For example, increasing IL-6 levels are associated with decreasing IGF-1 levels during the first months after preterm birth, and infants treated for ROP have continuously higher postnatal levels of IL-6 than infants with no history of ROP, indicating a negative correlation between IGF-1 and pro-inflammatory cytokines among preterm infants, regardless of ROP62. Here, IL6 is linked to retinopathy of prematurity.