SUMMARYAlthough vitamin D deficiency is one of the most common health problems throughout the world, including Iran, conflicting information exists on the potential association between serum vitamin D levels and semen quality. This study intended to evaluate the association between serum vitamin D [25(OH) D3] with semen quality and hormones in Iranian subfertile men. We also compared mean vitamin D and hormone levels in normospermic men with oligoasthenoteratozoospermia (OAT) men. This cross-sectional study was conducted on 278 men who were referred to Royan Infertility Clinic (Tehran, Iran) from March to September 2014. The participants were categorized into two groups; of 186 normospermic and 92 OAT patients according to World Health Organization 2010 criteria. Each participant provided informed consent prior to launching research. Participants completed two general questionnaires of nutritional status. Blood and semen samples were obtained for assessment, and all data were adjusted for age, body mass index (BMI), and season. Vitamin D levels were classified according to Institute of Medicine guidelines. Vitamin D deficiency, insufficiency, and normal levels were observed in 8.6%, 43.6%, 47.8% of participants, respectively. No association was found between daily dietary intake of vitamin D and calcium with sperm parameters. Serum vitamin D was inversely correlated with PTH (p < 0.045). In normospermic men, serum vitamin D levels categorized were not correlated with semen parameters and reproductive hormones (FSH, LH, testosterone(T), and FT), whereas sperm motility showed a positive correlation with vitamin D categorized in OAT men (rs = 0.131, p = 0.028). In conclusion, there was a high incidence of deficiency and insufficiency 25(OH) D Levels (<20ng/ml) observed in Iranian men (52.2%). Moreover, our findings showed a correlation between vitamin D levels and sperm motility in OAT men, which requires further studies.

Study question To evaluate the association between sperm functionality parameters and biochemical, hormonal, and inflammatory indices in obese and diabetic men. Summary answer Metabolic changes,hormonal dysfunction,and the presence of inflammatory mediators might be considered possible mechanisms in the development of sub-fertility in obese and diabetic sub-fertile men What is known already Although the higher prevalence of subfertility in obese and diabetic men during the reproductive age is evident, the mechanisms by which obesity and diabetes mellitus (DM) cause male infertility are not entirely understood. Several pathways might be involved in the role of obesity in semen quality, thereby inducing alterations in hormonal profiles, abnormal lipid metabolism, and possibly the formation of inflammatory cytokines, ultimately leading to impaired sperm function Study design, size, duration We enrolled normal weight (BMI&lt;25 kg/m2) and non-type–2 diabetic (control=40), obese and non- type–2 diabetic (obese=40), non-obese and type–2 diabetic (Lean-DM=35), and obese and type–2 diabetic (Obese-DM=35) sub-fertile men, aged 20–50 years, referring to Royan infertility clinic (Tehran, Iran) from March to September 2014 Participants/materials, setting, methods After enrollment and receiving informed consent, all men underwent face-to-face private interviews. The obesity-associated markers, insulin resistance, beta-cell function, hormonal and lipid profile, inflammatory indices, and semen analysis were assessed in four experimental groups. Semen analysis was examined after 2–5 days of sexual analysis).abstinence based on WHO-recommended methods by CASA system (computer-assisted sperm Main results and the role of chance Main results and the role of chance: Our finding showed that diabetic markers were significantly increased in two diabetic groups, while obesity indices were markedly increased in two obese groups. Conventional sperm parameters were significantly lower in obese DM, lean DM, and obese groups compared with the control (p &lt; 0.05). Serum levels of total testosterone (TT) and sex hormone-binding globulin (SHBG) were significantly lower in men with obesity and DM compared with the control (p &lt; 0.05).There was a significant difference in the concentration of high-sensitivity C-reactive protein (hs-CRP) among four experimental groups. Moreover, serum leptin was significantly increased in obese DM, lean DM, and obese groups. Serum insulin levels had a positive correlation with metabolic-associated indices (WC, BMI, FBS,HbA1c,and HOMA-IR), as well as hs-CRP levels, whereas it had a negative correlation with count, motility, and morphology. There is also a negative association between metabolic-associated indices (WC, BMI, FBS, HbA1c, and HOMA-IR) and semen parameters. Limitations, reasons for caution It was better to evaluate inflammatory biomarkers be examined in other tissues Wider implications of the findings: The results of this study demonstrated the association of metabolic changes, hormonal dysfunction, and inflammatory responses with the semen parameters of sub-fertile men with obesity and diabete. Trial registration number Not applicable