Sexual Function and Hormone Levels in Women Aged 42-52 Years
Sexual Function and Hormone Levels in Women Aged 42-52 Years
The role of testosterone in female sexual function remains uncertain and has been the topic of much high-quality investigation. When considering research in this area, it is important to distinguish between studies investigating the impact of testosterone in normal female sexual physiology and those examining the potential effectiveness of testosterone in the treatment of women with sexual dysfunction. The current study uses the SWAN database to address whether reproductive hormones are related to sexual function during the menopause transition. SWAN provides a great opportunity to examine this important question, as following a large group of women longitudinally over 10 years provides many observations and high statistical power to identify even small relationships between hormones and behavior. In addition, the study population is a community-based, multi-ethnic cohort, so findings should be generalizable to US women.
Prior research has identified a potential role for endogenous androgens in normal female sexuality. In women of reproductive age, an increase in midcycle sexual activity, correlating with the midcycle peak in testosterone, is seen in some but not all studies. An association is more likely to be seen in partner-independent activities, such as masturbation, likely because partnered activity is affected by a multitude of factors besides hormones and inherent level of desire, such as relationship quality, partner interest, and habit.
In contrast, a significant association between normal and impaired sexual function and serum androgen levels has not been seen in the majority of population-based studies using validated sexual function questionnaires and high-quality androgen assays. In the Melbourne Women's Midlife Health Project, relationship factors (rather than changes in hormone levels) were the principal predictors of sexual function across the menopausal transition. In a community-based, cross-sectional study of over 1,000 women aged 18 to 75 years, there was no clinically significant relationship between androgens and level of sexual function. In an earlier study of correlates of circulating androgens in midlife women from SWAN, testosterone levels were associated minimally with increased sexual desire.
In the current SWAN study, masturbation, arousal, and sexual desire were positively associated with testosterone. As the authors clearly state, the relationships between sexual function and androgens are subtle and may be of limited clinical significance. The adjusted odds ratios for a change in sexual function associated with a single standard deviation increase in testosterone levels was 1.052 for desire and 1.073 for masturbation. These very small increases in odds ratios likely are only statistically significant due to the large number of data points available. Although prior research has shown a relationship between estradiol and dyspareunia in midlife women, likely due to the effect of estrogen deficiency on vulvovaginal atrophy, estradiol was not related to any sexual function domain measured in this study, including pain with intercourse.
Limitations of this study are that sexual function was assessed by a questionnaire designed by the SWAN investigators, not validated in other studies, and that hormone levels were drawn between cycle days 2 and 5 (in cycling women), a time when hormone levels are generally low. Interestingly, these findings do not necessarily support the general decline in sexual function observed with aging and across the menopausal transition, as testosterone changed in a U-shaped pattern in this study, with higher median testosterone levels reported at year 10 compared with year 5.
This well-designed study supports a relationship between endogenous androgens and sexual function in midlife women, increasing our understanding of the complex role of reproductive hormones in female sexuality.
Commentary by Jan L. Shifren, MD, NCMP
The role of testosterone in female sexual function remains uncertain and has been the topic of much high-quality investigation. When considering research in this area, it is important to distinguish between studies investigating the impact of testosterone in normal female sexual physiology and those examining the potential effectiveness of testosterone in the treatment of women with sexual dysfunction. The current study uses the SWAN database to address whether reproductive hormones are related to sexual function during the menopause transition. SWAN provides a great opportunity to examine this important question, as following a large group of women longitudinally over 10 years provides many observations and high statistical power to identify even small relationships between hormones and behavior. In addition, the study population is a community-based, multi-ethnic cohort, so findings should be generalizable to US women.
Prior research has identified a potential role for endogenous androgens in normal female sexuality. In women of reproductive age, an increase in midcycle sexual activity, correlating with the midcycle peak in testosterone, is seen in some but not all studies. An association is more likely to be seen in partner-independent activities, such as masturbation, likely because partnered activity is affected by a multitude of factors besides hormones and inherent level of desire, such as relationship quality, partner interest, and habit.
In contrast, a significant association between normal and impaired sexual function and serum androgen levels has not been seen in the majority of population-based studies using validated sexual function questionnaires and high-quality androgen assays. In the Melbourne Women's Midlife Health Project, relationship factors (rather than changes in hormone levels) were the principal predictors of sexual function across the menopausal transition. In a community-based, cross-sectional study of over 1,000 women aged 18 to 75 years, there was no clinically significant relationship between androgens and level of sexual function. In an earlier study of correlates of circulating androgens in midlife women from SWAN, testosterone levels were associated minimally with increased sexual desire.
In the current SWAN study, masturbation, arousal, and sexual desire were positively associated with testosterone. As the authors clearly state, the relationships between sexual function and androgens are subtle and may be of limited clinical significance. The adjusted odds ratios for a change in sexual function associated with a single standard deviation increase in testosterone levels was 1.052 for desire and 1.073 for masturbation. These very small increases in odds ratios likely are only statistically significant due to the large number of data points available. Although prior research has shown a relationship between estradiol and dyspareunia in midlife women, likely due to the effect of estrogen deficiency on vulvovaginal atrophy, estradiol was not related to any sexual function domain measured in this study, including pain with intercourse.
Limitations of this study are that sexual function was assessed by a questionnaire designed by the SWAN investigators, not validated in other studies, and that hormone levels were drawn between cycle days 2 and 5 (in cycling women), a time when hormone levels are generally low. Interestingly, these findings do not necessarily support the general decline in sexual function observed with aging and across the menopausal transition, as testosterone changed in a U-shaped pattern in this study, with higher median testosterone levels reported at year 10 compared with year 5.
This well-designed study supports a relationship between endogenous androgens and sexual function in midlife women, increasing our understanding of the complex role of reproductive hormones in female sexuality.