Table 3. Hazard ratios.

Follow-up duration (years)	Chronic periodontitis		Control		HR†	95% CI
	No. of event	ID	No. of event	ID		Lower	Upper
<7 yrs	649	5.5	347	2.9	1.87**	1.64	2.13
7–10 yrs	163	0.9	102	0.5	1.66**	1.30	2.13
≧10 yrs	57	0.2	34	0.1	1.65*	1.08	2.53

Notes:

Hazard ratios of primary Sjögren’s syndrome stratified by follow-up duration.

ID: Incidence density, per 1,000 person-years.

^†Adjusted for age, gender, monthly income, urbanization, hypertension, hyperlipidemia, chronic insomnia, and Charlson comorbidity index.

^*p < 0.05.

^**p < 0.01.