RT Journal
A1 Shadick NA, Karlson EW, Lee I
T1 C-reactive protein is still a potential aid in rheumatoid arthritis predictors—reply
JF Archives of Internal Medicine
JO Archives of Internal Medicine
YR 2007
FD July 23
VO 167
IS 14
SP 1552
OP 1552
DO 10.1001/archinte.167.14.1552-b
UL http://dx.doi.org/10.1001/archinte.167.14.1552-b
AB 
Tanzer raises 2 issues for discussion related to potential confounders in our study examining the association of CRP level with the risk of developing RA.1 First, as he indicates, smoking is a known risk factor for incident RA. In our cohort, 38% of RA cases were never smokers and 52% were past smokers at the time of diagnosis vs 52% and 37%, respectively, among women who did not develop RA. In our analyses, we adjusted for smoking status; thus, our findings were unlikely to reflect confounding by smoking. Second, regarding statin use, the blood samples in our study were collected between 1993 and 1995, a period when the prevalence of statin use was relatively low. We did not have data on statin use at baseline to adjust for this; however, there was unlikely to be major confounding because there was unlikely to be many women using statins.