Levels of PAH–DNA adducts in placental tissue and the risk of fetal neural tube defects in a Chinese population

We examined the relationship between PAH–DNA adduct levels in the placental tissue, measured by a highly sensitive 32P-postlabeling assay, and the risk of fetal neural tube defects (NTDs). We further explored the interaction between PAH–DNA adducts and placental PAHs with respect to NTD risk. Placental tissues from 80 NTD-affected pregnancies and 50 uncomplicated normal pregnancies were included in this case-control study. Levels of PAH–DNA adducts were lower in the NTD group (8.12 per 108 nucleotides) compared to controls (9.92 per 108 nucleotides). PAH–DNA adduct concentrations below the median was associated with a 3-fold increased NTD risk. Women with a low PAH–DNA adduct level in concert with a high placental PAH level resulted in a 10-fold elevated risk of having an NTD-complicated pregnancy. A low level of placental PAH–DNA adducts was associated with an increased risk of NTDs; this risk increased dramatically when a low adduct level was coupled with a high placental PAH concentration.

► A low placental level of PAH–DNA adducts was associated with an increased risk of NTDs.
► Women with a low PAH–DNA adduct level but a high placental PAH level had an elevated risk of an NTD-affected pregnancy.
► PAHs may exert their teratogenic effect through mechanisms other than DNA damage induced by the formation of adducts.