Maternal serum homocysteine and risk for neural tube defects in a Texas-Mexico border population.
BACKGROUND
To better understand the neural tube defect (NTD) causal pathway, the authors measured homocysteine, an indicator of tissue micronutrient deficiencies. The authors examined independent and joint associations of serum homocysteine, B12, and folate and red blood cell (RBC) folate with NTD-affected pregnancies.


METHODS
Case women in this population-based study had NTD-affected pregnancies and resided and delivered in one of the 14 Texas-Mexico border counties from 1995 through 2000. Control women were study area residents delivering normal live births during the same period. The authors measured homocysteine levels using tandem mass spectroscopy; competitive binding was used for other biomarkers.


RESULTS
Homocysteine testing was done on 103 cases and 139 controls. Odds ratios (ORs) were increased in all upper homocysteine quintiles compared to the lowest quintile (1.7, 1.3, 2.8, 2.4). Women with high homocysteine values had increased ORs regardless of high versus low levels for B12 (OR = 3.5, 4.8, respectively) or RBC folate (OR = 2.9, 3.5, respectively).


CONCLUSIONS
High serum homocysteine levels are associated with NTD-affected pregnancies. Moreover, high homocysteine levels have a detrimental effect on NTD-risk even when serum B12 or RBC folate levels are high. Excess homocysteine might play an independent role in the development of NTDs.
Felkner
Marilyn
M
Texas Department of State Health Services, Austin, Texas. Marilyn.felkner@dshs.state.tx.us
Suarez
Lucina
L
Canfield
Mark A
MA
Brender
Jean D
JD
Sun
Qin
Q
D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D005492:Folic Acid / Q000378:metabolism; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008800:Mexico; D009436:Neural Tube Defects / Q000097:blood*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood*; D012189:Retrospective Studies; D012307:Risk Factors; D013781:Texas; D014805:Vitamin B 12 / Q000097:blood
D006710:Homocysteine; D005492:Folic Acid; D014805:Vitamin B 12