Tea catechins inhibit the activity of the enzyme dihydrofolate reductase, which catalyzes the inactive form of folate 7,8-dihydrofolate to the active form of folate 5,6,7,8-tetrahydrofolate. This inhibition leads to disturbance of the folate metabolic pathway and to lower bioavailability of folate to cells; therefore, it may increase the risk of neural tube defects (NTDs) in a developing embryo. We examined the association between tea drinking during the periconceptional period and the risk of NTDs.
Cases were fetuses or neonates with an NTD as ascertained through a population-based surveillance system in 4 rural counties of Shanxi Province in northern China during 2002 through 2007. Controls were term infants without congenital malformations. Demographic, reproductive, and exposure data were obtained through a face-to-face interview.
A total of 631 NTD cases and 857 controls were included in the analysis. Compared with women who did not drink tea during the periconceptional period (487 cases and 688 controls), women who drank tea daily (20 cases and 9 controls) had a 3-fold increased risk (odds ratio = 3.1 [95% confidence interval = 1.4–7.0]) of having an NTD-affected pregnancy. The elevated risk associated with daily tea drinking remained after adjusting for maternal age, educational level, occupation, and periconceptional folic acid supplementation (3.4 [1.4–8.3]). The association was present for all 3 major subtypes of NTDs (ie, anencephaly, spina bifida, and encephalocele).
Daily tea drinking during the periconceptional period was associated with an elevated risk of NTDs in this Chinese population.
From the Institute of Reproductive and Child Health and Ministry of Health Reference Laboratory for Reproductive Health, Peking University Health Science Center; bDepartment of Epidemiology and Biostatistics, School of Public Health, Peking University; and cInstitute of Population Research/WHO Collaborating Center on Reproductive Health and Population Science, Peking University.
Submitted 19 July 2010; accepted 3 January 2011; posted 12 April 2011.
Supported partly by the National Key Technologies Research and Development Program (Grant No. 2002BA709B11) and by the State Key Development Program for Basic Research (Grant No. 2007CB5119001), People's Republic of China.
Correspondence: Aiguo Ren, Institute of Reproductive and Child Health, Peking University Health Science Center, 38 Xueyuan Rd, Haidian District, Beijing 100191, People's Republic of China. E-mail: email@example.com or firstname.lastname@example.org or Xiaoying Zheng, Institute of Population Research/WHO Collaborating Center on Reproductive Health and Population Science, Peking University, 5 Yiheyuan Rd, Haidian District, Beijing 100871, Beijing 100191, People's Republic of China. E-mail: email@example.com.