Relationship between physical occupational exposures and health on semen quality Data from the Longitudinal Investigation of Fertility and the Environment LIFE Study

Capsule:
Occupational and medical comorbidity may negatively impact semen quality.

Authors:
Michael L. Eisenberg, M.D., Zhen Chen, Ph.D., Aijun Ye, Ph.D., Germaine M. Buck Louis, Ph.D.

Volume 103, Issue 5, Pages 1271-1277

Abstract:

Objective:
To study the relationship among occupation, health, and semen quality in a cohort of men attempting to conceive.

Design:
Observational prospective cohort.

Setting:
Not applicable.

Patient(s):
A total of 501 couples discontinuing contraception were followed for 1 year while trying to conceive; 473 men (94%) provided one semen sample, and 80% provided a second sample.

Intervention(s):
None.

Main Outcome Measure(s):
Semen data obtained through at-home semen collection with next-day analysis/quantification.

Result(s):
In all, complete data were available for 456 men, with a mean age of 31.8 years. Work-related heavy exertion was consistently associated with lower semen concentration and total sperm count. Thirteen percent of men who reported heavy exertion displayed oligospermia, compared with 6% who did not report workplace exertion. Shift work, night work, vibration, noise, heat, and prolonged sitting were not associated with semen quality. Men with high blood pressure had significantly lower strict morphology scores compared with normotensive men (17% vs. 21%). In contrast, hyperlipidemia, diabetes, and composite of total comorbidities were not associated with semen quality. The number of medications a man was taking as a proxy of health status was associated with semen quality. There was a negative association between number of medications and sperm count.

Conclusion(s):
A negative relationship among occupational exertion, hypertension, and the number of medications with semen quality was identified. As these are potentially modifiable factors, further research should determine whether treatment or cessation may improve male fecundity.

  • Bob Brannigan

    This is an important contribution to the literature. Congratulations. The data that is being collected by the Andrology Research Consortium will provide a great opportunity to expand on these issues, especially in terms of geography. It will be interesting to see if increasing sample size results in statistical significance for some of these parameters.

  • Michael Eisenberg

    The study examined occupational sources of heat. While some “hot jobs” may cause reproductive harm, the current study found no evidence based on self reported exposure. I do suspect an association would have been found with the recreational use of hot tubs and/or saunas.

  • Ali Dabaja

    Well written paper and very clinically useful, I am surprised that heat exposure does not have any effect on sperm parameters. It goes against the classical recommendation that we give to patients about avoiding hot tubs and sauna. Is there any explanation for this finding?

  • Michael Eisenberg

    Thanks for the kind words. It may be that with more granular detail about shift work/night work (e.g. how many hours, shifts per week, etc) a trend may have been apparent. However, as with many studies of occupational exposure, conditions to vary around the country and it may be that in Texas and Michigan a relationship does not exist.

  • ranjithrama

    Great study Mike. It is surprising that shift work or night work was not associated with semen quality. Studies have demonstrated an association between altered circadian rhythm and low serum testosterone as well as impaired semen parameters. Can you posit an explanation for why this could be the case?

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