therapy (both pharmaceutical and nonpharmaceutical) of exercise-induced bronchoconstriction or exercise-induced asthma (which is no longer a preferred term); asthma; and exercise and asthma. References assessed as relevant to the topic were evaluated to search for additional relevant references. Published clinical studies were appraised by category of evidence and used to document the strength of the recommendation. The parameter was then evaluated by Joint Task Force reviewers and then by reviewers assigned by the parent organizations, as well as the general membership. Based on this process, the parameter can be characterized as an evidence- and consensus-based document.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Asthma exacerbations: predisposing factors and prediction rules

PURPOSE OF REVIEW

Asthma is a multifaceted disease that is associated with decreased lung function, multiple symptoms, varying levels of asthma control, and risk of acute exacerbations. The ability to predict the risk of developing acute exacerbations may improve the management of asthmatics and facilitate identification of these patients for interventional studies.

RECENT FINDINGS

Factors that are associated with different manifestations of asthma differ. Biomarkers that are correlated with airways hyper-responsiveness do not necessarily correlate with risk of future exacerbations. Genetic factors that segregate with exacerbation risk are beginning to emerge. Outcome measures that demonstrate predictive validity have been developed and may facilitate patient management and provide novel clinically meaningful endpoints in clinical trials.

SUMMARY

This review will emphasize underlying factors associated with asthma exacerbations and clinical prediction rules that correlate with the risk of developing severe exacerbations of asthma.

Predicting hospitalization in children with acute asthma

BACKGROUND

Acute asthma is one of the most common medical emergencies in children. Appropriate assessment/treatment and early identification of factors that predict hospitalization are critical for the effective utilization of emergency services.

OBJECTIVE

To identify risk factors that predict hospitalization and to compare the concordance of the Modified Pulmonary Index Score (MPIS) with the Global Initiative for Asthma (GINA) guideline criteria in terms of attack severity.

METHODS

The study population was composed of children aged 5-18 years who presented to the Emergency Departments (ED) of the tertiary reference centers of the country within a period of 3 months. Patients were evaluated at the initial presentation and the 1(st) and 4(th) hours.

RESULTS

Of the 304 patients (median age: 8.0 years [interquartile range: 6.5-9.7]), 51.3% and 19.4% required oral corticosteroids (OCS) and hospitalization, respectively. Attack severity and MPIS were found as predicting factors for hospitalization, but none of the demographic characteristics collected predicted OCS use or hospitalization. Hospitalization status at the 1(st) hour with moderate/severe attack severity showed a sensitivity of 44.1%, specificity of 82.9%, positive predictive value of 38.2%, and negative predictive value of 86.0%; for MPIS ≥ 5, these values were 42.4%, 85.3%, 41.0%, and 86.0%, respectively. Concordance in prediction of hospitalization between the MPIS and the GINA guideline was found to be moderate at the 1(st) hour (κ = 0.577).

CONCLUSION

Attack severity is a predictive factor for hospitalization in children with acute asthma. Determining attack severity with MPIS and a cut-off value ≥ 5 at the 1(st) hour may help physicians in EDs. Having fewer variables and the ability to calculate a numeric value with MPIS makes it an easy and useful tool in clinical practice.

Asthma in late adolescence--farm childhood is protective and the prevalence increase has levelled off

While the prevalence of and risk factors for asthma in childhood have been studied extensively, the data for late adolescence are more sparse. The aim of this study was to provide up-to-date information on the prevalence of and risk factors for asthma in the transitional period between childhood and adulthood. A secondary aim was to analyze whether the increase in asthma prevalence has levelled off. A large-scale, detailed postal questionnaire focusing on asthma and respiratory symptoms, as well as possible risk factors, was mailed to 30 000 randomly selected subjects aged 16-75 in Gothenburg and the surrounding western Sweden region. The present analyses are based on the responses from 1261 subjects aged 16-20 (560 men and 701 women). The prevalence of physician-diagnosed asthma was 9.5%, while 9.6% reported the use of asthma medicine. In the multivariate analysis, the strongest risk factors for physician-diagnosed asthma and other asthma variables were heredity for asthma and heredity for allergy, particularly if they occurred together. Growing up on a farm significantly reduced the prevalence of physician-diagnosed asthma and the likelihood of using asthma medication, OR 0.1 (95% CI 0.02-0.95). Smoking increased the risk of recurrent wheeze, long-standing cough, and sputum production. In conclusion, the prevalence of physician-diagnosed asthma and the use of asthma medication in the 16- to 20-yr age group support the notion that the increase in asthma prevalence seen between the 1950s and the 1990s has now levelled off. In line with the hygiene hypothesis, a farm childhood significantly reduced the likelihood of asthma. The adverse effects of smoking could already be seen at this young age.

Predictors for failed dose reduction of inhaled corticosteroids in childhood asthma

BACKGROUND AND OBJECTIVE

Studies of Western populations have shown that increased exhaled nitric oxide (FeNO) and/or sputum eosinophils (sp-Eos) are predictive of asthma exacerbations. However, the utility of these measurements in different populations and settings is unknown. This study aimed to determine the predictors for failure of reduction of inhaled corticosteroid (ICS) doses in children with stable asthma.

METHODS

Fifty children (median age 11.8 years, interquartile range (IQR) 5.9 years) had their dose of ICS halved every 8 weeks until they reached the study end-point (exacerbation or weaned off ICS). Spirometry, FeNO and induced sputum cells were measured at baseline and at each stage of ICS reduction.

RESULTS

Eleven subjects suffered an asthma exacerbation and the remainder was successfully weaned off ICS. Subjects with an exacerbation were older (15.4 years (IQR 5.4) vs 11.4 years (IQR 3.9), P = 0.019) and more likely to be boys (P = 0.035). FeNO (median 156 p.p.b. (IQR 131) vs 76.1 p.p.b. (IQR 79.5), P = 0.013) and sp-Eos (17.3% (IQR 33.8%) vs 7.1% (IQR 9.9%), P = 0.019) were significantly greater in those who had an exacerbation. The areas under the receiver operating characteristic curves for FeNO (0.78, 95% CI: 0.59-0.97, P = 0.013) and sp-Eos (0.76, 95% CI: 0.56-0.96, P = 0.016) were similar (P = 0.88) and both were significantly greater than that for FEV(1)% predicted (0.12, 95% CI: 0.08-0.56, P = 0.0013).

CONCLUSIONS

Older boys with raised FeNO and sp-Eos are at higher risk of failure of reduction in their ICS dose. Monitoring airway inflammation in children with asthma using FeNO or sp-Eos is clinically useful in guiding ICS dose reduction in a non-Western outpatient setting.

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.

Asthma symptoms in early childhood--what happens then?

AIM

To study the outcome in early adulthood for children with early asthma symptoms and to analyse the factors associated with current asthma.

METHODS

In a prospective study, we have re-investigated 89/101 children who were hospitalized before the age of two years due to wheezing. The children were investigated using a questionnaire and allergy and bronchial hyper-responsiveness tests at the age of 17-20 years and compared with age-matched controls.

RESULTS

In the cohort, 43% had had asthma symptoms in the preceding 12 months compared with 15% in the control group. The strongest risk factors for asthma were current allergy, bronchial hyper-responsiveness and female gender. Female gender and passive smoking in infancy were independent infantile risk factors. In addition to female gender, two pathways led to current asthma: an allergic pathway from family atopy via the development of allergy and another pathway from early passive smoking via hyper-responsiveness and active smoking.

CONCLUSION

In children with early wheezing disorder, current allergy, bronchial hyper-responsiveness and female gender were the strongest risk factors for asthma in early adulthood, while female gender and passive smoking in infancy were independent infantile risk factors. The effects of early passive smoking persist longer than previously reported.

Sex Differences in the Presentation and Course of Asthma Hospitalizations

OBJECTIVE

To distinguish between differences in prevalence, asthma severity, and treatment to explain sex-related differences in hospitalized asthma patients.

DESIGN

Medical record review.

SETTING

Thirty US hospitals as part of the University HealthSystem Consortium Asthma Clinical Benchmarking Project.

PATIENTS

A random sample of patients aged 2 to 54 years and admitted to the hospital for acute asthma from 1999 to 2000.

MEASUREMENTS

Demographics, medical history, initial oxygen saturation, initial peak expiratory flow (adults), initial pulmonary index (children), emergency department course, length of hospital stay, and discharge plans.

RESULTS

The cohort included 606 pediatric (aged 2 to 17 years) and 680 adult (aged 18 to 54 years) inpatients. The sex ratio varied significantly by age: 40% were girls 2 to 17 years of age, and 68% were women 18 to 54 years of age p < 0.001). Among children, girls did not differ from boys according to asthma history, pulmonary index scores, or hospital length of stay. Among adults, women were more likely to have a primary care provider (90% vs 73%, p < 0.001) but did not differ according to asthma history or recent medication use. Women had a higher mean initial PEF compared to men (43% of predicted vs 36% of predicted, p < 0.001) and higher median initial oxygen saturation (95% vs 93%, p = 0.002) but did not differ by hospital length of stay. No sex differences in discharge regimens were identified in children or adults.

CONCLUSIONS

Among US inpatients with acute asthma, male children are more common than female children, while women are more common in adults. The results in children are probably explained by prevalence differences, since no sex differences were seen in markers of asthma severity or treatment. In adults, increased symptoms in response to a given level of airway obstruction in women may contribute to the female predominance in asthma hospitalizations.

Relation between phase of the menstrual cycle and asthma presentations in the emergency department

BACKGROUND

The phase of the menstrual cycle is thought to influence the course of asthma in women. One recent study reported a large increase in exacerbations during the perimenstrual phase, while another found a preovulatory increase. A study was undertaken to determine the relation between phase of the menstrual cycle and acute asthma in patients presenting to the emergency department (ED).

METHODS

All women aged 18-54 years presenting with a diagnosis of acute asthma exacerbation were considered for enrollment in the study. Women who were pregnant, postmenopausal, following hysterectomy, with a >28 day menstrual cycle or incomplete reproductive history were excluded. The 792 eligible women were classified by menstrual phase based on both date of symptom onset and date of ED visit.

RESULTS

When classified by date of symptom onset, 28% were preovulatory (days 5 to 11), 25% were periovulatory (days 12 to 18), 21% were postovulatory (days 19 to 25), and 27% were perimenstrual (days 26 to 4; p = 0.03). When classified by date of ED visit, 28% were preovulatory, 22% were periovulatory, 22% were postovulatory, and 27% were perimenstrual (p = 0.004). Using either approach, there were no significant differences in demographic factors or in asthma severity of women in the various menstrual phase groups.

CONCLUSION

Acute asthma exacerbations do not markedly increase during the perimenstrual phase. The results support the suggestion that both preovulatory and perimenstrual phases are actual triggers of asthma exacerbation in some women, or that these two phases serve as "co-factors" that worsen other recognised triggers of acute asthma.