Table 3. Subgroup analysis of the association between number of natural teeth and depressive symptom scores among Chinese older adults — China, 2014–2018.

Subgroup	Number of natural teeth (95% CI)				Pfor interaction
	0	1–9	10–19	20+
Note: Coefficients were based on linear regression model 4. Effect modification by age (Pfor interaction <0.001), gender ( Pforinteraction =0.021), and denture use (Pfor interaction <0.001). Abbreviation: CI=confidence interval. * P≤0.05. ** P≤0.01. *** P≤0.001.
Age					<0.001
65–79 years	0.48 (0.17, 0.79)**	0.31 (0.05, 0.58)*	0.55 (0.32, 0.78)***	Reference
≥80 years	0.16 (−0.11, 0.44)	0.54 (0.28, 0.80)***	0.49 (0.20, 0.77)**	Reference
Gender					0.021
Women	0.14 (−0.14, 0.42)	0.42 (0.15, 0.68)***	0.53 (0.26, 0.80)***	Reference
Men	0.29 (0.02, 0.55)*	0.51 (0.28, 0.75)***	0.42 (0.18, 0.66)***	Reference
Ethnicity					0.548
Han	0.28 (0.01, 0.41)*	0.58 (0.30, 0.67)***	0.57 (0.29, 0.66)***	Reference
Minorities	0.59 (−0.16, 1.19)	0.62 (−0.21−0.95)*	0.97 (0.12, 1.29)**	Reference
Smoking					0.107
Never smoke	0.19 (−0.21, 0.58)	0.78 (0.34, 1.21)***	0.47 (0.24, 0.70)***	Reference
All the time	0.18 (−0.21, 056)	0.78 (0.35, 1.21)***	0.48 (0.26, 0.71)***	Reference
Stop smoking	0.35 (−0.06, 0.76)	0.36 (−0.11, 0.83)	0.18 (−0.07, 0.43)	Reference
Drinking					0.309
Never drink	0.39 (−0.02, 0.80)	0.90 (0.42, 1.39)**	0.44 (0.22, 0.67)***	Reference
All the time	0.19 (−0.22, 0.60)	0.64 (0.18, 1.10)**	0.53 (0.31, 0.75)***	Reference
Stop drinking	0.29 (−0.16, 0.75)	0.24 (−0.29, 0.76)	0.23 (−0.01, 0.47)*	Reference
Denture use					<0.001
Yes	0.60 (−0.15, 0.65)**	0.71 (0.21, 0.95)	0.48 (0.07, 0.77)	Reference
No	0.11 (0.35, 0.75)***	0.51 (0.24, 0.65)***	0.56 (−0.15, 0.33)*	Reference