Abstract
Study question
Is men’s adherence to the Mediterranean diet (MD) associated with sperm parameters and couples’ outcomes of assisted reproductive technologies (ART)?
Summary answer
Higher men’s adherence to the MD was associated with an increased probability of clinical pregnancy and live birth among couples undergoing ART.
What is known already
There is growing literature supporting the hypothesis that some nutrients, foods, and dietary patterns may be related to sperm quality and fertility. However, no previous studies analyzed the relationship of men’s adherence to the Mediterranean diet with sperm parameters and ART outcomes in the same cohort.
Study design, size, duration
The Environmental and Reproductive Health (EARTH) Study is a prospective preconception cohort of couples seeking fertility treatment at the Massachusetts General Hospital Fertility Center (Boston, USA). This analysis includes 314 men and their female partner, who underwent 791 ART cycles (2007–2020). Diet intake was measured by a validated semi-quantitative food frequency questionnaire completed prior to ART. Men’s adherence to the MD was estimated using the Trichopoulou score.
Participants/materials, setting, methods
Primary outcomes included: conventional sperm parameters (volume, sperm count, concentration, motility, and morphology), and ART outcomes (implantation, clinical pregnancy, and live birth). We estimated the marginal means and 95% confidence interval (95%CI) for semen parameters and the probability of ART (95%CI) by employing generalized linear mixed models while adjusting for several potential confounders. Sensitivity analyses by changing the cut-off points of adherence to the MD were tested.
Main results and the role of chance
At baseline, men had a median (IQR) age of 35.6 (32.6, 38.8) years and a BMI of 26.7 (24.0, 29.4) kg/m2. Female partner age median (IQR) was 35.0 years (32.0, 38.0) and BMI 23.3 (21.3, 26.6) kg/m2. Couples were mostly white and had never smoked. Men’s adherence to the MD was not associated with seminal parameters in the multivariable-adjusted models but it was related to a higher probability of clinical pregnancy and live birth. The predicted marginal proportions and confidence intervals among men in the lowest compared with the highest quartile of adherence to the MD were 0.25 (0.14, 0.40), 0.55 (0.41, 0.68) for clinical pregnancy (P-trend=0.005), and 0.19 (0.10, 0.32), 0.42 (0.30, 0.55) for live birth (P-trend=0.014). Male partner MD dietary pattern scores were unrelated to the probability of implantation. Sensitivity analyses using tertiles and quintiles of men’s adherence to the MD showed similar associations.
Limitations, reasons for caution
Although we have adjusted our models by several potential confounding factors, residual confounding cannot be ruled out, and therefore our results should be interpreted with caution. The findings may not be generalizable to other populations or couples attempting conception without ART.
Wider implications of the findings: According to our knowledge, this is the first study suggesting that adherence to MD could be suitable dietary guidance for men whose partners are undergoing infertility treatment.
Trial registration number
Not applicable
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