Leisure-time energy expenditure in asthmatics and non-asthmatics

Association between Asthma and Lower Levels of Physical Activity: Results of a Population-Based Case-Control Study in Spain

(1) Background: Our aim was to determine changes in the prevalence of physical activity (PA) in adults with asthma between 2014 and 2020 in Spain, investigate sex differences and the effect of other variables on adherence to PA, and compare the prevalence of PA between individuals with and without asthma. (2) Methods: This study was a cross-sectional, population-based, matched, case-control study using European Health Interview Surveys for Spain (EHISS) for 2014 and 2020. (3) Results: We identified 1262 and 1103 patients with asthma in the 2014 and 2020 EHISS, respectively. The prevalence of PA remained stable (57.2% vs. 55.7%, respectively), while the percentage of persons who reported walking continuously for at least 2 days a week increased from 73.9% to 82.2% (p < 0.001). Male sex, younger age, better self-rated health, and lower body mass index (BMI) were significantly associated with greater PA. From 2014 to 2020, the number of walking days ≥2 increased by 64% (OR1.64 95%CI 1.34-2.00). Asthma was associated with less PA (OR0.87 95%CI 0.47-0.72) and a lower number of walking days ≥2 (OR0.84 95%0.72-0.97). (4) Conclusions: Walking frequency improved over time among people with asthma. Differences in PA were detected by age, sex, self-rated health status, and BMI. Asthma was associated with less LTPA and a lower number of walking days ≥2.

Recommendations for Physical Activity in Asthma: A Work Group Report of the AAAAI Sports, Exercise, and Fitness Committee

Regular physical activity not only improves general health but also can positively impact asthma outcomes, such as control and quality of life. Despite this, many asthma patients do not engage in regular physical activity because they mistakenly believe that they should restrict exercise participation. Health care providers have an opportunity to influence the physical activity levels of their patients during regular office visits. Nonetheless, health care providers often overlook physical activity counseling as an adjunct to pharmacological therapy in asthma patients, and in particular, overlook physical activity counseling. Some providers who acknowledge the benefits of physical activity report being unaware how to approach a conversation with patients about this topic. To address these issues, members of the Sports, Exercise, and Fitness Committee of the American Academy of Allergy, Asthma, and Immunology (AAAAI) performed a focused literature search to identify and evaluate the effects of physical activity in patients with asthma. The purpose of this report is to summarize the evidence for physical activity's impact on asthma patients' disease control, pulmonary function, and overall well-being. Several subpopulations of patients with asthma, including children, adolescents, and older adults, are considered individually. In addition, this report offers practical recommendations for clinicians, including how to identify and overcome barriers to counseling, and methods to incorporate physical activity counseling into asthma treatment practice.

Health-Related Quality of Life and Health Utilities of Mild, Moderate, and Severe Asthma: Evidence from the Medical Expenditure Panel Survey

Background

Little information is known about the health-related quality of life (HRQOL) and the patient's preference values by the severity of asthma. We evaluated the HRQOL and health utility impairment associated with asthma severity using the SF-12 and SF-6D.

Methods

We conducted a cross-sectional analysis of 2010-2016 Medical Expenditure Panel Survey database of asthma patients aged ≥18 years and categorized them into mild, moderate, and severe asthma. Study outcomes included the SF-12 physical component summary (PCS) and mental component summary (MCS) for measuring HRQOL and SF-6D for health utility. Survey regression models were used to estimate HRQOL and utilities for mild, moderate, and severe asthma.

Results

Of 10,222 patients with asthma, 75.4%, 23.9%, and 0.8% had mild, moderate and severe asthma. We observed that the greater the severity, the lower the SF-6D scores: 0.731 in mild, 0.723 in moderate, and 0.659 in severe asthma (P < 0.001). Patients with severe asthma had a significantly lower PCS compared to those with mild asthma (-5.3; P < 0.001) but there was no significant difference in MCS (-1.9; P = 0.309) controlling for socioeconomic and clinical variables. Asthma severity, women, older age, and having a lower level education and public insurance were significantly associated with lower PCS (P < 0.01).

Conclusion

Asthma patients had worse physical HRQOL than mental health, especially patients with severe asthma. These data suggest that the management of physical health of female, older aged, and low education patients with asthma should be focused on improving HRQOL.

Levels of Physical Activity in Spanish Asthmatics: A Cross-Sectional Study

Background and objectives: 339 million people in the world suffer from asthma. Regular physical activity (PA) could help in its control. Therefore, the aim of this research was to determine the level of PA in Spanish people with asthma considering variation by, age, sex, education, marital status, living together, smoking habits, alcohol intake and body mass index (BMI). Materials and Methods: 1014 Spanish people from 15 to 69 years were included in the study. Data of the Spanish Health Survey (year 2017) were analysed. PA levels were measure with the international physical activity questionnaire short version (IPAQ-SF). PA was categorized as low, moderate and high, and analyzed by sample characteristics. Mann-Whitney U test, Kruskall Wallis H and crosstabs were used to calculate statistical significance (p < 0.05). Results: On average, Spanish asthmatics engaged in a weekly volume of 2228.9 metabolic equivalent of task (MET)·min/week. Males revealed significantly higher PA than females (2516.8 vs. 2019.5 MET·min/week; p = 0.005), younger participants (<30 years) compared to people aged 30–60 years and older than 60 years (2699.0; 2243.2; 1619.3 MET·min/week; p < 0.001) and those with tertiary level of education than those without secondary (2368.3 vs. 2168.3 MET·min/week; p = 0.001). Level of PA was lower in those married (p = 0.001) and/or living together (p = 0.010). Alcohol consumers showed a higher level than the participants who did not drink (2378.3 vs. 1907.9 MET·min/week; p = 0.001), but no significant differences were found within current, past and never smokers (p = 0.890). Obese asthmatics engaged in less PA than their normal weight and overweight peers (p < 0.001). Overall, moderate level was significantly the most frequent (47.7%), but 31.6% showed a low level. Conclusions: Three out of ten Spanish people with asthma do not achieve PA recommendations, so PA programs should be executed to make people aware of its benefits in asthma control, focusing on those groups with lower PA levels.

Physical activity experiences of children and adolescents with asthma: a qualitative systematic review protocol

OBJECTIVE

The objective of the review is to synthesize existing knowledge about experiences of children and adolescents with asthma related to participation in, or limitation of, physical activity.

INTRODUCTION

Limitations of physical activity, expressed as a barrier of bodily movement, may relate to physiological restraints, as well as emotional and social delimitation, in children and adolescents with asthma. Participation in physical activity is related to management of asthma and is important for social inclusion. Through childhood and adolescence, physical activity enhances physical, cognitive, and social development, and a dose-response relationship between physical activity and several indicators of improved health has been established. Knowledge is needed about experiences of physical activity in children and adolescents with asthma to tailor care and implement exercise and physical activity supporting interventions into clinical practice.

INCLUSION CRITERIA

This review will consider qualitative studies that include subjective experiences related to participation in, or limitation of, physical activity in children and adolescents (six to 18 years of age) with asthma. All contexts and countries will be included.

METHODS

MEDLINE, Embase, PsycINFO, CINAHL, SPORTDiscus, SocINDEX, and Social Science Citation Index List will be searched for relevant studies. Studies published in English with no date limitation will be included. Study selection, assessment of methodological quality, data extraction, synthesis, and assessment of confidence in the findings will be conducted using the JBI meta-aggregation approach.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42020164797.

Are adults with asthma less physically active? A systematic review and meta-analysis

OBJECTIVE

To systematically review the evidence on whether having current, ever asthma and asthma control is associated with levels of total, moderate and vigorous physical activity.

METHODS

We searched EMBASE, MEDLINE, and CINAHL databases, limiting searches to English language papers from inception until Oct 2019. We synthesized the evidence comparing levels of total, moderate and vigorous physical activity between adults with and without current asthma or ever asthma by random effects meta-analyses.

RESULTS

A total of 25 studies were included, with 18 of these included in meta-analyses. A meta-analysis of 4 case-control studies found that adults with current asthma were less active, with 942.12 steps fewer per day, than adults without current asthma (SMD = -0.39, 95%CI: -0.54, -0.24, I² = 0). Meta-analysis of four-high quality cross-sectional studies found that those with current or ever asthma were more likely to be inactive than those without asthma (binary OR _{current asthma} = 0.85, 95%CI: 0.82, 0.89, I² = 45.6%, and binary OR _{ever asthma} = 0.83, 0.75, 0.91, I² = 0, respectively). Meta-analysis, inclusive of all 10 cross-sectional studies with binary ORs, supported this finding. There was also some evidence that adults with current asthma and ever asthma (6 studies with categorical ORs) were less likely to exercise moderately and vigorously, but these meta-analyses were limited by high heterogeneity. No synthesis of the studies considering asthma control was possible.

CONCLUSION

Adults with current or ever asthma had lower levels of total, moderate and vigorous physical activity than those without asthma and may be missing out on the health benefits of being physically active. The association between asthma control and physical activity warrants further investigation.

A Systematic Review of Associations of Physical Activity and Sedentary Time with Asthma Outcomes

BACKGROUND

Physical inactivity and high sedentary time are associated with adverse health outcomes in several diseases. However, their impact in asthma is less clear.

OBJECTIVE

We aimed to synthesize the literature characterizing physical activity and sedentary time in adults with asthma, to estimate activity levels using meta-analysis, and to evaluate associations between physical activity and sedentary time and the clinical and physiological characteristics of asthma.

METHODS

Articles written in English and addressing the measurement of physical activity or sedentary time in adults ≥18 years old with asthma were identified using 4 electronic databases. Meta-analysis was used to estimate steps/day in applicable studies.

RESULTS

There were 42 studies that met the inclusion criteria. Physical activity in asthma was lower compared with controls. The pooled mean (95% confidence interval) steps/day for people with asthma was 8390 (7361, 9419). Physical activity tended to be lower in females compared with males, and in older people with asthma compared with their younger counterparts. Higher levels of physical activity were associated with better measures of lung function, disease control, health status, and health care use. Measures of sedentary time were scarce, and indicated a similar engagement in this behavior between participants with asthma and controls. High sedentary time was associated with higher health care use, and poorer lung function, asthma control, and exercise capacity.

CONCLUSIONS

People with asthma engage in lower levels of physical activity compared with controls. Higher levels of physical activity may positively impact on asthma clinical outcomes. Sedentary time should be more widely assessed.

Effects of an unsupervised pedometer-based physical activity program on daily steps of adults with moderate to severe asthma: a randomized controlled trial

Supervised exercise has shown benefits for subjects with asthma, but little is known about the effectiveness of unsupervised physical activity on this population. We investigated the effects of a 12-week unsupervised pedometer-based physical activity program on daily steps and on clinical and psychological parameters of adults with asthma. Clinically stable adults with moderate to severe asthma were encouraged to take daily 30-minute walks and were randomized to pedometer and control groups. The pedometer group received pedometers and individualized daily step targets. Changes in daily steps (average of steps taken during six consecutive days), six-minute walk test (6MWT), health-related quality of life, asthma control and anxiety and depression levels were assessed 12 weeks after intervention and 24-28 weeks after randomization. Thirty-seven participants were recruited and 30 completed the intervention. At 12 weeks, the groups differed significantly in daily steps (adjusted average difference, 2488 steps; 95% confidence interval [CI], 803 to 4172; p = 0.005) and in the 6MWT (adjusted average difference, 21.9 m; 95% CI, 6.6 to 37.3; p = 0.006). These differences were not significant 24-28 weeks after randomization. The program was effective in increasing daily steps of adults with moderate to severe asthma 12 weeks after intervention.

Objectively measured daily-life physical activity of moderate-to-severe Brazilian asthmatic women in comparison to healthy controls: A cross-sectional study

Considering the complex relationship between asthma symptoms and exercise, asthmatics are usually believed to be less active in daily life than healthy subjects. However, few studies have objectively assessed daily-life physical activity (DLPA) of asthmatic adults.

OBJECTIVE

To objectively assess DLPA of a sample of Brazilian asthmatic women in comparison to healthy controls, and to investigate the associations between DLPA and asthma control, health-related quality of life, anxiety and depression levels, and the Six-minute walk test (6MWT) in this population.

METHODS

Sixty-six women were included, 36 in the asthma group (AG) and 30 in the control group (CG). The AG was composed by clinically stable moderate-to-severe asthmatics. The CG was composed by apparently healthy volunteers. All subjects underwent DLPA assessment (considered as the average of steps taken during six consecutive days measured by a pedometer) and performed the 6MWT. Additionally, participants in the AG were assessed using the Asthma Control Questionnaire, the Asthma Quality of Life Questionnaire (AQLQ), and the Hospital Anxiety and Depression Scale.

RESULTS

There was no difference between the AG and the CG regarding DLPA (7490.3 ± 3330.2 vs 6876.4 ± 3242.1 steps respectively, p = 0.45), even after adjustment for covariates. DLPA was significantly correlated to the activity limitation domain of the AQLQ among asthmatics (r = 0.43, p < 0.01).

CONCLUSION

Despite the association between self-perceived activity limitation and DLPA among asthmatics, there were no differences regarding DLPA between a sample of moderate-to-severe Brazilian asthmatic women and apparently healthy controls.

Physical activity and incident asthma in adults: the HUNT Study, Norway

OBJECTIVE

We aimed to investigate the associations of physical activity and change in physical activity with incident asthma in a cohort of Norwegian adults.

DESIGN

We conducted a prospective cohort study using data on self-reported physical activity from 3 waves of the Nord-Trøndelag Health Study. Physical activity was reported at the first and second surveys (1985-1986 and 1995-1997). Physical activity was defined from the second survey as inactive or active and the active group was further defined as very low, low, moderate and high. Change in physical activity was defined from the first and second surveys.

SETTING

A large population-based health survey in Norway.

PARTICIPANTS

We followed 18 894 adults over 11 years who were free from asthma at baseline in 1995-1997.

OUTCOME

Incident asthma was reported in the third survey (2006-2008).

RESULTS

The cumulative incidence of asthma was 3.6% over the 11 years. The adjusted OR for incident asthma among active participants compared with inactive participants was 0.95 (95% CI 0.69 to 1.34). The adjusted OR for those who were active in the first or second survey versus those who were inactive in both surveys was 0.64 (95% CI 0.34 to 1.38); however, this association was strongly attenuated in sensitivity analysis (OR 0.93, 95% CI 0.38 to 3.09).

CONCLUSIONS

We did not observe statistically significant associations of physical activity or change in physical activity with incident asthma in adults over the 11-year follow-up.

Sociodemographic, health-related and lifestyle correlates of physical activity in adults with current asthma

OBJECTIVE

Regular physical activity is associated with better asthma control; however, little is known of the determinants of physical activity in a population of adults with asthma. Thus, the purpose of this study was to identify important sociodemographic, health and lifestyle correlates of physical activity among adults with asthma.

METHODS

Data from adults with asthma aged 18-44 years (n = 2740) from the Canadian Community Health Survey (CCHS), 2011-2012 annual component were used for analysis. The main outcome was Daily Energy Expenditure (DEE). This variable was based on frequency and duration of leisure activities in the past 3 months. Self-reported sociodemographic (age, sex, total household income, highest education level, and ethnicity), health-related (body mass index (BMI), self-perceived health, mood disorder, anxiety disorder, and asthma symptoms/attacks, past year) and lifestyle (type of smoker, sedentary time, fruit and vegetable consumption) variables were assessed as correlates for DEE. Data were analysed using linear regressions.

RESULTS

In the final model, sociodemographic correlates accounted for 4.2% of the variation in DEE. Adding health correlates increased the R² to 12.1%. Finally, adding lifestyle correlates increased the R² to 17.6%.

CONCLUSIONS

In adults with current asthma, the main correlates of physical activity are age, total household income, BMI, self-perceived health, anxiety disorder, sedentary time, and fruit and vegetable consumption. These data are important for informing education and exercise interventions for adults with asthma. Future research is needed to determine asthma-specific correlates of physical activity.

Activity limitation and exertional dyspnea in adult asthmatic patients: What do we know?

Limitation of activity is the most cited symptom described by uncontrolled asthma patients. Assessment of activity limitation can be undertaken through several ways, more or less complex, subjective or objective. Yet little is known about the link between patients sensations and objective measurements. The present review reports the current knowledge regarding activity limitation and symptom perception (i.e., exertional dyspnea) in adult patients with asthma. This work is based on references indexed by PubMed, irrespective of the year of publication. Overall, patients with stable asthma do not have a more sedentary lifestyle than healthy subjects. However, during a cycle ergometric test, the maximal load is reduced when FEV1, FVC and muscle strengths are decreased. Additionally, during the six-minute walking test, mild asthma patients walk less than healthy subjects even if the minimal clinically important difference is not reached. The major complaint of asthma patients when exercising is dyspnea that is mainly related to the inspiratory effort and also to dynamic hyperinflation in some circumstances. Finally, the administration of bronchodilator does not improve the ventilatory pattern and the exercise capacity of asthma patients and little is known on its effect on exertional dyspnea. The present review allows to conclude that until now there is no gold standard test allowing the objective assessment of "activity limitation and exertional dyspnea" in asthma patients.

High levels of physical activity are associated with poorer asthma control in young females but not in males

BACKGROUND AND OBJECTIVE

Earlier studies on the levels of physical activity in asthma patients compared with controls have yielded varying results. We have previously reported that high versus moderate levels of physical activity were associated with higher prevalence of wheezing, especially in females. Here we studied the levels of physical activity in young patients with asthma and healthy subjects and their effect on asthma control.

METHODS

Four hundred eight physician-diagnosed patients with asthma and 118 controls (10-34 years) answered questions concerning frequency and/or duration of physical activity and undertook the Asthma Control Test (ACT), spirometry, methacholine challenges and exhaled nitric oxide measurements.

RESULTS

Asthma patients were more frequently physically active (P = 0.01) and for longer durations (P = 0.002) than controls. Highly versus moderately physically active patients with asthma had a higher prevalence of not well-controlled asthma (ACT < 20) when physical activity was assessed by frequency (40.6% vs 24.1%, P = 0.001) or duration (39.0% vs 21.7%, P < 0.001). This was only seen in females who had reduced ACT items (P < 0.05). Frequently versus moderately active females had an odds ratio of 4.81 (2.43, 9.51) to have ACT < 20, while no such effect was found in males (OR 1.18 (0.61, 2.30)) and this interaction was statistically significantly associated with gender (P = 0.003). No differences in fraction of exhaled nitric oxide or methacholine reactivity were found between moderately and highly physically active females with asthma.

CONCLUSION

Young asthma patients were more active than controls. High levels of physical activity were associated with poor asthma control as judged by the ACT in females, but not in males, and this appears unrelated to airway inflammation or responsiveness.

Cardiorespiratory and sensory responses to exercise in well-controlled asthmatics

OBJECTIVES

The purpose of this study was to evaluate detailed ventilatory, cardiovascular and sensory responses to cycle exercise in sedentary patients with well-controlled asthma and healthy controls.

METHODS

Subjects included sedentary patients meeting criteria for well-controlled asthma (n = 14), and healthy age- and activity-matched controls (n = 14). Visit 1 included screening for eligibility, medical history, anthropometrics, physical activity assessment, and pre- and post-bronchodilator spirometry. Visit 2 included spirometry and a symptom limited incremental cycle exercise test. Detailed ventilatory, cardiovascular and sensory responses were measured at rest and throughout exercise.

RESULTS

Asthmatics and controls were well matched for age, body mass index and physical activity levels. Baseline forced expiratory volume in 1 second (FEV(1)) was similar between asthmatics and controls (98 ± 10 versus 95 ± 9% predicted, respectively, p > 0.05). No significant differences were observed between asthmatics and controls for maximal oxygen uptake (31.8 ± 5.6 versus 30.6 ± 5.9 ml/kg/min, respectively, p > 0.05) and power output (134 ± 35 versus 144 ± 32 W, respectively, p > 0.05). Minute ventilation (V(E)) relative to maximum voluntary ventilation (V(E)/MVV) was similar between groups at maximal exercise with no subjects showing evidence of ventilatory limitation. Asthmatics and controls achieved similar age-predicted maximum heart rates (92 ± 7 versus 93 ± 8% predicted, respectively, p > 0.05). Ratings of perceived breathing discomfort and leg fatigue were not different between groups throughout exercise.

CONCLUSIONS

The results of this study indicate that sedentary patients with well-controlled asthma have preserved sensory and cardiorespiratory responses to exercise with no evidence of exercise impairment or ventilatory limitation.

Physical fitness and amount of asthma and asthma-like symptoms from childhood to adulthood

OBJECTIVE

The potential benefits of physical activity on the development of respiratory symptoms are not well known. The present study investigated the longitudinal association between physical fitness and the development of asthma-like symptoms from childhood to adulthood in a longitudinal community-based study.

METHODS

Participants were assessed at ages 9, 15, 20 and 29 years. Asthma-like symptoms and physical fitness was assessed at each age.

RESULTS

Tracking for physical fitness was high from age 9 to 29 years. Using logistic regression, high physical fitness at age 9 predicted a lower prevalence of asthma-like symptoms at ages 9, 20 and 29 years. Asthma at age 9 and female sex and smoking at any age were also independently associated with the presence of asthma-like symptoms. Our findings suggest that the risk for the development of asthma is reduced by 3% and of asthma-like symptoms reduced by 2% from early adolescence to young adulthood (ages 9-29 years) by increasing the maximal workload with 1 W/kg.

CONCLUSION

This finding provide further evidence of a possible beneficial effect of physical activity in childhood on the development of respiratory symptoms in adulthood and supports the notion that the lower levels of physical activity in recent decades may have contributed to an increase in the prevalence of asthma and asthma-like symptoms.

Asthma and physical activity--a population based study results from the Swedish GA(2)LEN survey

BACKGROUND

Having asthma has in previous reports been related to a lower physical activity level. At the same time the prevalence of asthma among elite athletes is high. The aim of this study was to investigate the association between physical activity level and asthma.

METHODS

A postal questionnaire was completed by 25,610 individuals in Sweden. Current asthma was defined as having had an asthma attack during the last 12 months or current use of asthma medication. The participants were asked how often and for how many hours a week they were physically active.

RESULTS

In the population 1830 subjects (7.1%) had current asthma. There was no significant difference in the proportion of subjects that reported being inactive or slightly physically active between asthmatic and non-asthmatics (57 vs. 58%) while the proportion of subjects that were vigorously physically active (≥2 times a week and ≥7 h per week) was higher among the subjects with asthma (6.7 vs. 4.8%, p < 0.0001). Being vigorously physically active was independently related to current asthma (OR (95% CI)) 1.40 (1.11-1.77)), wheeze (1.39 (1.17-1.65)), wheeze and breathlessness (1.68 (1.38-2.04)), and wheezing without having a cold (1.39 (1.13-1.71)). The association between being vigorously physically active and wheeze was significantly stronger in women compared to men.

CONCLUSIONS

There was no difference in the proportion of subjects with a reported low level of physical activity between asthmatics and non-asthmatics. Health care professionals should, however, be aware of the increased prevalence of asthma and asthma-related symptoms in vigorously physically active subjects.

Physical activity in adults with controlled and uncontrolled asthma as compared to healthy adults: a cross-sectional study

Background

Though exercise-induced bronchoconstriction is common among asthmatics, physical activity (PA) seems important in asthma management. Still, various studies point at avoidance of sports and certain daily life activities like walking stairs, even by patients with mild symptoms. We aimed to compare physical activity levels between healthy subjects and asthmatics with controlled and uncontrolled disease.

Methods

Data on asthma and PA were drawn from the Portuguese National Asthma Survey. The short telephone version of the International Physical Activity Questionnaire (IPAQ) was used to measure PA levels. Current asthma was defined as self-reported asthma and at least one of these criteria: one or more asthma symptoms in the last twelve months, currently taking asthma medication or an asthma medical appointment in the previous twelve months. Controlled asthma was defined as a CARAT global score > 24 or a CARAT second factor score ≤ 16. Healthy subjects were defined as individuals without atopy, heart disease or any respiratory symptom. X² and Mann–Whitney/Kruskall-Wallis tests were used to compare groups. Logistic regression analyses were performed to assess relations between asthma status and PA dimensions.

Results

A total of 606 non-asthmatics, 125 controlled and 78 uncontrolled asthmatic subjects were included. In both genders, overall PA level did not differ significantly between groups. Controlled (men) and uncontrolled (women) asthmatics did more vigorous PA than healthy respondents. Male controlled asthmatics also did more moderate PA. Crude logistic regression showed positive relations between daily sitting time, vigorous and moderate PA and controlled asthma in men and between vigorous PA and uncontrolled asthma in women. After adjustments for confounders, moderate PA remained a predictor of controlled asthma in men, while vigorous PA doubled the risk of uncontrolled asthma in women.

Conclusion

Our study showed that adult asthmatics, independent of asthma control, do not seem to have a more sedentary lifestyle than their peers. Nevertheless, PA should be encouraged, as only about half of them reached activity recommendations.

Attitudes of asthmatic and nonasthmatic children to physical exercise

PURPOSE

The aim of this study was to examine the physical activity of children with and without asthma in Greece, the factors affecting their intention to exercise, and the influence of gender.

METHOD

The study involved 50 children with asthma and 50 children without asthma, aged 9-14-years old. We used the leisure time exercise questionnaire to assess the frequency and intensity of exercise. The planned behavior scale examined seven factors affecting physical activity: attitude, intention, self-identity, attitude strength, social role model, information, and knowledge.

RESULTS

Asthmatic children did not differ significantly in mild, moderate, and overall level of physical activity from children without asthma but they participated less in intense and systematic exercise. The two asthmatic groups did not differ in any of the planned behavior factors. Significant differences between genders occurred with respect to self-identity and social role model. Boys appeared to exercise more regularly and intensely compared to girls.

CONCLUSION

Asthmatic children did not systematically participate in physical activity, preferring mostly mild and moderate intensity activities. Children with and without asthma had comparable positive attitudes and intentions toward exercise.

Physical activity and asthma: a systematic review and meta-analysis

INTRODUCTION

This review aims to give an overview of available published evidence concerning the association between physical activity and asthma in children, adolescents and adults.

METHODS

We included all original articles in which both physical activity and asthma were assessed in case-control, cross-sectional or longitudinal (cohort) studies. Excluded were studies concerning physical fitness, studies in athletes, therapeutic or rehabilitation intervention studies such as physical training or exercise in asthma patients. Methodological quality of the included articles was assessed according to the Newcastle-Ottawa Scale (NOS).

RESULTS

A literature search was performed until June 2011 and resulted in 6,951 publications derived from PubMed and 1,978 publications from EMBASE. In total, 39 studies met the inclusion criteria: 5 longitudinal studies (total number of subjects n = 85,117) with physical activity at baseline as exposure, and asthma incidence as outcome. Thirty-four cross-sectional studies (n = 661,222) were included. Pooling of the longitudinal studies showed that subjects with higher physical activity levels had lower incidence of asthma (odds ratio 0.88 (95% CI: 0.77-1.01)). When restricting pooling to the 4 prospective studies with moderate to good study quality (defined as NOS≥5) the pooled odds ratio only changed slightly (0.87 (95% CI: 0.77-0.99)). In the cross-sectional studies, due to large clinical variability and heterogeneity, further statistical analysis was not possible.

CONCLUSIONS

The available evidence indicates that physical activity is a possible protective factor against asthma development. The heterogeneity suggests that possible relevant effects remain hidden in critical age periods, sex differences, or extremes of levels of physical activity (e.g. sedentary). Future longitudinal studies should address these issues.

Improvement in asthma quality of life in patients enrolled in a prospective study to increase lifestyle physical activity

OBJECTIVE

Asthma patients know the benefits of exercise but often avoid physical activity because they are concerned that it will exacerbate asthma. The objective of this analysis was to assess longitudinal asthma status in 256 primary care patients in New York City enrolled in a trial to increase lifestyle physical activity.

METHODS

Patients were randomized to two protocols to increase physical activity during a period of 12 months. At enrollment, patients completed the Asthma Quality of Life Questionnaire (AQLQ) and the Asthma Control Questionnaire (ACQ) and received asthma self-management instruction through an evaluative test and workbook. Exercise and self-management were reinforced every 2 months. The AQLQ was repeated every 4 months and the ACQ was repeated at 12 months.

RESULTS

The mean age was 43 years and 75% were women. At 12 months there were clinically important increases in physical activity with no differences between groups; thus, data were pooled for asthma analyses. The enrollment AQLQ score was 5.0 ± 1.3 and increased to 5.9 ± 1.1 corresponding to a clinically important difference. Correlations between AQLQ and physical activity were approximately 0.35 (p < .0001) at each time point. In a mixed effects model, the variables associated with improvement in AQLQ scores over time were male sex, less severe asthma, not taking asthma maintenance medications, fewer depressive symptoms, and increased physical activity (all variables, p < .03). According to the ACQ, asthma was well controlled in 38% at enrollment and in 60% at 12 months (p < .0001).

CONCLUSION

With attention to self-management, increased physical activity did not compromise asthma control and was associated with improved asthma.

Asthma and obesity: a known association but unknown mechanism

The obese asthma phenotype is an increasingly common encounter in our clinical practice. Epidemiological data indicate that obesity increases the prevalence and incidence of asthma, and evidence that obesity precedes the development of asthma raises the possibility of a causal association. Obese patients with asthma experience more symptoms and increased morbidity compared with non-obese asthma patients. Despite more than a decade of research into this association, the exact mechanisms that underlie the interaction of obesity with asthma remain unclear. It is unlikely that the asthma-obesity association is simply due to comorbidities such as obstructive sleep apnoea or gastroesophageal reflux disease. Although inflammatory pathways are purported to play a role, there is scant direct evidence in humans that systemic inflammation modulates the behaviour of the asthmatic airway or the expression of symptoms in the obese. The role of non-eosinophilic airway inflammation also requires further study. Obesity results in important changes to the mechanical properties of the respiratory system, and these obesity-related factors appear to exert an additive effect to the asthma-related changes seen in the airways. An understanding of the various physiological perturbations that might be contributing to symptoms in obese patients with asthma will allow for a more targeted and rational treatment approach for these patients.

Association between asthma and physical activity in Korean adolescents: the 3rd Korea Youth Risk Behavior Web-based Survey (KYRBWS-III)

BACKGROUND

Asthma is the leading chronic illness among children and adolescents in several nations. This study investigated the association between asthma and physical activity (PA).

METHODS

The findings in this study are based on the data obtained from the 2007 3rd Korea Youth Risk Behavior Web-Based Survey (KYRBWS-III), a cross-sectional survey of health-risk behaviours among a representative sample of Korean middle- and high-school students aged 13-18 years. This survey is conducted annually by the Korea Centers for Disease Control and Prevention. The 72 943 study subjects were selected using the complex sampling design of the survey. The association between asthma and PA was assessed by conducting multiple logistic regression analyses of the data by using the statistical software SPSS 17.0 Complex Sample.

RESULTS

Compared with the adolescents without current asthma, significantly fewer adolescents with current asthma had a sedentary time of 3 h or less per day (odds ratio, 0.86; 95% confidence interval, 0.75-0.97). Sedentary time was defined as time spent watching television, surfing the Internet, or playing computer games and excluded the time spent doing homework or study during leisure time. The analysis was adjusted for age, gender, family affluence level (FAL), obesity, allergic rhinitis, atopy and smoking. With regard to participation in adequate vigorous or moderate PA, strengthening exercise or physical education class, no significant differences were found between the adolescent students with current asthma and those without current asthma. In addition, it was found that all PA had no significant differences in their effects on asthma severity (medication, inability to work and absence from school).

CONCLUSION

Our results show that the amount of sedentary time influenced asthma prevalence; however, PA did not influence asthma prevalence in Korean adolescents.

Physical activity participation among adult Nevadans with self-reported asthma

OBJECTIVE

This study looked at physical activity patterns among adults (≥ 18 years old) with self-reported asthma living in Nevada and investigated how physical inactivity is associated with asthma prevalence.

METHODS

We examined data from the 2009 Nevada Behavioral Risk Factor Surveillance System. Different physical activity measures among individuals were compared by asthma status.

RESULTS

Among 3840 respondents, 13.9% and 9.0% of them self-reported lifetime and current asthma, respectively. Significantly higher proportions of people with lifetime (12.9%) and current (17.7%) asthma did not engage in regular physical activity or exercise than those without lifetime (7.0%) and current (6.8%) asthma (p < .01). Over 30% of the respondents with asthma had no leisure-time physical activity compared with about 23% of those without asthma (p < .05). Moreover, these findings were statistically significant after adjusting for body mass index as well as other common sociodemographic variables. It was also found that asthmatic people spent significantly less time on moderate and vigorous physical activity than their nonasthmatic counterparts (223 minutes/week vs. 283 minutes/week for moderate physical activity; 214 minutes/week vs. 281 minutes/week for vigorous physical activity; p < .001). More than half of the respondents with asthma and close to half of those without asthma did not meet the current physical activity recommendation.

CONCLUSION

A majority of adults with self-reported asthma living in Nevada are physically inactive. It appears that physical inactivity is associated with an increased prevalence of asthma.

Gasto energético em adolescentes asmáticos com excesso de peso: calorimetria indireta e equações de predição

OBJETIVO: Comparar o gasto energético medido por calorimetria indireta com o estimado por equações de predição entre adolescentes asmáticos e não asmáticos. MÉTODOS: Trata-se de estudo transversal com 69 adolescentes de 10 a 18 anos. Foram comparados três grupos pareados (asmáticos com excesso de peso, asmáticos eutróficos e não asmáticos com excesso de peso). Para avaliação nutricional utilizaram-se medidas antropométricas e de composição corporal. O gasto energético foi medido por calorimetria indireta e estimado por fórmulas de predição. RESULTADOS: Cada grupo foi composto por 23 adolescentes, dos quais 10 do sexo feminino, com média de idade de M=12,4, DP=2,4 anos. O gasto energético de repouso, pela calorimetria indireta nos asmáticos com excesso de peso, foi de M=1550,2, DP=547,2kcal/dia; nos asmáticos eutróficos, M=1540,8, DP=544,2kcal/dia; e nos não asmáticos com excesso de peso, M=1697,2, DP=379,8kcal/dia, com resultado semelhante entre os grupos, mesmo quando ajustado pela massa magra e massa gorda (f=0,186; p=0,831). Obtiveram-se achados semelhantes entre o gasto energético medido pela calorimetria indireta e o estimado pelas fórmulas de predição, com exceção da fórmula de Harris-Benedict, que subestimou o gasto energético nos asmáticos eutróficos e nos não asmáticos com excesso de peso. CONCLUSÃO: O gasto energético de repouso não foi estatisticamente diferente entre os grupos asmáticos e não asmáticos, mesmo quando ajustado pela massa magra e massa gorda. Para os três grupos, as equações de predição são úteis para estimar o gasto energético de repouso e o gasto energético total.

Energy expenditure and estimated caloric intake in asthmatic adolescents with excess body weight

OBJECTIVE

To measure resting energy expenditure (REE) and to estimate caloric intake of asthmatic adolescents with excess body weight and compare results with those groups of eutrophic asthmatic adolescents and non-asthmatic adolescents with excess body weight.

METHODS

This cross-sectional study categorized 69 adolescents aged 10 to 18 y into three matched groups. Nutritional status was assessed using anthropometric and body composition measurements. Indirect calorimetry was used to measure energy expenditure, and caloric intake was estimated from dietary recalls.

RESULTS

In each group, there were 23 adolescents (10 girls) aged 12.39 ± 2.40 y. Results for each group were as follows. For asthmatic adolescents with excess body weight, body mass index (BMI) was 24.83 ± 2.73 kg/m(2), REEs were 1550.24 ± 547.23 kcal/d and 27.69 ± 11.33 kcal · kg(-1) · d(-1), and estimated caloric intake was 2068.75 ± 516.66 kcal/d; for eutrophic asthmatic adolescents, BMI was 19.01 ± 2.10 kg/m(2), REEs were 1540.82 ± 544.22 kcal/d and 36.65 ± 15.04 kcal · kg(-1) · d(-1), and estimated caloric intake was 2174.05 ± 500.55 kcal/d; and for non-asthmatic adolescents with excess body weight, BMI was 25.35 ± 3.66 kg/m(2), REEs were 1697.24 ± 379.84 kcal/d and 28.18 ± 6.70 kcal · kg(-1) · d(-1), and estimated caloric intake was 1673.17 ± 530.68 kcal/d. Absolute REE values between groups were not statistically different, even after correction for lean mass and fat mass (F = 0.186, P = 0.831). REE (kilocalories per kilogram per day) was significantly higher in the group of eutrophic asthmatic adolescents (P = 0.016). Estimated caloric intake was greater than REE only in the group of adolescents with asthma.

CONCLUSION

The REE was not significantly different among groups, and REE (kilocalories per kilogram per day) was higher in the group of eutrophic asthmatic adolescents. Estimated caloric intake was greater than REE in the group of adolescents with asthma.

Barriers and Facilitators to Healthy Physical Activity in Asthma Patients

Preliminary evidence indicates that asthma patients limit exercise and healthy lifestyle activities to avoid respiratory symptoms. This self-imposed decrease in activity, even among those with mild disease, may predispose to long-term general health risks. The objectives of this qualitative study were to determine patients' views about exercise and lifestyle activities and to determine if these views varied depending on asthma characteristics. During in-person interviews, 60 patients were asked open-ended questions about asthma and perceived barriers and facilitators to exercise and lifestyle activities, particularly walking. Responses were coded and corroborated by independent investigators and then compared according to asthma severity, knowledge, self-efficacy, and attitudes. Although most patients acknowledged the importance of exercise, many either limited or did not participate in exercise because of asthma and other conditions. Patients cited both internal and external barriers to exercise, such as lack of motivation, time constraints, and extreme weather affecting asthma. Patients identified multiple facilitators, such as social support and the desire to be healthy. Lifestyle activities were preferred over formal exercise regimens. Patients with more severe disease were more likely to believe that exercise was not good for asthma. Patients with less knowledge, less self-efficacy, and worse attitudes toward asthma also were more likely to have negative perspectives about exercise. In conclusion, for many patients, asthma is a deterrent to physical activity and predisposes to inactivity. Developing interventions to foster prudent lifestyle activities and exercise among asthma patients should be a priority to decrease long-term health risks.

Prospective study of physical activity and risk of asthma exacerbations in older women

RATIONALE

The potential role of physical activity in preventing asthma exacerbations is unknown.

OBJECTIVES

To investigate the longitudinal association between regular physical activity and asthma exacerbations.

METHODS

A total of 2,818 women with asthma from a large U.S. cohort (the Nurses' Health Study) were monitored from 1998 to 2000. Physical activity was self-reported at baseline, using a validated questionnaire, and categorized in quintiles. Exacerbations during follow-up were defined as a self-report of asthma-related hospitalization, emergency department visit, or urgent office visit. Baseline information about severity of asthma, treatment, previous exacerbations, sociodemographic factors, smoking, and other potential confounders was obtained.

MEASUREMENTS AND MAIN RESULTS

Participants had a mean age of 63 years, and 71% had mild-to-moderate persistent asthma. About half of the women were ever-smokers (48% former, 6% current), and median physical activity was 10 MET x hours/week (equivalent to walking at a brisk pace for 20 minutes three times per week). Risk of exacerbations during follow-up decreased with increasing level of physical activity. In a multivariate logistic regression model, the higher level of physical activity, the lower risk of admission (odds ratio 0.85, 0.81, 0.78, and 0.76, for the 2nd, 3rd, 4th, and 5th quintiles compared with the 1st quintile, P for trend = 0.05). There were no relevant differences on stratifying by age group, smoking status, body mass index, baseline use of inhaled corticosteroids, or previous exacerbations.

CONCLUSIONS

Regular physical activity was associated with reduced risk of exacerbations in women with asthma in this longitudinal study.

The association of BMI and sedentary time with respiratory symptoms and asthma in 5th grade schoolchildren in Kaohsiung, Taiwan

This study aimed to evaluate the association of body fatness and sedentary status with asthma and respiratory symptoms in schoolchildren in Kaohsiung, Taiwan. A questionnaire study elicited episodes of respiratory symptoms and data on lifestyle and anthropometric parameters in 1329 5th grade schoolchildren. Results showed that 12.4% of boys and 9.5% of girls had physician-diagnosed asthma, whereas 15.1% of boys and 12.4% of girls had suspected asthma. Significantly greater proportions of boys had non-exercise-induced respiratory symptoms than girls (p < 0.05). The number of respiratory symptoms was positively correlated with TV-watching time per day and self-reported sedentary time per weekend-day in girls (p < 0.05). Underweight was positively associated with one of the seven respiratory symptoms in girls (p < 0.05). At risk of overweight was positively associated with two of the seven respiratory symptoms in boys and one of the seven respiratory symptoms in girls (all p < 0.05). The risk of having physician-diagnosed asthma and suspected asthma increased 93% and 72%, respectively, in schoolchildren at risk of overweight (p < 0.05). Overweight was associated with a 78% increase in physician-diagnosed asthma (adjusted odd ratio (aOR) = 1.78, 95% CI = 1.08-2.91, p < 0.05). Higher sedentary time was significantly associated with more occurrences of one of the seven respiratory symptoms in girls (aOR = 1.05, 95% CI = 1.00-1.11, p < 0.05). Higher body mass index (BMI) was significantly correlated with longer TV-watching time per day in girls and longer self-reported sedentary time per weekday in boys (p < 0.05). In summary, schoolchildren who are at risk of overweight or overweight and/or have more sedentary time have increased risk of respiratory symptoms and asthma. Weight and sedentary statuses of schoolchildren can affect their respiratory health.

Asthmatic symptoms, physical activity, and overweight in young children: a cohort study

OBJECTIVE

Prevalence of asthma and overweight has increased simultaneously during the past decades. Several studies have reported an association between these two health problems, but it is unclear whether this relation is causal. We hypothesize that children with asthmatic symptoms are less physically active, which may contribute to the development of overweight.

PATIENTS AND METHODS

The study included children from the KOALA Birth Cohort Study who were invited at 4 to 5 years of age to wear an Actigraph accelerometer for 5 days (n = 305; 152 boys). Information on wheezing was gathered by repeated questionnaires completed by parents at child ages 7 months and 1, 2, and 4 to 5 years. Questionnaires on physical activity were completed at child age 4 to 5 years, and height, weight, and abdominal circumference were measured. Accelerometer data were expressed as mean counts per minute, minutes per day performing vigorous activity, and moderate-to-vigorous physical activity during > or = 1 minute.

RESULTS

Children who had wheezed in the last 12 months showed very similar activity levels compared with children who had never wheezed. By contrast, boys who had wheezed at least once but not in the last 12 months were more physically active than boys who had never wheezed (geometric mean: 694 vs 625 cpm; adjusted geometric mean ratio: 1.11). This was not found for girls. Similar results were found in parent-reported physical activity data. No association was found between wheezing at any age and overweight at the age of 4 to 5 years.

CONCLUSIONS

These results do not support our hypothesis and previous studies that showed that wheezing children are less physically active. Our data provide no evidence that asthmatic symptoms induce a lower physical activity level and more overweight. Additional research could concentrate on the effect of physical activity and overweight on the development of asthmatic symptoms.

Symposium on obesity and asthma - November 2, 2006

Asthma and obesity are frequently associated, and obesity has been considered a factor contributing to both an increase in severity of asthma and to its development. The present document summarizes the proceedings of a symposium held in Montreal, Quebec, on November 2, 2006, under the auspices of the Réseau en santé respiratoire du Fonds de la recherche en santé du Québec in collaboration with the McGill University - Strauss Severe Asthma Program, Université Laval (Quebec City) and Université de Montréal. It includes an overview of the various aspects of the relationships between asthma and obesity with regard to animal models; genetic, hormonal and physiological determinants; influence of comorbidities (eg, sleep apnea syndrome); epidemiology; clinical and psychological features; and management of asthma in the obese population.

Body mass index and physical activity in relation to asthma and atopic diseases in young adults

BACKGROUND

Obesity has been shown to increase the risk of asthma and wheezing. Conditioning exercise might decrease the asthma risk, and that could partly explain the association. The relation between obesity and allergic diseases is quite conflicting.

METHODS

The association between body mass index (BMI) and physician-diagnosed asthma, allergic rhinitis or conjunctivitis, atopic dermatitis, and self-reported wheezing was investigated in a questionnaire study among 10,667 Finnish first-year university students aged 18-25 years. Logistic regression was used to evaluate possible confounding by parental education, passive smoking at age 0-2, childhood residential environment, current and past smoking and leisure time physical activity index.

RESULTS

In men, there was a greater risk of asthma, but not wheezing with increasing BMI. Compared to those with BMI below 20, OR for male asthma was 1.98 (95% CI 1.11-3.52) in BMI category 20.0-22.4, 1.90 (95% CI 1.05-3.41) in BMI 22.5-24.9, and 3.5 (95% CI 1.63-7.64) in BMI > or = 27.5. Among women, the risks of asthma and wheezing were about two-fold among the overweight-obese subjects. Moderate leisure time physical activity was associated with lower risk of asthma in men (OR 0.62, 95% CI 0.62 (0.42-0.92), but not among women. The risk of allergic rhinoconjunctivitis and atopic dermatitis increased quite linearly with BMI among women but not men.

CONCLUSIONS

Low leisure time physical activity seems not to explain the greater risk of asthma among obese men and women. The quite linear association between BMI and both allergic rhinoconjunctivitis and wheezing among women suggests the independent effect of body fat on atopic diseases.

The incidence of asthma in young adults

STUDY OBJECTIVES

Longitudinal data on adult asthma are sparse. The objectives of this study were to determine the incidence of asthma and to establish the risk factors for the development of asthma in subjects who were 12 to 41 years old over an 8-year period.

DESIGN

From birth cohorts over the period 1953 to 1982 in The Danish Twin Registry, 19,349 subjects with no history of asthma, as determined by a questionnaire-based survey in 1994, answered a follow-up questionnaire in 2002. The subjects were regarded as incident asthma cases when answering "yes" to the question "Do you have, or have you ever had asthma?" in 2002, and "no" to the same question in 1994.

RESULTS

A total of 838 cases (4.3%) of new asthma were identified in 2002. The incidence rates of asthma were 4.5 and 6.4 per 1,000 person-years, respectively, among male and female subjects. For all ages, the probability of adult-onset asthma was greater for female subjects (odds ratio [OR], 1.49; p < 0.001), and for both sexes there was a slow decline in probability with increasing age. There was a positive association between increasing body mass index (BMI) and risk of adult-onset asthma applying to both sexes (OR, 1.05 per unit; p < 0.001). Furthermore, positive associations were found between incident asthma and a history of hay fever (OR: male subjects, 4.2; female subjects, 3.7; p < 0.001), eczema (OR: male subjects, 3.5; female subjects, 2.0; p < 0.001), and both (OR: male subjects, 6.9; female subjects, 8.0; p < 0.001).

CONCLUSIONS

There is a continuing high incidence of asthma past childhood that is most pronounced among female subjects. Increasing levels of BMI are associated with a greater likelihood of developing asthma for both sexes. A substantial portion of cases of adult asthma is preceded by upper airway allergic symptoms and/or eczema, thus indicating a shared pathogenesis.

Decreased physical activity among Head Start children with a history of wheezing: use of an accelerometer to measure activity

Asthma is a severe problem among inner city children, and recent evidence suggests that both allergen exposure and lifestyle can impact the disease early in childhood. This study was designed to investigate the association between physical activity and wheezing among a population of inner city children enrolling in Head Start. The parents of children aged 3-5 years responded to a questionnaire (N = 144) to determine the presence and severity of wheezing and asthma. Information was also gathered regarding home environment, food frequency, and presence of other allergic diseases. Serum was obtained to measure total IgE and specific IgE levels to common allergens. Height and weight for body mass index were recorded. Lastly, motion sensor wristwatches (Actiwatch) were worn continuously by a subset of these children (n = 54) for 6 or 7 days. Physical activity measured with the motion sensor was decreased among children with a history of wheezing. The significant differences involved those measures of activity relating to prolonged or sustained physical activity. The correlates of asthma associated with decreased levels of physical activity included: 1) a history of wheezing in the last 12 months, 2) the diagnosis of asthma, and 3) presentation to the emergency room in the last 12 months for wheezing or asthma. In a preschool-age population, decreased physical activity was observed among children with a history of asthma or wheezing. Decreased physical activity could contribute to persistence of asthma or put children at higher risk for obesity and other chronic diseases.

Are inhaled corticosteroids associated with an increased risk of fracture in children?

Inhaled corticosteroids are widely used in the long-term management of asthma in children. Data on the relationship between inhaled corticosteroid therapy and osteoporotic fracture are inconsistent. We address this issue in a large population-based cohort of children aged 4-17 years in the UK (the General Practice Research Database). The incidence rates of fracture among children aged 4-17 years taking inhaled corticosteroids (n=97,387), taking bronchodilators only (n=70 984) and a reference group (n=345,758) were estimated. Each child with a non-vertebral fracture (n=23,984) was subsequently matched by age, sex, practice, and calendar time to one child without a fracture. Fracture incidence was increased in children using inhaled corticosteroids, as well as in those receiving bronchodilators alone. With an average daily beclomethasone dose of 200 microg or less, the crude fracture risk relative to nonusers was 1.10 [95% confidence interval (CI), 0.96-1.26]; with dosage of 201-400 microg, it was 1.23 (95% CI, 1.08-1.39); and with dosages over 400 microg, it was 1.36 (95% CI, 1.11-1.67). This excess risk disappeared after adjustment for indicators of asthma severity. The increased risk of fracture associated with use of inhaled corticosteroids is likely to be the result of the underlying illness, rather than being directly attributable to inhaled corticosteroid therapy.

Effect of weight reduction on respiratory function and airway reactivity in obese women

BACKGROUND

Population-based studies have documented an association between obesity and an increased prevalence of asthma in women.

METHODS

We prospectively studied 58 obese women with a body mass index of > 30 kg/m(2), 24 of whom had asthma, who were enrolled in an intensive 6-month weight loss program to determine whether loss of body mass would be correlated with improvements in bronchial reactivity, lung function, and disease-specific health status.

RESULTS

Patients lost an average of 20 kg over the 6-month period. For every 10% relative loss of weight, the FVC improved by 92 mL (p = 0.05) and the FEV(1) improved by 73 mL (p = 0.04), however, bronchial reactivity did not significantly change with weight loss (p = 0.23). Patients who lost > 13% of their pretreatment weight experienced improvements in FEV(1) (p = 0.01), FVC (p = 0.02), and total lung capacity (p = 0.05) compared to patients in the lowest quartile who failed to lose significant amounts of weight. Neither group experienced any significant change in methacholine responsiveness (p = 0.57). Patients who completed the 6-month weight loss program experienced improvements in respiratory health status, irrespective of weight loss.

CONCLUSION

We concluded that weight loss can improve lung function in obese women, however, the improvements appear to be independent of changes in airway reactivity.

Body mass index and asthma severity among adults presenting to the emergency department

STUDY OBJECTIVES

Among adults presenting to the emergency department (ED) with acute asthma, we sought to determine the prevalence of obesity, and the relation of body mass index (BMI) to asthma severity in this high-risk population.

DESIGN

Multicenter, prospective cohort study.

SETTING

Twenty-six North American EDs.

PARTICIPANTS

Five hundred seventy-two patients aged 18 to 54 years presenting with acute asthma.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

A standardized interview assessed demographic characteristics, asthma history, and details of the current asthma exacerbation. Data on ED medical management and disposition were obtained by chart review. Three of four asthmatic patients were either overweight (BMI, 25 to 29.9; 30%) or obese (BMI, > or =30; 44%). Normal weight/underweight, overweight, and obese patients did not differ on several markers of chronic asthma severity; obese subjects tended to rate symptoms more severely and to use more inhaled beta-agonists in the 6 h hours prior to ED presentation despite a significantly higher initial percentage of predicted peak expiratory flow (PEF) [44%, 45%, and 51%, respectively; p < 0.05]. The three BMI groups responded similarly to acute therapy in the ED, with all groups demonstrating reversible airway obstruction. The sex distribution by BMI group differed markedly (p < 0.001), with women less often overweight (40% vs 24%) and more often obese (30% vs 52%). Since women were more likely have a higher initial PEF (45% vs 53%, p < 0.001), we stratified by sex to further examine the relation of BMI to asthma severity. The observed BMI-asthma associations were due largely, but not entirely, to confounding by sex.

CONCLUSIONS

Despite lingering concerns about the veracity of "asthma" among obese individuals, asthma exacerbations among obese and nonobese adults were remarkably similar. Potential differences (eg, in symptom perception, use of inhaled beta-agonists before ED presentation, initial PEF rate) were due, in large part, to confounding by sex.

Leisure-time physical activity patterns among US adults with asthma

BACKGROUND

Little is known about the physical activity patterns among US adults who have asthma.

METHODS

Using data for 165,123 respondents of the 2000 Behavioral Risk Factor Surveillance System, we examined leisure-time physical activity.

RESULTS

After adjusting for age, about 30% of participants with current asthma (12,489 participants), 24% with former asthma (4,892 participants), and 27% who never had asthma (147,742 participants) were considered to be inactive (p < 0.001). After adjusting for age, the estimated energy expenditure from leisure-time physical activity was 206 kilocalories (kcal) per week lower among respondents with current asthma than among respondents with former asthma (p < 0.001) and 91 kcal/week lower than respondents who had never had asthma (p < 0.001). About 27% of participants with current asthma, 28% of participants with former asthma, and 28% of participants who had never had asthma were participating in recommended levels of physical activity. Walking was the most frequently reported activity for all three groups (respondents with current asthma, 39%; respondents with former asthma, 39%; and respondents who had never had asthma, 38%. Participants with asthma were less likely to engage in running (p < 0.001), basketball (p = 0.001), golf (p < 0.001), and weightlifting (p = 0.001) but were more likely to use an exercise bicycle (p = 0.035) than were participants without asthma.

CONCLUSIONS

Like most US adults, the majority of those with asthma were not meeting the current recommendations for physical activity.

Obesity and asthma: evidence for and against a causal relation

The evidence for an association between asthma and obesity in adults, and in children and adolescents, is reviewed. Few studies in adults measured height and weight, whereas the majority in children did. Evidence for the association is strong, but that for a gender interaction is weak. There is sufficient evidence to rule out asthma preceding obesity as an explanation, and that increased perception of symptoms in the obese, or a purely mechanical effect, is responsible. However, direct causality is unlikely, because in children the association is of recent origin, and trends in obesity do not explain the rising prevalence of asthma. Atopy was not associated with obesity in a large adult study. Potential explanations that require further investigation are that gastroesophageal reflux as a result of obesity causes asthma, that physical inactivity may promote both obesity and asthma, and that the diets of obese subjects may potentiate asthma.

Factors associated with asthma in young Danish adults

BACKGROUND

The prevalence of asthma appears to be increasing, but our knowledge about factors associated with asthma in young adults is limited. Factors associated with asthma were studied in 624 (66% of those invited) young Danish adults (aged 19 to 29 years).

OBJECTIVE

The purpose of this study was to investigate the prevalence and predictors of asthma in young Danish adults.

METHODS

Case history, including respiratory symptoms, smoking habits, education, and employment, was obtained by interview, and a questionnaire and was used to evaluate the presence or absence of asthma. Pulmonary function, beta2-reversibility, airway responsiveness to histamine, and blood eosinophil count were measured using standard techniques.

RESULTS

The lifetime prevalence of asthma in these young Danish adults was 17%, and the prevalence of current asthma was 9%. The proportion of current smokers was disturbingly high, 41%, and, further, the proportion of current smokers was significantly higher among those with asthma than among those without asthma (52% and 38%, respectively; P < 0.01). Asthma was significantly associated with current smoking, with lower than predicted forced expiratory volume in 1 second, with lower than predicted ratio of forced expiratory volume in 1 second/forced vital capacity, atopy, higher eosinophil count, and higher degree of airway responsiveness to histamine. The proportion of subjects with no education after junior high school was higher among those with asthma than among those without asthma (P < 0.05). Further, 16 of the 103 (16%) people with asthma had work-related worsening of their respiratory symptoms.

CONCLUSIONS

The presence of current asthma was predicted by current smoking, lower level of lung function, less education, higher blood eosinophil count, and more pronounced airway responsiveness. Further, the proportion of current smokers was higher among asthmatic subjects than among nonasthmatic subjects. Greater efforts must be made to encourage young people with asthma not to smoke.

Beta(2)-adrenoceptor polymorphism and body mass index are associated with adult-onset asthma in sedentary but not active women

STUDY OBJECTIVE

Beta(2)-adrenoceptor Gly16 polymorphism has been associated with asthma severity and beta(2)-adrenoceptor receptor downregulation, but not with the diagnosis of asthma. Glu27 polymorphism may limit beta(2)-adrenoceptor downregulation and predict body mass index (BMI), particularly among sedentary persons. In addition, BMI predicts asthma. We hypothesized that these DNA sequence variants predict adult-onset asthma only in sedentary women.

DESIGN

Nested case-control study.

SETTING

Nurses' Health Study, a large, prospective cohort study with participants throughout the United States.

PARTICIPANTS

Among lifelong nonsmokers, 171 women with adult-onset, medication-requiring asthma and 137 age-matched control subjects.

MEASUREMENTS

Physical activity and BMI were self-reported by previously validated questionnaire items. Genomic DNA was obtained from buccal brushings collected via first-class mail.

RESULTS

Of 76 sedentary women, the adjusted odds ratios of Gly16 allele were 7.4 (p = 0.047) for asthma and 13.8 (p = 0.02) for steroid-requiring asthma. No similar associations were observed among 232 active women (p = 0.91). Sedentary individuals with both Gly16 and Glu27 alleles had a less elevated risk for asthma. BMI was associated with asthma and Glu27 allele among sedentary women.

CONCLUSION

This exploratory analysis suggests an important gene/environment interaction for asthma involving physical activity level. Further study in larger populations is warranted to confirm if sedentary lifestyle unmasks a genetic risk for asthma.