text: classiﬁcation accounted for 12% of the total variability 
  of dyspnea. 
  
  exposure in an array of risky occupations. These risk 
  factors, taken as a whole, accounted for 21% of the 
  variability in dyspnea. 
  
  Table 6 presents the contribution of lung function 
  measures of physiologic impairment after accounting for 
  patient-related risk factors and disease classiﬁcation. For 
  the PRISm disease group, a higher post-BD FEV1/FVC 
  ratio and a lower post-BD FEV1 % predicted value were 
  associated with greater dyspnea impact. For the COPD 
  disease group, a lower post-BD FEV1/FVC ratio was 
  associated with greater dyspnea impact. Reversibility of 
  FEV1 was associated with higher dyspnea impact only in 
  patients with asthma or COPD. Lung function measures 
  of disease severity accounted for 2% of the variability in 
  dyspnea. 
  
  After adjustment for patient-speciﬁc risk factors in the 
  ﬁrst stage analysis, we adjusted for spirometry-deﬁned 
  disease (PRISm, asthma, COPD, or normal 
  spirometry) in Table 5. Adjustment for disease 
  
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