Age-Related Factors that Impact Sexual Functioning
Although the results from the Pfizer Global study indicates that the only sexual problem that increases with age is difficulty with lubrication, and other studies have reported that female sexual satisfaction does not decline appreciably with age (Laumann et al. 1999; Avis et. al 2000) research on the impact of menopause and sexual functioning has produced inconsistent and equivocal results, partially related to disagreements as to appropriate outcome measures. Avis et al. evaluated studies on postmenopausal sexual functioning and found wide variations in sexual functioning questions asked, time frames, inclusion of women without partners, and nature of study samples.[Avis. Menopause 2000] Very diverse outcome measures also were found, including satisfaction, frequency of activity, desire, sexual thoughts/fantasies, arousal, beliefs/attitudes, pain, and anorgasmia. Furthermore, only a few large, general population-based studies have evaluated the impact of menopause on sexuality [Hällström. Clin Obstet Gynaecol 1977; Koster. Maturitas 1993; Dennerstein. Maturitas 1997; Avis. Menopause 2000] Of these, only one the Massachusetts Women’s Health Study [Avis. Menopause 2000] evaluated North American women. In this study, menopause (but not serum estrogen levels) was found to be significantly associated with several sexual function measurements, including lower sexual desire, a belief that interest in sexual activity declines with age, and women’s reports of decreased arousal compared with their 40s. The investigators also evaluated the impact of several other variables including sociodemographic variables, health, psychological variables, partner variables (particularly partner health or sexual problems), and lifestyle variables.Their results suggest that these other factors have a greater impact on sexual functioning than does menopausal status, underscoring the importance of the need to understand the context of women’s lives when studying sexuality.
With regard to the impact of declining ovarian hormones on sexual function, diminishing estrogen levels have not been found to be associated with declining sexual interest. However, declining estrogen levels that occur during perimenopause often result in vaginal dryness and atrophy due to diminished blood flow to the vagina. The vagina is a cylindrical organ 7 to 15 cm in length. With sexual arousal, lubrication occurs as a result of secretions from the uterine glands and transudate from the subepithelial vasculature. The blood and nerve supplies to the vagina are similar to those of the penile shaft. Arterial blood flow branches off the uterine, pudendal, and ovarian arteries. The changes in the epithelial lining of the vagina occur relatively rapidly as estrogen levels decline. Subsequent vascular, muscular, and connective tissue changes occur over time. Decreased vascularization starves the surrounding tissues of nutrients and makes it more difficult for engorgement and lubrication. The vagina also loses its elasticity. Estrogen replacement therapy, unless medically contraindicated, will often prevent genital atrophy and preserves the epithelial integrity of urogenital tissues (Freedman, 2000). Topical estrogen cream or a vaginal estradiol ring may also help prevent genital atrophy and vaginal dryness (Berman & Goldstein, 2001). While vaginal dryness and dyspareunia are associated with estrogen loss, this may not become a significant problem affecting sexual function until well after menopause. Hot flashes can cause chronic sleep disturbances, which may affect psychological function. Negative changes in mood and well-being as well as poor self-esteem may also be related to decreased sexual function associated with menopause. It is also reasonable to assume that a male partner’s erectile difficulties or decline in drive play a role in a woman’s sexual activities.
Some experts believe that changes in sexual function are the result of either diminished estrogen effects on the cardiovascular system, which impairs arterial blood flow to the urogenital area, or decreased estrogenic effects on the central and peripheral nervous system, which impair touch and vibration perception. However, this would result in decreased arousability and orgasm and it is hypoactive desire that is the most prevalent sexual dysfunction for women.
The clitoris is composed of the clitoral gland and two corporal bodies that extend for perhaps 9 to 10 centimeters behind the head of the clitoris and along the under surface of the vagina. These corporal bodies are made of erectile tissue covered with a unilaminar tunica, rather than the trilayer tunica found in the penis. Therefore, the clitoris can become engorged, but it does not become erect. Clitoral changes from aging include shrinkage, a decrease in perfusion, diminished engorgement during the desire and arousal phases, and a decline in the neurophysiological response, including slowed nerve impulses and a decrease in touch perception, vibratory sensation, and reaction time. Decreased muscle tension may increase the time it takes for arousal to lead to orgasm, diminish the peak of orgasm, and cause a more rapid resolution. Additionally, the uterus typically contracts with orgasm, and with advancing age, those contractions may become painful. However, while all this sounds pretty ominous for older women, the actual perception of sexual satisfaction does not necessarily change.
Regardless of the cause, data have shown that sexual drive decreases with age, and the decrease is common in women in their 40s and 50s. [Diokno. Arch Intern Med 1990; Hawton. Arch Sex Behav 1994] Desire, however, is one of the outcome variables that has suffered from inconsistent measurement and lack of a clear definition.