FEW DATA ARE AVAILABLE on sexually transmitted diseases (STDs) in older persons. 1 Most studies on STDs have been among young people who carry the highest burden of these diseases and are at risk for reproductive sequelae such as ectopic pregnancy and infertility.
Although older persons traditionally have not been considered at risk for STDs, several factors may put them at risk. Physiologically, men and women are able to experience a fulfilling sex life well into advanced ages if they are in good health. 2 The estimated average frequency of sexual activity in persons 50 years of age or older is two to four times a month. 3 Older adults are not necessarily monogamous, and they use condoms infrequently. A national survey from 1990 to 1991 found that more than 2% of older Americans (ages 50–75 years) reported having two or more sexual partners in the preceding year. In the same survey, less than 4% of sexually active heterosexual older Americans with at least one risk factor for HIV infection had used condoms consistently in the preceding 6 months. 4 The sexual communication skills necessary for the adoption of safe sex practices may be less well developed in older persons. 3 Also, the aging process is accompanied by biologic age-related increases in susceptibility to STDs. In older women, the increased friability of the vaginal mucosa can result in tears and microabrasions during sexual intercourse, facilitating disease transmission. 5,6
Finally, Viagra (sildenafil citrate; Pfizer Inc., New York, NY), the newly available oral medication for erectile dysfunction, may increase sexual activity or facilitate its return in older persons. 7 The availability of new medicines such as Viagra could precipitate a rise in the number of STDs in older persons.
There are difficulties in conducting studies of STDs in older persons. Older persons may be reluctant to discuss information related to sexual practices and more vulnerable to the social stigma associated with STDs, making it difficult to obtain a sexual history. 8,9 Studies among older persons are further complicated by the lack of an ideal recruiting venue because older patients usually represent only a small fraction of the patient population at STD and family planning clinics. For these reasons, few studies have been reported, although some studies of STDs in older persons have been reported from genitourinary clinics in the United Kingdom. 10–12
This study analyzed surveillance data from Washington State to characterize the burden of disease, the source of care, and the risk factors for reportable STD in older persons. For STD surveillance, Washington State uses a provider-based reporting system, which collects more information on the patient and the healthcare provider than surveillance systems in many other states. This study included cases of syphilis, gonorrhea, chlamydia, genital herpes (first clinical episode), and nongonococcal urethritis (NGU) reported from 1992 to 1998.
In Washington State, all healthcare providers are required by law to report STD cases to local public health authorities or to the state health department. A single report form is used statewide. Laboratory evidence is required for the diagnosis of syphilis, gonorrhea, and chlamydia. Genital herpes can be diagnosed through clinical observation of typical lesions or by laboratory test. Only a patient’s first disease episode is reported. Nongonococcal urethritis is diagnosed by at least two of the following three features: history of urethral discharge or dysuria, purulent or mucopurulent urethral discharge on clinical examination, or urethral Gram stained smear showing four or more polymorphonuclear leukocytes per oil immersion field. Patients with positive laboratory tests for gonorrhea or chlamydia are reported as gonorrhea or chlamydia cases only, not as NGU cases.
In Washington State’s STD surveillance system, each healthcare setting in the state is assigned a unique identifier and classified into 19 clinic or provider types. Demographic variables including age, date of birth, and reason for examination are reported along with a healthcare setting identifier. For chlamydia and gonorrhea, the medication used for treatment is reported. For this study, azithromycin, doxycycline, erythromycin, ofloxacin, or amoxicillin (only in pregnant women) was considered appropriate treatment for chlamydia. For gonorrhea, ceftriaxone, cefixime, ciprofloxacin, spectinomycin, or ofloxacin was considered appropriate treatment.
For this analysis, the patient’s age at diagnosis was calculated from the date of birth, if known, or the reported age. In this report, the term “older persons” refers to persons 50 to 80 years of age. The unit of analysis is an episode of infection, so a patient may be counted two or more times if he or she had more than one infection at the same time or multiple infections during the study period. Rare STDs (fewer than 50 during the study period) such as chancroid were not included in this study. Chlamydial or gonococcal infections involving the eye only and patients at the extremes of age (younger than 10 years or older than 80 years) also were excluded. For syphilis, only cases of primary or secondary syphilis were included because latent cases could reflect disease acquired in the distant past. Data analyses were performed using SAS version 6.12 (SAS Institute Inc., Cary, NC).
From 1992 to 1998, age, date of birth, or both was available for 96.3% of the STD episodes reported in Washington State. Altogether, 115,701 episodes of STDs met the criteria for inclusion in this analysis.
During the study period, more than 94% of STDs were reported in persons younger than 40 years of age (Table 1). Over the period of 7 years, 1370 episodes of STDs were reported in persons ages 50 to 64 years and 165 episodes in persons ages 65 to 80 years. In addition, 4900 episodes of STDs were reported in persons 40 to 49 years of age. For all the men 50 years of age or older, the most common STD was NGU, followed by gonorrhea. For all the women in the same age group, the most common STD was genital herpes, followed by chlamydia.
The percentages of STDs reported in older persons varied by disease and gender (Table 1). Overall, approximately 1.3% (1,535/115,701) of STDs were reported in persons ages 50 to 80 years. The percentages of all STDs reported in persons 50 to 64 years of age ranged from 0.4% (chlamydia) to 4.1% (syphilis), and only 0.5% or less of STDs were reported in persons between 65 and 80 years of age. The percentages of STDs contributed by older persons also varied by gender. With the exception of herpes in women ages 65 to 80 years, higher percentages of STDs were reported in older men than in older women. For example, the percentage of gonorrhea cases diagnosed in 50- to 64-year-old men was 2%, as compared with only 0.3% in women of the same age group. For gonorrhea, the male-to-female case ratio increased sharply with age: from 0.7 in persons ages 10 to 24 years to 6.8 in those ages 50 to 80 years. A similar trend with age was found for chlamydia and early syphilis cases. For herpes, however, there were about twice as many cases in women as in men for all age groups.
To characterize STDs in older persons, selected factors were analyzed by age group and gender (Table 2). Because the number of cases reported in persons ages 65 to 80 years was small, all persons 50 years of age or older were combined into one group. This analysis also was limited to chlamydia and gonorrhea because data on treatment were available only for these two infections. Because only 33 cases of gonococcal infection were reported in women 50 years or older, data for men exclusively were presented.
As compared with younger men, older men with STDs were more likely to be white. For chlamydia, 64.8% of the reported cases in older persons involved white individuals, as compared with 51.3% in the younger age groups combined (P = 0.02, chi-square test;Table 2). For gonorrhea, the percentages were 52.2% for older persons and 38.3% for younger individuals (P = 0.001, chi-square test).
With increasing age, male patients also sought care more frequently at private clinics and had symptoms at the time of testing for both chlamydia and gonorrhea (P < 0.001, chi-square test for trend). Similar trends with age were found in women with chlamydia infection. However, there were differences in the source of care by gender, with men more likely than women to seek care at STD clinics.
For chlamydia, the percentages of cases that had been appropriately treated was high for both men (96%) and women (94%) and did not differ between the younger and the older age groups (P = 0.4 for men and 0.5 for women;Table 2). The percentage of appropriately treated cases was lower for gonorrhea among men (91%). When stratified by source of care, the proportion of patients who had been appropriately treated was similar for private and public clinics (data not shown).
In Washington State, although STDs in older persons were relatively rare compared with the high level of STDs in younger populations, a small but notable number of cases was reported among older persons for each of the five diseases studied. The burden of STDs varied by disease and gender. Of the four STDs affecting both older men and women, early syphilis and gonorrhea were predominantly reported in men, whereas more infections with chlamydia and genital herpes were reported in women.
The source of care for STDs varied by patient age. This might be expected for women. When the need for contraception decreases with age, gynecologic care inevitably shifts away from family planning clinics and toward providers at other clinics, especially private clinics. Because older persons are more likely to seek care from private providers, ascertaining asymptomatic STDs in older persons can be improved only if providers who do not routinely provide STD services have a greater awareness of the possibility of STDs and obtain a sexual history from older patients. A survey of primary care physicians found that most physicians reported that they rarely or never discuss HIV or AIDS with patients older than 50 years. 13 To increase detection of asymptomatic STDs in older persons, providers in various clinical settings should be aware of STD risk among older persons.
The current study had several potential limitations. First, as with most analyses using surveillance data, the study could have been subject to the bias associated with underdetection of asymptomatic infections and underreporting. Underdetection may be a greater problem for chlamydia in men and older women because annual screening for chlamydia is recommended only in women 24 years of age or younger. The bias of underreporting may be greater in older persons because older patients more frequently seek care at private clinics, and because private clinics may have worse compliance with reporting than publicly funded clinics. The underreporting bias because of provider noncompliance also may be larger for NGU and herpes, diseases for which laboratory testing may or may not be used for diagnosis. For these infections, the local health authorities cannot actively solicit cases from providers using laboratory-based reports, as they can for syphilis, gonorrhea, and chlamydia in Washington State.
Second, the diagnosis of NGU and genital herpes may be based solely on clinical impressions. The syndrome of NGU may represent an infection of different etiologies. Whereas some cases may be caused by common STD pathogens such as chlamydia or herpes, others may caused by microorganisms that are not sexually transmitted. 14 A clinical diagnosis of genital herpes in an older person may actually represent an activation of infection acquired in the remote past. Finally, the data in this study may have been subject to the bias of selective reporting. For example, the finding that the medications selected for treatment of most patients with chlamydia or gonorrhea were appropriate may have resulted, in part, from the fact that providers who complied with reporting requirements may have had better knowledge about STD treatments than those who did not report.
The aging of U.S. population and new developments in medicine necessitate more attention to the issue of STDs in older persons. Sildenafil (Viagra) was first marketed in April 1998 in the United States. Through the end of 1999, more than 17 million prescriptions had been written (personal communication, Pfizer Inc., December 1999). It is possible that many older persons have become sexually active because of this medication, and the pool of older persons at risk for STDs may have expanded. In 1998, 12,414 gonorrhea cases were reported in persons 45 years of age or older in the United Sates, an increase of 18.2% from 10,504 cases in 1997 in this age group, whereas the overall increase in younger persons was 17.3%. 15 The STDs in older persons should be monitored to determine whether this increasing trend continues in the future. Even when STD rates in older persons remain constant, older persons will contribute an increasing proportion of disease because the population older than 50 years is growing rapidly in the United States.
It is apparent that STDs, including HIV infection, affect individuals age 50 years or older. 10–12,16–18 Although STD prevention efforts should be focused on younger people, who are the population at highest risk, STD counseling regarding safer sex and risk reduction should be considered for persons of all ages, not just adolescents and young adults. More information about STD risk in older populations should be provided through various channels to increase the awareness of risk and to promote safe sex in older persons.
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