Table 2

Adjusted OR (aOR) for independent predictors associated with risk of different severity of COPD defined by lower limits of normal in male and female never-smokers

VariablesCOPD mildCOPD moderate-severe
AllMenWomenAllMenWomen
Age, +70 years (vs 40–49 years)2.19* (1.15 to 4.16)2.50 (0.77 to 8.16)2.28* (1.02 to 5.06)4.46* (1.84 to 10.8)6.09* (1.14 to 35.4)3.54* (1.23 to 10.1)
Education (# years)0.98 (0.92 to 1.04)0.88* (0.78 to 0.99)1.02 (0.95 to 1.11)0.95 (0.88 to 1.02)0.96 (0.83 to 1.10)0.94 (0.86 to 1.03)
Biomass, ≥10 years heating (yes/no)†0.88 (0.39 to 1.96)2.09 (0.59 to 7.44)0.62 (0.21 to 1.82)2.26 (0.93 to 5.52)0.44 (0.08 to 2.42)3.58* (1.42 to 9.01)
Passive smoking (yes/no)2.18 (0.99 to 4.75)1.33 (0.26 to 6.72)2.60* (1.05 to 6.43)1.25 (0.42 to 3.73)0.69 (0.08 to 6.21)1.65 (0.46 to 5.88)
Childhood hospitalisation for respiratory illness (yes/no)1.57 (0.68 to 3.62)2.95 (0.84 to 10.4)1.18 (0.35 to 4.00)4.80* (2.43 to 9.46)10.1* (3.71 to 27.5)2.24 (0.73 to 6.84)
HD/HT/DM‡ (yes/no)0.72 (0.43 to 1.21)1.55 (0.61 to 3.95)0.51* (0.26 to 0.98)1.11 (0.63 to 1.94)1.48 (0.57 to 3.90)1.07 (0.53 to 2.16)
Asthma (yes/no)2.23* (1.36 to 3.66)3.39* (1.25 to 9.21)2.14* (1.20 to 3.82)4.94* (2.94 to 8.30)7.34* (3.01 to 17.9)3.89* (2.02 to 7.50)
  • Data are aORs and 95% CI. Adjustment made for all other covariates in model: BMI, exposure to organic dust, inorganic dust, gases/vapours, biomass cooking ≥10 years and TB. Plus sex (for ‘all’ cohorts).

  • *Significant at 5% level (all variables shown in online supplementary table X2).

  • †Calculated based on six sites with available biomass data.

  • ‡Heart disease, systemic hypertension or diabetes.

  • BMI, body mass index; HD/HT/DM, heart disease/ systemic hypertension/diabetes mellitus.