Table 1

Frequencies of MTHFR genotypes in NTD cases and controls during 1988-1998

1988–mid 1994Mid 1994-1998
GenotypesAla/Ala (male/female)Ala/Val (male/female)Val/Val (male/female)Ala/Ala (male/female)Ala/Val (male/female)Val/Val (male/female)
*Number of subjects/number in all three genotypes combined in each period (%).
†The difference in genotype frequencies between the two periods was significant (p=0.02).
‡Information on the gender of fetuses was not available for all subjects.
§The difference in male/female ratios between the two periods was significant (p<0.0025).
¶The difference in male/female ratios between the two periods was significant (p<0.003).
NTD cases15/37 (41)*19/37 (51)†3/37 (8)25/40 (63)10/40 (25)†5/40 (13)
(10/5)§(7/11)‡¶(1/2)(11/13)§(5/1)¶(3/2)
Controls31/35 (89)4/35 (11)0/35 (0)33/42 (79)7/42 (17)2/42 (5)
(16/15)(2/2)(0/0)(12/17)(3/3)(0/2)
Risk ratios (95% CI)1.09.8 (2.8-34.0)12.4 (0.58-263.6)1.01.9 (0.63-5.7)0.30 (0.05-1.7)