Table 4.

Odds Ratios for Incident Rheumatoid Arthritis by Categories of Either Baseline Periodontal Disease or Tooth Loss among Smoking Subgroups: Longitudinal Results from The First National Health and Nutrition Examination Survey and Its Epidemiologic Follow-up Study. Adjusted for age, sex, race, education.

Periodontal Status
n=4424 never smokers (218 RA cases); n=1845 former smokers (93 RA cases); n=2,761 current smokers (119 RA cases); P for interaction = 0.03
Smoking Subgroup	Healthy Periodontium Reference	Gingivitis		Periodontitis	Edentulous
Never^*	^**70/1658	41/990		41/686	66/1090
Never^*	1.0	0.97(0.53,1.77)		1.58(0.92,2.74)	1.47(0.87,2.46)
Former	26/704	28/376		16/350	23/415
Former	1.0	2.32(1.17,4.60)		0.71(0.31,1.63)	0.92(0.39,2.19)
Current	42/949	28/732		21/545	28/535
Current	1.0	1.15(0.56,2.36)		0.80(0.40,1.59)	0.63(0.35,1.14)

Tooth Loss
n=4424 never smokers (218 RA cases); n=1845 former smokers (93 RA cases); n=2,761 current smokers (119 RA cases) P for interaction = 0.73
Subgroup	0–4 Missing Teeth Reference	5–8 Missing Teeth	9–14 Missing Teeth	15–31 Missing Teeth	Edentulous
Never^*	^**33/959	40/903	35/671	44/801	66/1090
Never^*	1.0	1.28(0.69,2.41)	1.56(0.81,3.01)	1.87(0.91,3.86)	1.92(1.00,3.66)
Former	13/380	17/419	24/294	16/337	23/415
Former	1.0	0.95(0.39,2.33)	1.85(0.79,4.33)	1.13(0.37,3.41)	0.92(0.36,2.34)
Current	17/634	23/592	30/485	21/515	28/535
Current	1.0	1.09(0.48,2.49)	1.58(0.68,3.66)	1.05(0.39,2.89)	0.77(0.30,1.99)

p for linear trend among never smokers across tooth loss categories =0.04 and 0.06 across periodontal disease categories;

^**

Number of incident rheumatoid arthritis cases/total number of participants