Studies Examine Effect of Age on Sperm

Among couples undergoing in vitro fertilization (IVF) cycles, increasing age in men was not associated with a rise in aneuploidy in embryos. However, in a separate study, researchers observed a decline in sperm quality among young men presenting for sperm donation during an 11-year period.

The results of the two studies were presented at the American Society for Reproductive Medicine (ASRM) Annual Meeting in Baltimore.

Older Male Age Does Not Affect Aneuploidy

Julian A. Gingold, MD, PhD, study investigator from the Women’s Health Institute at the Cleveland Clinic Foundation, explained in an interview that ovarian aging has long been known to be the primary determinant of embryonic aneuploidy, a condition in which embryos have an abnormal number of chromosomes.

“Male aging has been associated with abnormal semen parameters and increased sperm DNA fragmentation,” Dr Gingold said. “In addition, children of older men have an increased risk of multiple rare disorders, including autism, schizophrenia, leukemia, and achondroplasia. However, the role of the male partner age in producing chromosomally normal embryos has never been examined before.”

This led Gingold and colleagues to conduct a retrospective cohort study evaluating whether embryo aneuploidy rates correlated with male age among couples pursuing IVF cycles, while controlling for oocyte age.

Researchers enrolled couples presenting for an IVF cycle and used aneuploidy screening between June 2010 and March 2015. Female and male patients were stratified by age, and researchers calculated the aneuploidy rate for each male-female age group interaction.

Overall, 819 couples underwent 1108 autologous IVF cycles. Of the 4658 embryos in which aneuploidy screening was performed, 2194 were aneuploid.

As female age increased, there was a stronger association with aneuploidy rates. Specifically, when compared with the youngest group (≤35 years), those in the 3 oldest groups (38-41 years, 41-43 years, and >43 years) had a stronger association with aneuploidy rates (P<.001) than the second youngest group (35-38 years; P<.05).

However, male partner age did not significantly impact aneuploidy rate at any age.

“As expected, we found that ovarian (ie, maternal) age was the primary determinant of chromosomal aneuploidy. While increased male age was also associated with an increased rate of chromosomal abnormalities, this effect disappeared after controlling for ovarian age,” Dr Gingold said.

“Thus, we found that after controlling for ovarian age there was no detectable independent association between male age and embryonic aneuploidy.”

Dr Gingold noted that the findings confirmed previous expectations, given the reported lack of paternal age effect on fertilization and live birth rates.

“However, [the data] were also very reassuring, given the large number of older men now seeking to father biological children using IVF technologies,” he said.

Dr Gingold did cite several study limitations, however, including the lack of power to examine the effect of paternal age extremes, as well as the effect of couples with a substantial age difference.

In addition, the technology used in the study was unable to assess the effect of paternal age on sub-chromosomal abnormalities or single nucleotide mutations, he said.

Declining Sperm Quality in Young Men

In a different retrospective analysis, Grace M. Centola, PhD, of the New England Cryogenic Center in Marlborough, Massachusetts, and colleagues aimed to evaluate semen parameters of young men who provided semen specimens at the same facility.

“We had been seeing a decrease in the sperm parameters of young adult men applying to be sperm donors,” Dr Centola told Endocrinology Advisor.

“Furthermore, more and more of the applicants were not being accepted because they did not meet our acceptable semen criteria. Many sperm banks have mentioned seeing the same pattern with their applicants, so we decided to look at our data.”

In all, Dr Centola and fellow researchers examined 9425 semen specimens from 489 individuals for several parameters, including volume, count, and motility before and after cryopreservation.

Between 2003 and 2013, significant declines were reported in initial sperm count (P<.001), sperm motility (P<.001), total count (P<.001), and total motile count (P<.001), although not in semen volume (P=.2).

After cryopreservation, post-thaw motility decreased with time (P<.001).

In addition, Dr Centola and colleagues found a significant decline in age (P=.003) and alcohol use (P=.005), and an increase in college grade point average (P=.02). BMI, education attainment, race/ethnicity, and lifestyle habits did not significantly differ during the study period.

“Although the sperm parameters did not fall to below the ‘normal’ fertile reference range, there was a significant decrease in sperm parameters in a presumably healthy population of young adult men,” Dr Centola said.

“We recommend that young men should consider sperm banking if they are planning to delay fertility. Further study is needed to determine the cause of these changes, and to possibly reverse the decrease in sperm count and motility.”

References

1. Centola GM, Blanchard A, Demick JL, Li S, Eisenberg ML. Abstract O-203. A Case for Banking Sperm Due to Increased Age: Decline in Sperm Count and Motility in Young Adult Men.
2. Gingold J, Whitehouse MC, Lee JA, et al. Abstract O-164. Male Partner Age Is Not Associated With Increased Rate of Embryonic Aneuploidy. Both presented at: ASRM Annual Meeting; Oct. 17-21, 2015; Baltimore.