FIGURE 2.

Homocysteine concentrations before and after folic acid fortification in the Framingham Offspring Cohort by use of B-vitamin supplements. In the Framingham Offspring Cohort, serum total homocysteine concentrations decreased in non–supplement users, but paradoxically increased in supplement users after the initiation of folic acid fortification. Dark-gray bars: prefortification; light-gray bars: postfortification. Non–supplement users: n = 248; supplement users: n = 102. Values are geometric means with 95% CIs. Significant differences (P < 0.05 by generalized linear model procedure). Graph created based on data reported in reference (38).