Table 2.

Univariate Distribution of Baseline Study Variables (N = 18,798 teeth)

Variable		Level	Frequency	Percent (%)
Outcome
Tooth loss		Yes	2589	13.8
		No	16,209	86.2
Endodontic involvement
RCT status		Yes	293	1.6
		No	18,505	98.4
AR status		≥ 4 mm	73	0.4
		1 – 3 mm	64	0.3
		No	18,661	99.3
Tooth-level covariates
Crown		Yes	759	4.0
		No	18,039	96.0
Tooth Type		Molar	5,070	27.0
		Premolar	5,053	26.9
		Anterior	8,675	46.2
No. of proximal contacts		0	939	5.0
		1	4,798	25.5
		2	13,061	69.5
Coronal caries*		Yes	3,547	18.9
		No	14,271	75.9
Periodontal status*	Alveolar bone loss	≥ 20%	2,203	11.7
		< 20%	6,454	34.3
		None	9,827	52.3
	Gingival bleeding	Yes	11,572	61.6
		No	7,032	37.4
	Mobility	Yes	1,994	10.6
		No	16,610	88.4
	Plaque score	All surfaces with 2/3 of tooth	2,350	12.5
		Interproximal with continuation  on buccal or lingual surface	8,008	42.6
		Interproximal only	5,811	30.9
		None	2,435	13.0
	Probing pocket depth	> 3mm	3,008	16.0
		≤ 3mm	15,596	83.0
Person-level covariates
Oral hygiene behaviors*	Frequency of brushing	≥ 2 times per day	8,049	42.8
		< 2 times per day	10,701	56.9
	Use floss	Yes	6,923	36.8
		No	11,850	63.0
	Any perio treatment	Yes	1,624	8.6
		No	17,149	91.2
	Any cleaning	Yes	15,891	84.5
		No	2,882	15.3
No. of teeth at baseline		≤ 17	890	4.7
		18-25	7,423	39.5
		26-32	10,485	55.8
Age at baseline (years old)		≥ 65	537	2.9
		55 -< 65	3,170	16.9
		< 55	15,091	80.3
Income*		> $25,000	6,716	35.7
		≤ $25,000	11,738	62.4
Education		High school or less	5,577	29.7
		Some college	6,961	37.0
		College graduate	6,260	33.3
Race		African-American	441	2.4
		White	18,357	97.7
Body mass index*		≥ 30 kg/m2	1,692	9.0
		25 -< 30 kg/m2	10,137	53.9
		< 25 kg/m2	6,941	36.9
Smoking history		Current smoker	7,822	41.6
		Former smoker	5,945	31.6
		Never smoker	5,031	26.8
Diabetes		Yes	562	3.0
		No	18,236	97.0
Hypertension		Yes	2,779	14.8
		No	16,019	85.2

^*N does not add up to 18,798 because of missing values.