Figure.

Study design for matched cohort study nested in the Nurses’ Health Studies performed among women who donated blood for research purposes, investigating pre-RA ACPA status and risks for incident chronic obstructive pulmonary disease or asthma. ACPA, anti-citrullinated protein antibodies; RA, rheumatoid arthritis.

*Each woman with RA was matched to 3 controls by age, time from blood draw to index date, cohort, calendar year, fasting status/time of day blood draw, menopausal status, and postmenopausal hormone use