ADELAIDE, Australia—Women who supplement with folic acid late in pregnancy may increase the chances of their children developing asthma, says a study in American Journal of Epidemiology (2009 170(12):1486-1493; doi:10.1093/aje/kwp315).
Using data from an Australian prospective birth cohort study (n = 557) from 1998 to 2005, researchers examined 490 children, aged 3.5 years and 5.5 years, and 423 mothers. Maternal folate intake from diet and supplements was assessed by food frequency questionnaire in early (<16 weeks) and late (30 to 34 weeks) pregnancy.
Asthma was reported in 11.6 percent of children at 3.5 years (n = 57) and in 11.8 percent of children at 5.5 years (n = 50). Folic acid taken in supplement form in late pregnancy was associated with an increased risk of childhood asthma at 3.5 years (relative risk (RR) = 1.26, 95 percent confidence interval (CI): 1.08, 1.43) and with persistent asthma (RR = 1.32, 95 percent CI: 1.03, 1.69). The association was similar at 5.5 years, but did not reach statistical significance (RR = 1.17, 95 percent CI: 0.96, 1.42).
These findings on childhood asthma support previous observations that supplementation with folate in pregnancy leads to an allergic asthma phenotype in mice and is associated with poorer respiratory outcomes in young children.
