Read But Don’t Believe

Posted on by Paul Turek, MD

Great news! Feel free to smoke. Drink as much booze as you want. Gain as much weight as you like. And feel free to indulge in whatever recreational drugs you can find. Have at it! None of these will affect your semen quality if you are trying to conceive. At least that’s what we are led to believe from a recent study from England.

Findings from the New Lifestyle Study

According to researchers who examined the semen analyses from infertile men recruited from 14 fertility clinics across England, here is how lifestyle issues correlated with semen quality:
Lifestyle Issue                Lower sperm counts             Higher sperm counts
Testicular surgery               2.4 fold
Manual labor work              1.3 fold
Unemployed                       1.8 fold
Black ethnicity                    2   fold
Using boxer shorts                                                      1.2 fold
Prior conception                                                         1.3 fold
Tobacco use                       No association
Alcohol                              No association
Recreational drugs              No association
Obesity                              No association
Mumps or fever                   No association

The Truth About Lifestyle Choices and Fertility

Honestly, I am concerned. These findings go directly against the grain of 3 decades of research showing exactly the opposite—that lifestyle factors in fact matter greatly to a man’s fertility potential.  Let me explain:

  • Smoking tobacco: No fewer than 57 studies show the negative effect of nicotine on sperm quality.
  • Alcohol is a long established gonadotoxin.
  • Marijuana lowers testosterone levels and puts men at risk for testis cancer.
  • Obesity has been correlated with low sperm counts in several studies.
  • The type of underwear men wear has been shown not to matter.
  • Clearly, fevers, illnesses and hot baths affect semen quality.

Problems with the Study

The study authors concluded “…delaying assisted conception [i.e. in vitro fertilization] to make changes to lifestyle is unlikely to enhance conception.” Why does this statement (and this study) make no sense to me? The devil is in the details:

  • All men in this study are infertile. Therefore, the study is not generalizable to other men. In other words, you can’t use this study to say anything about whether these lifestyle issues affect fertile men or men who might want to conceive.
  • Only one of every 5 men recruited to the study actually participated in it. This is very low and introduces what’s called “selection bias” into the research. How would the vast number of non-participating men have answered those lifestyle questions? Maybe very differently; you just don’t know, and this greatly reduces the power of the study.
  • This research was based on the outcome of semen analyses, not actual fertility. These are two very different things. As I have said before, unless the semen analysis shows no sperm, it is a terrible predictor of conception and fertility rates. Making statements about fertility rates based on semen analyses is a treacherous path on which to embark.
  • Since fertility involves two partners, we really need to know more about the female partners to make statements about a man’s true fertility potential. There is no such data in this study.

My advice: Ignore this. This is epidemiology at its worst. There is no doubt in my mind that the semen analysis is a “biomarker” of overall health. Fertility is the first thing to go in a stressed, unhealthy body. Nuf said. Continue to treat your body like a temple, stay as healthy as you possibly can, and partake of things in moderation.