A polygenic risk score and age of diagnosis of COPD.

BACKGROUND

Genetic susceptibility may be associated with earlier onset of chronic obstructive pulmonary disease (COPD). We hypothesised that a polygenic risk score (PRS) for COPD would be associated with earlier age of diagnosis of COPD.

METHODS

In 6647 non-Hispanic White (NHW) and 2464 African American (AA) participants from COPDGene, and 6812 participants from the Framingham Heart Study (FHS), we tested the relationship of the PRS and age of COPD diagnosis. Age at diagnosis was determined by: 1) self-reported age at COPD diagnosis or 2) age at visits when moderate-to-severe airflow limitation (Global Initiative for Chronic Obstructive Lung Disease (GOLD) grade 2-4) was observed on spirometry. We used Cox regression to examine the overall and time-dependent effects of the PRS on incident COPD. In the COPDGene study, we also examined the PRS's predictive value for COPD at age <50 years (COPD50) using logistic regression and area under the curve (AUC) analyses, with and without the addition of other risk factors present at early life ( childhood asthma).

RESULTS

In Cox models, the PRS demonstrated age-dependent associations with incident COPD, with larger effects at younger ages in both cohorts. The PRS was associated with COPD50 (OR 1.55 (95% CI 1.41-1.71) for NHW, OR 1.23 (95% CI 1.05-1.43) for AA and OR 2.47 (95% CI 2.12-2.88) for FHS participants). In COPDGene, adding the PRS to known early-life risk factors improved prediction of COPD50 in NHW (AUC 0.69 0.74; p<0.0001) and AA (AUC 0.61 0.64; p=0.04) participants.

CONCLUSIONS

A COPD PRS is associated with earlier age of diagnosis of COPD and retains predictive value when added to known early-life risk factors.