Table 3.

Summary of studies in adult populations

Study	Population	Intervention	Control	Timing	Outcome(s)	Result(s)
Freitas et al. 2017 (38) NCT02188940	55 obese patients (30–60 yr old) with moderate to severe asthma (50 of 51 included for analysis were women)	Individual hypocaloric diet counseling sessions plus aerobic and resistance exercise	Individual hypocaloric diet counseling sessions, plus sham exercise (stretching and breathing)	3 mo (weekly counseling sessions, exercise sessions twice a week)	Primary: ACQ score. Other: BMI, body composition, fitness and strength measures, FEV1, FVC, TLC, ERV, AQLQ, ACQ improvement, AQLQ improvement, FeNO, leptin, adiponectin, TNF-α, CRP, vitamin D, IL-4, IL-6, IL-10, other biomarkers	Weight: Significant between-group differences in BMI and total fat mass improvements
						PFTs: Significant between-group differences in ERV and FeNO
						Inflam: Significant between-group differences in leptin, adiponectin, TNF-α, IL-4, IL-6, and IL-10
						QOL: Significant between-group differences in ACQ and AQLQ scores. ACQ improvement correlated with improvements in aerobic fitness, fat and lean mass, FVC, FeNO, IL-6, IL-10, and adiponectin
Ma et al. 2015 (36) NCT00901095	330 obese adults (18–70 yr old) with uncontrolled asthma	Multistage intervention with increased physical activity and counseling focused on weight loss	Standard care plus weight and asthma self-management tools	12 mo; frequency of sessions varied by stage	Primary: ACQ score. Other: Weight, BMI, waist circumference, physical activity, energy expenditure, FEV1, FVC, FEV1/FVC, ACT, mini AQLQ, medication use, exacerbations requiring corticosteroids, healthcare encounters	Weight: Significant between-group differences in BMI and proportion of participants with weight loss ≥5%, 7%, and 10% of baseline
						PFTs: No significant differences reported at 6 or 12 mo
						QOL: No significant differences at 6 or 12 mo. Participants who lost >10% of baseline weight (including both groups) were more likely to show clinically significant improvements in ACQ (OR, 3.8; 95% CI, 1.72–8.31); those who lost 5–10% had a smaller effect (OR, 2.2; 95% CI, 1.08-4.46)
Scott et al. 2015 (35) ACTRN12611000235909 (A/NZ)	38 overweight and obese adults (mean age, 40 yr) with asthma	1) Dietary intervention with partial meal replacement, 2) exercise intervention with regular gym sessions, or 3) combined diet and exercise	Not applicable; the three intervention arms were compared	10 wk, with exercise sessions 3 times per week	Weight, waist circumference, percentage body fat, eating behaviors, energy intake, food diary, steps/d, FEV1, FVC, FEV1/FVC, AQLQ, ACQ; as well as effect of sex on body composition, eating behaviors, intake, and physical activity.	Weight: Subjects in the diet or combined arms lost more weight than those in the exercise-only group.
						PFTs: Did not report pulmonary function tests postintervention. Lower baseline FEV1 was associated with greater weight loss.
						QOL: Subjects with lower asthma-related QOL at baseline showed a greater weight loss.
Dias-Júnior et al. 2014 (37) NCT01049657	33 moderately obese adults (mean age, 43 yr) with severe uncontrolled asthma	Weight loss program with low caloric intake, daily sibutramine (10 mg), and daily orlistat (max 120 mg/d) plus bimonthly asthma clinics	Bimonthly asthma clinics	6 mo	Primary: ACQ. Other: BMI, ACT, SABA use, symptom-free days, ED visits, exacerbations, SGRQ, FEV1, FVC, FEV1/FVC, FEF25–75%, IC, TLC, ERV, RV, RV/TLC, Raw, Gaw, PD20, FeNO, sputum cell counts, serum biomarkers (IgE, CRP, leptin, eotaxin, TGF-β1) .	Weight: Significant within-group and between-group differences in BMI in the intervention group
						PFTs: Significant within-group change in FVC (liters, but not % predicted); also significant between-group difference in FVC (liters) for those with >10% weight loss. All other pulmonary function outcomes nonsignificant
						Inflam: All changes in sputum and serum inflammatory markers were nonsignificant.
						QOL: Within-group and between-group differences were significant for ACQ, ACT, and SGRQ scores.
Scott et al. 2013 (34) ACTRN12611000235909 (A/NZ)	46 overweight and obese nonsmoking adults (mean age, 40 yr) with asthma	1) Dietary intervention with partial meal replacement, 2) exercise intervention with regular gym exercise sessions, or 3) combined diet and exercise	Not applicable; the three intervention arms were compared	10 wk, with exercise sessions 3 times per week	Weight, weight loss, waist circumference, fat and lean mass, total energy intake, dietary intake, physical activity, FEV1, FVC, FEV1/FVC, TLC, FRC, ERV, RV, airway hyperresponsiveness (hypertonic saline provocation test), ACQ, AQLQ, induced sputum cell counts, leptin, adiponectin, CRP, IL-6	Weight: Both the dietary (8.5%) and combined (8.3%) intervention groups achieved significant weight loss.
						PFTs: Between-group differences in TLC were seen in the exercise (+2.2%) and combined (+1.2%) groups vs, the dietary group. ERV increased (21.4%) from baseline to postintervention in the dietary group. The proportion of subjects with AHR decreased in combined group (100% vs. 66.7%). When stratified by weight loss (rather than by intervention), FRC and ERV increased among those in the highest weight loss group.
						Inflam: Within-group improvements: airway eosinophilia decreased from baseline in the exercise group only (−1.3%), leptin decreased in the dietary (−5.3 µg/L) and combined (−6.2 µg/L) groups, and IL-6 decreased in the combined group (−0.18 pg/mL).
						QOL: ACQ scores improved in the dietary (−0.6 points) and combined (−0.5 points) arms compared with baseline; AQLQ scores improved in all groups compared with baseline. No between-group differences.
Stenius-Aarniala et al. 2000 (39)	38 obese patients (mean age, 49 yr) with asthma	12 weight reduction group sessions, low-energy diet preparation	12 nonspecific group sessions	14 wk, with an 8-wk “dieting period” in the intervention group, and follow-up at 1 year	Weight, weight loss, PEF, FEV1, FVC, cough, dyspnea, medication use, exacerbations, oral steroid courses, SGRQ, serum and urine cortisol.	Weight: Mean weight loss in the treatment group was 14.2 kg at 14 wk (end of program) and 11.1 kg at 1 yr; the control group lost 0.3 kg at 14 wk and gained 2.3 kg at 1 yr (no P values reported).
						PFTs: Significant between-group improvements in FEV1 and FVC at all time points. At 1 yr, the mean changes in both FEV1 and FVC were 7.6% higher in the intervention group. No between-group differences in PEF.
						QOL and medications: Dyspnea and rescue medication use decreased by the end of the intervention. Significant reduction in exacerbations between groups. At 1 yr, SGRQ symptom score was 12 points lower and total score 10 points lower in total score in the intervention group.

Definition of abbreviations: ACQ = Asthma Control Questionnaire; ACT = Asthma Control Test; AHR = airway hyper-reactivity; A/NZ = Australia/New Zealand; AQLQ = Asthma Quality of Life Questionnaire; BMI = body mass index; CI = confidence interval; CRP = C-reactive protein; ED = emergency department; ERV = expiratory residual volume; FEF_25–75% = forced expiratory flow at 25–75% of pulmonary volume; Fe_NO = fractional exhaled nitric oxide; FEV₁ = forced expiratory volume in 1 second; FRC = functional residual capacity; FVC = forced vital capacity; G_aw = airway conductance; IC = inspiratory capacity; IgE = immunoglobulin E; IL = interleukin; inflam = inflammatory markers; OR = odds ratio; PD₂₀ = provocative dose of methacholine causing a 20% fall in FEV₁; PEF = peak expiratory flow; PFTs = pulmonary function tests; QOL = quality of life; R_aw = airway resistance; RV = residual volume; SABA = short-acting β-agonist; SGRQ = St. George’s Respiratory Questionnaire; TGF = transforming growth factor; TLC = total lung capacity; TNF = tumor necrosis factor.

Results group by weight loss, PFTs, inflammatory markers, and QOL. Between-group differences refer to those between the intervention arm versus the control subjects. Within-group differences refer to those comparing postintervention to baseline within the intervention arm.