. 2023 Jul 28;9(3):e003059. doi: 10.1136/rmdopen-2023-003059

Table 3.

Studies reporting age (or age at RA onset) as a risk factor

	Study type	N	Association with ILD	Adjusted for one or more baseline variables?	Grading
Li et al²⁵	Retrospective, longitudinal, single-centre cohort	923	OR 1.485 (95% CI 1.011 to 2.181); p=0.044	Sex, smoking, RA duration and severity, ACPA, RF	3
Wang and Du²⁷	Retrospective, single-centre cohort	544	Age at RA onset OR 2.55 (95% CI 1.11 to 5.90); p=0.028	Sex, steroid use, ACPA, RF, smoking, disease duration, HBsAg, Tripterygium wilfordii use	3
Juge et al¹⁵	Retrospective, multicentre cohort	1234	Higher age, p<0.0001	Sex, country of origin	3
Salaffi et al³⁰	Retrospective, single-centre cohort	151	Higher age, p<0.0001 Higher age at RA onset p=0.0253	Sex, disease duration, smoking, RF, ACPA, Disease severity, HAQ-DI	3
Doyle et al³²	Prospective cohort from two centres	189	Higher age, p<0.05	No	3
Kronzer et al³⁸	Prospective, single centre cohort	317	p=0.41	No	3
Furukawa et al³³	Prospective, single-centre cohort	450	Higher age, p<0.0001	No	2
Juge et al³⁵	Retrospective, multicentre cohort	253	Higher age at RA onset p<0.0001	Disease duration	2
Giles et al³⁴	Prospective, single-centre cohort	177	Higher age, p=0.065	No	2
Yin et al³⁷	Retrospective, single-centre cohort	285	Higher age, p<0.001	No	2
Paulin et al³⁶	Prospective, single-centre cohort	118	Higher age, p=0.001	No	1
Yang et al²⁹	Retrospective, single-centre cohort	308	p=0.731	No	1

Grading was performed using Oxford criteria as detailed in the methods.

ACPA, anticitrullinated peptide antibodies; HBsAg, hepatitis B surface antigen; ILD, interstitial lung disease; RA, rheumatoid arthritis; RF, rheumatoid factor.