Folate status of women in Toronto: Implications of folate fortification and supplementation

To assess the percentage of women of childbearing age with suboptimal levels of folate for protecting against neural tube defects (<906 nM), and assess folate status among the elderly.

A total of 1,035 anonymous blood samples from a centralized clinical laboratory, with a catchment area across the Greater Toronto Area, were assessed for red blood cell (RBC) folate concentrations using a chemiluminescent immunoassay. Folate analysis was requested by physicians as part of clinical care. Available data included age, sex, and RBC folate concentration. Descriptive statistics were used to characterize the percent of women who had suboptimal blood folate concentrations, and a multiple regression was used to analyze determinants of folate status.

Our data from 2013 show that 7% of women of childbearing age (15-45 years) had RBC folate concentrations below 906 nM, a substantially lower percentage than in our 2006 study (40%). Results from the multiple regression showed that age is a significant positive predictor of higher RBC folate status (p < 0.001).

Compared to our earlier data, we report a significant decrease in the suboptimal folate status among women of childbearing age. We also show that age is a predictor of higher RBC folate levels. Our data are limited due to a lack of information regarding patient or physician characteristics, and to the nature of our sample, yet our results are consistent with the continued increase in folate status observed among several population-level studies in the US and Canada post-fortification. Further research is needed to determine the reasons for and future implications of this continued increase in the elderly.