In preterm cohort A, a majority of TLR4-299 heterozygous genotypes were observed in infants with moderate or severe BPD (60%; [95%CI: 41% to 85%]) compared to infants without BPD (i.e. defined as no oxygen at 28 days or 36 weeks; 5%; [95%CI: 0.01% to 25%]). Here, TLR4 is linked to bronchopulmonary dysplasia.