Background characteristics of a sample of Swedish women with and without rheumatoid arthritis.

Table 1: Background characteristics of a sample of Swedish women with and without rheumatoid arthritis.

	With RA	n^d	Without RA	n^d	*P-value*
Age, median (IQR), years	55 (45-61)	149	47 (36-56)	162	< 0.001^a**
Weight, median (IQR), kg	70 (60-79)	148	65 (60-72)	162	0.007^a**
BMI, median (IQR), kg/m²	25 (22-28)	148	23 (21-26)	162	0.001^a**
BMI category, %		147		162	0.008^b**
Underweight	2	3	3	5
Normal weight	50	73	67	108
Overweight	32	48	23	37
Obese	16	23	7	12
Education, %		148		163	< 0.001^b**
None	1	2	0	0
Compulsory school (9 yrs.)	14	20	4	7
Upper secondary school, vocational education or equivalent (2 yrs.)	21	31	11	18
Upper secondary school (3 yrs)	17	25	16	26
University	47	70	69	112
Use of nicotine, %	14	150	12	163	0.65^c
Other illness than RA, %	36	150	18	162	< 0.001^b**

^aDetermined by Mann-Whitney U test; ^bDetermined by Fisher’s exact test; ^cDetermined by Chi2-test; ^dDue to missing data for some variables exact numbers are given; BMI: Body Mass Index; RA: Rheumatoid arthritis; ^**p < 0.01.