Correlation of Myopia with Physical Exercise and Sleep Habits among Suburban Adolescents

Table 1

Demographic characteristics of the study population and the factors of the myopia and nonmyopia groups during the semester and holidays.

	Nonmyopia	Myopia	χ^2	(chi-square test)	(logistic regression analysis)	OR	95% CI
	(N = 585)	(N = 1246)					Lower	Upper
Gender, male, N (%)	361 (61.71)	623 (50.00)	21.956	<0.001	0.002	0.693	0.549	0.876
Parental myopia
Father, N (%)	104 (17.78)	487 (39.09)	82.682	<0.001	<0.001	2.463	1.900	3.193
Mother, N (%)	118 (20.17)	578 (46.39)	112.490	<0.001	<0.001	2.853	2.232	3.646
Age (mean ± SD, years)	14.53 ± 1.66	15.10 ± 1.21	53.030	<0.001
Junior group (11–14 years), N (%)	227 (38.80)	280 (22.47)
Senior group (15–18 years), N (%)	358 (61.20)	966 (77.53)			<0.001	2.216	1.720	2.855
During the semester
Average number of days per week participating in outdoor activities, N (%)			6.864	0.009
≤2 days	271 (46.32)	659 (52.89)
3–7 days	314 (53.68)	587 (47.11)			0.033	0.764	0.597	0.978
Average number of hours spent on each outdoor activity session, N (%)			16.150	<0.001
<Half an hour	149 (25.47)	328 (26.32)			0.139
≥Half an hour and < one hour	253 (43.25)	634 (50.88)			0.198	1.212	0.904	1.624
≥One hour	183 (31.28)	284 (22.80)			0.753	0.946	0.671	1.334
Average number of hours per week of outdoor activities, N (%)			0.016	0.900
<3 hours	315 (53.85)	667 (53.53)
≥3 hours	270 (46.15)	579 (46.47)			0.046	1.320	1.006	1.732
Average number of hours per week of indoor activities, N (%)			1.468	0.226
<3 hours	464 (79.32)	1018 (81.70)
≥3 hours	121 (20.68)	228 (18.30)			0.925	0.985	0.713	1.359
Mid-day nap, N (%)			2.440	0.118
Yes	142 (24.27)	262 (21.03)			0.068	0.781	0.598	1.019
No	443 (75.73)	984 (78.97)
Average number of hours per night of sleep, N (%)			22.093	<0.001
<6 hours	98 (16.75)	218 (17.50)			0.260
≥6 hours and <8 hours	371 (63.42)	883 (70.87)			0.188	1.249	0.897	1.739
≥8 hours	116 (19.83)	145 (11.63)			0.879	1.035	0.666	1.608
Average night bedtime, N (%)			20.636	<0.001
Before 10 pm (excluding 10 pm)	220 (37.61)	338 (27.13)			0.775
10 pm-11 pm (excluding 11 pm)	244 (41.71)	607 (48.71)			0.996	1.001	0.756	1.326
After 11 pm (including 11 pm)	121 (20.68)	301 (24.16)			0.554	1.118	0.773	1.617
Average daily wake time, N (%)			13.738	<0.001
Before 6 am (excluding 6 am)	229 (39.15)	603 (48.39)
After 6 am (including 6 am)	356 (60.85)	643 (51.61)			0.037	0.782	0.621	0.985
During holidays
Average number of days per week participating in outdoor activities, N (%)			0.007	0.933
≤2 days	381 (65.13)	809 (64.93)
3–7 days	204 (34.87)	437 (35.07)			0.136	1.214	0.941	1.566
Average number of hours spent on each outdoor activity session, N (%)			24.048	<0.001
<Half an hour	128 (21.88)	277 (22.23)			0.035
≥Half an hour and < one hour	144 (24.62)	373 (29.94)			0.742	1.056	0.762	1.464
≥One hour and <2 hours	144 (24.62)	359 (28.81)			0.507	1.129	0.789	1.615
≥2 hours	169 (28.88)	237 (19.02)			0.096	0.719	0.487	1.061
Average number of hours per week of outdoor activities, N (%)			0.760	0.383
<3 hours	268 (45.81)	598 (47.99)
≥3 hours	317 (54.19)	648 (52.01)			0.521	0.909	0.680	1.216
Average number of hours per week of indoor activities, N (%)			0.255	0.614
<3 hours	414 (70.77)	896 (71.91)
≥3 hours	171 (29.23)	350 (28.09)			0.469	1.114	0.832	1.492
Mid-day nap, N (%)			1.938	0.164
Yes	168 (28.72)	398 (31.94)			0.063	1.259	0.987	1.605
No	417 (71.28)	848 (68.06)
Average number of hours per night of sleep, N (%)			4.579	0.205
<6 hours	46 (7.86)	83 (6.66)			0.892
≥6 hours and <8 hours	169 (28.90)	415 (33.31)			0.873	1.039	0.650	1.661
≥8 hours and <10 hours	281 (48.03)	584 (46.87)			0.740	1.081	0.682	1.715
≥10 hours	89 (15.21)	164 (13.16)			0.503	1.198	0.705	2.035
Average night bedtime, N (%)			42.891	<0.001
Before 10 pm (excluding 10 pm)	155 (26.50)	188 (15.09)			0.002
10 pm-11 pm (excluding 11 pm)	172 (29.40)	422 (33.87)			0.012	1.516	1.095	2.100
11 pm-12 am (excluding 12 am)	150 (25.64)	438 (35.15)			<0.001	1.966	1.383	2.795
After 12 am (including 12 am)	108 (18.46)	198 (15.89)			0.071	1.479	0.967	2.263
Average daily wake time, N (%)			11.160	0.025
Before 7 am (excluding 7 am)	100 (17.09)	168 (13.49)			0.165
7 am-8 am (excluding 8 am)	121 (20.68)	316 (25.36)			0.059	1.423	0.986	2.053
8 am-9 am (excluding 9 am)	142 (24.27)	320 (25.68)			0.555	1.120	0.770	1.629
9 am-10 am (excluding 10 am)	107 (18.30)	244 (19.58)			0.225	1.284	0.857	1.925
After 10 am (including 10 am)	115 (19.66)	198 (15.89)			0.819	0.950	0.615	1.469

Statistical significance ().