Design and evaluation of interventions promoting periconceptional multivitamin use.

BACKGROUND: Periconceptional folic acid use reduces the risk of neural tube defects and possibly other birth defects. The effectiveness of two interventions to increase the use of multivitamins among women of childbearing ages was evaluated.
METHODS: Quasi-experimental interrupted time series design with a nonequivalent control group. Participants included female members of Kaiser Foundation Health Plan aged 18 to 39 years residing in the three geographic service areas of California under study from 1998 through 2000. The central component of the direct mail/pharmacy information intervention was the mailing of "starter kits" of 100 multivitamins, while the provider education intervention used primary care providers to deliver the study message. Main outcomes included the use of multivitamins containing folic acid at least four times per week ("regularly"), intention to use multivitamins regularly, and knowledge and attitudes about multivitamins. Outcomes were measured via telephone interviews of nonpregnant women of childbearing age.
RESULTS: A total of 3438 women were interviewed. There was a small but significant increase in the percentage of women using multivitamins in the direct mail/pharmacy information intervention group at the beginning of the intervention period (p =0.006), but this increase was not sustained after the interventions ended. No other significant change was observed.
CONCLUSIONS: Despite our ability to reach many women of childbearing age with multiple messages about regularly using multivitamins, only a small temporary increase was found in the percentage of women using multivitamins who received the messages in the mail. Other interventions and further evaluation of the impact of food fortification with folic acid should be considered.