Table 2.

Vision impairment prevalence in middle-aged and elderly Chinese according to sleep durations (CHARLS 2011–2012).

		Sleep duration groups (h/night)			P
	Overall	≤6 h	6–8 h	>8 h
All	n = 13,959	n = 6,970	n = 5,784	n = 1,205
Vision impairment, n (%)	4,776 (35.83)	2,718 (40.78)	1,646 (26.10)	412 (35.33)	<0.001
Age
≥45 and ≤ 58 years	n = 7,239	n = 3,315	n = 3,320	n = 604
Vision impairment, n (%)	2,101 (31.08)	1,125 (35.78)	813 (23.60)	163 (25.80)	<0.001
>58 years	n = 6,720	n = 3,655	n = 2,464	n = 601
Vision impairment, n (%)	2,675 (40.98)	1,593 (42.97)	833 (31.68)	249 (40.19)	<0.001
Sex
Male	n = 6,384	n = 3,172	n = 2,849	n = 553
Vision impairment, n (%)	1,980 (32.89)	1,097 (35.61)	721 (26.88)	162 (30.82)	<0.001
Female	n = 7,385	n = 3798	n = 2,935	n = 652
Vision impairment, n (%)	2,796 (38.47)	1,621 (45.84)	925 (30.26)	250 (39.65)	<0.001