Improved diet quality is associated with decreased concentrations of inflammatory markers in adults with uncontrolled asthma.

BACKGROUND: Asthma has become one of the major public health challenges, and recent studies show promising clinical benefits of dietary interventions, such as the Dietary Approaches to Stop Hypertension (DASH) diet. OBJECTIVE: The objective of this study was to examine whether changes in diet quality are associated with changes in inflammatory markers important in asthma pathophysiology. METHODS: In this exploratory study in patients with poorly controlled asthma participating in a randomized controlled trial of a DASH intervention study, changes in concentrations of a broad panel of serum proteins (51-plex Luminex assay, Affymetrix) were determined, and their relation to diet quality (DASH score) assessed by combining data of both intervention and usual-care control groups. Second, the relation between the serum proteins, other biomarkers of inflammation and nutrition, and Asthma Control Questionnaire (ACQ) was assessed. RESULTS: During the first 3 mo, diet quality (DASH scores) were inversely associated (P < 0.05, false discovery rate P < 0.09) with serum concentrations of a large number serum proteins, reflecting not only general proinflammatory markers such as IL-1ß, transforming growth factor α (TGF-α), and IL-6 (r = -0.31 to -0.39) but also a number of proteins associated with asthmatic conditions, specifically several T-helper (Th) 2 (Th2; r = -0.29 to -0.34) and Th17 (r = -0.4) associated cytokines and growth factors. Monokine induced by gamma/chemokine (C-X-C motif) ligand 9 (CXCL9) (MIG/CXCL9), a T-cell attractant induced by IFN-γ previously linked to asthma exacerbations, appeared to be the marker most consistently associated with DASH diet quality for the entire 6-mo study period (r = -0.40 and -0.30 for 0-3 and 3-6 mo, respectively, and standardized coefficient loadings -0.13 in the partial least squares analyses). Decreases in 19 serum protein concentrations were also correlated with improved asthma control during the 6-mo study period. CONCLUSIONS: Our data in adult patients with poorly controlled asthma suggest that dietary changes, like the introduction of DASH, may have beneficial effects on reducing inflammatory status. This trial was registered at http://www.clinicaltrials.gov as NCT01725945.

Acceptability and feasibility of the 'DASH for Asthma' intervention in a randomized controlled trial pilot study.

OBJECTIVE: 'DASH for Asthma' (n 90) was a 6-month randomized controlled trial that demonstrated potential benefits of a DASH (Dietary Approaches to Stop Hypertension) behavioural intervention for improving diet quality and asthma control by comparing intervention to usual care in adults with uncontrolled asthma. The present study examined acceptability and feasibility of the intervention from the perspective of intervention participants and lifestyle coaches. DESIGN: Grounded in Social Cognitive Theory, the 3-month intensive stage, including three individual and eight group sessions, focused on diet modifications and behavioural self-regulation. The 3-month maintenance stage contained telephone consultations. Participants and lifestyle coaches completed surveys including 5-point Likert scales and open-ended questions. We analysed data using descriptive and inductive content analyses. SUBJECTS: Forty-six intervention participants (survey response rate was 65-72 %) and two lifestyle coaches. RESULTS: Participants and lifestyle coaches were highly satisfied (all mean ratings >4) with individual and group sessions. Participants identified mastery of knowledge and skills (awareness, goal setting, self-monitoring, problem solving), social learning (class members sharing experiences and ideas) and good coaching skills (reflective listening, empathy, motivational counselling) as important contributors to self-efficacy and programme satisfaction. Participants also valued personalized feedback received in individual sessions. Lifestyle coaches viewed participant engagement as a facilitator to effective sessions. Finally, participants and lifestyle coaches identified food tasting as beneficial for observational learning and facilitation of participant engagement. High class attendance and self-monitoring rate also reflected the high engagement among participants. CONCLUSIONS: The DASH behavioural intervention was feasible and highly acceptable to participants with uncontrolled asthma and lifestyle coaches.

Pilot randomised trial of a healthy eating behavioural intervention in uncontrolled asthma.

Rigorous research on the benefit of healthy eating patterns for asthma control is lacking.We randomised 90 adults with objectively confirmed uncontrolled asthma and a low-quality diet (Dietary Approaches to Stop Hypertension (DASH) scores <6 out of 9) to a 6-month DASH behavioural intervention (n=46) or usual-care control (n=44). Intention-to-treat analyses used repeated-measures mixed models.Participants were middle-aged, 67% female and multiethnic. Compared with controls, intervention participants improved on DASH scores (mean change (95% CI) 0.6 (0, 1.1) versus -0.3 (-0.8, 0.2); difference 0.8 (0.2, 1.5)) and the primary outcome, Asthma Control Questionnaire scores (-0.2 (-0.5, 0) versus 0 (-0.3, 0.3); difference -0.2 (-0.5, 0.1)) at 6 months. The mean group differences in changes in Mini Asthma Quality of Life Questionnaire overall and subdomain scores consistently favoured the intervention over the control group: overall 0.4 (95% CI 0, 0.8), symptoms 0.5 (0, 0.9), environment 0.4 (-0.1, 1.0), emotions 0.4 (-0.2, 0.9) and activities 0.3 (0, 0.7). These differences were modest, but potentially clinical significant.The DASH behavioural intervention improved diet quality with promising clinical benefits for better asthma control and functional status among adults with uncontrolled asthma. A full-scale efficacy trial is warranted.

Behavioral weight loss and physical activity intervention in obese adults with asthma. A randomized trial.

RATIONALE: The effect of weight loss on asthma in obese adults warrants rigorous investigation. OBJECTIVES: To examine an evidence-based, practical, and comprehensive lifestyle intervention targeting modest weight loss and increased physical activity for asthma control. METHODS: The trial randomized 330 obese adults with uncontrolled asthma to receive usual care enhanced with a pedometer, a weight scale, information about existing weight management services at the participating clinics, and an asthma education DVD, or with these tools plus the 12-month intervention. MEASUREMENTS AND MAIN RESULTS: The primary outcome was change in Asthma Control Questionnaire (ACQ) scores from baseline to 12 months. Participants (mean [SD] age, 47.6 [12.4] yr) were 70.6% women, 20.0% non-Hispanic black, 20.3% Hispanic/Latino, and 8.2% Asian/Pacific Islander. At baseline, they were obese (mean [SD] body mass index, 37.5 [5.9] kg/m(2)) and had uncontrolled asthma (Asthma Control Test score, 15.1 [3.8]). Compared with control subjects, intervention participants achieved significantly greater mean weight loss (±SE) (intervention, -4.0 ± 0.8 kg vs. control, -2.1 ± 0.8 kg; P = 0.01) and increased leisure-time activity (intervention, 418.2 ± 110.6 metabolic equivalent task-min/wk vs. control, 178.8 ± 109.1 metabolic equivalent task-min/wk; P = 0.05) at 12 months. But between-treatment mean (±SE) differences were not significant for ACQ changes (intervention, -0.3 ± 0.1 vs. control, -0.2 ± 0.1; P = 0.92) from baseline (mean [SD], 1.4 [0.8]), nor for any other clinical asthma outcomes (e.g., spirometric results and asthma exacerbations). Among all participants regardless of treatment assignment, weight loss of 10% or greater was associated with a Cohen d effect of 0.76 and with 3.78 (95% confidence interval, 1.72-8.31) times the odds of achieving clinically significant reductions (i.e., ≥0.5) on ACQ as stable weight (<3% loss or gain from baseline). The effects of other weight change categories were small. CONCLUSIONS: Moderately and severely obese adults with uncontrolled asthma can safely participate in evidence-based lifestyle intervention for weight loss and active living. The modest average weight and activity improvements are comparable to those shown to reduce cardiometabolic risk factors in studies of similar interventions in other populations but are not associated with significant net benefits for asthma control or other clinical asthma outcomes in the current population. Instead, weight loss of 10% or greater may be required to produce clinically meaningful improvement in asthma. Clinical trial registered with www.clinicaltrials.gov (NCT00901095).

Abdominal and general adiposity and level of asthma control in adults with uncontrolled asthma.

RATIONALE: Abdominal adiposity may be an important risk factor for uncontrolled asthma in adults, controlling for general obesity. Whether the relationship, if present, is explained by other factors (e.g., asthma onset age, sex, and/or coexisting conditions) is unclear. OBJECTIVES: To examine whether clinically applicable anthropometric measures of abdominal adiposity--waist circumference and waist-to-height ratio (WHtR)--are related to poorer asthma control in adults with uncontrolled asthma controlling for body mass index (BMI), and whether the relationship (if present) is explained by gastroesophageal reflux disorder (GERD), sleep quality, or obstructive sleep apnea (OSA) or differs by age of asthma onset or sex. METHODS: Patients aged 18 to 70 years with uncontrolled asthma (n = 90) participated in a 6-month randomized clinical trial. MEASUREMENTS AND MAIN RESULTS: Baseline measures included sociodemographics, standardized anthropometrics, Asthma Control Test (ACT), GERD Symptom Assessment Scale, Pittsburgh Sleep Quality Index, and Berlin Questionnaire for Sleep Apnea. Participants (mean [SD] age, 52 [12] yr) were racially and ethnically diverse, 67% women, and 69% overweight or obese, and 71% reported their age of asthma onset was 12 years or older. Participants had uncontrolled asthma (mean [SD] ACT score, 14.9 [3.7]) and low GERD symptoms score (0.6 [0.4]); 67% reported poor sleep quality, and 42% had a high OSA risk. General linear regression results showed that worse ACT scores were significantly associated with every SD increase in waist circumference (ß = -1.03; 95% confidence interval [CI], -1.96 to -0.16; P = 0.02) and waist-to-height ratio (ß = -1.16; 95% CI, -2.00 to -0.33; P = 0.008), controlling for sociodemographics. Waist-to-height ratio remained correlated with ACT (ß = -2.30; 95% CI, -4.16 to -0.45; P = 0.02) after further adjusting for BMI. The BMI-controlled relationship between WHtR and ACT did not differ by age of asthma onset or sex (P > 0.05 for interactions) and persisted after additional adjustment for GERD, sleep quality, or OSA scores. Poor sleep quality was associated with worse ACT scores (ß = -0.87; 95% CI, -1.71 to -0.03; P = 0.045) controlling for waist-to-height ratio, BMI, and sociodemographics. CONCLUSIONS: Abdominal adiposity by waist-to-height ratio and poor sleep quality correlated with poorer asthma control in adults with uncontrolled asthma, after controlling for BMI and sociodemographics. These results warrant replication in larger studies of diverse populations. Clinical trial registered with www.clinicaltrials.gov (NCT 01725945).

DASH for asthma: a pilot study of the DASH diet in not-well-controlled adult asthma.

This pilot study aims to provide effect size confidence intervals, clinical trial and intervention feasibility data, and procedural materials for a full-scale randomized controlled trial that will determine the efficacy of Dietary Approaches to Stop Hypertension (DASH) as adjunct therapy to standard care for adults with uncontrolled asthma. The DASH diet encompasses foods (e.g., fresh fruit, vegetables, and nuts) and antioxidant nutrients (e.g., vitamins A, C, E, and zinc) with potential benefits for persons with asthma, but it is unknown whether the whole diet is beneficial. Participants (n = 90) will be randomized to receive usual care alone or combined with a DASH intervention consisting of 8 group and 3 individual sessions during the first 3 months, followed by at least monthly phone consultations for another 3 months. Follow-up assessments will occur at 3 and 6 months. The primary outcome measure is the 7-item Juniper Asthma Control Questionnaire, a validated composite measure of daytime and nocturnal symptoms, activity limitations, rescue medication use, and percentage predicted forced expiratory volume in 1 second. We will explore changes in inflammatory markers important to asthma pathophysiology (e.g., fractional exhaled nitric oxide) and their potential to mediate the intervention effect on disease control. We will also conduct pre-specified subgroup analyses by genotype (e.g., polymorphisms on the glutathione S transferase gene) and phenotype (e.g., atopy, obesity). By evaluating a dietary pattern approach to improving asthma control, this study could advance the evidence base for refining clinical guidelines and public health recommendations regarding the role of dietary modifications in asthma management.

The Breathe Easier through Weight Loss Lifestyle (BE WELL) Intervention: a randomized controlled trial.

BACKGROUND: Obesity and asthma have reached epidemic proportions in the US. Their concurrent rise over the last 30 years suggests that they may be connected. Numerous observational studies support a temporally-correct, dose-response relationship between body mass index (BMI) and incident asthma. Weight loss, either induced by surgery or caloric restriction, has been reported to improve asthma symptoms and lung function. Due to methodological shortcomings of previous studies, however, well-controlled trials are needed to investigate the efficacy of weight loss strategies to improve asthma control in obese individuals. METHODS/DESIGN: BE WELL is a 2-arm parallel randomized clinical trial (RCT) of the efficacy of an evidence-based, comprehensive, behavioral weight loss intervention, focusing on diet, physical activity, and behavioral therapy, as adjunct therapy to usual care in the management of asthma in obese adults. Trial participants (n = 324) are patients aged 18 to 70 years who have suboptimally controlled, persistent asthma, BMI between 30.0 and 44.9 kg/m2, and who do not have serious comorbidities (e.g., diabetes, heart disease, stroke). The 12-month weight loss intervention to be studied is based on the principles of the highly successful Diabetes Prevention Program lifestyle intervention. Intervention participants will attend 13 weekly group sessions over a four-month period, followed by two monthly individual sessions, and will then receive individualized counseling primarily by phone, at least bi-monthly, for the remainder of the intervention. Follow-up assessment will occur at six and 12 months. The primary outcome variable is the overall score on the Juniper Asthma Control Questionnaire measured at 12 months. Secondary outcomes include lung function, asthma-specific and general quality of life, asthma medication use, asthma-related and total health care utilization. Potential mediators (e.g., weight loss and change in physical activity level and nutrient intake) and moderators (e.g., socio-demographic characteristics and comorbidities) of the intervention effects also will be examined. DISCUSSION: This RCT holds considerable potential for illuminating the nature of the obesity-asthma relationship and advancing current guidelines for treating obese adults with asthma, which may lead to reduced morbidity and mortality related to the comorbidity of the two disorders. TRIAL REGISTRATION: NCT00901095.

Shared treatment decision making improves adherence and outcomes in poorly controlled asthma.

RATIONALE: Poor adherence to asthma controller medications results in poor treatment outcomes. OBJECTIVES: To compare controller medication adherence and clinical outcomes in 612 adults with poorly controlled asthma randomized to one of two different treatment decision-making models or to usual care. METHODS: In shared decision making (SDM), nonphysician clinicians and patients negotiated a treatment regimen that accommodated patient goals and preferences. In clinician decision making, treatment was prescribed without specifically eliciting patient goals/preferences. The otherwise identical intervention protocols both provided asthma education and involved two in-person and three brief phone encounters. MEASUREMENTS AND MAIN RESULTS: Refill adherence was measured using continuous medication acquisition (CMA) indices-the total days' supply acquired per year divided by 365 days. Cumulative controller medication dose was measured in beclomethasone canister equivalents. In follow-up Year 1, compared with usual care, SDM resulted in: significantly better controller adherence (CMA, 0.67 vs. 0.46; P < 0.0001) and long-acting beta-agonist adherence (CMA, 0.51 vs. 0.40; P = 0.0225); higher cumulative controller medication dose (canister equivalent, 10.9 vs. 5.2; P < 0.0001); significantly better clinical outcomes (asthma-related quality of life, health care use, rescue medication use, asthma control, and lung function). In Year 2, compared with usual care, SDM resulted in significantly lower rescue medication use, the sole clinical outcome available for that year. Compared with clinician decision making, SDM resulted in: significantly better controller adherence (CMA, 0.67 vs. 0.59; P = 0.03) and long-acting beta-agonist adherence (CMA, 0.51 vs. 0.41; P = 0.0143); higher cumulative controller dose (CMA, 10.9 vs. 9.1; P = 0.005); and quantitatively, but not significantly, better outcomes on all clinical measures. CONCLUSIONS: Negotiating patients' treatment decisions significantly improves adherence to asthma pharmacotherapy and clinical outcomes. Clinical trials registered with www.clinicaltrials.gov (NCT00217945 and NCT00149526).

Adherence to prescribed treatment for asthma: evidence from pharmacy benefits data.

BACKGROUND: Failure to use asthma controller medications as prescribed is associated with more asthma-related adverse events. Medication utilization may vary with ease of drug administration, efficacy, and tolerability as well as other factors. We hypothesized that in usual-care clinical practice settings, there would be greater adherence to oral controller than to inhaled controller asthma medications. METHODS: We compared adherence to newly initiated asthma controller therapy among patients initiating monotherapy with leukotriene receptor antagonists (LTRAs), inhaled corticosteroids (ICS), or inhaled long-acting beta-agonists (ILBA) from March 1998 to July 1999. We measured adherence as the sum of drug supply days between first and last fill dates divided by length of drug therapy. Analyses were stratified by the number of short-acting beta-agonists (SBA) prescriptions per year to control for disease severity. RESULTS: Pharmacy claims data from 48,751 subjects (6 to 55 years) were analyzed (mean age 30.4 years; 56% female). Mean adherence to new start monotherapy on LTRA was 67.7%, to ICS was 33.8%, and to ILBA was 40.0%. Adherence to all three controller agents increased with increasing SBA use. The percent of patients persistent to asthma controller monotherapy at both 6 and 9 months was significantly greater among those on LTRA monotherapy than on either ICS or ILBA. CONCLUSIONS: In clinical practice settings, patients initiating LTRA monotherapy have about twice the adherence as patients initiating ICS or ILBA monotherapy. Because adherence to treatment is a critical component of treatment response, it is important to consider this factor in the prescription of oral vs. inhaled asthma medications.