Sexual dysfunction, primarily low libido, is common among women, with prevalences of 8 percent to 50 percent, according to background information in the article. Although multiple psychosocial and health factors contribute to low sexual desire and arousal, it has been proposed that androgen levels are significant independent determinants of sexual behavior in women. It is widely believed that a low serum free testosterone level is the diagnostic marker for the cluster of symptoms described as characterizing "female androgen insufficiency" based on therapeutic trials, and expert opinion. However, evidence that a low serum testosterone level distinguishes women with low sexual function from others, is lacking.
Susan R. Davis, M.D., Ph.D., of Monash Medical School, Alfred Hospital, Victoria, Australia, and colleagues conducted a study to determine if low self-reported sexual function is associated with low serum androgen levels. The study included 1,423 women aged 18 to 75 years who were randomly recruited from April 2002 to August 2003. Women were excluded from the analysis if they were younger than 45 years and using oral contraception. Women were surveyed with the Profile of Female Sexual Function (PFSF) and serum levels of total and free testosterone, androstenedione (an androgenic steroid), and dehydroepiandrosterone sulfate (DHEAS, a natural steroid hormone) were measured.
The researchers write: "We found no evidence of associations between low scores for any of the sexual domains evaluated and low serum total and free testosterone levels. In contrast, we observed significant associations between low sexual desire, arousal, and responsiveness in younger women [aged 18 to 44 years] and low responsiveness in older women [aged 45 years or older] and low serum DHEAS level relative to age."
"In addition to demonstrating that the measurement of testosterone is not useful for the diagnosis of the proposed female androgen insufficiency syndrome, our findings also do not support a diagnostically useful role for the measurement of DHEAS. This is because despite the increased likelihood that women with low sexual function have a low DHEAS level, the majority of women with a low DHEAS level did not report low sexual function," the authors write.
"Our results are not in conflict with testosterone being used pharmacologically to treat [abnormally inactive] sexual desire disorder, nor do they provide support for efficacy of DHEA therapy. Rather, our data, taken together with what is already known about the intracrine [a type of hormone function] physiology, suggest that sex steroids influence female sexual function, but that there is no serum androgen level that defines female androgen insufficiency. The measurement of serum testosterone, free testosterone, or DHEAS in individuals presenting with low sexual function is not informative and levels of these hormones should not be used for the purpose of diagnosing androgen insufficiency in women," the researchers conclude.
(JAMA. 2005;294:91-96. Available pre-embargo to the media at www.jamamedia.org)
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