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)

P value^a

Ever (n = 96)

P value^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).

Mattey et al. Arthritis Research & Therapy 2012 14:R127   doi:10.1186/ar3857