Figure 1.

Relative risk with contributions from low education level, urban living environment, or a combination of both factors for anxiety (A) and depression (B). Multiple confounder adjustment included age, sex, smoking history, body mass index, COPD Assessment Test, percentage predicted forced expiratory volume in 1 second, oxygen therapy, modified Medical Research Council score, and Charlson Comorbidity Index.

Note: U means the odds ratio was equal to 1.