Table 1.

Comparison of baseline data of cases and controls^*

Characteristic	Cases (n = 231)	Controls (n = 722)
Age, mean ± SD years	54.0 ± 8.1	50 ± 8.4†
Female	85	81
White	94	92
More than high school education	63	75†
More than US median income‡	31	56†
RA duration, mean ± SD years	15 ± 9.9	13 ± 9.4§
HAQ score, mean ± SD¶	1.0 ± 0.7	0.7 ± 0.6†
RA global severity, mean ± SD#	3.8 ± 2.6	2.7 ± 2.2†
Use anti-TNF agent	46	49
Hours worked per week, mean ± SD	29 ± 15.6	37 ± 13.0†
Community difficulty, mean ± SD**	4.8 ± 5.2	3.7 ± 4.1†
Self-employed	25	15†
Professional/managerial job	30	48†
Stressful job††	23	19
Work preference
Full time	22	48†
Part time	45	41
Not to work	33	11

^*Values are the percentage unless otherwise indicated. RA = rheumatoid arthritis; HAQ = Health Assessment Questionnaire; anti-TNF = anti–tumor necrosis factor.

^†P < 0.001.

^‡Personal income from employment.

^§P ≤ 0.05.

^¶Measure of functional limitation (0 –3 scale, 3 = greater limitation).

^#Status considering all effects of RA illness (0 –10 scale; 0 = very well, 10 = poor).

^**0 –10 scale, 10 = reater difficulty.

^††High-demand, low-control job.