American Journal of Epidemiology

Abstract The Folic Acid and Zinc Supplementation Trial (FAZST) was a multi-center, double-blind, block-randomized, placebo-controlled trial to determine whether folic acid and zinc supplementation in men improves semen quality and increases live birth rate among couples seeking infertility treatment (2013-2017). Eligible men were ages 18 years or older with their female partners ages 18-45 seeking infertility treatment. Men were randomized (1:1) to 5 mg folic acid and 30 mg elemental zinc daily or matching placebo for six months. Randomization was stratified by site and intended infertility treatment (in vitro fertilization (IVF), non-IVF/study site, and non-IVF/outside clinic). Follow-up of men continued for 6 months, while female partners were passively followed for a minimum of nine months. Women who conceived were followed throughout pregnancy. Overall, 2,370 men were randomized between 2013-2017 (1185 folic acid and zinc, 1185 placebo), with mean age of 33 years and body mass index of 29.8. Participants were mostly white (82%), well-educated (83% with some college), and employed (72%). Participant characteristics were balanced across intervention arms. Study visits were completed by 89%, 77%, and 75% of men at months 2, 4, and 6, respectively. Herein, we describe the study design, recruitment, data collection, lessons learned, and baseline characteristics. folic acid, zinc, semen quality, male fertility, live birth, supplements This content is only available as a PDF. © The Author(s) 2019. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: [email protected] This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)