Medical students in North America were invited to participate in an internet-based survey. Invitations were extended via postings on the American Medical Student Association (AMSA) list-serves, the Student-Doctor Network (www.studentdoctor.net
), and a news story posted at Medscape (www.medscape.com/viewarticle/574229
). The survey was posted at QuestionPro.com and was available from February 22, 2008 until July 31, 2008. Approval for this study was granted by the Committee for Human Research (CHR) at our institution. Implied consent was assumed by subject participation in, and completion of, the survey instrument. Our CHR deemed this methodology for consent as adequate and compliant with relevant ethical and legal standards. Only one response per IP address was permitted so as to limit the potential for repeated submissions by a single individual.
The primary outcome measure was a single item question: “Which of the following statements best summarizes your feelings about your sexual function at this time?” Subjects could select just one response; options included 1) “I am satisfied with my sexual function and would not change anything”, 2) “I am mostly satisfied with my sexual function but there are things I would like to change”, 3) “I am dissatisfied with my sexual function but I don’t want to change anything at this time”, 4) “I am dissatisfied with my sexual function and there are things I would like to change”, 5) “I have a sexual problem or dysfunction and would like to do something about it”, and 6) “Sexual function and dysfunction are not issues for me”. Subjects who selected response “4” or “5” (endorsing a problem and desire for change) were considered to have “sexual bother” on subsequent analyses. Subjects who had not engaged in partnered sexual activity were not included in subsequent analyses.
The survey also consisted of a questionnaire that assessed age, ethnicity, relationship status, maternity, medical school location, year in medical school, and several other demographic characteristics. A sexuality survey was appended which assessed variables such as sexual orientation, age at first partnered sexual activity (if any), number of lifetime sexual partners, recent (past 6 months) sexual partners and past participation (yes/no) in specific sexual activities (masturbation, oral sex [giving and receiving], vaginal sex, anal sex [insertive and receptive], bondage/restraint [giving and receiving], sexual sadism, and sexual masochism).
To assess psychological morbidity in the study population, subjects completed the Center for Epidemiological Studies Depression Scale (CES-D), a 20 item instrument designed to assess presence and severity of depressive symptoms. A score of 16 or greater on the CES-D was taken as evidence of significant depressive symptoms.13
Subjects completed the FSFI for assessment of sexual function.4
A total score of 26.55 or less on the FSFI (score range 2–36) has been utilized as a cut-off value for “high risk” of female sexual dysfunction (HRFSD).14
In this validation study women with a diagnosed sexual dysfunction were compared to women without sexual dysfunction. The cut-off of 26.55 correctly classified 88% of the sexually functional women and 70% of the sexually dysfunctional women and was the optimal cut-point per their analyses.14
Subjects who were in relationships were asked to complete the Index of Sex Life (ISL), an 11 item validated instrument for the assessment of three domains including sexual drive, sexual life satisfaction, and general life satisfaction in women.6
The ISL also assesses disruption of sexual life from stress, tiredness, disease, and gynecological problems. The ISL was initially developed to assess sexual life and response to treatment in women whose partners had ED; however, the specific questions pertain to sexual and emotional variables relevant to her relationship with her partner and were therefore deemed of interest for this research.6
The sexuality specific instruments were developed and validated for use in subjects engaging in heterosexual coitus within the past 4 weeks. Subtle modifications to instructions and wording were made so as to maximize their applicability to subjects whose primary means of sexual expression is not heterosexual coitus (i.e. subjects in same sex relationships as well as heterosexual/bisexual subjects who engage in non-coital partnered sexual activity). These changes consisted primarily of 1) removing gender specific terms for the subject’s partner and replacing them with gender neutral pronouns/nouns and 2) expanding the scope of what constitutes “sexual intercourse” as “vaginal intercourse and/or stimulation of the genitalia with hands or mouth in the intent of producing orgasm (not as part of foreplay)” for the FSFI. A version of the FSFI similar to ours has been previously validated for use in lesbian women;15
we therefore deemed this instrument most appropriate for conducting a study in women of diverse sexual orientations.
Descriptive statistics were used to characterize the study population. Independent samples t-test and ANOVA were used to assess differences for continuous variables, while Chi squared tests were used for categorical variables. Levene’s test for unequal variance was used to ascertain differences in variance between comparison groups. The unequal variance t-test was used when variance was found to be unequal between groups. We report Odds Ratios (ORs) and their 95% confidence intervals to estimate the association between subject characteristics and sexual distress. Multivariable logistic regression models for sexual bother were developed with a-priori
selected predictor variables including gender, race, year in school, ethnicity, marital status, sexual orientation, sexual frequency, number of sexual partners in the last 6 months, and HRFSD. A second multivariable analysis was conducted examining individual domain scores for the FSFI and ISL; this was intended to ascertain which specifics aspects of sexual function were most clearly associated with odds of sexual bother in this population. For these domain specific analyses, we selected a change of ½ of a standard deviation from the mean for each domain as a clinically significant unit of change for bivariable and multivariable analysis.16
Subjects who had not ever had partnered sexual activity (virgins), had not had sexual activity within the past 4 weeks, and/or those that did not have complete data for all of the above were excluded from all analyses. Statistical significance was set at p<0.05 and all tests were 2-sided. STATA 10 (Statacorp, College Station, TX, USA) was used for all analysis.