Looking for Causes of Neural Tube Defects: Where Does the Environment Fit in?

Abstract

The neural tube defects anencephaly and spina bifida are important causes of infant mortality and morbidity. Recent studies suggest that many of these defects can be prevented by the periconceptional use of folic acid. At the same time, we do not know what causes most cases of neural tube defects and there is evidence to suggest that they are etiologically heterogeneous. Additional research needs to be directed toward the role of occupational and environmental exposures in the etiology of these defects. Importantly, studies need to examine embryologically and anatomically specific types of defects and develop accurate information on biologically relevant exposures. Exposures toward which attention needs to be directed include organic solvents; agricultural chemicals, including pesticides; water nitrates; heavy metals such as mercury; ionizing radiation; and water disinfection by products. We also recommend that additional attention be paid to mechanisms of neural tube closure and to the potential role of genetic heterogeneity in the absorption and metabolism of xenobiotics and in their effects on the neural tube. -Environ Health Perspect 103(Suppl 6): 165-171 (1995)

Maternal caffeine consumption and risk of neural tube defects

“…The inconsistent effects across NTD types were consistent with differences in etiologies across types as suggested by varied epidemiologic risk factors and developmental processes (Khoury et al, 1982;Sever, 1995). However, it is also possible the differences observed could have resulted from differential bias among NTD types.…”

Trends in the postfortification prevalence of spina bifida and anencephaly in the United States

“…The same pattern was evident in the states that included prenatally ascertained cases and for the majority of the individual states. This may lend support to the concept that anencephaly and spina bifida do not necessarily share the same risk factors and may therefore be etiologically heterogeneous (Khoury et al, 1982;Sever, 1995). Further research is needed to determine potential causes of this trend.…”

Pesticide consumption, central nervous system and cardiovascular congenital malformations in the South and Southeast region of Brazil

“…and risk of CNS, CVS and other birth defects is limited [11,13]. Overall, further individual-level epidemiological studies are needed examining this relationship.…”

“…Despite the importance of these malformations, the causes of most cases of CVS and CNS malformations are not known. Etiologic factors that have been identified include genetics, maternal illnesses, dietary factors, maternal drug exposures, and maternal and paternal environmental exposures [11][12][13]. It is well known that the fetus is extremely sensitive to environmental exposures during certain critical windows IJOMEH 2014;27(3) 476 …”