Body mass index and asthma in the military population of the northwestern United States

Association between prevalence of obstructive lung disease and obesity: results from The Vermont Diabetes Information System

BACKGROUND

The association of obesity with the development of obstructive lung disease, namely asthma and/or chronic obstructive pulmonary disease, has been found to be significant in general population studies, and weight loss in the obese has proven beneficial in disease control. Obese patients seem to present with a specific obstructive lung disease phenotype including a reduced response to corticosteroids. Obesity is increasingly recognized as an important factor to document in obstructive lung disease patients and a critical comorbidity to report in diabetic patients, as it may influence disease management. This report presents data that contributes to establishing the relationship between obstructive lung disease in a diabetic cohort, a population highly susceptible to obesity.

METHODS

A total of 1003 subjects in community practice settings were interviewed at home at the time of enrolment into the Vermont Diabetes Information System, a clinical decision support program. Patients self-reported their personal and clinical characteristics, including any history of obstructive lung disease. Laboratory data were obtained directly from the clinical laboratory, and current medications were obtained by direct observation of medication containers. We performed a cross-sectional analysis of the interviewed subjects to assess a possible association between obstructive lung disease history and obesity.

RESULTS

In a multivariate logistic regression model, a history of obstructive lung disease was significantly associated with obesity (body mass index ≥30) even after correcting for potential confounders including gender, low income (<$30,000/year), number of comorbidities, number of prescription medications, cigarette smoking, and alcohol problems (adjusted odds ratio (OR) = 1.58, P = 0.03, 95% confidence interval (CI) = 1.05, 2.37). This association was particularly strong and significant among female patients (OR = 2.18, P = < 0.01, CI = 1.27, 3.72) but not in male patients (OR = 0.97, P = 0.93, CI = 0.51, 1.83).

CONCLUSION

These data suggest an association between obesity and obstructive lung disease prevalence in patients with diabetes, with women exhibiting a stronger association. Future studies are needed to identify the mechanism by which women disproportionately develop obstructive lung disease in this population.

Obesity and childhood asthma

PURPOSE OF REVIEW

Asthma is a common chronic disease of the airways characterized by recurrent respiratory symptoms, bronchoreactivity, and airway inflammation. The high toll on quality of life has led to sustained efforts to understand the factors leading to asthma inception and poor disease control. Obesity is another increasingly common pediatric disease, which appears to increase the risk for incident asthma and worsened disease severity. Currently, our understanding of how obesity affects asthma risk and affects its phenotypic characteristics remains incomplete. The current review describes our current understanding of the epidemiology, clinical characteristics, and management considerations of obesity-related asthma in children.

RECENT FINDINGS

The epidemiologic relationship between obesity in children and incident asthma remains confusing despite numerous longitudinal cohort studies, and appears to be influenced by early life exposures, patterns of somatic growth and underlying familial risks of allergic disease. Children with comorbid obesity and asthma demonstrate diverse phenotypic characteristics which are still becoming clear.

SUMMARY

Like any child with asthma, a child with comorbid obesity requires an individualized approach adhering to current best-practice guidelines and an understanding of how obesity and asthma may interact.

Prevalence and impact of risk factors for poor asthma outcomes in a large, specialist-managed patient cohort: a real-life study

Background

Risk factors for poor asthma outcomes may have considerable influence on the control level and medical care of asthmatic patients. Our objective was to conduct a study that provides data on the level of symptom control and the frequency of specific risk factors for poor asthma outcomes on a large patient cohort.

Methods

A cross-sectional, non-interventional real-life study was conducted among asthmatic patients treated by respiratory specialists in Hungary. Asthma control and risk factor assessment were done according to Global Initiative for Asthma guideline (Box 2–2). In the data analysis, phase descriptive statistics, graphical outputs, and Fisher’s exact tests were used.

Results

Of 12743 patients enrolled by 187 specialists, asthma was well controlled in 36.0%, partially controlled in 29.29%, and uncontrolled in 34.71% of the cases. The most common comorbidities were rhinitis/sinusitis (66.84%), cardiovascular diseases (43.81%), and gastroesophageal reflux disease (20.11%). The following risk factors had the strongest relationship with uncontrolled disease: incorrect inhaler technique causing side effects (odds ratio, OR 4.86, 3.51–6.8), previous severe exacerbation (OR 4.79, 4.02–5.72), high short-acting beta agonist (SABA) use (OR 4.46, 4.03–4.93), incorrect inhaler technique associated with an exacerbation (OR 3.91, 3.06–5.03), and persistently low forced expiratory volume in 1 s (FEV₁, OR 3.14, 2.8–3.52). The most frequent risk factors were smoking (OR 1.47, 1.36–1.59) and obesity (OR 1.34, 1.24–1.45). Furthermore, high loss of control was associated with an initial low FEV₁ (OR 2.21, 2.01–2.44), frequent oral corticosteroid (OCS) use (OR 1.83, 1.64–2.05), poor adherence to treatment (OR 2.51, 2.21–2.86), and allergen exposure (OR 1.63, 1.47–1.81).

Conclusions

This study indicated that the presence of risk factors for poor asthma outcomes listed by the Global Initiative for Asthma document significantly influenced actual control level in a real-world large patient cohort, with high SABA use, previous severe exacerbation, incorrect inhaler technique, persistently low FEV₁, and poor adherence to treatment having the highest impact.

Managing comorbid conditions in severe asthma

Asthma care has increasingly focused on personalised management for severe asthma, and recognition of the role and importance of comorbid conditions has increased. Severe asthma can be crippling; associated comorbid conditions often play a key role in the significant disease morbidity and frequently contribute to a severe and difficult-to-treat asthma phenotype. Comorbid conditions can be broadly grouped as being either airway-related or airway-unrelated. Airway-related comorbid conditions with the greatest impact are allergic rhinitis, chronic rhinosinusitis, vocal cord dysfunction, lung fungal sensitisation and underlying structural lung disease. The most important airway-unrelated comorbid conditions are obesity, obstructive sleep apnoea, gastro-oesophageal reflux disease and anxiety and depression. A diagnostic and management algorithm for comorbid conditions in severe asthma is outlined. It concentrates initially on the group with common comorbid conditions that can be managed in primary care. If asthma remains troublesome, emphasis can shift to identifying uncommon and more complex factors. The algorithm allows for personalised diagnostic and management pathways to be implemented. Personalised diagnosis and management of comorbid conditions are essential to achieving effective and improved outcomes for patients with severe asthma.

Use of various obesity measurement and classification methods in occupational safety and health research: a systematic review of the literature

BACKGROUND

This study systematically examined obesity research in occupational safety and health regarding the use of various obesity measurement and classification methods.

METHODS

A systematic search of the PubMed database on English language publications from 2000 to 2015 using related keywords and search of citations resulted in selection of 126 studies. They were categorized into two groups based on their main research question: 1) general physical or mental work-related functioning; and 2) task or body part specific functioning.

RESULTS

Regardless of the study group, body mass index (BMI) was the most frequently used measure. Over 63% of the studies relied solely on BMI to define obesity. In only 22% of the studies, body fat was directly measured by methods such as dual energy x-ray absorptiometry. Abdominal obesity was defined using waist circumference in recent years, and waist-hip ratio in earlier years. Inconsistent cut-offs have also been used across studies investigating similar topics.

CONCLUSIONS

Few authors acknowledged the limitations of using indirect obesity measures. This is in part due to the limited understanding of some occupational safety and health researchers regarding the complex issues surrounding obesity classification and also the mixed recommendations over the past 2-3 decades and across populations. Efforts need to be made to promote appropriate obesity measurement and reporting in this field.

Outcome of Morbid Obesity in the Intensive Care Unit

This was a retrospective chart review of consecutive obese patients admitted to the medical intensive care unit. Patients were divided into 2 groups: mild to moderately obese (group 1, body mass index =30-40 kg/m2) and morbidly obese (group 2, body mass index >40 kg/m2). Acute Physiology and Chronic Health Evaluation II scores were not significantly different between the 2 groups. Morbidly obese patients (group 2) had higher rates of mortality and nursing home admission. They also showed higher rates of intensive care unit complications including sepsis, nosocomial pneumonia, acute respiratory distress syndrome, catheter infection, tracheostomy, and acute renal failure. Their median length of mechanical ventilation was longer (2 days, range 2-12 vs 9 days, range 1-37, P = .009). In a logistic regression analysis, morbid obesity remained a significant predictor of death or disposition to nursing home even after controlling for age ( P = .019, odds ratio = 7.60, 95% confidence interval = 1.39-41.6). Morbidly obese patients (body mass index >40 kg/m2) admitted to intensive care units have higher rates of mortality, nursing home admission, and intensive care unit complications and have longer stays in the intensive care unit and time on mechanical ventilation.

Sex difference in the association between obesity and asthma in U.S. adults: Findings from a national study

BACKGROUND

Obesity and asthma are both prevalent in the U.S. The a few studies that have examined the differences in association between obesity and asthma by sex provided mixed results. Reason for the sex differences is not well understood.

OBJECTIVE

Using U.S. nationally representative data we aimed to examine the association between obesity and asthma and potential sex differences.

METHODS

Data were obtained from the 2012 National Health Interview Survey (n = 33,153 adults, 4197 had asthma). Asthma was determined by a positive response to the question "Has a doctor or health care professional ever told you had asthma?" Obesity was determined as a Body Mass Index (BMI)≥30. Obese status was categorized as BMI = 30-34.9 (Class I obesity), BMI = 35-39.9 (Class II obesity), and BMI≥40 (Class III obesity).

RESULTS

The prevalence of asthma was 12.6% (11.0% in men, 14.2% in women), and was higher in the obese than non-obese individuals (16.6% vs. 11.1%, p < 0.0001). After controlling for potential confounders, Class I obesity (OR = 1.27, 95% CI = 1.11-1.44), Class II obesity (OR = 1.55, 95% CI = 1.31-1.84), Class III obesity (OR = 1.85, 95% CI = 1.54-2.21) were positively associated with asthma. The association between Class III obesity and asthma was stronger in women than men (2.11 (1.70-2.63) vs. 1.40 (1.01-1.96), p < 0.05), although the sex difference in the association between BMI and asthma was not significant. Positive associations between class II and class III obesity and asthma were observed among young and middle-aged women compared to young and middle-aged men. Stratified by allergic status, obesity remained being positively associated with asthma.

CONCLUSION

The prevalence of asthma was higher in women than men. Obesity (and BMI) was positively associated with asthma, overall or stratified by allergic status. The association between Class III obesity and asthma was stronger in women. Obesity and sex may be taken into consideration for the management of asthmatic patients.

Factor structure and psychometric properties of the Body Appreciation Scale among adults in Hong Kong

Previous research has suggested that the factor structure of Body Appreciation Scale (BAS), a widely-used measure of positive body image, may not be cross-culturally equivalent. Here, we used confirmatory factor analysis to evaluate the conceptual equivalence of a Chinese (Cantonese) translation of the BAS among women (n=1319) and men (n=1084) in Hong Kong. Results showed that neither the one-dimensional nor proposed two-dimensional factor structures had adequate fit. Instead, a modified two-dimensional structure, which retained 9 of the 13 BAS items in two factors, had the best fit. However, only one of these factors, reflective of General Body Appreciation, had adequate internal consistency. This factor also had good patterns of construct validity, as indicated through significant correlations with participant body mass index, self-esteem, and (among women) actual-ideal weight discrepancy. The present results suggest that there may be cultural differences in the concept and experience of body appreciation.

Elevated sputum interleukin-5 and submucosal eosinophilia in obese individuals with severe asthma

RATIONALE

The relationship between airway inflammation and obesity in severe asthma is poorly understood.

OBJECTIVES

We sought to determine the relationship between sputum mediator profiles and the distribution of eosinophilic inflammation and obesity in people with severe asthma.

METHODS

Clinical parameters and eight mediators in sputum were assessed in 131 subjects with severe asthma from a single center categorized into lean, overweight, and obese groups defined by their body mass index. In an independent group of people with severe asthma (n = 45) and healthy control subjects (n = 19) eosinophilic inflammation was enumerated in bronchial submucosa, blood, and sputum and related to their body mass index.

MEASUREMENTS AND MAIN RESULTS

Sputum IL-5 geometric mean (95% confidence interval) (pg/ml) was elevated in the obese (1.8 [1.2-2.6]) compared with overweight (1.1 [0.8-1.3]; P = 0.025) and lean (0.9 [0.6-1.2]; P = 0.018) subjects with asthma and was correlated with body mass index (r = 0.29; P < 0.001). There was no relationship among body mass index, the sputum cell count, or other sputum mediators. In the bronchoscopy group the submucosal eosinophil number in the subjects with asthma was correlated with body mass index (Spearman rank correlation, rs = 0.38; P = 0.013) and the median (interquartile range) number of submucosal eosinophils was increased in obese (19.4 [11.8-31.2]) (cells per square millimeter) versus lean subjects (8.2 [5.4-14.6]) (P = 0.006). There was no significant association between sputum or peripheral blood eosinophil counts and body mass index.

CONCLUSIONS

Sputum IL-5 and submucosal eosinophils, but not sputum eosinophils, are elevated in obese people with severe asthma. Whether specific antieosinophilic therapy is beneficial, or improved diet and lifestyle in obese asthma has antiinflammatory effects beyond weight reduction, requires further study.

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.

Effect of lifestyle on asthma control in Japanese patients: importance of periodical exercise and raw vegetable diet

Background

The avoidance of inhaled allergens or tobacco smoke has been known to have favorable effects on asthma control. However, it remains unclear whether other lifestyle-related factors are also related to asthma control. Therefore, a comprehensive study to examine the associations between various lifestyle factors and asthma control was conducted in Japanese asthmatic patients.

Methods

The study subjects included 437 stable asthmatic patients recruited from our outpatient clinic over a one-year period. A written, informed consent was obtained from each participant. Asthma control was assessed using the asthma control test (ACT), and a structured questionnaire was administered to obtain information regarding lifestyle factors, including tobacco smoking, alcohol drinking, physical exercise, and diet. Both bivariate and multivariate analyses were conducted.

Results

The proportions of total control (ACT = 25), well controlled (ACT = 20-24), and poorly controlled (ACT < 20) were 27.5%, 48.1%, and 24.5%, respectively. The proportions of patients in the asthma treatment steps as measured by Global Initiative for Asthma 2007 in step 1, step 2, step 3, step 4, and step 5 were 5.5%, 17.4%, 7.6%, 60.2%, and 9.4%, respectively. Body mass index, direct tobacco smoking status and alcohol drinking were not associated with asthma control. On the other hand, younger age (< 65 years old), passive smoking, periodical exercise (> 3 metabolic equivalents-h/week), and raw vegetable intake (> 5 units/week) were significantly associated with good asthma control by bivariate analysis. Younger age, periodical exercise, and raw vegetable intake were significantly associated with good asthma control by multiple linear regression analysis.

Conclusions

Periodical exercise and raw vegetable intake are associated with good asthma control in Japanese patients.

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.

The role of vitamin D in asthma

Vitamin D metabolites are important immune-modulatory hormones and are able to suppress Th2-mediated allergic airway disease. Some genetic factors that may contribute to asthma are regulated by vitamin D, such as vitamin D receptor (VDR), human leukocyte antigen genes (HLA), human Toll-like receptors (TLR), matrix metalloproteinases (MMPs), a disintegrin and metalloprotein-33 (ADAM-33), and poly(ADP-ribosyl) polymerase- 1 (PARP-1). Vitamin D has also been implicated in asthma through its effects on the obesity, bacillus Calmettee Guérin (BCG) vaccination and high vitamin D level, vitamin D supplement, checkpoint protein kinase 1 (Chk1), plasminogen activator inhibitor-1 (PAI-1) and gamma delta T cells (gdT). Vitamin D plays a role in asthma and exerts its action through either genomic and/or non-genomic ways.

Respiratory complications of obesity

Obesity, well known as a cardiovascular risk factor, can also lead to significant respiratory complications. The respiratory changes associated with obesity extend from a simple change in respiratory function, with no effect on gas exchange, to the more serious condition of hypercapnic respiratory failure, characteristic of obesity hypoventilation syndrome. More recently, it has been reported that there is an increased prevalence of asthma which is probably multifactorial in origin, but in which inflammation may play an important role. Hypoventilation in the obese subject is the result of complex interactions that involve changes in the ventilatory mechanics and anomalies in breathing control. Two other conditions (COPD and sleep apnea-hypopnea syndrome [SAHS], often present in obese patients, can trigger or aggravate it. The prevalence of hypoventilation in the obese is under-estimated and the diagnosis is usually established during an exacerbation, or when the patient is studied due to suspicion of SAHS. Ventilatory management of these patients includes either CPAP or NIV. The choice of one or another will depend on the underlying clinical condition and whether or not there is another comorbidity. Both NIV and CPAP have demonstrated their effectiveness, not only in the control of gas exchange, but also in improving the quality of life and survival of these patients.

Prevalence of allergic diseases and risk factors of wheezing in Korean military personnel

The objective of this study was to evaluate the prevalence of asthma, allergic rhinitis, and atopic dermatitis, as well as the risk factors of wheezing among young adults in the Korean military. Young military conscripts in five areas completed a modified International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. For subjects with current wheeze in one sample area, baseline spirometry and bronchodilator response were measured. For subjects without a significant response to bronchodilator (improvement in FEV1 of more than 200 mL and 12%), methacholine challenge tests (MCT) were also performed. Of 3,359 subjects that completed the questionnaire, 354 (10.5%) had current wheeze, 471 (14.0%) had current allergic rhinitis, and 326 (9.7%) had current eczema. Current wheeze was associated with family history of allergic disease, overweight, current smoking, allergic rhinitis, and atopic dermatitis. Of 36 subjects with current wheeze who underwent PFT with or without MCT in the Anyang area, 24 (66.7%) were confirmed to have current asthma. In conclusion, the prevalence of allergic disease in young adults of Korean military is not low, and the risk factors of wheezing include family history of allergic disease, overweight, current smoking, allergic rhinitis, and atopic dermatitis.

Relationship between obesity and asthma symptoms among children in Ahvaz, Iran: a cross sectional study

BACKGROUND

Obesity has been identified as a risk factor for higher prevalence of asthma and asthma-related symptoms in children. The objective of this study was to evaluate the relationship between the prevalence of asthma symptoms and obesity among school-age children in the city of Ahvaz, Iran.

METHODS

A total of 903 children, 7 to 11 years of age, were enrolled in this study through cluster sampling. The International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was used to identify the children who were currently suffering from asthma. Height and weight were measured and body mass index (BMI) was calculated in kg/m2. Overweight was defined as BMI greater than the age- and sex-specific 85th percentile, and obesity as BMI greater than the 95th percentile. We determined the relationship between obesity and asthma symptoms by chi-square tests.

RESULTS

The prevalence of wheeze ever, current wheezing, obesity, and overweight was 21.56%, 8.7%, 6.87%, and 9.5%, respectively. The current prevalence of wheezing among obese and overweight children was 68.75% and 37%, respectively, and there was a statistical association between obesity and the prevalence of current wheezing (p < 0.001), night cough (p < 0.001), and exercise-induced wheezing (p = 0.009), but obesity and overweight were not associated with eczema and allergic rhinoconjunctivitis, so it seems that the pathophysiology of asthma in obese and overweight children is not related to allergy.

CONCLUSION

There is a strong association between asthma symptoms and both overweight and obesity in both sexes among school-age children.

Body mass and fat mass in refractory asthma: an observational 1 year follow-up study

Background. Asthma and obesity are common; however the impact of obesity upon asthma remains uncertain. Objectives. To assess relationships between obesity and fat mass with airway inflammation, lung function, and disease control in patients with refractory asthma. Methods. 151 refractory asthma patients were characterised for measures of airway inflammation, lung function, Juniper asthma control questionnaire (JACQ), body mass index (BMI), and fat mass index (FMI) derived from dual energy X-ray absorptiometry. Patients were reassessed over 12 months. Results. 74% of patients had an elevated BMI. BMI and FMI correlated (r = 0.9, P < .001). FMI and JACQ correlated in men (r = 0.3, P = .01). After 12 months 23% lost weight. Weight change over 12 months correlated with FEV₁ change (r = −0.3, P = .03), but not with change in JACQ or exacerbations. Conclusion. Increased fat mass is common in refractory asthma and is associated with asthma symptom control in men. Loss of weight is associated with improvement in lung function in refractory asthma.

Epidemiology of asthma: risk factors for development

This comprehensive review of the recent literature was undertaken to determine the current state of knowledge of the risk factors involved in the development of asthma in order to focus investigations in a proposed new longitudinal birth cohort study. The origins of asthma appear to lie in the prenatal and early postnatal period, and renewed investigations in this period with long-term close follow-up and objective phenotypic characterization will help to unravel the role of the multiple putative environmental factors in the development of asthma. It is only after understanding these effects that one can hope to design rational prevention studies for asthma.

The impact of morbid obesity and bariatric surgery on comorbid conditions: a comprehensive examination of comorbidities in an employed population

OBJECTIVE

Find conditions with significantly different prevalence among employees diagnosed with morbid obesity (DMO). Examine the effect of bariatric surgery on the prevalence of all categories of comorbid conditions after surgery.

METHODS

This large employer retrospective database analysis used matching to create two cohorts: Those with a DMO and those without.

RESULTS

The DMO cohort had higher diagnosis rates in every Agency for Healthcare Research and Quality major diagnostic category except pregnancy, and it had significantly higher prevalence in 147 of 261 Agency for Health care Research and Quality specific categories. Those electing to undergo bariatric surgery experienced significant prevalence decreases in 26 of 261 specific categories.

CONCLUSION

Employees DMO are at higher risk for many serious diseases. Bariatric surgery has been effective in promoting weight loss and decreasing the rates of many serious comorbidities.

Obesity and respiratory diseases

Obesity is a worldwide epidemic and is known to increase the risk of cardiovascular disease, type 2 diabetes, and certain forms of cancer. In addition, obesity is now recognized as an important risk factor in the development of several respiratory diseases. Of these respiratory diseases, it has already been well established that obesity can lead to obstructive sleep apnea (OSA) and obesity-hypoventilation syndrome (OHS). More recent data suggest that the prevalence of wheezing and bronchial hyper-responsiveness, two symptoms often associated with asthma, are increased in overweight and obese individual. Indeed, epidemiological studies have reported that obesity is a risk factor for the development of asthma. Furthermore, a number of studies indicate that obesity is also associated with a higher risk of developing deep vein thrombi, pulmonary emboli, pulmonary hypertension, and pneumonia. Finally, weight reduction has been shown to be effective in improving the symptoms and severity of several respiratory diseases, including OSA and asthma. Thus, overweight and obese patients should be encouraged to lose weight to reduce their risk of developing respiratory diseases or improve the course of pre-existing conditions.

Improvement in comorbid illness after placement of the Swedish Adjustable Gastric Band

BACKGROUND

Obesity and its related comorbid illnesses have become a national health priority. We report comorbidity and quality of life (QoL) data after weight loss with gastric banding using the Swedish Adjustable Gastric Band (SAGB).

METHODS

Data were collected prospectively for 838 consecutive morbidly obese patients who underwent laparoscopic adjustable gastric banding (LAGB) between January 2001 and July 2007. Patients were followed-up by a multidisciplinary team consisting of a surgeon, physician, dietician, and exercise consultant, all of whom were involved in the evaluation of clinical outcomes. Continuous data were reported as mean +/- SD; categorical data were reported as number and percentage. Patients served as their own controls.

RESULTS

Respective preoperative mean age, weight, and body mass index (BMI) were 44 years (range 16-76), 122 kg (range 86-240), and 44 kg/m2 (range 35-86), respectively. SAGB implantation was accomplished by the pars flaccida technique with no conversion to an open procedure. Mature follow-up data were available for 35% of patients at 24 months and 21% at 36 months. In the total cohort of 838 patients, BMI (mean +/- SD) decreased to 32 +/- 5 kg/m2 and 32 +/- 7 kg/m2 at 24 months and 36 months, respectively. Percentage excess weight loss (%EWL) (mean +/- SD) was 32% +/- 14% (n = 506), 47% +/- 15% (n = 461), 52% +/- 16% (n = 291), and 54% +/- 23% (n = 175) at 6, 12, 24, and 36 months, respectively (P < .001). There were 545 patients identified with comorbid illness at >6-month follow-up. After a median follow-up of 13 months (range 6-36 months), resolution and/or improvement of comorbidities was as follows: type 2 diabetes mellitus, 79%; metabolic syndrome, 78%; hypertension, 67%; dyslipidemia, 66%; gastroesophageal reflux, 66%; asthma, 57%; arthritis/joint pain, 70%; polycystic ovarian syndrome, 48%; and depression, 57%. There was a significant improvement in QoL (as measured by the Short Form-36 Health Survey [SF-36]), bringing patients' QoL to a level consistent with that of community norms in all 8 domain scores. Of 342 patients surveyed with the Beck Depression Inventory (BDI-II), a statistically significant improvement in depressive mood was also observed (P < .001).

CONCLUSION

Weight loss achieved by use of the SAGB provides a dramatic reduction in many serious comorbid illnesses as well as improvement in the psychosocial wellbeing of morbidly obese patients.

Effect of weight change on asthma-related health outcomes in patients with severe or difficult-to-treat asthma

OBJECTIVE

To evaluate the effects of weight change on asthma control, asthma-related quality of life, number of steroid bursts, and exacerbation of asthma symptoms in a population of adult patients with severe or difficult-to-treat asthma who participated in The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) study.

METHODS

We categorized 2396 TENOR patients > or = 18 years into three groups (> or = 5 lb loss, stable, > or = 5 lb gain), based on a +/-5 lb (2.27 kg) difference between baseline and 12-month follow-up weight. We used proportional odds and logistic regression models to evaluate the effect of weight change on Asthma Therapy Assessment Questionnaire (ATAQ) and Asthma Quality of Life Questionnaire (AQLQ) scores, exacerbations, and steroid bursts at the 12-month follow-up.

RESULTS

Asthma patients who gained > or = 5 lb (2.27 kg) during the 12-month interval between baseline and follow-up reported poorer asthma control (adjusted odds ratio [OR]: 1.22; 95% confidence interval [CI]: 1.01-1.49; p=0.04), worse quality of life (least square means: -0.18; 95% CI: -0.30 to -0.06; p=0.003), and a greater number of steroid bursts (OR: 1.31; CI: 1.04-1.66; p=0.02) than patients who maintained their baseline weight or lost > or = 5 lb (2.27 kg).

CONCLUSION

Increased weight is associated with worse asthma-related health outcomes. Strategies to prevent weight gain could help patients achieve better asthma control and improve asthma-related quality of life.

Pulmonary function in the morbidly obese

BACKGROUND

Only limited data exist on the relationship of lung function to patients with extreme obesity. To assess the relationship between lung function tests and clinical characteristics in a cohort of morbidly obese patients undergoing evaluation for bariatric procedures in a university hospital in the United States.

METHODS

Consecutive patients undergoing clinical evaluation were reviewed. The variables included demographic, anthropometric, clinical, and pulmonary function data.

RESULTS

A total of 229 patients underwent a standardized preoperative evaluation. Of these 229 patients, 136 (59%) had evaluable data and 102 (75%) were women. The mean +/- standard deviation age was 45 +/- 10 years, the mean weight was 164 +/- 42 kg, and the mean body mass index was 57 +/- 13 kg/m2. Smoking or asthma was reported in 38% and 24% of patients, respectively. The mean forced vital capacity and forced expiratory volume in 1 s was 80% +/- 17% of predicted and 76% +/- 19% of predicted, respectively. Of the 136 patients, 29% had a measured forced expiratory volume in 1 s/forced vital capacity of >or=.08 below the predicted ratio. The mean total lung capacity was 86% +/- 14% of predicted; 26% of subjects had a total lung capacity <80% of predicted. Multivariate logistic regression analysis demonstrated an association of obstructive ventilatory defects with male gender (odds ratio [OR] 2.35, 95% confidence interval [CI] 1.00-5.50) and current or previous smoking (OR 2.41, 95% CI 1.10-5.30), but not body mass index. Restrictive defects were associated with body mass index (OR 1.06, 95% CI 1.01-1.10), in particular, obesity hypoventilation syndrome (OR 3.7, 95% CI 1.2-11.1).

CONCLUSION

The mean preoperative spirometry, lung volumes, and gas exchange values were within the established reference ranges. Restrictive ventilatory defects were less common than obstructive ventilatory patterns and were most prominently associated with obesity hypoventilation syndrome.

Obesity and asthma

Over the last two decades, the convergence of secular trends indicating increases in the prevalence of obesity and asthma has led to a hypothesis that these two disorders might be related. Although the mechanisms underlying a putative relationship between obesity and asthma have not been fully described, a relatively mature body of literature suggests that obesity increases the risk of incident asthma. This article addresses studies that could be interpreted as supporting the hypothesis that obesity leads to asthma. We evaluate animal studies that provide biological underpinnings to an association between the two disorders and clinical and epidemiologic studies that suggest that the relationship between these two disorders is clinically important.

Pediatric obesity in acute and critical care

Pediatric obesity has reached epidemic proportions in the United States. Significant obesity-related comorbidities are being noted at earlier ages and often have implications for the acute and critically ill child. This article will review the latest in epidemiologic trends of pediatric obesity and examine how it affects multisystem body organs. The latest data evaluating the specific effects of obesity on acute and critically ill children will be reviewed. Available nonpharmacologic, pharmacologic, and surgical strategies to combat pediatric obesity will be discussed.

Cost associated with being overweight and with obesity, high alcohol consumption, and tobacco use within the military health system's TRICARE prime-enrolled population

PURPOSE

To estimate medical and indirect costs to the Department of Defense (DoD) that are associated with tobacco use, being overweight or obese, and high alcohol consumption.

DESIGN

Retrospective, quantitative research.

SETTING

Healthcare provided in military treatment facilities and by providers participating in the military health system.

SUBJECTS

The 4.3 million beneficiaries under age 65 years who were enrolled in the military TRICARE Prime health plan option in 2006.

MEASURES

The findings come from a cost-of-disease model developed by combining information from DoD and civilian health surveys and studies; DoD healthcare encounter data for 4.1 million beneficiaries; and epidemiology literature on the increased risk of comorbidities from unhealthy behaviors.

RESULTS

DoD spends an estimated $2.1 billion per year for medical care associated with tobacco use ($564 million), excess weight and obesity ($1.1 billion), and high alcohol consumption ($425 million). DoD incurs nonmedical costs related to tobacco use, excess weight and obesity, and high alcohol consumption in excess of $965 million per year.

CONCLUSION

Unhealthy lifestyles are significant contributors to the cost of providing healthcare services to the nation's military personnel, military retirees, and their dependents. The continued rise in healthcare costs could impact other DoD programs and could potentially affect areas related to military capability and readiness. In 2006, DoD initiated Healthy Choices for Life initiatives to address the high cost of unhealthy lifestyles and behaviors, and the DoD continues to monitor lifestyle trends through the DoD Lifestyle Assessment Program.

Environmental factors and allergic disorders

Despite numerous studies on possible associations between environmental exposure and allergic disorders, any conclusions made remain a matter of controversy. We conducted a review of evidence in relation to environmental and nutritional determinants and wheeze, asthma, atopic dermatitis, and allergic rhinitis. Identified were 263 articles for analysis after consideration of 1093 papers that were published since 2000 and selected by electronic search of the PubMed database using keywords relevant to epidemiological studies. Most were cross-sectional and case-control studies. Several prospective cohort studies revealed inconsistent associations between various environmental factors and the risk of any allergic disorder. Therefore, the evidence was inadequate to infer the presence or absence of a causal relationship between various environmental exposures and allergic diseases. However, evidence is suggestive of positive associations of allergies with heredity. Because almost all the studies were performed in Western countries, the application of these findings to people in other countries, including Japan, may not be appropriate. Further epidemiological information gained from population-based prospective cohort studies, in particular among Japanese together with other Asians, is needed to assess causal relationships between various environmental factors and allergic diseases.

Childhood overweight increases hospital admission rates for asthma

OBJECTIVES

Although childhood overweight has been associated with increased hospital lengths of stay for patients with asthma, the possible relationship between overweight and hospital admission for asthma has not been well studied. We hypothesized that overweight children who presented to the emergency department with asthma exacerbations were more likely to be admitted to the hospital than nonoverweight children.

METHODS

A retrospective chart review was conducted of all children who were older than 2 years and presented to the emergency department with an asthma exacerbation in calendar year 2005. Children with chronic medical conditions other than asthma were excluded. Children were classified as nonoverweight (< or = 95% weight-for-age percentile) or overweight (> 95% weight for age).

RESULTS

During the study period, there were 884 visits to the emergency department for an asthma exacerbation by 813 children; 238 (27%) were admitted to the hospital, and 33 (4%) were admitted to the ICU. Overall, hospital admission was associated with higher clinical asthma score but not with age, gender, or poverty status (as quantified as home in zip-code areas designated as "impoverished"). Overweight children (n = 202 [23%]) were significantly older (8.5 +/- 4.4 vs 7.3 +/- 4.3 years) and more likely to live in an impoverished area (37% vs 28%). Presenting clinical asthma score and therapeutic interventions in the emergency department were similar for overweight and nonoverweight children; however, overweight children were significantly more likely to be admitted to the hospital.

CONCLUSIONS

Overweight children who present to the emergency department with acute asthma exacerbations are significantly more likely to be admitted to the hospital than nonoverweight children. This identifies an important area in which childhood overweight has a significant impact on the health of children with asthma.

Prospective study of short stature and newly diagnosed asthma in women

The authors tested the hypothesis that short stature predicts adult-onset asthma independent of obesity among women in the Nurses' Health Study. Height, weight, and physician-diagnosed asthma were assessed with validated questionnaire items. Proportional hazard models adjusted separately for weight and body mass index. The rate of newly diagnosed asthma was 1.55 times greater in the shortest versus the tallest quintile after adjustment for weight (95% CI, 1.26-1.91). After adjustment for body mass index, the rate ratio was 1.16 (95% CI, 0.94-1.42). Short stature predicted adult-onset asthma in a large cohort of women, but this association was not independent of obesity.

Asthma hospitalizations among US military personnel, 1994 to 2004

BACKGROUND

Acute asthma attacks strike unpredictably and may lead to hospitalization in otherwise healthy individuals. The burden of asthma hospitalization on the US health care system has greatly interested health care workers, many of whom see the incidence of asthma as increasing.

OBJECTIVES

To examine the annual incidence of hospitalization and the frequency of subsequent hospitalization for asthma among all active-duty US military personnel between 1994 and 2004 and to determine demographic and occupational risk factors of asthma hospitalization within this generally healthy US population.

METHODS

Annual demographic and occupational data were combined with electronic hospitalization records for patients with a discharge diagnosis of asthma. Using Cox proportional hazard modeling, the authors investigated demographic and occupational risk factors for asthma hospitalization.

RESULTS

Women, married persons, health care workers, enlisted personnel, US Army personnel, and older persons were found to have a significantly greater risk of asthma hospitalization. Yearly rates of hospitalization declined from 22.3 per 100,000 persons to 12.6 per 100,000 persons between 1994 and 2004.

CONCLUSIONS

Although these data have some limitations, they suggest that the burden of asthma hospitalizations in the large, healthy population of US military personnel has declined during the last decade. The decrease in hospitalization potentially reflects improved outpatient management strategies.

Potential mechanisms connecting asthma, esophageal reflux, and obesity/sleep apnea complex--a hypothetical review

Obstructive sleep apnea (OSA) and asthma are potentially linked at several levels. The pathophysiology of these two conditions seems to overlap significantly, as airway obstruction, inflammation, obesity, and several other factors are implicated in the development of both diseases. Gastroesophageal reflux disease (GERD), cardiovascular complications, obesity itself, and the underlying inflammatory processes are all complex contributory factors that provide hypothetical links. Furthermore, a collateral rise in prevalence of both OSA and asthma has been noticed during the past few years, occurring in association with the emerging epidemic of obesity, a common risk factor for both conditions. OSA and asthma share many other risk factors as well. We propose a hypothetical OSA-asthma relationship that has implications on the diagnosis and management of patients presenting with either condition singly. Clinicians should be aware that OSA might complicate asthma management. Based on this hypothesis, we suggest that the treatment of the individual patient who experiences both asthma and OSA needs to be multidisciplinary and comprehensive. This hypothetical association of asthma and OSA, though described anecdotally, has not been systematically studied. In particular, the influence of continuous positive airway pressure therapy (for sleep apnea) on asthma outcomes (such as quality of life, steroid utilization, emergency room visits) and fatality needs to be studied further.

Paediatric asthma and obesity

None of the explanations proposed for the increase in paediatric asthma have been adequate. It is becoming apparent that the cause of the increase in asthma must be multi-factorial. Increasing attention has been focused on the role of lifestyle in the development of asthma. Lifestyle changes that have occurred in children are those in diet and decreased physical activity, with obesity being the product of these changes. The increase in asthma, obesity and a sedentary lifestyle have occurred together. However, a temporal relationship between asthma, obesity and decreased physical activity has not been determined in the paediatric literature. Limited data suggest that decreased physical activity could be playing a role in the aetiology of asthma independent of obesity. Furthermore, there has been substantial research on the benefits of exercise programmes for paediatric patients with asthma. Longitudinal trials monitoring physical activity, obesity and the development of asthma are needed.

Childhood obesity increases duration of therapy during severe asthma exacerbations

OBJECTIVES

Childhood obesity contributes to a wide array of medical conditions, including asthma. There is also increasing evidence in adult patients admitted to the intensive care unit (ICU) that obesity contributes to increased morbidity and to a prolonged length of stay. We hypothesized that obesity is associated with the need for increased duration of therapy in children admitted to the ICU with status asthmaticus.

DESIGN

Retrospective cohort study.

SETTING

A tertiary pediatric ICU in a university-affiliated children's hospital.

PATIENTS

We retrospectively examined data from all children older than 2 yrs admitted to the ICU with status asthmaticus between April 1997 and June 2004. Children were classified as normal weight (<95% weight-for-age percentile) or obese (>95% weight-for-age).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of the 209 children admitted to the ICU with asthma, 45 (22%) were obese. Compared with children of normal weight, the obese children were older (9.7 +/- 4.4 vs. 8.0 +/- 4.3 yrs, p = .02), more likely to be female (60% vs. 37%, p < .01), and more likely to have been admitted to the ICU previously (40% vs. 20%, p = .01). The obese children also had a statistically significant difference in race (more likely to be Hispanic) and in baseline asthma classification (more likely to have persistent asthma). Despite similar severity of illness at ICU admission, obese children had a significantly longer ICU length of stay (116 +/- 125 hrs vs. 69 +/- 57 hrs, p = .02) and hospital length of stay (9.8 +/- 7.0 vs. 6.5 +/- 3.4 days, p < .01). Obese children also received longer courses of supplemental oxygen, continuous albuterol, and intravenous steroids.

CONCLUSIONS

Childhood obesity significantly affects the health of children with asthma. Obese children with status asthmaticus recovered more slowly from an acute exacerbation, even after adjustment for baseline asthma severity and admission severity of illness.

Effect of obesity on clinical presentation and response to treatment in asthma

Obesity is a risk factor for being diagnosed with asthma, but there is conflicting evidence on whether obesity is a risk factor for lung function abnormalities characteristic of asthma. We studied a cohort of 488 subjects, 47% of whom were obese. Obese and non-obese subjects with asthma had similar airflow limitation and bronchodilator responsiveness, but obese participants had increased sleep disturbance and gastroesophageal reflux disease, higher cytokine levels, and a trend towards increased exacerbations when treated with theophylline. Obese and non-obese asthmatics have similar lung function abnormalities, but comorbidities and altered responses to medications may significantly affect asthma control in obese people.

The association between obesity and asthma is stronger in nonallergic than allergic adults

STUDY OBJECTIVE

To determine the modifying effects of sex and allergy history on the association between body mass index (BMI) and asthma prevalence.

DESIGN

Cross-sectional study of 86,144 Canadians who were 20 to 64 years of age in 2000-2001.

SETTING

A national survey.

MEASUREMENTS AND ANALYSIS

Self-reported asthma, allergy history, height, and weight. Logistic regression analysis was used to detect effect modification and to adjust for covariates. Population weight and design effects associated with complex survey design were taken into consideration.

RESULTS

The adjusted odds ratios (ORs) for obesity associated with asthma was 1.85 (95% confidence interval [CI], 1.65 to 2.07) for women and 1.21 (95% CI, 1.05 to 1.40) for men. One unit of increased BMI was associated with an approximate 6% increase in asthma risk in women, and 3% in men. A stronger association between obesity and asthma was observed in nonallergic women than in allergic women, with the adjusted ORs being 2.53 (95% CI, 2.11 to 3.04) and 1.57 (95% CI, 1.36 to 1.82), respectively. For men, the corresponding ORs were 1.30 (95% CI, 1.05 to 1.62) and 1.18 (95% CI, 0.98 to 1.53), respectively.

CONCLUSIONS

Obesity is likely to have a larger effect on nonallergic asthma. The greater prevalence of nonallergic asthma in women may explain the stronger obesity-asthma association seen in women compared with men and children who have a greater prevalence of allergic asthma.

Boys with high body masses have an increased risk of developing asthma: findings from the National Longitudinal Survey of Youth (NLSY)

OBJECTIVE

To determine the relation between body mass index and the development of asthma in children.

DESIGN

Prospective study of 4393 asthma-free children followed for up to 14 years.

SETTING

Children of participants in the National Longitudinal Survey of Youth.

METHODS

Analysis was limited to children who were followed from birth and were asthma-free during the first 24 months of life. The outcome was the development of asthma during follow-up (incident asthma). Body mass index (BMI) was our main predictor of interest. Survival analyses, using time to development of asthma as the main endpoint, were stratified by sex and controlled for race/ethnicity, poverty status, and prenatal maternal smoking.

RESULTS

Asthma developed in 218 (5.0 %) children during the follow-up period. The relation between BMI and incident asthma varied by sex. A BMI > or =85th percentile at age 2-3 years was a risk factor for subsequent asthma development in boys (hazard ratio (HR) 1.6 95% confidence interval (CI) 1.1, 2.4) but not girls (HR 0.8, 95% CI 0.5, 1.4). Similarly, boys with BMIs always > or =85th percentile were at increased risk for subsequent asthma development (HR 2.4, 95% CI 1.4, 4.4) but not girls (HR 1.5, 95% CI 0.7, 2.9).

CONCLUSION

Boys with high body masses may be at an increased risk for developing asthma.

Perianesthesia respiratory care of the bariatric patient

Our nation's obesity problem has reached epidemic proportions and is only projected to worsen. The morbidly obese patient is at risk for experiencing a multitude of health-related conditions. Morbidly obese patients are presenting for surgery at an increasing rate, especially with the growing popularity of weight-loss surgery. Therefore the perianesthesia nurse has to remain informed of optimal care strategies for this sometimes challenging population. The obese patient presents with distinct respiratory care considerations of which the perianesthesia nurse must be knowledgeable. This review article will specifically focus on the respiratory care of the bariatric patient presenting for surgery.

Asthma prevalence among US adults, 1998-2000: role of Puerto Rican ethnicity and behavioral and geographic factors

OBJECTIVES

We analyzed asthma prevalence among US adults by age, gender, race, Puerto Rican ethnicity, and other demographic, behavioral, health, and geographic variables. We hypothesized that high prevalences would be observed among Puerto Ricans and in the Northeast census region.

METHODS

We used data from the 1998 through 2000 US National Health Interview Surveys. Information on lifetime history of asthma and asthma in the past year was collected from 95615 adults. We calculated weighted prevalence estimates and odds ratios from logistic regression.

RESULTS

Of US adults, 8.9% had ever been diagnosed with asthma, and 3.4% had experienced an episode in the past 12 months. Asthma diagnosis rates were highest among Puerto Ricans (17.0%) and lowest among Mexican Americans (3.9%); rates were 9.6% and 9.2% among non-Hispanic Blacks and non-Hispanic Whites, respectively. Geographically, asthma prevalence was highest in the West (10.5%) and lowest in the Northeast (8.6%). Puerto Ricans in all regions had high asthma rates.

CONCLUSIONS

final logistic regression model included race/ethnicity, obesity, poverty, female gender, and cigarette smoking. Higher asthma rates were confirmed among Puerto Ricans but not in the Northeast region.

Women with asthma: a review of potential variables and preferred medical management

OBJECTIVES

To summarize the potential variables that contribute to the increased risk of asthma in women, outline therapeutic strategies that address these variables, and review current treatment recommendations for both pregnant and nonpregnant women with asthma.

DATA SOURCES

Literature searches (MEDLINE and cross-references) were performed using the keywords asthma and women in combination with the terms compliance, depression, emergency department, hormones, menstruation, mortality, National Asthma Education and Prevention Program, osteoporosis, pregnancy, prevalence, smoking, and treatment. Searches were limited to human studies with data published before 2005.

STUDY SELECTION

The author selected relevant articles for inclusion in this review.

RESULTS

Fluctuations in sex hormones, menstruation, pregnancy, obesity, depression, medication nonadherence, and smoking may contribute to increased asthma symptoms or severity in women. Asthma control may be improved if physicians address conditions and behaviors associated with asthma variability and severity in women. Notably, asthma must be managed aggressively in pregnant women, because uncontrolled asthma can lead to perinatal complications. Asthma treatment in women is optimized through patient and physician adherence to national guideline recommendations, including provision of patient education and asthma action plans.

CONCLUSIONS

Multiple variables throughout the female life cycle may influence asthma control. Successful asthma management requires an ongoing partnership between the patient and her physician to address physiologic (eg, sex hormones, pregnancy, obesity, depression) and nonphysiologic (eg, smoking, medication nonadherence) factors that may contribute to decreased asthma control.

A meta-analysis of the effect of high weight on asthma

BACKGROUND

Prevalence rates for both overweight and asthma have been increasing among children in developed countries over the past two decades. Some recent studies have postulated a causal relation between these but have lacked power to form a definitive conclusion.

AIM

To estimate the effect of high body weight in childhood on the future risk of asthma.

METHODS

Medline search (1966 to October 2004), supplemented by manual search of reference lists and grey literature. Cohort studies that examined high body weight at birth or during childhood and future outcome of asthma were included. Data from each study were extracted on exposure status, clinical outcome, and study characteristics.

RESULTS

A total of 402 studies were initially identified, of which 12 met the inclusion criteria. The combined results from four studies that examined the effect of high body weight during middle childhood on the outcome of subsequent asthma showed a 50% increase in relative risk (RR 1.5, 95% CI 1.2 to 1.8). The combined results from nine studies that examined the effect of high birth weight on subsequent asthma had a pooled RR of 1.2 (95% CI 1.1 to 1.3). There was consistency among the results in sensitivity analyses examining studies containing only estimates of odds ratios, studies containing only the outcome of physician diagnosis of asthma, and studies including all definitions of high body weight.

CONCLUSIONS

Children with high body weight, either at birth or later in childhood, are at increased risk for future asthma. Potential biological mechanisms include diet, gastro-oesophageal reflux, mechanical effects of obesity, atopy, and hormonal influences. Further research might elucidate the causal pathway, which could improve our understanding of the pathophysiology of asthma and perhaps lead to knowledge of potential preventive interventions.

Are overweight asthmatics more difficult to control?

The relationship between asthma and obesity appears to be quite complex. The aim of this study was to assess the effect of excess weight on asthma control evolution in a cohort of asthmatics. A prospective database was set up, which enrolled adult asthmatics with persistent (mild, moderate or severe) asthma. The control of asthma was defined as a binary variable, acceptable or unacceptable. In order to evaluate the effect of body mass index (BMI; <25 or > or =25), data were analysed using a continuous time homogeneous Markov model in which the forces ruling the transition between the two health states were estimated. The following confounding covariates were also evaluated in the model: severity of asthma, current treatment with oral corticosteroids (OCS) and history of OCS over the year preceding inclusion. About 406 asthmatics were included who made a total of 1639 consultations; the median length of follow up was 182 days. Using a univariate model, overweight patients had a lower risk of transiting from the unacceptable to the acceptable health state (RR = 0.45; P < 0.01). The effect of weight remained significant (RR = 0.53; P < 0.01) in the multivariate model including the other covariates. Moreover, transition probabilities stabilized more rapidly for patients with BMI < 25 (200 vs 300 days). In this study, we thus demonstrated that there is an association between excess weight and transition from unacceptable to acceptable control. Because control of asthma clearly drives asthma management, this finding has consequences for defining original new strategies for managing asthma in overweight patients.

Sex specificity of asthma associated with objectively measured body mass index and waist circumference: the Humboldt study

STUDY OBJECTIVE

To investigate the possibility of sex specificity for the association of obesity and asthma using objective measures of body mass index (BMI) and waist circumference (WC).

DESIGN

Cross-sectional study of adults (n = 2,057) living in Humboldt, SK, Canada in 2003.

SETTING

A rural community.

MEASUREMENTS

Ever-asthma was defined as lifetime physician-diagnosed asthma, and recent asthma was defined as asthma diagnosed by a physician during the past 12 months. BMI and WC were objectively measured.

RESULTS

Among the participants, 5.6% of men and 10.0% of women reported having ever-asthma, and 2.7% and 6.0% had recent asthma, respectively. Higher levels of both BMI and WC were significantly associated with asthma in women but not in men. The adjusted odds ratios for women with a BMI of at least 30.0 kg/m2 relative to women with a BMI of < 25.0 kg/m2 were 2.06 (95% confidence interval [CI], 1.42 to 4.05) for ever-asthma and 3.47 (95% CI, 1.64 to 7.32) for recent asthma.

CONCLUSIONS

Our study demonstrated that the increased risk of asthma associated with obesity was only significant in women but not in men even when BMI was objectively measured, and this association was robust to the anthropometric measures.

Obesity and asthma

Obesity is an important public health problem. An increasing body of data supports the hypothesis that obesity is a risk factor for asthma. These data include numerous large cross-sectional and prospective studies performed in adults, adolescents, and children throughout the world. With few exceptions, these studies indicate an increased relative risk of asthma in the obese and overweight and demonstrate that obesity antedates asthma. Obesity appears to be a particularly important issue for severe asthma. Studies showing improvements in asthma in subjects who lose weight, as well as studies showing that obese mice have innate airway hyperresponsiveness (AHR) as well as increased responses to certain asthma triggers also suggest a causal relationship between obesity and asthma. The mechanistic basis for this relationship has not been established. It may be that obesity and asthma share some common etiology, such as a common genetic predisposition, common effects of in utero conditions, or that obesity and asthma are both the result of some other predisposing factor such as physical activity or diet. However, there are also plausible biological mechanisms whereby obesity could be expected to either cause or worsen asthma. These include co-morbidities such as gastroesophageal reflux, complications from sleep-disordered breathing (SDB), breathing at low lung volume, chronic systemic inflammation, and endocrine factors, including adipokines and reproductive hormones. Understanding the mechanistic basis for the relationship between obesity and asthma may lead to new therapeutic strategies for treatment of this susceptible population.

Elevated atopy in healthy obese women

BACKGROUND

Allergic disorders, including asthma, have increased dramatically in the United States in the past 20 y. Epidemiologic studies have found body mass index (body weight in kg/height squared in m) to be a positive independent correlate of atopy in women but not in men.

OBJECTIVE

We investigated the prevalence of atopy among healthy obese and nonobese women and its relation to fat mass (FM), insulin resistance, and plasma concentrations of 17beta-estradiol, interleukin 4 (IL-4), and leptin.

DESIGN

A cross-sectional study of 21 obese (> or = 30% body fat) and 22 nonobese (< 30% body fat) women (18-41 y of age) was performed. The following measurements were taken: FM by plethysmography, total and specific immunoglobulin E (IgE) by automated immunosorbent analysis, and blood glucose, insulin, C-peptide, 17beta-estradiol, sex hormone-binding globulin, and IL-4. Insulin sensitivity was determined on the basis of the fasting insulin resistance index and with an oral-glucose-tolerance test.

RESULTS

The frequency of specific IgE in the obese group was almost 3 times that in the nonobese group (P = 0.008). The total IgE concentration was not significantly different between groups. Plasma concentrations of 17beta-estradiol, the ratio of 17beta-estradiol to sex hormone-binding globulin, the fasting insulin resistance index, and C-peptide and leptin concentrations were higher in the obese than in the nonobese group (P < 0.05) after adjustment for oral contraceptive use. All factors correlated positively with FM. Logistic regression showed FM to be the only positive predictor of specific IgE (P = 0.01).

CONCLUSION

The findings confirm a direct relation between obesity and a T helper 2 cell immune response in women.

Health surveillance for asthma in the US Navy: experience of 9,185,484 person-years

PURPOSE

To measure trends and demographic risk factors for hospitalization for asthma.

METHODS

Time trends and demographic risk factors, for hospitalized asthma (1CD-9-CM Code 493) were analyzed by measuring age-specific and age-adjusted first hospitalization rates in a defined population of active-duty enlisted members of the US Navy worldwide during 1980-1999, consisting of 9,185,484 person-years.

RESULTS

There were 3911 patients first hospitalized for asthma, including 2916 men and 995 women. The age-adjusted incidence rate of first hospitalization for asthma was three times higher in women than men, 110 per 100,000 person-years (95% confidence interval [CI], 104-117), compared with 35 per 100,000 person-years (95% CI, 33-37), respectively (p < 0.0001). The rate in black women was twice as high as in white women, 186 per 100,000 person-years, compared with 99 per 100,000 person-years, respectively (p < 0.001). The rate in black men was higher than in white men, 45 per 100,000, compared with 34 per 100,000 (p < 0.001). Age-adjusted rates in women doubled from 73 per 100,000 in 1980-1983 to 159 in 1997-1999 (p for trend < 0.01), while those in men remained stable.

CONCLUSIONS

Age-adjusted incidence rates of first hospitalization for asthma were three times as high in women as in men, and doubled during the period between 1980 and 1999. The rates in black women were twice as high as in white women. The reasons are unknown.