The impact of metabolically healthy obesity in primary infertile men: Results from a cross-sectional study

Abstract

Background: A number of studies showed that obesity may negatively impact on sperm quality and consequently couple's fertility. Recently, specific attention was given to a clinical condition known as metabolically healthy obesity (MHO).

Objectives: To evaluate the effects of MHO on semen and hormonal parameters of men presenting for primary couple's infertility associated with pure male factor infertility (MFI).

Materials and methods: Data from a homogenous cohort of 512 white-European primary infertile men belonging to couples with pure MFI have been cross-sectionally analyzed. Semen analysis was based on 2010 WHO reference criteria. Patients were segregated into eugonadal, secondary hypogonadal, primary hypogonadal, and compensated hypogonadal. The Harmonized International Diabetes Federation criteria were used to define metabolic syndrome (MetS). Based on BMI and MetS, patients were further segregated into the following: (a) metabolically healthy non-obese (MHNO); (b) metabolically unhealthy non-obese (MUNO) (c) metabolically healthy obesity (MHO); and, (d) metabolically unhealthy obesity (MUHO). Main outcome measures were the prevalence of MHO and the impact of MHO on semen and hormonal parameters in this cohort of MFI primary infertile men.

Results: Overall, MHNO, MUNO, MHO, and MUHO were found in 462 (90%), 13 (2.5%), 27 (5.2%), and 10 (1.9%) men, respectively. MHO patients had lower total testosterone and SHBG levels (all P < .05) but higher E₂ values (P < .005) compared with MHNO men. Groups did not differ in terms of semen parameters. At multivariable logistic regression, analysis MHO was associated with an increased risk of primary and secondary hypogonadism (all P ≤ .02) compared with MHNO, after accounting for age and comorbid conditions.

Discussion and conclusions: Metabolically healthy obesity is threefold more prevalent than unhealthy obesity in primary infertile men. Despite semen parameters are comparable among groups, MHO patients show worse endocrine parameters and a higher risk of primary and secondary hypogonadism compared with metabolically healthy normal infertile men.

Keywords: healthy obesity; infertility; male infertility; obesity; spermatozoa; testosterone.