Table 1.

Study design, sample size, and demographics of 12 articles meeting inclusion criteria.

Study, Year, Reference	Journal	Article/Abstract	Country	Design	Meeting NY Criteria for AS, %	JoAS Sample Size	AoAS Sample Size	JoAS Age, mean yrs	AoAS Age, mean yrs	JoAS Disease Duration, mean yrs	AoAS Disease Duration, mean yrs	Comments on Methods
Chen, 2012¹¹	J Rheumatol	Article	Taiwan	Pro, single center	100	67	460	26.8	33.9	12.3	9.5	19 LoAS cases
Yacoub, 2012⁵	EULAR	Abstract	Morocco	Pro, single center	NA	37	83	NA	NA	NA	NA
Ozgocmen, 2009¹²	J Rheumatol	Article	Turkey	Pro, multicenter	100	43	279	29.3	36.1	16.8	10.5
O’Shea, 2009⁷	Ann Rheum Dis	Article	Canada	Pro database, single center	100	84	183	27.5	42.6	14.7	16.7
Lin, 2009¹⁶	J Chinese Med Assoc	Article	Taiwan	Retro, chart review and interviews. Single center	100	47	122	26.9	37.3	14.1	12.5
Gensler, 2008¹⁴	Ann Rheum Dis	Article	USA	Retro, cross sectional multicenter	100	79	323	49.8	56.2	35.6	30.9
Stone, 2005⁶	Arthritis Rheum	Article	USA & Canada	Retro, postal questionnaire study	NA	326	2021	46.5	50.9	18.3	13.4	Diagnosed by rheumatologists in 63%, generalists in 15%, orthopedic surgeons in 13%, ophthalmologists in 5.4%, chiropractors in 4.5%
Baek, 2002⁸	J Rheumatol	Article	S. Korea	Pro, single center	100	41	57	22.0	33.0	10.0	11.2
Calin, 1988⁹	Br J Rheumatol	Article	UK	Retro, postal questionnaire and case-note review. Single center	NA	135	135	37.3	49.6	24.5	23.5
Garcia-Morteo 1983¹⁰	Scand J Rheum	Article	Argentina	Pro, single center	99	24	71	NA	NA	NA	NA
Marks, 1982¹³	J Rheumatol	Article	USA	Retro, single center	NA	22	22	24.7	40.0	13.0	14.0
Riley, 1971¹⁵	Ann Rheum Dis	Article	UK	Retro, 2 centers	NA	28	107	NA	NA	NA	NA

NA: not available; JoAS: juvenile-onset ankylosing spondylitis; AoAS: adult-onset ankylosing spondylitis; LoAS: late-onset ankylosing spondylitis; EULAR: European League Against Rheumatism; Pro: prospective; Retro: retrospective.