Notably, 7–12 months of breastfeeding increased the risk for severer ptosis by 4-fold (for the LH scale, OR = 4.136, 95% CI 1.579–10.838, P = 0.004; for the RP scale, OR = 4.010, 95% CI 1.667–9.642, P = 0.002), whereas ≥13 months of breastfeeding was associated with a 6-fold increase in the risk of ptosis (for the LH scale, OR = 6.934, 95% CI 2.643–18.194, P<0.001; for the RP scale, OR = 6.707, 95% CI 2.775–16.208, P<0.001) compared with no breastfeeding. This evidence concerns the gene PLOD1 and ptosis.