Relationship Between Early-Life Factors and Self-Reported Age at Myopia Onset: A Study Based on a Sample of Chinese Adults.

Aim: To investigate the influence of early-life factors (Season of birth, premature birth and breastfeeding) on the age at myopia onset.

Methods: A total of 331 myopic students aged 18 years or above were recruited from one medical university in Wenzhou, China. Questionnaires were administered to collect data on age at myopia onset, early-life factors, and vision hygiene habits. Participants underwent noncycloplegic autorefraction. Generalized Linear Model was used to analyse the influencing factors of the age at myopia onset, early life factors as independent variables, spherical equivalent, parental myopia and eye hygiene habits as confounding factors into the generalized linear model.

Results: In this study, the mean spherical equivalent (SE) of myopic university students was -4.55±2.19 D, and the mean age at myopia onset was 13.31±2.64 years old. Subjects born in the summer had a younger age at myopia onset (β=-1.79, P=0.001); subjects born prematurely tended to have a younger age at myopia onset (β=-1.50, P=0.011); and breastfeeding was not statistically associated with the age at myopia onset.

Conclusion: Season of birth and premature birth were associated with age at myopia onset, and children born in the summer and born prematurely had a younger age at myopia onset.