P–106 The evaluation of dietary score representing the overall effect of men’s diet to semen quality on couple’s fertility
Authors: Mitsunami M , Salas-Huetos A , Mínguez-Alarcón L , Attaman J , Ford J , Kathrins M , Souter I , Chavarro J 
Published: August 2021

Abstract

Study question
Is men’s diet associated with assisted reproductive technology (ART) outcomes?

Summary answer
An empirical dietary score representing the overall effect of men’s diet on semen quality was unrelated to ART outcomes.

What is known already
Multiple studies have related various aspects of men’s diet to semen quality. Generally, healthier foods, such as fish, vegetables, and fruits, have been related to better semen quality, whereas unhealthy foods, like processed and red meats, have had the opposite relationship. Nevertheless, while bulk semen parameters are important biomarkers of male fertility and a diagnostic cornerstone for male factor infertility, they are imperfect predictors of a couple’s fertility.

Study design, size, duration
Couples presenting to the Massachusetts General Hospital Fertility Center between April 2007 and April 2018 were invited to participate in the Environment and Reproductive Health (EARTH) study, a prospective cohort study. Men’s diet was assessed with a previously validated food frequency questionnaire. A dietary score reflecting the overall relation of men’s food intake with semen quality parameters was empirically derived using reduced rank regression (RRR). The resulting dietary score was related to ART outcomes.

Participants/materials, setting, methods
We used information from 349 men (908 semen samples) to derive the empirical diet pattern and data from 231 couples (407 ART cycles). The primary outcome was the probability of live birth per treatment cycle; secondary outcomes were semen quality, and fertilization, implantation, and clinical pregnancy rates. We evaluated the association between the dietary score and these outcomes using logistic generalized linear mixed models to account for repeated cycles while adjusting for confounders.

Main results and the role of chance
Men had a median baseline age and BMI of 36.8 years and 26.9 kg/m2, respectively. The empirical diet pattern was significantly associated with all semen parameters. One standard deviation increase in the empirical diet pattern was associated with lower volume (–0.10 standard units [95% CI: –0.17 to –0.04]) and to higher sperm total sperm count (0.13 standard units [0.06 to 0.20]), concentration (0.17 standard units [0.10 to 0.24]), total motility (0.14 standard units [0.07 to 0.20]), progressive motility (0.08 standard units [0.01 to 0.15]), and normal morphology (0.18 standard units [0.11 to 0.25]). Couples with men in the lowest quartile of the empirical score were more likely to have a diagnosis of male infertility than couples with men in the highest quartile (49% vs 24%). Despite the association with semen parameters, the empirical diet score was not related to any clinical outcome of infertility treatment with ART. The adjusted probabilities of implantation, clinical pregnancy and live birth in the lowest and highest quartile of the empirical score were 0.62 (0.50–0.73) and 0.55 (0.45–0.66), 0.57 (0.46–0.69) and 0.50 (0.40–0.61), and 0.49 (0.37–0.62) and 0.36 (0.25–0.48), respectively. Analyses excluding couples with a diagnosis of male factor infertility yielded similar results.

Limitations, reasons for caution
We evaluated the relationship only among couples presenting to a fertility center and therefore it is unclear whether findings can be generalized to couples trying to conceive without ART.
Wider implications of the findings: Given ART is a robust intervention including stringent sperm selection procedures, any effect that empirical diet may have on a couple’s chances of conceiving through assisted reproduction is unlikely to reflect the effect of these factors on bulk semen quality parameters.

Trial registration number
The project was funded by ES009718, ES022955, ES026648, and ES000002 from the National Institute of Environmental Health Sciences, and P30DK46200 from the National Institute of Diabetes and Digestive and Kidney Diseases