Habitual alcohol consumption associated with reduced semen quality and changes in reproductive hormones; a cross-sectional study among 1221 young Danish men
- Tina Kold Jensen1,2,
- Mads Gottschau1,
- Jens Otto Broby Madsen1,
- Anne-Maria Andersson2,
- Tina Harmer Lassen2,
- Niels E Skakkebæk2,
- Shanna H Swan3,
- Lærke Priskorn1,
- Anders Juul2,
- Niels Jørgensen2
- 1Department of Environmental Medicine, University of Southern Denmark, Copenhagen, Denmark
- 2The Faculty of Medical and Health Sciences, University Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- 3Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Correspondence to Professor Tina Kold Jensen;
- Received 11 April 2014
- Revised 24 June 2014
- Accepted 26 June 2014
- Published 2 October 2014
Objective Study associations between three measures of alcohol consumption (recent, typical/habitual, binging), semen quality and serum reproductive hormones.
Design Cross-sectional population based study.
Setting and participants 1221 young Danish men, aged 18–28 years were recruited when they attended a compulsory medical examination to determine their fitness for military service from 2008 to 2012. Total alcohol consumption: (1) in the week preceding (habitual/typical) the visit (recent alcohol intake), (2) in a typical week and (3) frequency of ‘binge drinking’ (consuming more than 5 units/day)) in the past 30 days was estimated.
Main outcome measures Semen quality (volume, sperm concentration, total sperm count, and percentages of motile and morphologically normal spermatozoa) and serum concentration of reproductive hormones (follicle-stimulating hormone, luteinising hormone, testosterone, sex hormone binding globulin, oestradiol, free testosterone and inhibin B).
Results Sperm concentration, total sperm count and percentage of spermatozoa with normal morphology were negatively associated with increasing habitual alcohol intake. This association was observed in men reporting at least 5 units in a typical week but was most pronounced for men with a typical intake of more than 25 units/week. Men with a typical weekly intake above 40 units had a 33% (95% CI 11% to 59%) reduction in sperm concentration compared to men with an intake of 1–5 units/week. A significant increase in serum free testosterone with increasing alcohol consumption the week preceding the visit was found. Binging was not independently associated with semen quality.
Conclusions Our study suggests that even modest habitual alcohol consumption of more than 5 units per week had adverse effects on semen quality although most pronounced associations were seen in men who consumed more than 25 units per week. Alcohol consumption was also linked to changes in testosterone and SHBG levels. Young men should be advised to avoid habitual alcohol intake.
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