P-020 Association between male age and the frequency of sperm abnormalities
Authors: Handzhiyska M , Parvanov D , Ganeva R , Ruseva M , Georgieva V , Gogeva S , Velikova D , Stamenov G 
Published: June 2023

Abstract

Study question
Does advancing male age influence the frequency of occurrence of sperm abnormalities?

Summary answer
Advancing male age was associated with increased incidence of certain head and tail defects – elongated head, nuclear vacuoles, and coiled tail.

What is known already
Evaluation of male reproductive potential is based mainly on sperm motility and sperm morphology. Morphological sperm features serve as a reliable indicator in predicting the fertilizing capacity of sperm. Nowadays, there are various sperm selection techniques based on sperm morphology. However, advancing male age has been associated with decrease in semen quality. Therefore, the aim of this study was to examine the effect of aging on the frequency of occurrence of sperm abnormalities.

Study design, size, duration
This retrospective study includes 3980 men aged between 15 and 72 years, with a mean of 36 years. Semen samples were collected between October 2015 and December 2022 in a private in-vitro hospital. Men were divided into three groups according to their age: 1) from 15 to 25 years (n = 144), 2) from 25 to 45 years (n = 3447), and 3) over 45 years (n = 393).

Participants/materials, setting, methods
Sperm morphology was evaluated according to the Kruger’s strict criteria. Totally, 23 types of abnormalities were determined. Head defects included small, large, amorphous, elongated, round, pear-shaped, double, detached head, acephalic cells, small or large acrosomal areas, and spermatozoa without acrosome. Midpiece defects included thick, thin, bent, asymmetric midpiece and cytoplasmic droplets. Tail defects included short, coiled, and double tail. Acrosomal vacuoles and nuclear vacuoles were also evaluated. Statistics: ANOVA, followed by LSD post-hoc test.

Main results and the role of chance
The results are presented as mean±SD. Among the studied population the percentage of normozoospermic men was 44%, while the percentage of teratozoospermic semen samples was 56%. The total mean frequencies of occurrence of head, midpiece and tail abnormalities were 85.9±7.9%, 34.1±12.8% and 4.7±5.1%, respectively. Only 3 (13%) of the analysed 23 types of sperm abnormalities were significantly more common with advanced male age – elongated head, nuclear vacuoles, and coiled tail.The frequency of occurrence of elongated head differed significantly between the age groups 1-2, and 1-3: 11.38±10.1% vs. 13.79±11.58%, p = 0.015, and 11.38±10.1% vs. 14.4±11. 8%, p = 0.008, respectively. No difference in the incidence of this defect was observed between groups 2 and 3 (p &gt; 0.05).Furthermore, the frequency of nuclear vacuoles significantly increased with age as observed in the following age group comparisons 1-2, 1-3, and 2-3: 4.28±4.93% vs. 5.4±6.1%, p = 0.04, 4.28±4.93% vs. 6.48±7.89%, p &lt; 0.001, and 5.4±6.1% vs. 6.48±7.89%, р=0.001, respectively.Finally, coiled tail was observed more frequently in age groups 2 and 3 compared to age group 1: 13.79±11.58% vs. 11.38±10.1%, p &lt; 0.001, and 14.4±11. 8% vs. 11.38±10.1%, p &lt; 0.001, respectively.

Limitations, reasons for caution
This is a single-institution retrospective study.

Wider implications of the findings
The findings of this study showed that aging is associated with an increased percentage of several sperm abnormalities: spermatozoa with elongated head, nuclear vacuoles, and coiled tail. Further studies are required to clarify the negative impact of aging on spermatogenesis leading to morphological defects.

Trial registration number
NA