Several epidemiological studies have investigated the associations of methylenetetrahydrofolate reductase ( MTHFR ) C677T and A1298C polymorphisms with hypertension ( H ) or hypertension in pregnancy ( HIP ). However, the results were controversial.
A comprehensive meta-analysis to provide empirical evidences on the associations was performed.
The English and Chinese databases were systematically searched to identify relevant studies.
A total of 114 studies with 15411 cases and 21970 controls were included, 111 studies with 15094 cases and 21633 controls for the C677T polymorphism and 21 with 2533 cases and 2976 controls for the A1298C polymorphism. Overall, the C677T polymorphism was significantly associated with hypertension and hypertension in pregnancy ( H & HIP: OR = 1.26; H: OR = 1.36; HIP: OR = 1.21 ).
Stratified analysis by ethnicity revealed a significant association among East Asians and Caucasians, but not among Latinos, Black Africans, and Indians and Sri Lankans.
In the stratified analyses according to source of controls, genotyping method, sample size and study quality, significant associations were observed in all the subgroups, with the exception of population based subgroup in hypertension studies and large sample size and others genotyping method subgroups in hypertension in pregnancy studies.
For the A1298C polymorphism, no significant association was observed either in overall or subgroup analysis under all genetic models.
In conclusion, this meta-analysis suggests that the MTHFR C677T rather than A1298C polymorphism may be associated with hypertension and hypertension in pregnancy, especially among East Asians and Caucasians. ( Xagena )
Yang B et al, PLoS One 2014; 9: e87497. doi: 10.1371/journal.pone.0087497. eCollection 2014