Body mass index and comorbidities in adult severe asthmatics

Are nighttime respiratory symptoms assessed by asthma control test affected by comorbidities?

OBJECTIVE

Nocturnal symptoms are common in the asthmatic population, reflecting an exaggerated airway narrowing overnight due to several factors; it is questioned to what extent the awakenings documented in the clinical assessment of asthma control are due to the disease itself or to comorbidities. To answer this question, we aimed to evaluate to what proportion rhinitis, gastroesophageal reflux and the likelihood of being affected by OSAS were related to poor asthma control, by means of ACT evaluation.

METHODS

Asthmatics attending the outpatient clinic were enrolled and administered the following questionnaires: ACT, Total 5 Symptom Score, GERD Impact Scale, Pittsburgh Sleep Quality Index and the Sleep Disorders Questionnaire.

RESULTS

One-hundred consecutive patients (M/F: 42/58, mean age 52 ± 15 years) were recruited. According to the ACT findings, 14 asthmatics resulted as fully controlled (FC, ACT equal to 25), 55 partially controlled (PC, 25 < ACT >19) and 31 as uncontrolled (UC, ACT <19). GERD was not associated with the ACT score neither did rhinitic symptomatology. On the other hand, the PSQI scores appeared to significantly increase with the lack of symptom control: FC, 2.0 (1-4); PC, 3.5 (2-5); UC, 6.6 (4-8) (p = 0.002). The SA-SDQ questionnaire results significantly increased with the loss of asthma control: FC, 11.0 (9-12); PC, 12.5 (10-14); UC, 15.1 (14-16) (p = 0.005).

CONCLUSIONS

These results confirm and extend previous findings showing that there is a higher likelihood that underlying unknown sleep disturbances worsen asthma control, suggesting that a more comprehensive assessment is necessary to clarify the cause of nocturnal symptoms in asthma.

Effect of obesity on airway and systemic inflammation in adults with asthma: a systematic review and meta-analysis

BACKGROUND

Obesity is associated with more severe asthma, however, the mechanisms responsible are poorly understood. Obesity is also associated with low-grade systemic inflammation; it is possible that this inflammation extends to the airways of adults with asthma, contributing to worse asthma outcomes. Accordingly, the aim of this review was to examine whether obesity is associated with increased airway and systemic inflammation and adipokines, in adults with asthma.

METHODS

Medline, Embase, CINAHL, Scopus and Current Contents were searched till 11 August 2021. Studies reporting measures of airway inflammation, systemic inflammation and/or adipokines in obese versus non-obese adults with asthma were assessed. We conducted random effects meta-analyses. We assessed heterogeneity using the I2 statistic and publication bias using funnel plots.

RESULTS

We included 40 studies in the meta-analysis. Sputum neutrophils were 5% higher in obese versus non-obese asthmatics (mean difference (MD)=5.0%, 95% CI: 1.2 to 8.9, n=2297, p=0.01, I2=42%). Blood neutrophil count was also higher in obesity. There was no difference in sputum %eosinophils; however, bronchial submucosal eosinophil count (standardised mean difference (SMD)=0.58, 95% CI=0.25 to 0.91, p<0.001, n=181, I2=0%) and sputum interleukin 5 (IL-5) (SMD=0.46, 95% CI=0.17 to 0.75, p<0.002, n=198, I2=0%) were higher in obesity. Conversely, fractional exhaled nitric oxide was 4.5 ppb lower in obesity (MD=-4.5 ppb, 95% CI=-7.1 ppb to -1.8 ppb, p<0.001, n=2601, I2=40%). Blood C reactive protein, IL-6 and leptin were also higher in obesity.

CONCLUSIONS

Obese asthmatics have a different pattern of inflammation to non-obese asthmatics. Mechanistic studies examining the pattern of inflammation in obese asthmatics are warranted. Studies should also investigate the clinical relevance of this altered inflammatory response.

PROSPERO REGISTERATION NUMBER

CRD42021254525.

Long-term prognosis of new adult-onset asthma in obese patients

Background

Obesity has been associated with poor outcomes of asthma in cross-sectional studies, but long-term effect of obesity on asthma remains unknown.

Aims

To study the effects of obesity, found at the time of diagnosis of adult-onset asthma, on 12-year prognosis by focusing on oral corticosteroid (OCS) use and respiratory-related hospital admissions.

Methods

Patients diagnosed with adult-onset asthma (n=203) were divided into three categories based on diagnostic body mass index (BMI) (<25 kg·m⁻², 25–29.9 kg·m⁻², ≥30 kg·m⁻²) and followed for 12 years as part of the Seinäjoki Adult Asthma Study. Self-reported and dispensed OCS were assessed for the 12-year period. Data on hospital admissions were analysed based on medical records.

Results

12 years after diagnosis, 86% of the patients who were obese (BMI ≥30 kg·m⁻²) at diagnosis remained obese. During the follow-up, no difference was found in weight gain between the BMI categories. During the 12-year follow-up, patients obese at diagnosis reported more frequent use of OCS courses (46.9% versus 23.1%, p=0.028), were dispensed OCS more often (81.6% versus 56.9%, p=0.014) and at higher doses (median 1350 (interquartile range 280–3180) mg versus 600 (0–1650) mg prednisolone, p=0.010) compared to normal-weight patients. Furthermore, patients who were obese had more often one or more respiratory-related hospitalisations compared to normal-weight patients (38.8% versus 16.9%, p=0.033). In multivariate logistic regression analyses, obesity predicted OCS use and hospital admissions.

Conclusions

In adult-onset asthma, patients obese at diagnosis mostly remained obese at long-term and had more exacerbations and respiratory-related hospital admissions compared to normal-weight patients during 12-year follow-up. Weight loss should be a priority in their treatment to prevent this outcome.

Obese patients with new adult-onset asthma often remain obese in the long-term and have more exacerbations and respiratory-related hospital admissions during follow-up. High priority should be given to weight loss during treatment to prevent this outcome.https://bit.ly/2G5HtRZ

Asthma medication use in obese and healthy weight asthma: systematic review/meta-analysis

BACKGROUND

Obesity is a common comorbidity in asthma and associated with poorer asthma control, more frequent/severe exacerbations, and reduced response to asthma pharmacotherapy.

OBJECTIVE

This review aims to compare use of all classes of asthma medications in obese (body mass index (BMI) ≤30 kg·m^-2) versus healthy-weight (BMI <25 kg·m^-2) subjects with asthma.

DESIGN

Databases including CINAHL (Cumulative Index to Nursing and Allied Health Literature), Cochrane, Embase and MEDLINE were searched up to July 2019 for English-language studies that recorded medication use or dose in obese and healthy-weight adults with asthma. A critical appraisal checklist was utilised for scrutinising methodological quality of eligible studies. Meta-analysis was performed and heterogeneity was examined with the use of the Chi-squared test. This review was conducted based on a published protocol (www.crd.york.ac.uk/PROSPERO CRD42020148671).

RESULTS

Meta-analysis showed that obese subjects are more likely to use asthma medications, including short-acting β₂-agonists (OR 1.75, 95% CI 1.17-2.60; p=0.006, I²=41%) and maintenance oral corticosteroids (OR 1.86, 95% CI 1.49-2.31; p<0.001, I²=0%) compared to healthy-weight subjects. Inhaled corticosteroid (ICS) dose (µg·day^-1) was significantly higher in obese subjects (mean difference 208.14, 95% CI 107.01-309.27; p<0.001, I²=74%). Forced expiratory volume in 1 s (FEV₁) % predicted was significantly lower in obese subjects (mean difference -5.32%, 95% CI -6.75--3.89; p<0.001, I²=42%); however, no significant differences were observed in FEV₁/forced vital capacity (FVC) ratio between groups.

CONCLUSIONS

We found that obese subjects with asthma have higher use of all included asthma medication classes and higher ICS doses than healthy-weight asthma subjects, despite lower FEV₁ and a similar FEV₁/FVC %. A better understanding of the factors driving increased medication use is required to improve outcomes in this subgroup of asthmatics.

Systematic Literature Review of Systemic Corticosteroid Use for Asthma Management

Systemic corticosteroid use to manage uncontrolled asthma and its associated healthcare burden may account for important health-related adverse effects. We conducted a systematic literature review to investigate the real-world extent and burden of systemic corticosteroid use in asthma. We searched MEDLINE and Embase databases to identify English-language articles published in 2010–2017, using search terms for asthma with keywords for oral corticosteroids and systemic corticosteroids. Observational studies, prescription database analyses, economic analyses, and surveys on oral/systemic corticosteroid use in children (>5 yr old), adolescents (12–17 yr old), and adults with asthma were included. We identified and reviewed 387 full-text articles, and our review included data from 139 studies. The included studies were conducted in Europe, North America, and Asia. Overall, oral/systemic corticosteroids were commonly used for asthma management and were more frequently used in patients with severe asthma than in those with milder disease. Long-term oral/systemic corticosteroid use was, in general, less frequent than short-term use. Compared with no use, long-term and repeated short-term oral/systemic corticosteroid use were associated with an increased risk of acute and chronic adverse events, even when doses were comparatively low. Greater oral/systemic corticosteroid exposure was also associated with increased costs and healthcare resource use. This review provides a comprehensive overview of oral/systemic corticosteroid use and associated adverse events for patients with all degrees of asthma severity and exposure duration. We report that oral/systemic corticosteroid use is prevalent in asthma management, and the risks of acute and chronic complications increase with the cumulative oral corticosteroid dosage.

Pro-inflammatory immunological effects of adipose tissue and risk of food allergy in obesity: Focus on immunological mechanisms

Over the past three decades, the number of obese people has risen steadily. The chronic low-grade inflammatory state and the non-specific activation of the immune system have contributed greatly to the development of obesity-related immunology. Food allergy as a kind of inflammatory disease with abnormal immune response may be associated with obesity. This review begins with the pro-inflammatory immunological effects of adipose tissue in obesity, and explains the possible effects of obesity on food allergy. In short, obesity not only directly causes imbalance of allergic-related immune cells in adipose tissue, but also indirectly causes this consequence through affecting expression of adipocytokines and peroxisome proliferator-activated receptor gamma (PPARγ) in adipose tissue. As a result, circulating levels of pro-inflammatory factors which are partly derived from adipose tissue increase, which might cause intestinal barrier injury. Therefore, obesity may increase the risk of food allergy.

[Woman's asthma throughout life: Towards a personalized management?]

In a woman's life, asthma can affect her in a variety of ways, with the onset of premenstrual asthma currently under-diagnosed. It is estimated that about 20% of women with asthma have premenstrual asthma, which is more common in patients with severe asthma. Women with asthma are at high risk of exacerbations and of severe asthma. Asthma is the most common chronic disease during pregnancy with potential maternal and foetal complications. Asthma medications are safe for the foetus and it is essential to continue pre-existing treatment and adapt it to the progress of asthma during the pregnancy. Sex steroids modulate the structure and function of bronchial and immune cells. Understanding their role in asthma pathogenesis is complicated by the ambivalent effects of bronchodilating and pro-inflammatory oestrogens as well as the diversity of response to their association with progesterone. Menopausal asthma is a clinical entity and is part of one of the phenotypes of severe non-allergic and low steroid-sensitive asthma. Targeted assessment of the domestic and professional environment allows optimization of asthma management.

The effects of obesity on pulmonary function in adults with asthma

Objective:

While the effects of obesity on asthma are unclear, an increased body mass index (BMI) is known to enhance the symptoms and severity of asthma and to impair asthma control. The present study evaluates the effects of nutritional habits and obesity on pulmonary function and asthma control in individuals with asthma.

Methods:

This cross-sectional study included 60 obese respondents and 60 respondents with normal body weight, who were referred to pulmonology clinics over a period of 2 months. The anthropometric measurements and macro–micro nutrient consumption records of the patients in both groups were obtained, and the two groups were compared in terms of pulmonary function and asthma control test (ACT) scores.

Results:

The mean age of the normal weight and obese respondents was 39.55 ± 11.0 and 45.1 ± 10.3 years, respectively. The ACT scores of the respondents decreased significantly with increasing BMI, waist circumference (WC), and waist–hip ratio (WHR) measurements (P < 0.05). The obese respondents had a lower mean forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁), midexpiratory flow (MEF) between 25% and 75% of the maximal expiration (MEF_25–75), MEF₇₅, MEF₅₀, MEF₂₅, and FEV₁/FVC values when compared to the respondents with normal weight (P < 0.05). The total energy and carbohydrate intake was higher in the obese respondents, while their total protein intake was lower when compared to the normal weight respondents (P < 0.05), and a significant positive correlation was found between the omega 3 intake and ACT scores of the respondents (P < 0.05).

Conclusions:

Pulmonary functions and ACT scores decrease with increasing BMI, WC, and WHR. Obese respondents with asthma should be referred to diet clinics to improve their asthma symptoms.

Factors reducing omalizumab response in severe asthma

BACKGROUND

Despite adding Omalizumab to conventional therapy, several severe asthmatics still show poor disease control. We investigated the factors that may affect a reduced Omalizumab response in a large population of severe asthmatics.

METHODS

340 patients were retrospectively evaluated. FEV₁%, FVC%, Asthma Control Test (ACT), fractional exhaled nitric oxide (FENO), possible step-downs/step-ups of concomitant therapies, exacerbations, disease control levels, ICS doses and SABA use, observed at the end of treatment, were considered as a response to Omalizumab.

RESULTS

Age was an independent risk factor for a reduced response concerning FEV₁%, FVC%, ACT and for a lower asthma control. Obesity (vs normal weight) was a determinant condition for exacerbations (OR:3.114[1.509-6.424], p = 0.002), for a disease partial/no control (OR:2.665[1.064-6.680], p = 0.036), for excessive SABA use (OR:4.448[1.837-10.768], p = 0.002) and for an unchanged/increased level of concomitant asthma medications. Furthermore, obesity also reduced the response in FEV₁ (β = -6.981,p = 0.04), FVC (β = -11.689,p = 0.014) and ACT (β = -2.585, p = 0.027) and was associated with a higher FENO level (β = 49.045,p = 0.040). Having at least one comorbidity was a risk factor for exacerbations (OR:1.383[1.128-1.697], p = 0.008) and for an ACT <20 (OR:2.410[1.071-3.690], p = 0.008). Specifically, chronic heart disease was associated with both a lower ACT and FVC% whereas gastroesophageal reflux with a partial/no asthma control. Nasal polyps were a predisposing factor leading both to exacerbations and to the use of higher inhaled corticosteroids doses. Moreover, smoking habits, pollen or dog/cat dander co-sensitizations may negatively influence Omalizumab response.

CONCLUSION

Age, obesity, comorbidities, smoking habits, nasal polyps, allergic poly-sensitization might reduce Omalizumab effectiveness independently to other asthma-influencing factors.

What is the impact of underweight on self-reported health trajectories and mortality rates: a cohort study

Background

Utilizing a cohort study design combining a survey approach with repeated physical examinations, we examined the independent effects of BMI on mortality and self-reported health (SRH) and whether these independent effects change as people grow older.

Methods

The Tromsø Study consists of six surveys conducted in the municipality of Tromsø, Norway, with large representative samples of a general population. In total, 31,985 subjects participated in at least one of the four surveys administered between 1986 and 2008. Outcomes of interest were SRH and all-cause mortality.

Results

Overweight and underweight subjects reported significantly lower levels of SRH, but age affected the thinnest subjects more than all others. The SRH trajectory of underweight subjects at age 25 was slightly above the other categories (0.08), but it fell to −.30 below the reference category at age 90. For obese subjects, the difference was −0.15 below the reference category at age 25 and −0.18 below at age 90. This implies that even though a low BMI was slightly beneficial at a young age, it represented an increasing risk with age that crossed the reference curve at age 38 and even crossed the obese trajectory at age 67 in the full fitted model. The proportional hazard ratio for those who were underweight was 1.69 (95% CI: 1.38-2.06) for all-cause death as compared to 1.12 (95% CI: 1.02-1.23) for obese subjects.

Conclusion

BMI affected SRH and all-cause mortality independently from comorbidity, mental health, health-related behaviors and other biological risk factors. Being underweight was associated with excess mortality as compared to all others, and age affected the thinnest subjects more than all others. Weight increase was beneficial for mortality but not for SRH among the underweight. The rapid decline of SRH with increasing age suggests that particular attention should be paid to underweight after 38 years of age.

Electronic supplementary material

The online version of this article (10.1186/s12955-017-0766-x) contains supplementary material, which is available to authorized users.

The role of airway hyperresponsiveness measured by methacholine challenge test in defining asthma severity in asthma-obesity syndrome

PURPOSE OF REVIEW

Asthma is a complex disease defined by chronic inflammation of the airways. In research and clinical practice measures used for diagnosis, an assessment of control and severity of asthma are varied and there exists no gold standard. To date, several studies have explored the link between obesity and asthma although the exact mechanism is not yet fully understood. A study undertaken by our research group in 2015, on the effects of weight loss on asthma severity in obese asthmatics, demonstrated that an improvement in airway hyperresponsiveness could be achieved after significant weight reduction with a weight loss program. The objective of this article is to review the current literature for the primary and secondary outcomes studied to estimate the effects of weight loss on asthma severity in adults with obesity and asthma.

RECENT FINDINGS

A review of the most recent research conducted since 2014 demonstrates that effects of weight loss on asthma severity in adults with obesity and asthma has not been the focus of majority of the studies. Apart from our study published in 2015, very few studies used airway hyperresponsiveness as the primary or secondary outcome measure. The literature reveals that significant weight loss does, however, lead to improvement in asthma severity and control in adults with obesity and asthma.

SUMMARY

The current literature suggests that improvement in lung function requires moderate to significant (5-10%) weight loss in adults with obesity and asthma. However, with a few exceptions, the majority of these studies were small and used variable and questionable asthma severity outcome measures. There is an urgent need for standardization of diagnosis of asthma, study inclusion criteria, and outcome measures to assess asthma severity in research setting. Long-term effects of weight loss interventions on asthma severity and control, in adults with obesity and asthma, also remain unanswered.

Multidimensional assessment of severe asthma: A systematic review and meta-analysis

The management of severe asthma is complex. Multidimensional assessment (MDA) of specific traits has been proposed as an effective strategy to manage severe asthma, although it is supported by few prospective studies. We aimed to systematically review the literature published on MDA in severe asthma, to identify the traits included in MDA and to determine the effect of MDA on asthma-related outcomes. We identified 26 studies and classified these based on study type (cohort/cross-sectional studies; experimental/outcome studies; and severe asthma disease registries). Study type determined the comprehensiveness of the assessment. Assessed traits were classified into three domains (airways, co-morbidities and risk factors). The airway domain had the largest number of traits assessed (mean ± SD = 4.2 ± 1.7) compared with co-morbidities (3.6 ± 2.2) and risk factors (3.9 ± 2.1). Bronchodilator reversibility and airflow limitation were assessed in 92% of studies, whereas airway inflammation was only assessed in 50%. Commonly assessed co-morbidities were psychological dysfunction, sinusitis (both 73%) and gastro-oesophageal reflux disease (GORD; 69%). Atopic and smoking statuses were the most commonly assessed risk factors (85% and 86%, respectively). There were six outcome studies, of which five concluded that MDA is effective at improving asthma-related outcomes. Among these studies, significantly more traits were assessed than treated. MDA studies have assessed a variety of different traits and have shown evidence of improved outcomes. This promising model of care requires more research to inform which traits should be assessed, which traits should be treated and what effect MDA has on patient outcomes.

Long-term effect of weight loss induced by bariatric surgery on asthma control and health related quality of life in asthmatic patients with severe obesity: A pilot study

BACKGROUND

The weight loss induced by bariatric surgery (BS) improves asthma clinical control evaluated usually after a short time. The long-term effects of weight loss attained by BS on asthma control and health related-quality of life (HRQoL) in patients affected by asthma and obesity are not known.

OBJECTIVE

To investigate the five-year effect of weight reduction induced by BS on asthma control, quality of life and pulmonary functional parameters in severely obese intermittent or mild-to-moderate asthmatic patients.

METHODS

Twenty-six consecutive severe obese subjects with previous diagnosis of asthma with indication for laparoscopic adjustable gastric banding (LAGB) were enrolled into the study. Fifteen of them agreed to undertake the surgery (treatment group, TG) while the remaining eleven non-operated patients represented the control group (CG). Body mass index (BMI), Asthma Control Test (ACT), Mini Asthma Quality of Life Questionnaire (mini-AQLQ) and spirometric parameters were evaluated at baseline and after one and five years from surgery.

RESULTS

Mean BMI of TG significantly decreased at one and five years after the surgery, while it remained unchanged in CG. After surgery, both the overall ACT and the mini-AQLQ score significantly improved in TG after one year, persisting improved after 5-years (p < 0.001), while these outcomes remained unchanged in CG. As compared with the pre-surgery values, the percentage of predicted FEV₁ and FVC significantly increased at five-year follow-up from surgery in TG, while it remained unchanged in CG.

CONCLUSIONS

In severe obese asthmatic patients, the significant improvement of asthma control test and HRQoL, observed one year after LAGB, persists five years after surgery.

Nutritional status and physical inactivity in moderated asthmatics: A pilot study

Preservation of nutritional status and of fat-free mass (FFM) and/or preventing of fat mass (FM) accumulation have a positive impact on well-being and prognosis in asthma patients. Physical inactivity is identified by World Health Organization as the fourth leading risk factor for global mortality. Physical activity (PA) may contribute to limit FM accumulation, but little information is available on the interactions between habitual PA and body composition and their association with disease severity in asthma severity.Associations between habitual PA, FM, FFM, and pulmonary function were investigated in 42 subjects (24 patients with mild-moderate asthma and 18 matched control subjects). Sensewear Armband was used to measure PA and metabolic equivalent of tasks (METs) continuously over 4 days, while body composition was measured by bioelectrical impedance analysis. Respiratory functions were also assessed in all study participants.FM and FFM were comparable in mild-moderate asthmatics and controls, but PA was lower in asthmatics and it was negatively correlated with FM and positively with the FFM marker body cell mass in all study subjects (P < 0.05). Among asthmatics, treated moderate asthmatics (ICS, n = 12) had higher FM and lower PA, METs, steps number/die, and forced expiratory volume in the 1st second (FEV1)/forced vital capacity (FVC) than in untreated intermittent asthmatics (UA, n = 12).This pilot study assesses that in mild-moderate asthma patients, lower PA is associated with higher FM and higher disease severity. The current results support enhancement of habitual PA as a potential tool to limit FM accumulation and potentially contribute to preserve pulmonary function in moderate asthma, considering the physical inactivity a strong risk factor for asthma worsening.

[New populations at increased cardiovascular risk: Cardiovascular disease in dermatological diseases]

The increased cardiovascular risk in some dermatological diseases has been demonstrated in recent decades. Diseases such as psoriasis and systemic lupus erythematosus are currently included in the guidelines for prevention of cardiovascular disease. Other diseases such as androgenic alopecia, polycystic ovary syndrome, hidradenitis suppurativa or lichen planus have numerous studies that point to an increased risk, however, they have not been included in these guidelines. In this article we review the evidence supporting this association, in order to alert the clinician to the need for greater control in cardiovascular risk factors in these patients.

Emerging Comorbidities in Adult Asthma: Risks, Clinical Associations, and Mechanisms

Asthma is a heterogeneous disease with many phenotypes, and age at disease onset is an important factor in separating the phenotypes. Most studies with asthma have been performed in patients being otherwise healthy. However, in real life, comorbid diseases are very common in adult patients. We review here the emerging comorbid conditions to asthma such as obesity, metabolic syndrome, diabetes mellitus type 2 (DM2), and cardiac and psychiatric diseases. Their role as risk factors for incident asthma and whether they affect clinical asthma are evaluated. Obesity, independently or as a part of metabolic syndrome, DM2, and depression are risk factors for incident asthma. In contrast, the effects of comorbidities on clinical asthma are less well-known and mostly studies are lacking. Cross-sectional studies in obese asthmatics suggest that they may have less well controlled asthma and worse lung function. However, no long-term clinical follow-up studies with these comorbidities and asthma were identified. These emerging comorbidities often occur in the same multimorbid adult patient and may have in common metabolic pathways and inflammatory or other alterations such as early life exposures, systemic inflammation, inflammasome, adipokines, hyperglycemia, hyperinsulinemia, lung mechanics, mitochondrial dysfunction, disturbed nitric oxide metabolism, and leukotrienes.

[Quality of life and associated factors in asthma in a Primary Care Center. Application of the reduced version of the Asthma Quality of Life Questionnaire]

INTRODUCTION

Asthma is a highly prevalent disease that can affect the quality of life (QoL). The objective of this study is to determine the QoL in patients with asthma and its relationship with different factors in a Primary Care centre.

MATERIAL AND METHODS

A descriptive, cross-sectional study was conducted in an urban health centre. The study included a total of 243 patients between 17 to 70 years who had a diagnosis of asthma in their medical records. The QoL was measured using the Spanish version of the Mini-Asthma Quality of Life Questionnaire, with age, sex, smoking, anxiety, depression, severity and control of asthma as associated variables.

RESULTS

The mean age was 44.5 years and 71.2% were women. More than half (54.3%) had intermittent asthma, and 45.7% persistent asthma. The overall score in the Mini-Asthma Quality of Life Questionnaire was 5.4 out of 7. The scores by dimensions were: symptoms 5.4; limitation of activities 5.8; emotional function 5.7, and environmental stimuli 4.7. The variables with a worse QoL score that remained statistically significant (P<.05) in the multivariate analysis were poor control of asthma (in all dimensions), history of depression (in all except environmental stimuli), educated to less than secondary level (symptoms and emotional function), and patients admitted to hospital in the past 3 years (symptoms) and who used long-term beta-adrenergics (emotional function).

CONCLUSIONS

Patients with intermittent, mild and moderate asthma have a good QoL. Poor control of the asthma and a history of depression negatively affect the QoL.

Obesity and atopy

The prevalence of obesity has increased worldwide, and weight gain has been shown to influence the development and clinical expression of various conditions including asthma. The relationships between atopy and obesity remain uncertain, both in adults and in children. Although there are physiopathologic mechanisms which could explain how obesity could influence the immune system and promote the process of sensitization, evidences in favour of a possible role of obesity on the development of atopy have been inconsistent. Furthermore, the bulk of evidence suggests that atopy does not mediate the relationship between obesity and asthma, although in some populations, particularly in children and women, such association has been reported. Such lack of relationship has also been found with rhinoconjunctivitis although it has been observed for atopic dermatitis. Several factors may explain these variable results, including populational or environmental characteristics, socioeconomic status, confounding factors, in addition to sample size, and methodology of the performed studies. The possibility that obesity influences atopy through its effects on sex hormones is suggested by a more frequent link between atopy and obesity in women, particularly postpuberal. Further research should be conducted on the influence of weight gain on atopy and atopic diseases.

Lifestyle-Related Factors and Atopy in Seven Danish Population-Based Studies from Different Time Periods

BACKGROUND

The prevalence of allergic respiratory disease tends to increase in populations that adopt the so-called Westernized lifestyle. We investigated the association between atopy and several possible lifestyle-related factors in seven Danish population-based studies.

METHODS

A total of 20048 persons participated in the seven studies. We used logistic regression to analyse the associations between possible determinants and atopy defined as serum specific IgE or skin prick test positivity against inhalant allergens. Associations were expressed as odds ratios (ORs) with 95% confidence intervals (95% CIs). In addition, individual participant data meta-analyses were performed.

RESULTS

Atopy was significantly associated with younger age (OR per 1 year increase in age: 0.97; 95% CI: 0.97, 0.98); male sex (OR for males versus females: 1.34; 95% CI: 1.24, 1.45), heavy drinking (OR for heavy drinkers versus light drinkers: 1.15; 95% CI: 1.04, 1.27), never smoking (OR for current versus never smokers: 0.73; 95% CI: 0.67, 0.80), and higher educational level (OR for educated versus uneducated: 1.27; 95% CI: 1.15, 1.41). Atopy was not associated with blood pressure, serum total cholesterol, physical activity or body mass except in women only, where we found a positive association (OR for obese vs. normal weight: 1.18; 95% CI: 1.00, 1.39) with ptrend = 0.032.

CONCLUSIONS

Of interest for preventive purposes, we found that atopy was associated with some of the reversible lifestyle-related factors that characterize a Westernized lifestyle.

Asthma and metabolic syndrome: Current knowledge and future perspectives

Asthma and obesity are epidemiologically linked; however, similar relationships are also observed with other markers of the metabolic syndrome, such as insulin resistance and dyslipidemia, which cannot be accounted for by increased body mass alone. Obesity appears to be a predisposing factor for the asthma onset, both in adults and in children. In addition, obesity could make asthma more difficult to control and to treat. Although obesity may predispose to increased Th2 inflammation or tendency to atopy, other mechanisms need to be considered, such as those mediated by hyperglycaemia, hyperinsulinemia and dyslipidemia in the context of metabolic syndrome. The mechanisms underlying the association between asthma and metabolic syndrome are yet to be determined. In the past, these two conditions were believed to occur in the same individual without any pathogenetic link. However, the improvement in asthma symptoms following weight reduction indicates a causal relationship. The interplay between these two diseases is probably due to a bidirectional interaction. The purpose of this review is to describe the current knowledge about the possible link between metabolic syndrome and asthma, and explore potential application for future studies and strategic approaches.