Association between Predictors of Vitamin D Serum Levels and Risk of Retinoblastoma in Children: A Case-Control Study

Background: vitamin D (VD) may be a protective factor for retinoblastoma, though no temporal association has been reported during pregnancy or the child's first year of life. Serum VD concentrations are determined by both distal (DF) and proximal factors (PF). Objective: To identify if DF and PF can predict VD insufficiency (VDI) and VD deficiency (VDD) in women of childbearing age; and to test whether maternal exposure to DF and PF during pregnancy and a child's exposure during the first 11.9 months postpartum are associated with sporadic retinoblastoma (SRb) in children. Methods: This is a secondary analysis of data from the Epidemiology of SRb in Mexico (EpiRbMx) study and the National Health and Nutrition Survey 2018-2019 (ENSANUT 2018-2019, for its acronym in Spanish). The association of DF and PF with VDD or VDI was estimated using ENSANUT 2018-2019, and the association of DF and PF with SRb using EpiRbMx. All were estimated using logistic regression, with comparable samples selected from ENSANUT 2018-2019 and EpiRbMx. Results: Altitude, latitude and obesity predicted VDI and VDD in ENSANUT women. In EpiRbMx, residence in a rural location during pregnancy increased the risk of SRb. For children, rural residence and latitude increased the risk of SRb, while the number of days exposed to the spring-summer season during months 6 to 11.9 of life was protective. Conclusions: risk of VDI and VDD in women (ENSANUT 2018-2019) increased with altitude, urban dwelling, overweight and obesity. The child and mother's place of residence, including altitude, latitude and rural classification were important predictors of SRb in EpiRbMx.