Fig. 2
From: Decreased COPD prevalence in Sweden after decades of decrease in smoking
Interaction analyses for the risk of COPD and a smoking habits and sex, and b packyears of smoking and sex. Results expressed as Odds Ratios (OR) with 95% Confidence Intervals (CI) adjusted for age, level of education, age category, exposure to gas, dust or fumes at work and family history of obstructive airway disease. COPD was defined as post-BD FEV1/FVC < 0.7 in combination with respiratory symptoms. P-values for comparison with reference category