Table 2. Pooled detection rates of periodontal disease among elderly population in mainland China during 1985–2015.

	BOP(+)				PD ≥ 4 mm				CAL ≥ 4 mm
	Number of surveys	Sample size	cases	Prevalence (%) [95% CI]	Number of surveys	sample size	cases	Prevalence (%) [95% CI]	Number of surveys	sample size	cases	Prevalence (%) [95% CI]
Overall	14	54,129	22,817	53.9[43.8–63.9]	16	32,876	17,492	57.0[50.8–63.2]	7	29,281	20,490	70.1[65.4–74.8]
Location
Urban	10	30,201	11,801	52.4[42.8–62.0]	12	16,197	9,308	57.4[51.0–63.8]	6	15,433	10,604	69.8[64.5–75.1]
Rural	7	21,094	10,383	54.1[43.1–65.0]	7	13,865	7,324	53.2[46.4–60.0]	6	13,838	9,886	71.4[66.7–76.1]
Gender
Male	10	25,536	11,031	55.1[44.8–65.5]	8	13,481	7,875	59.3[53.4–65.2]	6	13,995	10,270	73.8[70.0–77.7]
Female	10	25,316	10,972	55.6[45.0–66.2]	8	13,265	6,633	50.8[43.5–58.0]	6	13,990	9,018	65.2[60.2–70.2]
Time periods
≤1990	2	473	193	40.8 [36.4–45.2]	2	473	318	72.0[45.6–98.5]	0	NA	NA	NA
1991–2000	2	24,116	3,705	10.1[9.8–10.5]	2	1,950	775	38.0[27.1–49.0]	1	1,286	1,202	93.5[92.1–94.8]
2001–2010	8	27,892	17,625	64.6[56.6–72.5]	8	27,892	14,507	54.7[49.1–60.3]	3	24,757	17,661	71.4[67.3–75.5]
≥2011	2	1,648	1,294	83.5[53.1–113.8]	4	2,561	1,892	80.4[60.9–100.0]	3	3,238	1,627	49.2[41.1–57.3]

BOP: bleeding on probing; PD: pocket depth; CAL: clinical attachment loss; CI: confidence interval; NA: not available.