The Association between Childhood Myopia Prevalence and Environmental Factors in China: A Metaregression Analysis

Table 1

Characteristics of all the studies included in the meta-analysis.

Authors (year of publication)	Myopia prevalence (combined or primary or secondary school ages)	Study location (city)	Age range (years)	Gender distribution (% males)	Sample size	Prevalence of myopia (%)	Annual sunshine hours (total hours)
Yuan et al. (2005) [47]	C, P	Kunming	6–12	NA	10312	36.59	2126
Zhong (2014) [48]	C	Guiyang	6–20	50%	12907	50.55	883
Liu et al. (2003) [49]	C, P	Dongguan	NA	NA	5650	31.88	1716
Zhang et al. (2014) [50]	C, P	Beijing	5–14	52%	4249	36.71	2520
Xie et al. (2013) [51]	C, P, S	Qinghai; Yunnan; Shandong; Wenzhou; Shanghai	NA	55%	19139	31.60^†	2830^†
Guo et al. (2017) [52]	C	Greater Beijing	6–18	51.1%	35745	70.90	2512
Yu et al. (2003) [53]	C, P, S	Shanwei	6–19	NA	1502	54.79	1752
Wei et al. (2014) [54]	C, P	Nanning	6–12	NA	6315	35.70	1277
Tu et al. (2013) [55]	C, P	Shaoxing	6–15	49%	2002	25.72	1893
Luo et al. (2013) [56]	C, P	Baotou	7–12	NA	4276	14.92	2681
Liu et al. (2009) [57]	C, P, S	Shaoyang	NA	48%	1000	58.70	1504.5
Yu et al. (1982) [58]	C, P, S	Fuzhou	NA	54%	1579	39.30	1762
Chen and Liu (2010) [59]	C, P, S	Zibo	NA	52%	156934	51.91	2403
Xiong (2013) [60]	C, P, S	Shiyan	NA	50%	2088	58.64	2003
Wang et al. (2014) [61]	C, P, S	Maanshan	6–15	53%	4062	38.00	1953
Gui et al. (2013) [62]	C, P, S	Wuhu	6–17	50%	94963	43.43	1938
Xin-fu et al. (2015) [63]	C, P	Sanya	6–13	51%	1218	25.12	1888
Si et al. (2006) [64]	C, P	Yongdeng; Tianzhu	NA	53% (Yongdeng) 55% (Tianzhu)	56386	12.69^†	2909^†
Zhao (2007) [65]	C, P, S	Jinan	NA	50%	4737	60.10	2446.8
Zhang (1994) [66]	C, P, S	Zhongwei	NA	50%	4762	25.49	2955
Zhang et al. (2003) [67]	C, P	Otog Banner	NA	50%	10365	19.62	2831.9
Shang et al. (2009) [68]	C, P	Shenyang	7–14	53%	636	28.07	2420
Jia (2005) [69]	C, P	Jinzhou	NA	50%	30510	14.34	2769
Wu (2011) [70]	C, P	Weinan	NA	NA	2683	27.32	2242
Liu et al. (1979) [71]	C, P	Xining	NA	NA	919	12.19	2759.3
Chen et al. (1990) [72]	C, P	Shigatse	6–14	54%	1770	2.99	3142
Cui and Fang (2002) [73]	C, P	Baicheng	8–13	50%	2236	14.22	2923
Liu et al. (2017) [74]	C, P	Tongcheng	6–13	54%	1802	15.59	2452
Yu et al. (2015) [75]	C	Jiading	6–16	51%	6321	29.68	2033
Li and Li (2010) [76]	C	Hami	6–18	56%	3197	25.81	3211
He et al. (2009) [37]	C	Zhongshan	7–18	47%	5622	52.70	1647
Liu et al. (2012) [77]	C, P, S	Chengdu	NA	51%	3162	57.75	1016.2
Bai et al. (2004) [78]	C, P, S	Daqing	NA	50%	13725	36.03	2424
Wei et al. (2007) [79]	C, P, S	Wuhan	6–20	51%	1061	44.67	1861.9
Yin et al. (2013) [80]	C	Karamay	NA	49%	658	26.44	2697
Chen et al. (2007) [81]	C, P, S	Emin	NA	48%	18061	23.08	2993.5
Guo et al. (2016) [82]	C	Guangzhou	NA	52%	3055	47.30	1499
Dong et al. (2007) [83]	C, P, S	Tongliao	7–18	50%	71888	4.89	3083
Aerke et al. (2014) [84]	C	Kashmir; Alkasu	7–18	50%	5737	12.95^†	2904^†
Du (2009) [85]	C, P, S	Baoji	8–19	55%	5489	49.41	2039.1
Gao et al. (2011) [86]	C, P, S	Lianyungang	6.5–20	49%	2480	33.27	2287
Song et al. (2010) [87]	C	Beijing	NA	49%	15316	53.87	2553.6
Wei et al. (2016) [88]	C	Heze	7–18	50%	2400	55.58	2231.7
Wu et al. (2013) [89]	C	Weihai and Guanxian	4–18	53%	6026	36.90	2462
Li et al. (2015) [90]	C, P, S	Shenzhen	6–17	58%	20568	37.01	1857
Qian et al. (2016) [91]	C	Mangshi	5–16	51%	7681	39.10	2029
Chin et al. (2015) [92]	C	Turpan	4–19	43%	632	17.25	2948
Li et al. (2014) [93]	C	Central Heilongjiang	5–18	54%	1675	5.01	2455
Pi et al. (2012) [94]	C	Chongqing	6–15	52%	3079	13.71	988

NA: not available from the study. The second column provides the age group of each study: C represents combined myopia prevalence for both primary and secondary schoolchildren, P represents primary only, and S represents secondary schoolchildren only. Prevalence was calculated based on the number of myopic eyes versus the total number of eyes. ^†Average myopia prevalence and annual sunshine hours from all the study locations.