Periodontitis combined with smoking increases risk of the ulcerative colitis: A national cohort study

Table 1 Baseline characteristics of the study population

	Periodontitis	Non-periodontitis	P value
Patients, n	1092825	8857723
Age, yr (mean ± SD)	51.4 ± 12.9	46.6 ± 14.2	< 0.01
Age, 3 groups (%)			< 0.01
20-39	188805 (17.2)	2929998 (33.1)
40-64	719197 (65.8)	4810132 (54.3)
≥ 65	184823 (16.9)	1117593 (12.6)
Male (%)	604307 (55.3)	4844383 (54.7)
BMI, kg/m2 (mean ± SD)	23.9 ± 3.1	23.7 ± 3.2	< 0.01
Waist circumference, cm (mean ± SD)	81.2 ± 8.8	80.1 ± 9.1	< 0.01
Cigarette smoking (%)			< 0.01
Nonsmoker	644790 (59.0)	5276142 (59.6)
Ex-smoker	188825 (17.3)	1238268 (14.0)
Current smoker	259210 (23.7)	2343313 (26.4)
Drinking (%)			< 0.01
Non	597901 (54.7)	4528675 (51.1)
Mild	423429 (38.8)	3718,835 (42.0)
Heavy	71495 (6.5)	610213 (6.9)
Exercise; yes (%)	572684 (52.4)	4544197 (51.3)	< 0.01
Income; low (less than 20% of total population) (%)	274356 (25.1)	2347661 (26.5)	< 0.01
Underlying illness			< 0.01
Hypertension (%)	338855 (31.0)	2220906 (17.8)
Systolic BP, mmHg (mean ± SD)	123.1 ± 15.0	122.3 ± 14.9
Diastolic BP, mmHg (mean ± SD)	76.6 ± 10.0	76.3 ± 10.0
Dyslipidemia (%)	244342 (22.4)	1574251 (17.8)
Diabetes (%)	131663 (12.1)	734481 (8.3)
Initial laboratory findings
Glucose, mg/dL (mean ± SD)	99.6 ± 25.3	96.8 ± 22.6	< 0.01
Total cholesterol, mg/dL (mean ± SD)	196.8 ± 37.0	191.7 ± 35.4	< 0.01
GGT, IU/L (median and 95%CI)	28.5 (28.4–28.6)	27.4 (27.4–27.42)	< 0.01
Triglycerides, mg/dL (median and 95%CI)	117.9 (117.7–117.9)	113.2 (113.1–113.2)	< 0.01

SD: Standard deviation; BMI: Body mass index; BP: Blood pressure; GGT: Gamma glutamyltransferase; CI: Confidence interval.

Table 2 The incidence and risk for inflammatory bowel disease in patients with periodontitis

		UC			CD
	n	UC	IR	aHR (95%CI)	CD	IR	aHR (95%CI)
Periodontitis
No	8857723	5224	7.1433	1 (ref.)	1300	1.7773	1 (ref.)
Yes	1092825	692	7.6730	1.091 (1.008-1.182)	126	1.3968	0.879 (0.731-1.057)

The incidence rate is represented by incident cases of ulcerative colitis or Crohn’s disease per 100000 person-years. The hazard ratio was adjusted for age, sex, body mass index, smoking, alcohol drinking, exercise, and income. UC: Ulcerative colitis; CD: Crohn’s disease; IR: Incidence rate; aHR: Adjusted hazard ratio; CI: Confidence intervals.