- Email: [email protected]
Validation of the International Index of Erectile Function (IIEF) and presentation of norms in older men
Sexologies (2013) 22, e20—e26
Disponible en ligne sur
www.sciencedirect.com
ORIGINAL ARTICLE
Validation of the International Index of Erectile Function (IIEF) and presentation of norms in older men夽 L. Dargis (PhD(c)) a, G. Trudel (PhD) a,∗,b, J. Cadieux (BSc) a, L. Villeneuve (PhD(c)) a, M. Préville (PhD) c, R. Boyer (PhD) b a
Département de psychologie, université du Québec, C.P. 8888, Succ. Centre-ville, Montréal, Québec, H3C 3P8, Canada Centre de recherche Fernand Séguin of Louis H. Lafontaine Hospital, Montréal, Canada c Faculty of medicine, University of Sherbrooke, Sherbrooke, Canada b
Available online 15 February 2012
KEYWORDS IIEF; Validation; Older adults; Sexual function; Norms; Men
Summary The International Index of Erectile Function (IIEF) is a validated psychometric tool used to assess sexual function in men. However, past validations have focused on clinical populations and the questionnaire has been mainly used as a diagnostic tool to screen for erectile dysfunction. Even if this questionnaire has seldom been used for population studies, no validation was available in such settings with older francophone men. Therefore, we attempted to validate the IIEF in an older (65 years and over), non-clinical population of francophone men living with their spouses in Quebec. The IIEF showed good reliability and comparable results when compared to past validations. Norms have been suggested for the 65—74 years old and the 75 years and over. Also, the issues concerning the high rate of non-respondents to this questionnaire in population-based studies are discussed. Moreover, recommendations were made regarding the use of questionnaires assessing sexual function in older men. © 2012 Elsevier Masson SAS. All rights reserved.
Introduction Sexuality in older people has been increasingly studied in recent decades. This subject arouses mixed reactions that DOI of original article: http://dx.doi.org/10.1016/j.sexol.2012.01.003. 夽 Également en version franc ¸aise dans ce numéro : Dargis, L, Trudel G, Cadieux J, Villeneuve L, Préville M, Boyer R. Validation de l’Index International de la Fonction Erectile (IIFE) et présentation de normes chez les hommes aînés. ∗ Corresponding author. E-mail address: [email protected] (G. Trudel).
stem from myths, and sometimes downright negative conceptions (Boudreau et al., in preparation). However, studies and publications indicate that older people often continue to have a satisfying sex life (Libman, 1989; Lindau et al., 2007). To improve scientific knowledge on the sexuality of older people, research should collect data based on valid measures of sexual functioning. Many psychometric tools that evaluate sexuality are aimed at younger populations and conceptualize sex in a limited way, that is to say that sexual intercourse and frequency of sexual behaviour are often the two criteria of healthy sexual functioning (see Trudel and Goldfarb, 2006). However, the fact that sex in old age is
1158-1360/$ – see front matter © 2012 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.sexol.2012.01.001
Validation of the IIEF and presentation of norms in older men being redefined as several of its parameters change does not mean that it is less satisfying or less adequate (Brecher, 1984; DeLamater and Sill, 2005; Trudel and Goldfarb, 2006; Trudel et al., 2010). Many studies have observed the evolution of sexuality from a developmental perspective. Several physiological changes are associated with aging in men’s sexuality, such as a longer time required to achieve full erection and a greater difficulty in maintaining it (e.g. Kinsey et al., 1948), weakened ejaculation and orgasms (Masters and Johnson, 1966, 1981, 1982), longer refractory periods (Kaplan, 1990) and a decrease in testosterone levels (Stearnes et al., 1974). Nevertheless, it is possible for men of advanced age to have satisfactory sexual intercourse, and a majority of them report having an interest in sex (Trudel, 2002, 2005). The International Index of Erectile Function (IIEF; Rosen et al., 1997) is used to screen for erectile dysfunction among sexually active men. It is available in full (IIEF15; Rosen et al., 1997) or short versions (IIEF-5; Rosen et al., 1999). Developed in conjunction with the marketing of drugs such as sildenafil, it is a short self-reported questionnaire that assesses male sexual function in five domains for the previous four weeks. It is widely used with diverse populations and has been validated in several languages and several countries (see Rosen et al., 2002). For these validations, clinical populations were used in the vast majority of cases, and the IIEF always proved to be a reliable and valid instrument to assess erectile function of participants in a clinical trial setting. However, it has never been specifically validated in a representative sample of the older general population and this is the main objective of our research. Given the particularities of the prior validation studies involving clinical populations, comparisons with the past validations will be limited. Standards and cut-off points suggested for the IIEF were calculated using a control or placebo group to compare with the clinical populations. The average age of the participants in these validation studies ranged from 40 to 62 years (see Rosen et al., 2002). All validation studies have recruited sexually active participants since the questionnaire seeks to assess their sexual performance during the previous four weeks. If no sexual activity like the one described in the question took place recently, there is often the option of with: ‘‘I had no sexual activity’’. However, the instructions for scoring the questionnaire when participants have selected that option are not clear. Because of this, many problems have occurred during a validation in a younger population (mean age 21.8 years).The fact that participants could not answer the questions on a consistent basis if they had not had sex recently resulted in ambiguous scores (Rynja et al., 2010). Similar issues occurred in validations made with sexually inactive populations like asexual men and prostate cancer patients attending a rehabilitation center (Yule et al., 2011). Moreover, in epidemiological studies on erectile dysfunction, a large number of respondents to the IIEF end up being unclassified due to lack of data (18%), twice as high compared to other tools with comparable reliability (i.e. Massachusetts Male Aging Study Single Question and Brief Male Sexual Function Inventory; Derby et al., 2000).
e21 Rosen and his colleagues have also developed the IIEF’s female counterpart: the Female Sexual Function Index (FSFI, Rosen et al., 2000). For this scale very similar to the IIEF, the authors were clear regarding the treatment of respondents who had not had sex within the last four weeks. When these cases occur, questionnaires should be excluded from the calculations of total scores. Otherwise, no information can be drawn from the total score without risk of ambiguity. However, an interpretation can be derived from subscales that are completed in full. What about people who do not have sex as frequently as once every four weeks? And what about people whose sex life is not oriented specifically towards coitus, but rather towards other forms of sexuality (Trudel and Goldfarb, 2006)? Considering the changes in sexual practices occurring with age, one might think that the standards that apply to an older population in a questionnaire like the IIEF would be different from those that apply to a younger population. That is what this study will attempt to clarify. A validation of the IIEF-15 and IIEF-5 in an older population is presented here with the standards of scores for that population. To highlight the effect of aging on sexual function, two age groups are represented in the norm tables (65—74 years and 75 years and over). Also, a discussion on how to treat those who did not have sex recently and the implications of this procedure will be presented.
Methodology Data was collected during a longitudinal study of couples aged 65 and over (n = 508), residing in Quebec. Participants were recruited by stratified random sampling. To be eligible, they had to meet the following criteria: be able to read and understand French, be living with their spouse for at least a year, and both partners had to agree to participate in the study. In addition, at least one partner had to be aged 65 or over and none of the participants could have a moderate or severe cognitive impairment (a minimum score of 22 was required on the Mini Mental State Examination; Folstein et al., 1975). The study included 508 couples at T1 and 394 couples at T2, 18 months later. The participation rate was 72% and the attrition rate 22%.
Procedure The randomly selected couples were contacted by telephone, and those wishing to participate received a letter detailing the research project, including the name and a picture of the nurse that would be conducting the interview. Each couple was met at home or in another location of their choice by a nurse trained to administer the questionnaires, but blind to the research hypotheses. Given the sensitive nature of some questionnaires, respondents used a numeric keypad to enter their answers and a confirmation symbol (*) appeared on the nurse’s screen, indicating that the participant had responded while ensuring the confidentiality of his/her answers. Each couple received a $30 incentive for its participation.
e22
Measures Sexual function was measured using the International Index of Erectile Function (IIEF-15; Rosen et al., 1997). Several French translations of this questionnaire were available, but none had been validated. From these French versions, the research team selected the best translated items to ensure the clarity of the questions (Fréchette and Trudel, 2006). The IIEF consists of 15 items in total, distributed among five specific areas of male sexual function: erectile function, orgasmic function, desire, satisfaction with sexual intercourse and overall sexual satisfaction. Participants were asked questions measuring their sexual experience over the previous 4 weeks on a 5-point Likert scale. For example, in response to the question: ‘‘Over the past 4 weeks, how often did you get an erection during your sexual activities?’’, participants had to choose among five response options ranging from‘‘never or almost never’’ to ‘‘almost always or always’’. Ten of the 15 questions also offered the possibility of the following answer: ‘‘I had no sexual activity’’. An abridged version of the IIEF-15, which has been validated in English, is available (IIEF-5; Rosen et al., 1999). The IIEF-5 includes items 2, 4, 5, 7 and 15 from the IIEF-15. In this research, we have obtained validation results for both versions of the IIEF. To verify the IIEF’s divergent validity (i.e. the ability to stand out from measures assessing concepts related but different from the concept in question; Hogan, 2003), the Dyadic Adjustment Scale (Spanier, 1976, translated to French by Baillargeon et al., 1986) was used. This measure assesses the quality of dyadic relationships in four areas. The French adaptation shows satisfactory reliability, Cronbach’s alpha coefficients for each subscale ranging from .61 to .85, with an alpha of .91 for the full scale (Baillargeon et al., 1986). In this research, the alphas obtained were comparable, ranging from .62 to .86 for the subscales and reaching .88 for the complete measure. A second scale was also selected to verify the IIEF’s divergent validity: the Short Form Health Survey (SF-12, Ware et al., 1996). This questionnaire assesses physical and psychological health in respondents. This questionnaire is the short version of the Short Form Health Survey (SF-36, Ware et al., 1998). The longer version has been validated in several languages, including French (Perneger et al., 1995; Ware et al., 1998). However, even if the short version has been validated in English (Ware et al., 1996), as well as for an elderly population (Resnick and Nahm, 2001), there has been no validation to date for the French translation of the abridged version. To validate the IIEF in an older French population, the internal consistency of the measure was evaluated using Cronbach’s Alpha (Cronbach, 1951) for all subscales, as well as for the whole measure, at T1 and T2. Because of the long period of time between the two measurement times, the test-retest reliability could not be assessed. Then, to ensure divergent validity from other measures, correlations were calculated between the scores of participants on the IIEF and their scores on the Dyadic Adjustment Scale (Spanier, 1976) and the SF-12 (Ware et al., 1996). The scores defining the quartiles have been reported to establish norms for an old (65—74 years) and older population (75 years and
L. Dargis et al. over). Finally, t-tests were applied to verify if the age groups (65—74 years, 75 years and over) differed from each other on the IIEF-15, IIEF-5 and on the subscale of erectile function.
Excluded participants Many respondents used the response alternative: ‘‘I had no sexual activity over the last 4 weeks’’ or felt that the statement did not apply to their situation, in one place or another across the IIEF (T1: n = 358, T2: n = 288). According to the instructions provided by the authors of the questionnaire, choosing that option gives the participant a score of zero for that question. Following the recommendations given by the creators of the IIEF when they developed the FSFI (Rosen et al., 2000), only the questionnaires without zeros were included in the statistical analysis in order to validate the questionnaire. The scores of the participants who answered all the items of a subscale were included in the calculations specific to this subscale only. However, for comparative purposes and for the sake of representing the sexual functioning of older people in the general population as accurately as possible, tables of norms including and excluding participants who did not have sexual activity over the previous 4 weeks will be presented. A discussion on the implications of this procedure follows.
Results Reliability of the measurement scale Internal consistency (Cronbach’s Alpha) was calculated separately for each subscale and for the total measure, both for the IIEF-15 and the IIEF-5. The coefficients obtained atT1 are strong for most subscales, ranging between 0.81 and 0.88 (Table 1). Only the subscale of sexual satisfaction shows a lower but acceptable internal consistency (␣ = 0.61). When considered in its entirety, the IIEF-15 has a very strong internal consistency with an alpha of 0.91. T2 and the IIEF-5 yielded similar coefficients. The results are comparable to those obtained by Rosen et al. (1997) when developing the IIEF-15.
Table 1 Internal consistency of the International Index of Erectile Function (Cronbach’s Alpha).
IIEF-15 Erectilefunction Orgasmicfunction Desire Sexual satisfaction Global satisfaction IIEF-5 a
T1
T2
Rosen et al. 1997a
0.9 0.88 0.81 0.87 0.66 0.86 0.83
0.91 0.89 0.82 0.84 0.61 0.87 0.85
0.91 0.92 0.92 0.77 0.73 0.74 —
Clinical sample including participants using sildenafil and a control group (n = 111).
Validation of the IIEF and presentation of norms in older men Table 2
Correlations between the International Index of Erectile Function’s subscales (T1). EF
EF OF DE SS GS
e23
1.00 0.55 0.40 0.59 0.31
OF (1.00)a (0.55) (0.30) (0.76) (0.60)
1.00 0.41 0.62 0.45
(1.00) (0.39) (0.47) (0.53)
DE
SS
GS
1.00 (1.00) 0.53 (0.35) 0.38 (0.37)
1.00 (1.00) 0.44 (0.53)
1.00 (1.00)
EF: erectile function; OF: orgasmic function; DE: desire; SS; sexual satisfaction; GS: global satisfaction. a Correlations from Rosen et al. (1997) in parentheses.
Correlations between subscales
Divergent validity
Table 2 shows the correlations between each subscale at T1, and compares these coefficients with those obtained by Rosen et al. (1997). The results show that the correlations between the subscales of IIEF-15 are statistically significant and comparable those obtained by Rosen et al. (1997) in most cases. Some results are slightly different from those of Rosen et al. (1997), especially the strength of the relationship between the subscales of sexual satisfaction and erectile function, but they are not exceptional given the fluctuations observed in various validations published since the creation of the measure (Lim et al., 2003; Wiltink et al., 2003). These correlations indicate that there exists a link between these variables, but it is not strong enough a link that they would be considered as a single concept(thus justifying the existence of the subscales). Similar results were obtained at T2.
To ensure that the IIEF does not measure a concept other than sexual functioning, a test of divergent validity was applied. An instrument with good divergent validity would show low correlations with measures assessing different concepts. In this research, these other measures were the Dyadic Adjustment Scale (Spanier, 1976) at T1, as well as measures of physical and mental health (SF-12, Ware et al., 1996) atT2. The correlations obtained between these measures and the IIEF-5 and IIEF-15 were low (Table 3), suggesting a good divergent validity.
Table 3
To establish the standards of the scores on the IIEF-5 and IIEF-15 for a sexually active population of older men, the
Divergent validity of the International Index of Erectile Function, Pearson correlations. T1: Dyadic Adjustment Scale (Spanier, 1976)
IIEF-15 Erectile function Orgasmic function Desire Sexual satisfaction Global satisfaction IIEF-5
Table 4
Norms
T2: Short Form Health Survey (SF-12; Ware et al. 1996) Physical health
r
p
r
p
r
p
0.26 0.22 0.14 0.16 0.26 0.33 0.25
0.001 0.004 0.04 0.001 0.001 <0.001 0.001
0.24 0.21 0.13 0.23 0.18 0.13 0.25
0.03 0.03 0.14 <0.001 0.06 0.02 0.01
0.09 0.07 —0.05 0 0.17 0.08 0.06
0.39 0.46 0.6 0.99 0.09 0.2 0.55
International Index of Erectile Function (IIEF)-15 norms for men 65 to 74 years old. General populationa
Sexually active
Mean 25e centile 50e centile 75e centile Standard deviation Range a
Mental health
T1 (n = 101)
T2 (n = 66)
T1 (n = 230)
T2 (n = 168)
55.54 49 57 64 10.14 25—3
54.61 47 56 63 9.98 32—72
38 20 36.5 55 18.34 15—73
36.17 20 31.5 52.75 18.01 15—72
Includes participants that have been sexually active over the past four weeks and those who have not.
e24
L. Dargis et al.
Table 5
International Index of Erectile Function (IIEF)-15 norms for men 75 years old and over. General populationa
Sexually active
Mean 25e centile 50e centile 75e centile Standard deviation Range a
T1 (n = 49)
T2 (n = 40)
T1 (n = 260)
T2 (n = 215)
49.18 40.50 51.00 57.00 11.89 23—71
49.13 36.00 51.00 60.00 14.12 22—72
28.16 18.00 23.00 34.00 13.88 15—71
28.17 19.00 23.00 33.00 14.21 15—72
Includes participants that have been sexually active over the past four weeks and those who have not
Table 6
International Index of Erectile Function (IIEF)-5 norms for a sexually active population. 65 to 74 years old
Mean 25e centile 50e centile 75e centile Std. deviation Range
75 years old and over
T1 (n = 120)
T2 (n = 73)
T1 (n = 62)
T2 (n = 57)
17.50 14.00 19.00 21.00 5.14 5—25
17.82 14.00 18.00 21.00 4.70 7—25
16.06 12.00 16.50 20.00 5.09 6—25
14.61 10.00 14.00 19.50 5.59 5—25
scores corresponding to the boundaries of the quartiles, the mean, the standard deviation and range for each measurement time are presented in Tables 4—6 for two age groups: 65—74 years and 75 years and over. Since the IIEF cannot be used as a reliable tool to measure sexual function in sexually inactive people (Rosen et al., 2000), they are not considered in some of the norms described here for the sake of validation and reproduction of Rosen’s protocol. However, since the absence of genital sexual activity within couples reflects a change in global sexual function, Tables 4 and 5 each include a column of standards for the IIEF-15 which apply not only to the sexually active population, but also to the elderly who have not had genital sex within the previous four weeks. The lowest scores were assigned to the items with missing responses due to sexual inactivity. Also, norms on the erectile function subscale are presented in Table 7, comparing them with results obtained in a research using a younger sample of men (Rynja et al., 2010).
Table 7
Mean 25e centile 50e centile 75e centile Std. deviation Range a
T-tests Independent samples t-tests were applied to check whether the two age groups (65-74 years and 75 years and over) of sexually active people differed with respect to their scores on the IIEF -15, the IIEF-5 and the subscale of erectile function. At T1, significant differences were found between the groups on two out of the three measures (IIEF15: t (148) = 3.40, p = .001; erectile function subscale: t
Erectile function subscale norms for a sexually active population. 65 to 74 years old
b
The IIEF-5, however, does not offer the option of answering questions as follows: ‘‘I did not have sex in the past 4 weeks’’ (unlike the IIEF-15), and so does not allow participants to respond if they have not had sex recently. Inclusive standards for those who gave answers other than the default 5 choices are therefore not possible for the abridged version.
75 years old and over
Rynja et al. (2010)a
T1 (n = 112)
T2 (n = 72)
T1 (n = 60)
T2 (n = 53)
18 to 35 yrs
21.39 17 23 27 6.35 6—30
21.15 16 22.5 26 6.22 6—30
18.27 14 19 23 6.22 6—29
17.57 12 17 23.5 6.8 6—29
29.6 — 29.0b — 0.8 —
Results from Rynja et al.’s (2010) validation in a sample including sexually active coupled men aged 18 to 35. Median includes men in a relationship and single men.
Validation of the IIEF and presentation of norms in older men (170) = 3.10, p = .002). The IIEF-5 did not show significant differences between the age groups, t (180) = 1.80, p = .07. However, the differences between the age groups obtained atT2 were significant on all 3 measures (IIEF-15: t (104) = 2.34, p = .02; IIEF-5: t (128) = 3.55, p = .001; erectile function subscale: t (123) = 3.06, p = 003). In all cases, men aged 75 and older had lower scores than those aged between 65 and 74. Other t-tests were performed on the scores of all respondents, sexually active or not, to determine whether the age groups differed on theIIEF-15 and the subscale of erectile function. At T1, significant differences were obtained for both measures (IIEF-15: t (488) = 6.74, p < 001; erectile function subscale: t (495) = 6.71, p < 001) indicating that men aged 75 and older have lower scores on these measures than younger men. Similar results were obtained at T2.
Discussion A validation of the IIEF-5 and -15 in a random population sample of people aged 65 and over was carried out and norms for this population were established. It was assumed that IIEF scores for the older population would differ from those obtained in a younger population. It turns out that the IIEF norms for an older population are indeed lower than those observed in a younger population. Moreover, this change has been verified by the statistically significant differences detected between men 65 to 74 years old and those aged 75 and older. It can also be seen by the prevalence of potential erectile dysfunction in the sample. Cappalleri et al. (1999) suggested the cut-off point of 25 points on the subscale of erectile function to signal a risk of erectile dysfunction in the respondent. Taking care to exclude sexually inactive participants, Rynja et al. (2010) found 0% of erectile dysfunction in men aged 18-35 and a median score of 29. Using the same cut-off point suggested by Cappalleri et al. (1999), (75)% of sexually active people in our study (65 years and up) scored 25 or less on the subscale of erectile function, signalling a risk of erectile dysfunction. The median score is 21. These results are not surprising since the decline of sexual function in aging men is well documented. Also, 54% of participants in our sample had to be excluded from validation calculations for lack of recent sexual activity. This figure is not negligible, considering the fact that the participants lived with a partner. Although the presence of a partner at an advanced age is the best predictor of sexual activities (Kontula and Haavio-Mannila, 2009), it seems that most couples in our sample did not have the type of sex corresponding to the specific questions of the IIEF as often as once every four weeks. It is important to note that this rate is strongly influenced by the fact that the questionnaire assesses a purely genital sexuality, and that sexuality at that age does not necessarily include this type of sex (Trudel and Goldfarb, 2006). In that sense, several authors have emphasized the persistence of sexual activities with increasing age while indicating that the repertoire of sexual behaviours changes. A study by Trudel and Goldfarb (2006) compared sexual activity in people of different age levels using the Inventory of Sexual Behaviour and showed reduced coital activity among older people. Another survey
e25 (Trudel, 2002) also highlights changes in sexual activity with increasing age. Jarousse (1995) indicates that activities associated with tenderness are particularly characteristic of the sexuality of older adults. Several biological, psychological and social influences can cause a decrease in the frequency of genital sexual activity (Rose and Soares, 1993; Rienzo, 1985). Even if we cannot identify a particular cause, this figure (54% of men excluded from our study) reflects a change in sexual function. Note that several participants let us know that the type of sexual activity described in the IIEF did not correspond to their current reality. It is appropriate to take this into account in order to set standards which represent all men of this age, not just the sexually active ones as per the IIEF’s standards. Therefore, in this study, we have also proposed standards that take into account the men who did not engage in the sexual activities described in the questions during the four weeks preceding the IIEF testing. If the IIEF is used as a tool to portray the reality of genital sexual function in general, and not specifically as a tool to screen for erectile dysfunction, new scores can be established by awarding the least points to participants who reported no recent sexual activity. We suggest that these standards, where lower scores indicate lower genital sexual function rather than lower general sexual functioning, provide a more adequate assessment of sexual functioning in both the more active and the less sexually active older men. Although these results provide information about sexuality in older men, the IIEF has many limitations in the overall assessment of sexual function in a population-based study. Some recommendations on the use of questionnaires on sexuality in the context of population studies of older men may be derived from this research. First, it would be advisable to have a longer evaluation period to adapt to the low frequency of genital sexual behaviour in this population. Extending this period to six months would allow the inclusion of a maximum number of participants, as this was done in other studies (Cheng et al., 2007). Also, measures of sexual functioning based on a broader definition of sexuality and focusing on a more diverse repertoire of sexual activities would be better suited to older people than those assessing genital sexuality exclusively, given the healthy and adaptive decline in the frequency of such activities in this population.
Disclosure of interest The authors declare that they have no conflicts of interest concerning this article.
Acknowledgements This research was conducted with the support of a grant to Dr Gilles Trudel, Ph.D. (Principal researcher) by Canadian Institute of Health Research (MOP - 81281) and by Fonds de Recherche en Santé du Québec. The authors wish to thanks Marie-Pascale Leblond for her helpful collaboration in the writing of this paper.
e26
References Baillargeon J, Dubois G, Marineau N. Traduction franc ¸aise de l’Échelle d’Ajustement Dyadique. Canadian Journal of Behavioral Sciences 1986;18(1):25—30. Brecher EM. Love, sex, and aging: a consumers’ union report. Boston, MA: Little, Brown; 1984. Cappalleri JC, Rosen RC, Smith MD, Mishra A, Osterloh IH. Diagnostic evaluation of the erectile function domain of the International Index of Erectile Function. Urology 1999;54:346—51. Cheng JYW, Ng EML, Ko JSN. Depressive symptomatology and male sexual functions in late life. J Affect Disord 2007;104:225—9. Cronbach LJ. Coefficient Alpha and the internal structure of tests. Psychometrika 1951;16:L297—334. DeLamater J, Sill M. Sexual desire in later life. Journal of Sex Research 2005;42:138—49. Derby CA, Araujo AB, Johannes CB, Feldman HA, McKinlay JB. Measurement of erectile dysfunction in population-based studies: the use of a single question self-assessment in the Massachusetts Male Aging Study. International Journal of Impotence Research 2000;12(4):197—204. Folstein MF, Folstein SE, McHugh PR. Mini-mental state. A practical method for grading the cognitive state of patients for the clinician. Journal of Psychiatric Research 1975;12(3): 189—98. Fréchette V, Trudel G. Version franc ¸aise de l’International Index of Erectile Function 2006. Unpublished document. Hogan PT. Psychological Testing. A Practical Introduction. New York, NY: John Wiley & Sons, Inc; 2003. Jarousse N. Sexualité et vieillissement. Ramonville Saint-Agne: Eres; 1995. Kaplan HS. Sex, intimacy, and the aging process. Journal of the American Academy of Psychoanalysis 1990;12:185—205. Kinsey AC, Pomeroy WB, Martin CE. Sexual Behavior in the Human Male. Philadelphia, PA: W.B. Saunders; 1948. Kontula O, Haavio-Mannila E. The impact of aging on human sexual activity and sexual desire. Journal of Sex Research 2009;46(1):46—56. Libman E. Sociocultural and cognitive factors in aging and sexual expression: conceptual and research issues. Psychologie canadienne 1989;30:560—7. Lim TO, Das A, Rampal S, Zaki M, Sahabudin RM, Rohan MJ, et al. Cross-cultural adaptation and validation of the English version of the International Index of Erectile Function (IIEF) for use in Malaysia. International Journal of Impotence Research 2003;15:329—36. Lindau ST, Schumm O, Laumann EO, Levinson W, O’Muircheartaigh CA, Waite LJ. A study of sexuality and health among older adults in the United States. New England Journal of Medicine 2007;257(8):762—74. Masters WH, Johnson VE. Human sexual response. Boston, MA: Little Brown; 1966. Masters WH, Johnson VE. Sex and the aging process. Journal of The American Geriatrics Society 1981;29:385—90. Masters WH, Johnson VE. Human sexuality. Boston, MA: Little Brown; 1982. Perneger TV, Leplege A, Etter J-F, Rougemont A. Validation of a French-language version of the MOS 36-item short form health
L. Dargis et al. survey (SF-36) in young healthy adults. Journal Clinical Epidemiology 1995;48(8):1051—60. Resnick B, Nahm ES. Reliability and validity testing of the Revised 12item short-form health survey in older adults. Journal of Nursing Measurement 2001;9(2):151—61. Rienzo BA. The impact of aging on human sexuality. J Sch Health 1985;55:66—8. Rose MK, Soares HH. Sexual adaptation of the frail elderly: a realistic approach. J Gerontol Soc Work 1993;19:167—78. Rosen RC, Riley A, Wagner G, Osterloh IH, Kirkpatrick J, Mishra A. The international index of erectile function (IIEF): a multidimensional scale for assessment of erectile dysfunction. Urology 1997;49(6):822—30. Rosen RC, Cappalleri JC, Smith MD, Lipsky J, Pena BM. Development and evaluation of an abridged, 5-item version of the International Index of Erectile Function (IIEF-5) as a diagnostic tool for erectile dysfunction. International Journal of Impotence Research 1999;11:319—26. Rosen R, Brown C, Heiman J, Leiblum S, Meston C, Shabsigh R, et al. The Female Sexual Function Index (FSFI): A multidimensional self-report instrument for the assessment of female sexual function. Journal of Sex Marital Therapy 2000;26:191—208. Rosen RC, Cappalleri JC, Gendrano III N. The international index of erectile function (IIEF): a state-of-the-science review. International Journal of Impotence Research 2002;14:226—44. Rynja S, Bosch R, Kok E, Wouters G, de Kort L. IIEF-15: Unsuitable for assessing erectile function of young men ? Journal of Sex Medicine 2010;7:2825—30. Spanier GB. Measuring dyadic adjustment: new scales for assessing the equality of marriage and similar dyads. Journal of Marriage and the Family 1976;38(1):15—28. Stearnes EL, MacDonnell JA, Kaufman BJ. Declining testicular function with age: hormonal and clinical correlates. American Journal of Medicine 1974;57:761—3. Trudel G. Sexuality and marital life: the results of a survey. Journal of Sex and Marital Therapy 2002;28:229—49. Trudel G. Les dysfonctions sexuelles : évaluation et traitement par des méthodes psychologique, interpersonnelle et biologique (2e éd.). Sainte-Foy, QC: Presses de l’Université du Québec; 2005. Trudel G, Goldfarb MR. L’effet de l’âge sur le répertoire et le plaisir sexuel. Sexologies 2006;15:266—72 [The effect of age on sexualrepertoire and its concomitant pleasure]. Trudel G, Turgeon L, Piché L. Marital and sexual aspects of old age. Sexual and Relationship Therapy 2010;25(3):316—41. Ware JE, Kosinski M, Keller SD. A 12-item Short Form Health Survey: Construction of scales and preliminary tests of reliability and validity Medical. Care 1996;34(3):220—33. Ware JE, Kosinski M, Gandek B, et al. The Factor Structure of the SF36 Health Survey in 10 Countries: results from the IQOLA Project. Journal Clinical Epidemiology 1998;51(11):1159—65. Wiltink J, Hauck EW, Phadayanon M, Weidner W, Beutel ME. Validation of the German version of the International Index of Erectile Function (IIEF) in patients with erectile dysfunction. Peyronie’s disease and controls. International Journal of Impotence Research 2003;15:192—7. Yule M, Davison J, Brotto L. The international index of erectile function: a methodological critique and suggestions for improvement. Journal of Sex and Marital Therapy 2011;31:255—69.
Disponible en ligne sur
www.sciencedirect.com
ORIGINAL ARTICLE
Validation of the International Index of Erectile Function (IIEF) and presentation of norms in older men夽 L. Dargis (PhD(c)) a, G. Trudel (PhD) a,∗,b, J. Cadieux (BSc) a, L. Villeneuve (PhD(c)) a, M. Préville (PhD) c, R. Boyer (PhD) b a
Département de psychologie, université du Québec, C.P. 8888, Succ. Centre-ville, Montréal, Québec, H3C 3P8, Canada Centre de recherche Fernand Séguin of Louis H. Lafontaine Hospital, Montréal, Canada c Faculty of medicine, University of Sherbrooke, Sherbrooke, Canada b
Available online 15 February 2012
KEYWORDS IIEF; Validation; Older adults; Sexual function; Norms; Men
Summary The International Index of Erectile Function (IIEF) is a validated psychometric tool used to assess sexual function in men. However, past validations have focused on clinical populations and the questionnaire has been mainly used as a diagnostic tool to screen for erectile dysfunction. Even if this questionnaire has seldom been used for population studies, no validation was available in such settings with older francophone men. Therefore, we attempted to validate the IIEF in an older (65 years and over), non-clinical population of francophone men living with their spouses in Quebec. The IIEF showed good reliability and comparable results when compared to past validations. Norms have been suggested for the 65—74 years old and the 75 years and over. Also, the issues concerning the high rate of non-respondents to this questionnaire in population-based studies are discussed. Moreover, recommendations were made regarding the use of questionnaires assessing sexual function in older men. © 2012 Elsevier Masson SAS. All rights reserved.
Introduction Sexuality in older people has been increasingly studied in recent decades. This subject arouses mixed reactions that DOI of original article: http://dx.doi.org/10.1016/j.sexol.2012.01.003. 夽 Également en version franc ¸aise dans ce numéro : Dargis, L, Trudel G, Cadieux J, Villeneuve L, Préville M, Boyer R. Validation de l’Index International de la Fonction Erectile (IIFE) et présentation de normes chez les hommes aînés. ∗ Corresponding author. E-mail address: [email protected] (G. Trudel).
stem from myths, and sometimes downright negative conceptions (Boudreau et al., in preparation). However, studies and publications indicate that older people often continue to have a satisfying sex life (Libman, 1989; Lindau et al., 2007). To improve scientific knowledge on the sexuality of older people, research should collect data based on valid measures of sexual functioning. Many psychometric tools that evaluate sexuality are aimed at younger populations and conceptualize sex in a limited way, that is to say that sexual intercourse and frequency of sexual behaviour are often the two criteria of healthy sexual functioning (see Trudel and Goldfarb, 2006). However, the fact that sex in old age is
1158-1360/$ – see front matter © 2012 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.sexol.2012.01.001
Validation of the IIEF and presentation of norms in older men being redefined as several of its parameters change does not mean that it is less satisfying or less adequate (Brecher, 1984; DeLamater and Sill, 2005; Trudel and Goldfarb, 2006; Trudel et al., 2010). Many studies have observed the evolution of sexuality from a developmental perspective. Several physiological changes are associated with aging in men’s sexuality, such as a longer time required to achieve full erection and a greater difficulty in maintaining it (e.g. Kinsey et al., 1948), weakened ejaculation and orgasms (Masters and Johnson, 1966, 1981, 1982), longer refractory periods (Kaplan, 1990) and a decrease in testosterone levels (Stearnes et al., 1974). Nevertheless, it is possible for men of advanced age to have satisfactory sexual intercourse, and a majority of them report having an interest in sex (Trudel, 2002, 2005). The International Index of Erectile Function (IIEF; Rosen et al., 1997) is used to screen for erectile dysfunction among sexually active men. It is available in full (IIEF15; Rosen et al., 1997) or short versions (IIEF-5; Rosen et al., 1999). Developed in conjunction with the marketing of drugs such as sildenafil, it is a short self-reported questionnaire that assesses male sexual function in five domains for the previous four weeks. It is widely used with diverse populations and has been validated in several languages and several countries (see Rosen et al., 2002). For these validations, clinical populations were used in the vast majority of cases, and the IIEF always proved to be a reliable and valid instrument to assess erectile function of participants in a clinical trial setting. However, it has never been specifically validated in a representative sample of the older general population and this is the main objective of our research. Given the particularities of the prior validation studies involving clinical populations, comparisons with the past validations will be limited. Standards and cut-off points suggested for the IIEF were calculated using a control or placebo group to compare with the clinical populations. The average age of the participants in these validation studies ranged from 40 to 62 years (see Rosen et al., 2002). All validation studies have recruited sexually active participants since the questionnaire seeks to assess their sexual performance during the previous four weeks. If no sexual activity like the one described in the question took place recently, there is often the option of with: ‘‘I had no sexual activity’’. However, the instructions for scoring the questionnaire when participants have selected that option are not clear. Because of this, many problems have occurred during a validation in a younger population (mean age 21.8 years).The fact that participants could not answer the questions on a consistent basis if they had not had sex recently resulted in ambiguous scores (Rynja et al., 2010). Similar issues occurred in validations made with sexually inactive populations like asexual men and prostate cancer patients attending a rehabilitation center (Yule et al., 2011). Moreover, in epidemiological studies on erectile dysfunction, a large number of respondents to the IIEF end up being unclassified due to lack of data (18%), twice as high compared to other tools with comparable reliability (i.e. Massachusetts Male Aging Study Single Question and Brief Male Sexual Function Inventory; Derby et al., 2000).
e21 Rosen and his colleagues have also developed the IIEF’s female counterpart: the Female Sexual Function Index (FSFI, Rosen et al., 2000). For this scale very similar to the IIEF, the authors were clear regarding the treatment of respondents who had not had sex within the last four weeks. When these cases occur, questionnaires should be excluded from the calculations of total scores. Otherwise, no information can be drawn from the total score without risk of ambiguity. However, an interpretation can be derived from subscales that are completed in full. What about people who do not have sex as frequently as once every four weeks? And what about people whose sex life is not oriented specifically towards coitus, but rather towards other forms of sexuality (Trudel and Goldfarb, 2006)? Considering the changes in sexual practices occurring with age, one might think that the standards that apply to an older population in a questionnaire like the IIEF would be different from those that apply to a younger population. That is what this study will attempt to clarify. A validation of the IIEF-15 and IIEF-5 in an older population is presented here with the standards of scores for that population. To highlight the effect of aging on sexual function, two age groups are represented in the norm tables (65—74 years and 75 years and over). Also, a discussion on how to treat those who did not have sex recently and the implications of this procedure will be presented.
Methodology Data was collected during a longitudinal study of couples aged 65 and over (n = 508), residing in Quebec. Participants were recruited by stratified random sampling. To be eligible, they had to meet the following criteria: be able to read and understand French, be living with their spouse for at least a year, and both partners had to agree to participate in the study. In addition, at least one partner had to be aged 65 or over and none of the participants could have a moderate or severe cognitive impairment (a minimum score of 22 was required on the Mini Mental State Examination; Folstein et al., 1975). The study included 508 couples at T1 and 394 couples at T2, 18 months later. The participation rate was 72% and the attrition rate 22%.
Procedure The randomly selected couples were contacted by telephone, and those wishing to participate received a letter detailing the research project, including the name and a picture of the nurse that would be conducting the interview. Each couple was met at home or in another location of their choice by a nurse trained to administer the questionnaires, but blind to the research hypotheses. Given the sensitive nature of some questionnaires, respondents used a numeric keypad to enter their answers and a confirmation symbol (*) appeared on the nurse’s screen, indicating that the participant had responded while ensuring the confidentiality of his/her answers. Each couple received a $30 incentive for its participation.
e22
Measures Sexual function was measured using the International Index of Erectile Function (IIEF-15; Rosen et al., 1997). Several French translations of this questionnaire were available, but none had been validated. From these French versions, the research team selected the best translated items to ensure the clarity of the questions (Fréchette and Trudel, 2006). The IIEF consists of 15 items in total, distributed among five specific areas of male sexual function: erectile function, orgasmic function, desire, satisfaction with sexual intercourse and overall sexual satisfaction. Participants were asked questions measuring their sexual experience over the previous 4 weeks on a 5-point Likert scale. For example, in response to the question: ‘‘Over the past 4 weeks, how often did you get an erection during your sexual activities?’’, participants had to choose among five response options ranging from‘‘never or almost never’’ to ‘‘almost always or always’’. Ten of the 15 questions also offered the possibility of the following answer: ‘‘I had no sexual activity’’. An abridged version of the IIEF-15, which has been validated in English, is available (IIEF-5; Rosen et al., 1999). The IIEF-5 includes items 2, 4, 5, 7 and 15 from the IIEF-15. In this research, we have obtained validation results for both versions of the IIEF. To verify the IIEF’s divergent validity (i.e. the ability to stand out from measures assessing concepts related but different from the concept in question; Hogan, 2003), the Dyadic Adjustment Scale (Spanier, 1976, translated to French by Baillargeon et al., 1986) was used. This measure assesses the quality of dyadic relationships in four areas. The French adaptation shows satisfactory reliability, Cronbach’s alpha coefficients for each subscale ranging from .61 to .85, with an alpha of .91 for the full scale (Baillargeon et al., 1986). In this research, the alphas obtained were comparable, ranging from .62 to .86 for the subscales and reaching .88 for the complete measure. A second scale was also selected to verify the IIEF’s divergent validity: the Short Form Health Survey (SF-12, Ware et al., 1996). This questionnaire assesses physical and psychological health in respondents. This questionnaire is the short version of the Short Form Health Survey (SF-36, Ware et al., 1998). The longer version has been validated in several languages, including French (Perneger et al., 1995; Ware et al., 1998). However, even if the short version has been validated in English (Ware et al., 1996), as well as for an elderly population (Resnick and Nahm, 2001), there has been no validation to date for the French translation of the abridged version. To validate the IIEF in an older French population, the internal consistency of the measure was evaluated using Cronbach’s Alpha (Cronbach, 1951) for all subscales, as well as for the whole measure, at T1 and T2. Because of the long period of time between the two measurement times, the test-retest reliability could not be assessed. Then, to ensure divergent validity from other measures, correlations were calculated between the scores of participants on the IIEF and their scores on the Dyadic Adjustment Scale (Spanier, 1976) and the SF-12 (Ware et al., 1996). The scores defining the quartiles have been reported to establish norms for an old (65—74 years) and older population (75 years and
L. Dargis et al. over). Finally, t-tests were applied to verify if the age groups (65—74 years, 75 years and over) differed from each other on the IIEF-15, IIEF-5 and on the subscale of erectile function.
Excluded participants Many respondents used the response alternative: ‘‘I had no sexual activity over the last 4 weeks’’ or felt that the statement did not apply to their situation, in one place or another across the IIEF (T1: n = 358, T2: n = 288). According to the instructions provided by the authors of the questionnaire, choosing that option gives the participant a score of zero for that question. Following the recommendations given by the creators of the IIEF when they developed the FSFI (Rosen et al., 2000), only the questionnaires without zeros were included in the statistical analysis in order to validate the questionnaire. The scores of the participants who answered all the items of a subscale were included in the calculations specific to this subscale only. However, for comparative purposes and for the sake of representing the sexual functioning of older people in the general population as accurately as possible, tables of norms including and excluding participants who did not have sexual activity over the previous 4 weeks will be presented. A discussion on the implications of this procedure follows.
Results Reliability of the measurement scale Internal consistency (Cronbach’s Alpha) was calculated separately for each subscale and for the total measure, both for the IIEF-15 and the IIEF-5. The coefficients obtained atT1 are strong for most subscales, ranging between 0.81 and 0.88 (Table 1). Only the subscale of sexual satisfaction shows a lower but acceptable internal consistency (␣ = 0.61). When considered in its entirety, the IIEF-15 has a very strong internal consistency with an alpha of 0.91. T2 and the IIEF-5 yielded similar coefficients. The results are comparable to those obtained by Rosen et al. (1997) when developing the IIEF-15.
Table 1 Internal consistency of the International Index of Erectile Function (Cronbach’s Alpha).
IIEF-15 Erectilefunction Orgasmicfunction Desire Sexual satisfaction Global satisfaction IIEF-5 a
T1
T2
Rosen et al. 1997a
0.9 0.88 0.81 0.87 0.66 0.86 0.83
0.91 0.89 0.82 0.84 0.61 0.87 0.85
0.91 0.92 0.92 0.77 0.73 0.74 —
Clinical sample including participants using sildenafil and a control group (n = 111).
Validation of the IIEF and presentation of norms in older men Table 2
Correlations between the International Index of Erectile Function’s subscales (T1). EF
EF OF DE SS GS
e23
1.00 0.55 0.40 0.59 0.31
OF (1.00)a (0.55) (0.30) (0.76) (0.60)
1.00 0.41 0.62 0.45
(1.00) (0.39) (0.47) (0.53)
DE
SS
GS
1.00 (1.00) 0.53 (0.35) 0.38 (0.37)
1.00 (1.00) 0.44 (0.53)
1.00 (1.00)
EF: erectile function; OF: orgasmic function; DE: desire; SS; sexual satisfaction; GS: global satisfaction. a Correlations from Rosen et al. (1997) in parentheses.
Correlations between subscales
Divergent validity
Table 2 shows the correlations between each subscale at T1, and compares these coefficients with those obtained by Rosen et al. (1997). The results show that the correlations between the subscales of IIEF-15 are statistically significant and comparable those obtained by Rosen et al. (1997) in most cases. Some results are slightly different from those of Rosen et al. (1997), especially the strength of the relationship between the subscales of sexual satisfaction and erectile function, but they are not exceptional given the fluctuations observed in various validations published since the creation of the measure (Lim et al., 2003; Wiltink et al., 2003). These correlations indicate that there exists a link between these variables, but it is not strong enough a link that they would be considered as a single concept(thus justifying the existence of the subscales). Similar results were obtained at T2.
To ensure that the IIEF does not measure a concept other than sexual functioning, a test of divergent validity was applied. An instrument with good divergent validity would show low correlations with measures assessing different concepts. In this research, these other measures were the Dyadic Adjustment Scale (Spanier, 1976) at T1, as well as measures of physical and mental health (SF-12, Ware et al., 1996) atT2. The correlations obtained between these measures and the IIEF-5 and IIEF-15 were low (Table 3), suggesting a good divergent validity.
Table 3
To establish the standards of the scores on the IIEF-5 and IIEF-15 for a sexually active population of older men, the
Divergent validity of the International Index of Erectile Function, Pearson correlations. T1: Dyadic Adjustment Scale (Spanier, 1976)
IIEF-15 Erectile function Orgasmic function Desire Sexual satisfaction Global satisfaction IIEF-5
Table 4
Norms
T2: Short Form Health Survey (SF-12; Ware et al. 1996) Physical health
r
p
r
p
r
p
0.26 0.22 0.14 0.16 0.26 0.33 0.25
0.001 0.004 0.04 0.001 0.001 <0.001 0.001
0.24 0.21 0.13 0.23 0.18 0.13 0.25
0.03 0.03 0.14 <0.001 0.06 0.02 0.01
0.09 0.07 —0.05 0 0.17 0.08 0.06
0.39 0.46 0.6 0.99 0.09 0.2 0.55
International Index of Erectile Function (IIEF)-15 norms for men 65 to 74 years old. General populationa
Sexually active
Mean 25e centile 50e centile 75e centile Standard deviation Range a
Mental health
T1 (n = 101)
T2 (n = 66)
T1 (n = 230)
T2 (n = 168)
55.54 49 57 64 10.14 25—3
54.61 47 56 63 9.98 32—72
38 20 36.5 55 18.34 15—73
36.17 20 31.5 52.75 18.01 15—72
Includes participants that have been sexually active over the past four weeks and those who have not.
e24
L. Dargis et al.
Table 5
International Index of Erectile Function (IIEF)-15 norms for men 75 years old and over. General populationa
Sexually active
Mean 25e centile 50e centile 75e centile Standard deviation Range a
T1 (n = 49)
T2 (n = 40)
T1 (n = 260)
T2 (n = 215)
49.18 40.50 51.00 57.00 11.89 23—71
49.13 36.00 51.00 60.00 14.12 22—72
28.16 18.00 23.00 34.00 13.88 15—71
28.17 19.00 23.00 33.00 14.21 15—72
Includes participants that have been sexually active over the past four weeks and those who have not
Table 6
International Index of Erectile Function (IIEF)-5 norms for a sexually active population. 65 to 74 years old
Mean 25e centile 50e centile 75e centile Std. deviation Range
75 years old and over
T1 (n = 120)
T2 (n = 73)
T1 (n = 62)
T2 (n = 57)
17.50 14.00 19.00 21.00 5.14 5—25
17.82 14.00 18.00 21.00 4.70 7—25
16.06 12.00 16.50 20.00 5.09 6—25
14.61 10.00 14.00 19.50 5.59 5—25
scores corresponding to the boundaries of the quartiles, the mean, the standard deviation and range for each measurement time are presented in Tables 4—6 for two age groups: 65—74 years and 75 years and over. Since the IIEF cannot be used as a reliable tool to measure sexual function in sexually inactive people (Rosen et al., 2000), they are not considered in some of the norms described here for the sake of validation and reproduction of Rosen’s protocol. However, since the absence of genital sexual activity within couples reflects a change in global sexual function, Tables 4 and 5 each include a column of standards for the IIEF-15 which apply not only to the sexually active population, but also to the elderly who have not had genital sex within the previous four weeks. The lowest scores were assigned to the items with missing responses due to sexual inactivity. Also, norms on the erectile function subscale are presented in Table 7, comparing them with results obtained in a research using a younger sample of men (Rynja et al., 2010).
Table 7
Mean 25e centile 50e centile 75e centile Std. deviation Range a
T-tests Independent samples t-tests were applied to check whether the two age groups (65-74 years and 75 years and over) of sexually active people differed with respect to their scores on the IIEF -15, the IIEF-5 and the subscale of erectile function. At T1, significant differences were found between the groups on two out of the three measures (IIEF15: t (148) = 3.40, p = .001; erectile function subscale: t
Erectile function subscale norms for a sexually active population. 65 to 74 years old
b
The IIEF-5, however, does not offer the option of answering questions as follows: ‘‘I did not have sex in the past 4 weeks’’ (unlike the IIEF-15), and so does not allow participants to respond if they have not had sex recently. Inclusive standards for those who gave answers other than the default 5 choices are therefore not possible for the abridged version.
75 years old and over
Rynja et al. (2010)a
T1 (n = 112)
T2 (n = 72)
T1 (n = 60)
T2 (n = 53)
18 to 35 yrs
21.39 17 23 27 6.35 6—30
21.15 16 22.5 26 6.22 6—30
18.27 14 19 23 6.22 6—29
17.57 12 17 23.5 6.8 6—29
29.6 — 29.0b — 0.8 —
Results from Rynja et al.’s (2010) validation in a sample including sexually active coupled men aged 18 to 35. Median includes men in a relationship and single men.
Validation of the IIEF and presentation of norms in older men (170) = 3.10, p = .002). The IIEF-5 did not show significant differences between the age groups, t (180) = 1.80, p = .07. However, the differences between the age groups obtained atT2 were significant on all 3 measures (IIEF-15: t (104) = 2.34, p = .02; IIEF-5: t (128) = 3.55, p = .001; erectile function subscale: t (123) = 3.06, p = 003). In all cases, men aged 75 and older had lower scores than those aged between 65 and 74. Other t-tests were performed on the scores of all respondents, sexually active or not, to determine whether the age groups differed on theIIEF-15 and the subscale of erectile function. At T1, significant differences were obtained for both measures (IIEF-15: t (488) = 6.74, p < 001; erectile function subscale: t (495) = 6.71, p < 001) indicating that men aged 75 and older have lower scores on these measures than younger men. Similar results were obtained at T2.
Discussion A validation of the IIEF-5 and -15 in a random population sample of people aged 65 and over was carried out and norms for this population were established. It was assumed that IIEF scores for the older population would differ from those obtained in a younger population. It turns out that the IIEF norms for an older population are indeed lower than those observed in a younger population. Moreover, this change has been verified by the statistically significant differences detected between men 65 to 74 years old and those aged 75 and older. It can also be seen by the prevalence of potential erectile dysfunction in the sample. Cappalleri et al. (1999) suggested the cut-off point of 25 points on the subscale of erectile function to signal a risk of erectile dysfunction in the respondent. Taking care to exclude sexually inactive participants, Rynja et al. (2010) found 0% of erectile dysfunction in men aged 18-35 and a median score of 29. Using the same cut-off point suggested by Cappalleri et al. (1999), (75)% of sexually active people in our study (65 years and up) scored 25 or less on the subscale of erectile function, signalling a risk of erectile dysfunction. The median score is 21. These results are not surprising since the decline of sexual function in aging men is well documented. Also, 54% of participants in our sample had to be excluded from validation calculations for lack of recent sexual activity. This figure is not negligible, considering the fact that the participants lived with a partner. Although the presence of a partner at an advanced age is the best predictor of sexual activities (Kontula and Haavio-Mannila, 2009), it seems that most couples in our sample did not have the type of sex corresponding to the specific questions of the IIEF as often as once every four weeks. It is important to note that this rate is strongly influenced by the fact that the questionnaire assesses a purely genital sexuality, and that sexuality at that age does not necessarily include this type of sex (Trudel and Goldfarb, 2006). In that sense, several authors have emphasized the persistence of sexual activities with increasing age while indicating that the repertoire of sexual behaviours changes. A study by Trudel and Goldfarb (2006) compared sexual activity in people of different age levels using the Inventory of Sexual Behaviour and showed reduced coital activity among older people. Another survey
e25 (Trudel, 2002) also highlights changes in sexual activity with increasing age. Jarousse (1995) indicates that activities associated with tenderness are particularly characteristic of the sexuality of older adults. Several biological, psychological and social influences can cause a decrease in the frequency of genital sexual activity (Rose and Soares, 1993; Rienzo, 1985). Even if we cannot identify a particular cause, this figure (54% of men excluded from our study) reflects a change in sexual function. Note that several participants let us know that the type of sexual activity described in the IIEF did not correspond to their current reality. It is appropriate to take this into account in order to set standards which represent all men of this age, not just the sexually active ones as per the IIEF’s standards. Therefore, in this study, we have also proposed standards that take into account the men who did not engage in the sexual activities described in the questions during the four weeks preceding the IIEF testing. If the IIEF is used as a tool to portray the reality of genital sexual function in general, and not specifically as a tool to screen for erectile dysfunction, new scores can be established by awarding the least points to participants who reported no recent sexual activity. We suggest that these standards, where lower scores indicate lower genital sexual function rather than lower general sexual functioning, provide a more adequate assessment of sexual functioning in both the more active and the less sexually active older men. Although these results provide information about sexuality in older men, the IIEF has many limitations in the overall assessment of sexual function in a population-based study. Some recommendations on the use of questionnaires on sexuality in the context of population studies of older men may be derived from this research. First, it would be advisable to have a longer evaluation period to adapt to the low frequency of genital sexual behaviour in this population. Extending this period to six months would allow the inclusion of a maximum number of participants, as this was done in other studies (Cheng et al., 2007). Also, measures of sexual functioning based on a broader definition of sexuality and focusing on a more diverse repertoire of sexual activities would be better suited to older people than those assessing genital sexuality exclusively, given the healthy and adaptive decline in the frequency of such activities in this population.
Disclosure of interest The authors declare that they have no conflicts of interest concerning this article.
Acknowledgements This research was conducted with the support of a grant to Dr Gilles Trudel, Ph.D. (Principal researcher) by Canadian Institute of Health Research (MOP - 81281) and by Fonds de Recherche en Santé du Québec. The authors wish to thanks Marie-Pascale Leblond for her helpful collaboration in the writing of this paper.
e26
References Baillargeon J, Dubois G, Marineau N. Traduction franc ¸aise de l’Échelle d’Ajustement Dyadique. Canadian Journal of Behavioral Sciences 1986;18(1):25—30. Brecher EM. Love, sex, and aging: a consumers’ union report. Boston, MA: Little, Brown; 1984. Cappalleri JC, Rosen RC, Smith MD, Mishra A, Osterloh IH. Diagnostic evaluation of the erectile function domain of the International Index of Erectile Function. Urology 1999;54:346—51. Cheng JYW, Ng EML, Ko JSN. Depressive symptomatology and male sexual functions in late life. J Affect Disord 2007;104:225—9. Cronbach LJ. Coefficient Alpha and the internal structure of tests. Psychometrika 1951;16:L297—334. DeLamater J, Sill M. Sexual desire in later life. Journal of Sex Research 2005;42:138—49. Derby CA, Araujo AB, Johannes CB, Feldman HA, McKinlay JB. Measurement of erectile dysfunction in population-based studies: the use of a single question self-assessment in the Massachusetts Male Aging Study. International Journal of Impotence Research 2000;12(4):197—204. Folstein MF, Folstein SE, McHugh PR. Mini-mental state. A practical method for grading the cognitive state of patients for the clinician. Journal of Psychiatric Research 1975;12(3): 189—98. Fréchette V, Trudel G. Version franc ¸aise de l’International Index of Erectile Function 2006. Unpublished document. Hogan PT. Psychological Testing. A Practical Introduction. New York, NY: John Wiley & Sons, Inc; 2003. Jarousse N. Sexualité et vieillissement. Ramonville Saint-Agne: Eres; 1995. Kaplan HS. Sex, intimacy, and the aging process. Journal of the American Academy of Psychoanalysis 1990;12:185—205. Kinsey AC, Pomeroy WB, Martin CE. Sexual Behavior in the Human Male. Philadelphia, PA: W.B. Saunders; 1948. Kontula O, Haavio-Mannila E. The impact of aging on human sexual activity and sexual desire. Journal of Sex Research 2009;46(1):46—56. Libman E. Sociocultural and cognitive factors in aging and sexual expression: conceptual and research issues. Psychologie canadienne 1989;30:560—7. Lim TO, Das A, Rampal S, Zaki M, Sahabudin RM, Rohan MJ, et al. Cross-cultural adaptation and validation of the English version of the International Index of Erectile Function (IIEF) for use in Malaysia. International Journal of Impotence Research 2003;15:329—36. Lindau ST, Schumm O, Laumann EO, Levinson W, O’Muircheartaigh CA, Waite LJ. A study of sexuality and health among older adults in the United States. New England Journal of Medicine 2007;257(8):762—74. Masters WH, Johnson VE. Human sexual response. Boston, MA: Little Brown; 1966. Masters WH, Johnson VE. Sex and the aging process. Journal of The American Geriatrics Society 1981;29:385—90. Masters WH, Johnson VE. Human sexuality. Boston, MA: Little Brown; 1982. Perneger TV, Leplege A, Etter J-F, Rougemont A. Validation of a French-language version of the MOS 36-item short form health
L. Dargis et al. survey (SF-36) in young healthy adults. Journal Clinical Epidemiology 1995;48(8):1051—60. Resnick B, Nahm ES. Reliability and validity testing of the Revised 12item short-form health survey in older adults. Journal of Nursing Measurement 2001;9(2):151—61. Rienzo BA. The impact of aging on human sexuality. J Sch Health 1985;55:66—8. Rose MK, Soares HH. Sexual adaptation of the frail elderly: a realistic approach. J Gerontol Soc Work 1993;19:167—78. Rosen RC, Riley A, Wagner G, Osterloh IH, Kirkpatrick J, Mishra A. The international index of erectile function (IIEF): a multidimensional scale for assessment of erectile dysfunction. Urology 1997;49(6):822—30. Rosen RC, Cappalleri JC, Smith MD, Lipsky J, Pena BM. Development and evaluation of an abridged, 5-item version of the International Index of Erectile Function (IIEF-5) as a diagnostic tool for erectile dysfunction. International Journal of Impotence Research 1999;11:319—26. Rosen R, Brown C, Heiman J, Leiblum S, Meston C, Shabsigh R, et al. The Female Sexual Function Index (FSFI): A multidimensional self-report instrument for the assessment of female sexual function. Journal of Sex Marital Therapy 2000;26:191—208. Rosen RC, Cappalleri JC, Gendrano III N. The international index of erectile function (IIEF): a state-of-the-science review. International Journal of Impotence Research 2002;14:226—44. Rynja S, Bosch R, Kok E, Wouters G, de Kort L. IIEF-15: Unsuitable for assessing erectile function of young men ? Journal of Sex Medicine 2010;7:2825—30. Spanier GB. Measuring dyadic adjustment: new scales for assessing the equality of marriage and similar dyads. Journal of Marriage and the Family 1976;38(1):15—28. Stearnes EL, MacDonnell JA, Kaufman BJ. Declining testicular function with age: hormonal and clinical correlates. American Journal of Medicine 1974;57:761—3. Trudel G. Sexuality and marital life: the results of a survey. Journal of Sex and Marital Therapy 2002;28:229—49. Trudel G. Les dysfonctions sexuelles : évaluation et traitement par des méthodes psychologique, interpersonnelle et biologique (2e éd.). Sainte-Foy, QC: Presses de l’Université du Québec; 2005. Trudel G, Goldfarb MR. L’effet de l’âge sur le répertoire et le plaisir sexuel. Sexologies 2006;15:266—72 [The effect of age on sexualrepertoire and its concomitant pleasure]. Trudel G, Turgeon L, Piché L. Marital and sexual aspects of old age. Sexual and Relationship Therapy 2010;25(3):316—41. Ware JE, Kosinski M, Keller SD. A 12-item Short Form Health Survey: Construction of scales and preliminary tests of reliability and validity Medical. Care 1996;34(3):220—33. Ware JE, Kosinski M, Gandek B, et al. The Factor Structure of the SF36 Health Survey in 10 Countries: results from the IQOLA Project. Journal Clinical Epidemiology 1998;51(11):1159—65. Wiltink J, Hauck EW, Phadayanon M, Weidner W, Beutel ME. Validation of the German version of the International Index of Erectile Function (IIEF) in patients with erectile dysfunction. Peyronie’s disease and controls. International Journal of Impotence Research 2003;15:192—7. Yule M, Davison J, Brotto L. The international index of erectile function: a methodological critique and suggestions for improvement. Journal of Sex and Marital Therapy 2011;31:255—69.