Table 2.

Results of multiple regression analyses to estimate the association between myopia and environmental factors.

	Axial length, mm (N = 53)			Cycloplegic objective refraction, diopter (N = 24)
	β	95% CI	P	β	95% CI	P
Overall
Fluorescein TBUT (seconds)	− 0.067	− 0.110 to − 0.023	0.004	0.149	− 0.195 to 0.492	0.41
Age (years)	0.065	0.012 to 0.118	0.02	0.227	− 0.308 to 0.762	0.42
Gender	− 0.102	− 0.381 to 0.178	0.48	0.658	− 1.75 to 3.07	0.60
Number of myopic parents
None	NA	NA	NA	NA	NA	NA
One	0.242	− 0.238 to 0.723	0.33	− 1.14	− 3.81 to 1.53	0.43
Both	0.497	0.033 to 0.960	0.04	− 4.10	− 8.590 to 0.385	0.10
Outdoor activity time (min/day)	− 0.027	− 0.034 to − 0.021	< 0.001	0.012	− 0.047 to 0.072	0.69
Sleeping time (min/day)	0.002	− 0.0002 to 0.004	0.08	0.010	− 0.007 to 0.028	0.26
Near work time (min/day)	0.001	− 0.001 to 0.003	0.33	− 0.009	− 0.021 to 0.003	0.15
Reading distance (cm)	− 0.011	− 0.033 to 0.011	0.36	− 0.069	− 0.222 to 0.085	0.40
R2		0.831			0.508

Two multiple regression models were used. Axial length or cycloplegic objective refraction was used as the outcome variable. P values less than statistically significant level (< 0.05) are marked in bold. For gender, boys were numbered 1 and girls were numbered 0. β coefficient, 95% CI 95% confidence interval, TBUT tear film breakup time, NA not applicable.