Folic Acid and Zinc Supplementation Trial (FAZST)

  • Robins, Jared Cory (PD/PI)

Project: Research project

Project Details


This is a multi-center, double-blinded, block randomized placebo-controlled clinical trial to assess the effects of folic acid and zinc dietary supplementation in males on semen quality and fertility rates among couples trying to conceive and seeking assisted reproduction. The primary objective of the study is to assess the impact of folic acid and zinc dietary supplementation in males on semen quality and indirectly fertility outcomes (i.e., live birth rate) among couples attempting to conceive and seeking assisted reproduction. A double-blind, placebo-controlled block randomized trial of folic acid and zinc dietary supplementation will be conducted. Following a screening/randomization visit, participants will return at 2, 4, and 6 months. The rate of adverse events will be noted throughout the double-blind trial. The FAZST trial is designed as a multi-center double-blinded block randomized controlled clinical trial with two cohorts: folic acid and zinc compared to placebo. The primary objectives are to compare the cohorts on four quantitative assessments of sperm quality (concentration, motility, morphology, and DFI) and live births in their partners. The study is designed with a sample size of 2400 randomized participants based on obtaining adequate power to detect meaningful differences in the live birth rate between cohorts. Since the comparison of sperm parameters are differences between continuous assay measurements, this sample size will be more than sufficient for the primary sperm parameter comparisons. The primary analysis plan is based on an “intention-to-treat” (ITT) approach comparing the two cohorts based on the randomized assignment, ignoring later changes in dietary supplement consumption. This analysis is described in Section F.2. The DCC will perform periodic safety analyses and present interim reports to the Data and Safety Monitoring Board (DSMB) as requested, during the recruitment phases of the trial. It is anticipated that safety analyses will be performed every 6-12 months. The final analysis will be performed upon completion of data collection and editing in the follow-up and close-out phase of the trial. Also one full formal interim analysis is planned and the power calculations with considerations for the choice of optimal time for the analysis are given in Section F.3.
Effective start/end date5/1/142/28/19


  • University of Utah (10026957-03 // HHSN275201200007C)
  • National Institute of Child Health and Human Development (10026957-03 // HHSN275201200007C)


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