Near work, outdoor activity, and myopia in children in rural China: the Handan offspring myopia study

BMC Ophthalmology

Table 3 Mean spherical equivalent (diopter)^a as a function of near work activity (tertiles of hours per day)

Near work activity (hours per day)^b	Low (0~4.0) N = 185	Moderate (4.0~5.1) N = 196	High (>5.1) N = 191	P value
Gender
Boys	0.33	0.08	0.06	0.17
Girls	−0.15	−0.19	−0.20	0.96
Refractive Status
Myopia	−1.73	−1.74	−1.80	0.95
No myopia	0.63	0.52	0.53	0.25
Number of myopic parents
None	0.09	−0.04	0.04	0.80
Either	0.30	0.04	0.01	0.17
Both	−0.29	−0.32	−0.46	0.89
Maternal education level
Illiteracy	0.15	0.19	0.12	0.97
Primary school	−0.01	−0.01	0.00	0.99
Junior high school	0.39^c	−0.13	−0.04	0.06
Senior high school and above	−1.30	−0.68	−0.85	0.88
Paternal education level
Illiteracy	0.08	0.27	0.53	0.50
Primary school	0.38^c	−0.11	−0.15	0.01
Junior high school	−0.06	−0.05	0.04	0.78
Senior high school and above	0.11	−0.01	−0.61	0.50
Total	0.10	−0.04	−0.06	0.35

^aAdjusted for children’s age, gender, average parental refractive error, maternal and paternal education level, and outdoor activity time as fixed effects, and family effect as a random effect
^bIncludes drawing, homework, reading, and handheld computer use. Cut-off points were based on population tertiles for average daily hours spent at near
^cSignificant (Bonferroni test) compared with the highest tertile of activity as the reference group

ISSN: 1471-2415