A recent study conducted in a large Japanese birth cohort suggests that supplementing with folic acid once weekly or more, and maintaining higher serum folic acid levels (≥10 ng/mL) during the second and third trimesters of pregnancy, is associated with a significantly reduced risk of developing Kawasaki Disease (KD) in the first 12 months of life.
The study, rated at Evidence Rating Level 2 (Good), focused on investigating potential preventive measures for KD, an acute systemic vasculitis primarily affecting young children under the age of 5. Despite a declining birth rate in Japan, there has been an increase in KD incidence among infants under the age of 1. The exact mechanism of KD remains unclear, but previous literature has suggested potential associations with prenatal exposures.
Researchers analyzed data from 87,702 children in a prospective multicenter Japanese birth cohort study known as the Japanese Environment and Children’s Study (JECS). The primary objective of the study was to examine the relationship between maternal folic acid levels in the second and third trimesters of pregnancy, frequency of folic acid supplementation throughout pregnancy, and the development of KD within the first year of life. Various parental characteristics such as maternal medical and social history, pregnancy BMI, other supplementation during pregnancy, mode of delivery, paternal medical history, and socioeconomic status were also taken into account.
The study findings revealed a significant negative association between higher maternal folic acid levels in the second and third trimesters of pregnancy and the risk of KD in infants during their first 12 months of life. The analysis controlled for dietary folic acid intake, which was similar among mothers of both KD-affected and non-KD-affected infants, suggesting that the specific supplementation of folic acid may play a role in reducing the risk of KD.
From an epidemiological perspective, the study highlighted a concerning trend where the incidence of KD has been on the rise while maternal folic acid supplementation has been decreasing, positing that the decline in folic acid supplementation may contribute to the higher rates of KD in the Japanese pediatric population.
While this research sheds light on the potential benefits of folic acid supplementation in reducing the risk of KD in infants, further studies are warranted to validate these findings across different geographical locations and epidemiological settings. Additionally, future research should extend beyond the 12-month mark to assess the long-term protective effects of folic acid supplementation against KD. Controlling for confounding variables, such as folic acid intake as part of a prenatal vitamin with other supplements, should also be considered in future studies to provide a more comprehensive understanding of the relationship between folic acid supplementation and KD prevention.
