Table 2. Prevalence of kidney stones in mainland China and subgroup analysis.

Variable	Kidney stone
	Number of surveys	Sample size	Cases	Prevalence (%)	95% CI	I2
Overall		18	115087	7032	7.54	5.94 to 9.15	99.4
Year	1991–2000	2	15024	895	5.95	3.89 to 8.00	96.6
	2001–2010	4	25924	1575	8.86	4.95 to 12.78	99.2
	2011-now	6	30248	2593	10.63	8.11 to 13.14	97.5
	NA	6	43891	1969	4.46	1.86 to 7.06	99.4
Age	<20	6	1444	14	0.27	−0.13 to 0.67	59.5
	20~	8	6855	249	3.15	1.44 to 4.87	96.9
	30~	8	8902	453	5.96	3.79 to 8.13	95.2
	40~	8	8216	511	8.18	5.22 to 11.14	96.5
	50~	8	8641	626	9.14	6.16 to 12.13	95.1
	>60	8	8623	696	9.68	6.73 to 12.63	94.8
gender	male	14	49080	3672	10.34	7.96 to 12.72	99.1
	female	14	52294	2478	6.62	5.12 to 8.12	98.7
Province	Beijing	1	818	25	3.10	1.91 to 4.29	NA
	Guangdong	6	40660	2830	7.70	6.25 to 9.15	95.7
	Guangxi	3	19691	1770	9.48	7.53 to 11.43	95.4
	Sichuan	2	7754	674	13.69	0.66 to 26.72	99.0
	Shanghai	2	15119	452	2.73	1.75 to 3.71	89.1
	Zhejiang	1	5915	578	9.80	9.04 to 10.56	NA
	Xinjiang	1	5892	440	7.50	6.83 to 8.17	NA
	Hebei	2	19341	263	1.36	1.16 to 1.56	10.1
Location	Urban	4	18934	1082	6.03	3.39 to 8.68	98.5
	Rural	4	15748	1106	7.48	3.39 to 11.57	99.1
Infection history	yes	3	716	155	31.99	11.35 to 52.62	94.1
	no	3	9614	1032	12.52	9.03 to 16.02	95.9
Educational level	elemantary and below	4	9622	920	9.84	7.40 to 12.29	94.2
	junior high	4	7686	589	8.12	4.76 to 11.48	97.0
	senior high	4	4692	241	7.11	3.92 to 10.31	95.3
	college and above	4	2250	135	7.91	3.31 to 12.51	94.9
Risk of bias	≥9	11	91141	5267	6.19	4.19 to 8.20	99.5
	<9	5	23946	1765	10.11	7.14 to 13.09	98.8