Breastfeeding and myopia: A cross-sectional study of children aged 6-12 years in Tianjin, China

This study aimed to determine whether an association existed between breastfeeding and myopia in children aged 6-12 years in Tianjin, China, using a cross-sectional study of 527 children. The spherical equivalent refraction (SER) and axial length (AL) were determined by ocular examination, and information regarding the children's demographics, breastfeeding history and other myopia-related risk factors were investigated using a questionnaire. The myopia prevalence rate, mean SER, and mean AL were 53.9%, -0.99 +/- 1.69 D, and 23.56 +/- 1.11 mm, respectively. In total, 442 (83.9%) participants were breastfed; among the breastfed participants, 132 (29.9%) were breastfed <6 months. Children who were breastfed were less likely to have myopia (breastfeeding duration <6 months: OR = 0.399, P = 0.011; >6 months: OR = 0.502, P = 0.033, multiple logistical regression). The mean SER of children breastfed <6 months was 0.653 D more hyperopic than that of non-breastfed children (P = 0.008, multiple linear regression). No significant association was observed between breastfeeding and AL. In conclusion, breastfeeding was associated with a decreased risk of myopia among children aged 6-12 years in Tianjin. Breastfeeding during the first 6 months of infancy was associated with more hyperopic SER. Furthermore, breastfeeding was associated with myopic refraction and was not related to AL, and this association could exist in childhood.