Mediators of Inflammation

Review Article

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

Table 1

(a) Background information of clinical studies evaluating the effect of obesity on asthma in adults. (b) Results of clinical studies evaluating the effect of obesity on asthma in adults.
(a)
StudyPatient
with asthma 		SettingCountryAsthma criteriaSeverity levels includedSmokers included Other exclusion criteriaOnset of asthma
(child/mixed/
adult)		Gender
(Females%)		Age
(mean; years)
Lessard et al., 2008 [46]88Cross-sectionalCanadaConfirmed diagnosis based on bronchodilator response or airway responsiveness measurementsAll NoCurrent smoking or ex-smoker for ≤6 moMixed68–10032–44
Pakhale et al., 2010 [44]346Cross-sectionalCanadaSequential lung testingAllYes (?)Asthma ruled out using sequential testingMixed66–7341–47
Holguin et al., 2011 (SARP early-onset) [47]543Cross-sectionalUS A 12% increase in FEV1 after a short-actingbronchodilator or a 20% decrease in FEV1after inhalation of methacholine (PC20, 25 mg/mL)AllNo Current smoking or smoking history of 5 years or more Childhood-onset (<12 years)49–6526–35
Holguin et al., 2011
(SARP late-onset) [47]		506Cross-sectional USAllNoLate-onset (12 years or more)65–7439–45
Gibeon et al., 2013 [48]666Cross-sectionalUKATS definition of refractory asthmaSevereYes (?)NRMixed6545
Bruno et al. 2014 [49]102Cross-sectional Italy/FranceATS 1987SevereNoPotential confounding diagnosis. Any persistent environmental trigger, COPD, or other differential diagnosesMixed5657
Ramasamy et al., 2014 [50]60Cross-sectional IndiaGINA 2009AllNoSmoker (current or ex), ICS/OCS during previous month, medication for obesity, hypertension, diabetes mellitus/CAD, unable to perform exhaled nitric oxide maneuverMixed5032–35
(inclusion 20–50 years)
Ciprandi et al., 2014 [51]286Cross-sectional Italy Documented asthma diagnosis by a specialist based on a history of intermittent wheezing in combination with reversibility to bronchodilators and/or BHR to methacholineAllNo (?)History of lung disease other than asthma, coronary artery disease, congestive heart failure, cor pulmonale, recent asthma exacerbation or presence of acute (in the last 4 weeks) or chronic upper and/or lower respiratory infectionsNR5948
NR = not reported, FEV1 = forced expiratory volume in 1 second, ATS = American Thoracic Society, SARP = the Severe Asthma Research Network, BHR = bronchial hyperresponsiveness, ICS = inhaled corticosteroid, OCS = oral corticosteroid, and CAD = coronary artery disease.
(b)
 AgeAge at onsetAsthma durationAsthma controlExacerbations last yearOral steroids for asthma in the previous yearHospital admissions last yearUrgent visits to health care due to respiratory symptoms or ED visit preceding yearHospitalization for asthma ever Intensive care unit for asthma ever or previous year Other
Lessard et al., 2008 [46]↔ND↔↓NDNDNDNDNDNDTLC, ERV, FRC, and RV lower in obese asthmatics
Pakhale et al., 2010 [44]↑↑↔NDNDND↔↔NDNDObese individuals who make urgent visits for respiratory symptoms are more likely to receive a misdiagnosis of asthma
Holguin et al., 2011, early-onset [47]↑↔↑NDND↑↑↑ND↑ Asthmatic subjects are differentially affected by obesity based on whether they had asthma early (<12 years of age) or later in life
Holguin et al., 2011, late-onset [47]↑↑↔NDND↔(↑)↑ND↑
Gibeon et al., 2013 [48]↔↔↔NDND↑↔↔ND↔No difference in FENO or sputum eosinophils
Bruno et al., 2014 [49]↔ND↔↓(↑)↑NDND↔↔BMI represents per se a factor for the deterioration in disease control in severe asthma
Ramasamy et al., 2014 [50] (↑)ND↔NDNDNDNDNDNDNDNo difference in FENO and hsCRP
Ciprandi et al., 2014 [51]↑NDND↔NDNDNDNDNDNDNo difference in FENO
 FEV1 (% pred.)FVC (% pred.)FEV1/FVCLABA useBlood eosinophilsTotal IgEAllergic sensitizationGERDDiabetes mellitusHypertensionObstructive sleep apnea syndromeAnxiety/depression
Lessard et al., 2008 [46]↔↔↔ND↔↔↔NDNDNDNDND
Pakhale et al., 2010 [44]↓NDNDNDNDNDND↑↑↑NDND
Holguin et al., 2011, early-onset [47]↓↓↓↑↔↔↔NDNDNDNDND
Holguin et al., 2011, late-onset [47]↓↓↔↑↔↔(↓)NDNDNDNDND
Gibeon et al., 2013 [48]↔↓↔ND↔↓(↓)↑NDNDNDND
Bruno et al., 2014 [49](↓)(↓)↔↑↔↔↔↔↑↔↑↔
Ramasamy et al., 2014 [50]↔↔↔NDNDND↔NDNDNDNDND
Ciprandi et al., 2014 [51]↓↓↓NDNDND↓NDNDNDNDND
ND = not defined; FEV1 = forced expiratory volume in 1 second. FVC = forced vital capacity. LABA = long-acting 2-agonist. GERD = gastroesophageal reflux disease, TLC = total lung capacity, ERV = expiratory reserve volume, FRC = functional residual capacity, RV = residual volume, FENO = forced exhaled nitric oxide, hsCRP = high sensitivity C-reactive protein, and ED = emergency department.