. Author manuscript; available in PMC: 2022 Feb 1.

Published in final edited form as: Arthritis Care Res (Hoboken). 2021 Feb;73(2):180–187. doi: 10.1002/acr.24115

Table 1.

Demographic characteristics of RA cases and controls at baseline questionnaire

	Number (%)
Characteristic	RA Cases (N = 821)	Controls (N = 2455)	p-value
Age, years (mean ±SD)	62 (±14)	62 (±14)	0.97
Age at RA diagnosis (or matched date)	50 (±16)	50 (±16)	0.98
Female sex	600 (73)	1792 (73)	0.96
White, non-Hispanic	804 (98)	2393 (98)	0.46
Body mass index, kg/m² (mean ±SD)	30 (±7)	29 (±7)	0.03
Received bachelor’s degree or higher	324 (40)	1182 (48)	< 0.001
Ever smoker	402 (49)	993 (40)	< 0.001

IQR = interquartile range, kg = kilograms, m = meters, RA = rheumatoid arthritis, SD = standard deviation