Semen characteristics and testosterone levels in the general population

Background:

Age-specific reference values for semen characteristics and testosterone levels in the general population are lacking, but can positively strengthen research concerning impaired spermatogenesis en testosterone deficiency in high risk populations. A general population control group is essential for the DCOG-LATER male gonadotoxicity study, which will provide an accurate estimate of overall and treatment specific relative and absolute risks of azoospermia and testosterone deficiency in male survivors of childhood cancer.



Objective:

1. Evaluation of the variation of semen characteristics in the general population

2. Evaluation of the variance of testosterone levels in the general population



Study design:

This study is an single-center, cross-sectional, observational study.



Study population:

This study will include 400 male participants from the Lifelines cohort study, a prospective, populationbased cohort study examining the health and health-related behaviors, who are aged between 18 and 55 years.



Primary study parameters:

Semen characteristics, including volume, sperm concentration and fraction of progressive motile spermatozoa) and testosterone levels.



Nature and extent of the burden and risks associated with participation, benefit and group relatedness:

Participants will be asked to complete one questionnaire at home, which will focus on reproductive history, pubertal development and questions concerning testosterone level. This questionnaire will take about 20 minutes to complete. In addition, participants will be asked to visit the University Medical Center Groningen (UMCG) once in order to provide one blood sample which will be collected in the morning, before 10 AM, and to provide a semen sample. The duration of the visit to the UMCG is estimated circa 90 minutes. There are no adverse events expected during the collection of
semen and blood samples. The provided reference dataset of semen characteristics and testosterone levels in the general population will serve as a control group in research assessing the effects of various factors on male gonadal
function, e.g. severe systemic illness (renal failure, hepatic cirrhosis, cancer), morbid obesity, exposure to toxins (alcohol, marijuana, smoking), and nutritional deficiencies.

The study objective is to evaluate the variation of semen characteristics and testosterone levels in the general population. These age-specific reference values can be used as a control group in research in male populations in which impaired spermatogenesis and/or testosterone deficiency is studied.

Participants will complete one questionnaire at home (which will take about 20 minutes) and they will visit the clinic once in order to provide one blood and one semen sample (the duration of the visit is estimated circa 90 minutes).

Not applicable