Table 2.

Main sources of occupational and non-occupational silica exposure in women with RA versus controls (expressed as the mean and SD of exposure score)

Activities	RA women n=76		Control women n=308		P value*	Bonferroni correction†
	Mean	SD	Mean	SD
Main occupational activities (OES)
Construction	0.19	1.71	0.12	1.22	0.99	NS
Farming	0.60	2.64	0.60	2.52	0.72	NS
Stone	0.09	0.57	0.03	0.32	0.13	NS
Wood	0.00	0.00	0.10	1.05	0.39	NS
Cleaning	1.03	1.71	0.46	1.32	<0.001	†
Metallurgy	0.05	0.46	0.03	0.51	0.29	NS
Painting	0.06	0.41	0.06	0.40	0.99	NS
Plumbing	0.00	0.00	0.00	0.00	–	NS
Steel welding	0.27	1.48	0.03	0.33	0.02	NS
Dusty work clothes laundry	1.00	1.86	0.19	0.86	<0.001	†
Main non-occupational activities (NOES)
Farming	2.30	4.07	1.06	1.88	0.13	NS
DIY	1.05	1.61	0.80	1.40	0.19	NS
Wood	0.32	0.97	0.29	0.96	0.73	NS
Cleaning	8.03	4.29	3.92	4.48	<0.001	†
Dusty work clothes laundry	2.55	3.71	1.76	3.30	0.064	NS
Cat litter	0.47	0.79	0.82	0.95	0.003	†
Mud bath	0.49	0.64	0.81	0.94	0.03	NS

*Wilcoxon test, level of significance p<0.05.

†Bonferroni correction, level of significance p<0.004 for occupational activities, p<0.006 for non-occupational activities.

NOES, non-occupational exposure score; OES, occupational exposure score; RA, rheumatoid arthritis.