Table 3

Socioeconomic status, race–ethnicity and pulmonary function impairment in chronic obstructive pulmonary disease

SES indicatorForced expiratory volume in 1 s % (per cent of predicted value)Forced expiratory volume in 1 /forced vital capacity (FEV1/FVC)×100
Model 1Model 2Model 3Model 1Model 2Model 3
Race
 WhiteReferentReferentReferentReferentReferentReferent
 Black3.5 (−0.03 to 7.0)5.0 (1.5 to 8.5)4.3 (0.8 to 7.7)1.8 (−0.5 to 4.0)2.2 (−0.07 to 4.5)1.2 (−1.0 to 3.3)
 Asian−3.1 (−10.8 to 4.6)−5.8 (−14 to 1.9)−6.6 (−14.3 to 1.2)3.2 (−1.7 to 8.2)2.1 (−2.9 to 7.1)2.8 (−1.9 to 7.6)
 Hispanic1.6 (−2.9 to 6.1)3.3 (−1.2 to 7.8)2.5 (−2.0 to 7.0)2.0 (−0.9 to 4.8)2.7 (−0.2 to 5.7)1.8 (−1.0 to 4.5)
 Other4.3 (−2.9 to 11.6)6.1 (−1.1 to 13.2)4.6 (−2.5 to 11.7)4.3 (−0.3 to 9.0)5.0 (0.4 to 9.6)3.2 (−1.1 to 7.6)
Education
 Less than high schoolN/A−6.2 (−9.8 to −2.7)−5.6 (−9.2 to −2.0)N/A−3.7 (−6.0 to −1.4)−3.4 (−5.6 to −1.2)
 Some collegeN/A−3.8 (−7.1 to −0.6)−3.7 (−6.9 to −0.4)N/A−1.4 (−3.4 to 0.7)−1.6 (−3.6 to 0.4)
 College degree+N/AReferentReferentN/AReferentReferent
Income
 LowN/A−11.3 (−16.2 to −6.4)−12.4 (−17.3 to −7.4)N/A−3.8 (−0.6 to 7.0)−5.9 (−9.0 to −2.9)
 MediumN/A−4.7 (−8.0 to −1.4)−4.9 (−8.2 to −1.7)N/A−0.8 (−3.0 to 1.3)−1.5 (−3.5 to 0.5)
 HighN/AReferentReferentN/AReferentReferent
  • Educational attainment categories are less than high school, some college, college degree or graduate school; income categories are low (<US$20 000), medium (US$20 000–80 000), high (>US$80 000) and missing.

  • Respiratory impairment was measured by spirometry (FEV1% is the per cent predicted value).

  • Multivariable linear regression analysis—all results are mean difference compared to referent group (95% CIs).

  • Model 1=impact of race, adjusting for age, sex and height; model 2=impact of race, educational attainment and household income, adjusting for age, sex and height; model 3=race, educational attainment and household income, adjusting for age, sex, and height; also including additional covariates (smoking history, occupational exposures on longest held job, body mass index, and comorbidities).

  • N/A, not applicable; SES, socioeconomic status.