Association of cytokine and matrix metalloproteinase profiles with disease activity and function in ankylosing spondylitis

Table 7 Levels of individual biomarkers comprising principal component 3 stratified by smoking status

	Smoking status
Variable (pg/ml)	Never (n= 61)	Past (n= 56)	Current (n= 40)	Pvalue^a	Ever (n= 96)	Pvalue^b
MMP-8	9,750 (4,767 to 14,668)	12,578 (6,906 to 26,066)	18,934 (10,792 to 28,988)	0.02	16,731 (8,001 to 27,241)	0.004
MMP-9	377,000 (258,488 to 607,190)	421,409 (248,758 to 627,056)	547,697 (344,692 to 802566)	0.01	466,416 (284,003 to 730,264)	0.04
CXCL8	27.0 (21.1 to 40.5)	30.0 (23.2 to 53.0)	34.0 (20.1 to 88.9)	0.4	31.9 (21.3 to 52.2)	0.2
HGF	421.7 (327.8 to 678.3)	430.3 (305.9 to 648.3)	408.4 (337.7 to 555.2)	1.0	427.1 (327.8 to 646.1)	0.9

HGF, hepatocyte growth factor; MMP, matrix metalloproteinase. ^aKruskal-Wallis test. ^bEver smoked versus never smoked (Mann-Whitney U test).

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