May 21, 2019

expert reaction to conference abstract discussing elite female athletes and testosterone levels

Reactions to a conference abstract at the European Congress of Endocrinology which claims sporting regulations should take into account the fact that top performing female athletes are more likely to have naturally occurring higher testosterone levels.

Prof Wiebke Arlt, Society for Endocrinology member, and Head of Centre for Endocrinology, Diabetes and Metabolism, University of Birmingham, said:

“There is an important caveat, which has to be taken into account, before introducing absolute cut-offs for acceptable blood testosterone levels in female athletes.  In individuals with androgen insensitivity, blood testosterone levels will be high but that does not mean that this gives them a competitive advantage.  Testosterone acts through binding and activation of the male hormone (=androgen) receptor in the cells of muscle, brain and other target tissues of male hormone action.  Individuals with androgen insensitivity syndrome have genetic mutations that result in their androgen receptor being much less responsive to testosterone and in some cases completely unresponsive.  These individuals will have very high testosterone levels in their blood, reflecting an attempt of the body to overcome the loss of function of the androgen receptor, but this will still elicit no or much less effect than observed in healthy individuals.  In these individuals, high circulating testosterone levels would not give them an unfair advantage.  Thus, rather than suggesting absolute cut-offs only, it is important to take into account the underlying condition that leads to testosterone excess, which would help to judge whether or not raised blood testosterone gives an unfair advantage.”

Dr Norman Taylor, Consultant Clinical Scientist, Steroid Laboratory, Department of Clinical Biochemistry, King’s College Hospital, said:

“The author of the abstract is very qualified to express the judgements that she has.  It is important to differentiate androgen excess in XX females which is usually related to PCOS, a condition that affects perhaps 10% of the female adult population and therefore might be classified as within the ‘normal’ spectrum, from forms of DSD, which are invariably due to a genetic abnormality.  The author discusses a relationship between testosterone levels and performance in the first category.  This may be likened to other sources of better performance within a continuous range such as has been argued for the swimmer Michael Phillips.  The author confirms, as would be expected from her identification of this relationship, that elite female athletes tend to have higher testosterone levels and a higher frequency of PCOS.  There is clearly a reluctance to invade the privacy of individual athletes to reveal which have a DSD, so that terms such as ‘naturally higher testosterone’ give the impression that there is a continuum when there is not.  The IAAF and IOC appear therefore to have chosen to differentiate on grounds of testosterone level rather than on whether the athlete has DSD, but that is in reality what they are doing.  This is more inclusive.  By offering the opportunity to use medical treatment to decrease the testosterone level below a cut-off, then DSD althetes can still compete.  The treatments are those that have been well established in endocrine practice for care of DSD patients.  These are identical with or closely similar to natural hormones, so do not pose unreasonable risks.  Prof Linden-Hirschberg recommended a cut off of 5 nmol/L based on her work, whereas the athletics bodies have set it at 10 nmol/L, so they have allowed a wide margin of error.”

Abstract title: ‘Female hyperandrogenism and elite sport’ by Angelica Lindén Hirschberg.  This is a conference talk from the European Congress of Endocrinology in Lyon. There is no paper as this is not published work.

Declared interests

Dr Norman Taylor: “My background is that I provide a urine steroid profiling service that is used to identify steroid metabolic disorders.  These include ones that result in XX DSD (disorders of sexual differentiation that result in androgen excess in genetic females, leading to them being born with ambiguous or male-looking genitalia) and XY DSD (disorders of sexual differentiation that result in androgen deficiency in genetic males, leading to them being born with ambiguous or female-looking genitalia).  I have also published on urinary steroid excretion in PCOS and am part of a group who have developed improved blood steroid assays, including testosterone.  The previous universal technique, immunoassay, was unacceptably unreliable for adult female testosterone analysis because of interference, leading to falsely high and variable results.  The new technique we now use of liquid chromatography-mass spectrometry is now widespread and will have enabled the setting of a testosterone limit to be considered for women athletes, which before would have been impossible.”

None others received.