Search tips
Search criteria 


Logo of nihpaAbout Author manuscriptsSubmit a manuscriptHHS Public Access; Author Manuscript; Accepted for publication in peer reviewed journal;
Surg Obes Relat Dis. Author manuscript; available in PMC 2010 November 1.
Published in final edited form as:
PMCID: PMC2788038

Prevalence and degree of sexual dysfunction in a sample of women seeking bariatric surgery

Dale S. Bond, Ph.D.,a Siva Vithiananthan, M.D.,b Tricia M. Leahey, Ph.D.,a J. Graham Thomas, Ph.D.,a Harry C. Sax, M.D.,b Dieter Pohl, M.D.,c Beth A. Ryder, M.D.,d G. Dean Roye, M.D.,d Jeannine Giovanni, M.D.,c and Rena R. Wing, Ph.D.a



Sexual functioning is shown to be impaired in women who are obese, particularly those seeking bariatric surgery. However, most prior studies evaluating sexual function in these populations have not used validated measures. We used the validated Female Sexual Function Index (FSFI) to assess prevalence of female sexual dysfunction (FSD) in a sample of over 100 women evaluated for bariatric surgery.


The FSFI was administered to reportedly sexually active women during their preoperative evaluation. Scores for individual FSFI domains (desire, arousal, lubrication, orgasm, satisfaction, and pain) ranging from 0(or 1.2) to 6 were summed to produce a FSFI-total score (range = 2-36). A FSFI-total cut-off score of ≤ 26.55 was used to identify participants with FSD. Participants' FSFI- total and domain scores were compared to previously published norms available for women diagnosed with female sexual arousal disorder (FSAD) and healthy controls.


Sixty-one of the 102 participants (59.8%) had FSFI-total scores ≤ 26.55, indicative of FSD. Older age and menopause were associated with FSD. Compared to published norms, bariatric surgery candidates had FSFI domain scores that were lower than the control group (ps <0.0001) but higher than the FSAD group (ps <0.0001), except for desire where scores were similar.


Women seeking bariatric surgery are clearly a population with substantial sexual function impairment, with 60% of participants reporting FSD. These findings highlight the need to initiate routine assessment of sexual functioning in this population and examine whether weight loss following bariatric surgery contributes to reversal of FSD.

Keywords: obesity, sexual dysfunction, women, bariatric surgery, Female Sexual Function Index


Female sexual dysfunction (FSD) encompasses a range of problems including diminished sexual desire, difficulty becoming aroused, inhibited orgasm, and feelings of pain during intercourse [1]. Epidemiological estimates indicate that FSD is prevalent, with approximately 43% of women in the U.S. reporting that they have at least one sexual problem [2]. Sexual dysfunctions in women are influenced by a wide array of physiological, medical, psychological and sociodemographic factors [1], and are accompanied by feelings of distress [2, 3], depressive symptoms [2, 4], poor self-reported health status [2, 3], and sexual incompatibility with one's partner [5].

A recent growing literature suggests that women who are overweight and obese have lower sexual function than normal-weight women [6, 7]. Additionally, studies indicate that increasing severity of obesity is associated with greater impairment in sexual quality of life, and that obese women experience greater sexual difficulties than obese men [8, 9]. Furthermore, the degree of impairment in female sexual quality of life is shown to vary by obesity-treatment seeking status, with women seeking bariatric surgery reporting higher levels of impairment than those in a residential obesity treatment program [8] and non-treatment seeking equally overweight controls [8, 10]. Taken together, these findings suggest that women with severe obesity, particularly those seeking bariatric surgery, are at considerable risk for having problems with sexual function.

However, most prior studies have not used validated measures to assess sexual function difficulties among bariatric surgery candidates and no study has examined the extent to which sexual problems in this population are indicative of clinical dysfunction (i.e. FSD). Only one study [11], to our knowledge, has used a validated measure of sexual function in female bariatric surgery patients preoperatively. In this study conducted in Greece, 60 bariatric surgery candidates and 50 healthy controls were administered the Female Sexual Function Index (FSFI).

The FSFI [12], the most widely used measure of female sexual function, is a brief, self-report instrument that provides scores on six functional domains, as well as a total score that can be used to differentiate women with and without FSD [13]. Findings revealed that the bariatric surgery candidates reported significantly lower overall sexual function and greater impairment on 5 of the 6 domains (i.e. sexual desire, arousal, lubrication, orgasm, satisfaction), compared to controls. However, the investigators did not employ the developed diagnostic cut-off score to distinguish participants with and without FSD.

Given that FSD has not been previously assessed in bariatric surgery candidates and use of validated measures to assess sexual function in this population has been limited, additional study is warranted. Therefore, using the FSFI, the objectives of this study were to: 1) assess sexual function and prevalence of FSD in a sample of women seeking bariatric surgery; 2) explore potential factors associated with FSD; and 3) evaluate participants' overall and domain-specific sexual function within the context of norms available for women with female sexual arousal disorder (FSAD) and healthy controls [12].


The procedures for this study were approved by The Miriam Hospital Institutional Review Board, Providence, RI, USA.

Participants and procedures

The sample for the present study was recruited from three clinic sites in Providence, Rhode Island between January 2008 and April 2009. Obese (BMI ≥ 35 kg/m2) women evaluated for either Roux-en-Y gastric bypass or laparoscopic adjustable gastric banding at a preoperative visit were briefly informed by a surgeon about a prospective study of changes in sexual function following bariatric surgery. Patients who expressed interest were taken to an office where they met with research personnel who conducted an initial screening, explained the study in greater detail, and obtained informed consent. To be eligible for the study, participants had to be between the ages of 21 and 70 and answer “yes” in response to the question “Are you currently involved in a stable and sexually active partner relationship?” Patients who consented to participate completed the questionnaire and provided data regarding demographics, health history, and current medication usage. Participants' height and weight was measured in the clinic using standard procedures. Individuals who expressed interest in participating but did not have the time to complete the questionnaires at the clinic were asked to complete the questionnaires at home and return them in a postage-paid envelope addressed to research personnel. Participants whose returned questionnaires contained omissions were contacted by research personnel in an attempt to obtain complete information. Of 212 patients screened for the study, 89 were either ineligible or declined to participate, leaving 123 participants. Of these participants, 21 reported being sexually inactive during the past 4 weeks on the FSFI and thus were excluded from analyses. This resulted in a total sample of 102 participants.


Sexual function

Sexual function was measured using the previously described Female Sexual Function Index (FSFI) [12], a 19-item self-report measure that assesses multiple domains of sexual function over the past 4 weeks. These domains include sexual desire (assessed as frequency and desire level), sexual arousal (assessed as frequency, level, confidence and satisfaction), lubrication (assessed as frequency, difficulty, frequency of maintaining and difficulty in maintaining), orgasm (assessed as frequency, difficulty, and satisfaction), sexual satisfaction (assessed as the amount of closeness with partner, sexual relationship and overall sex life), and sexual pain (assessed as pain frequency during vaginal penetration and pain frequency following vaginal penetration). The measure provides scores for each domain as well an overall score, with higher scores indicating greater levels of sexual function (sexual desire: 1.2-6; sexual satisfaction: 0.8-6; sexual arousal, lubrication, orgasm, and sexual pain: 0-6; total: 2-36). The FSFI was first validated in a study of 128 women (age range 21-69 years) clinically diagnosed with sexual arousal disorder and 131 age-matched normal controls [12]. Results demonstrated high test-retest reliability for each of the individual domains (r = 0.79-0.86), a high degree of internal consistency (Chronbach's α ≥ 0.82), and good discriminant validity as evidenced by significant differences between the patient and controls groups on all of the domains (p < 0.001). In a more recent FSFI validation study [13] which included 307 women with a variety of sexual dysfunctions (e.g., sexual arousal disorder, hypoactive sexual disorder, female sexual orgasm disorder dyspareunia/vaginismus) and 261 controls, a FSFI total score of 26.55 was shown to be the optimal cut-off for differentiating women with and without FSD.

Demographic characteristics, health history and current medication usage

Demographic data (i.e. age, race/ethnicity, marital status, and educational level) was collected via questionnaire. Participants' health history was assessed using a questionnaire that asked participants to check “yes” or “no” to whether: 1) they had ever received a doctor diagnosis for certain health conditions (e.g., hypertension, diabetes, depression, etc.), and 2) they experienced certain gynecological health conditions/events (i.e. menopause, gynecological surgery, urinary tract symptoms, polycystic ovary syndrome). Finally, participants were asked to list the names and dosages of medications that they were currently taking.

Statistical analyses

Statistical analyses were conducted using the Statistical Package for Social Sciences, version 14.0 (SPSS for Windows, SPSS, Chicago, IL). Descriptive statistics were generated for all variables. A FSFI-total score cut-off score (i.e. ≤ 26.55) was used to distinguish participants with and without FSD [14]. Examination of differences between participants with and without SD was performed using χ2 analyses for categorical variables and independent t-tests for continuous variables. Comparisons of participants' FSFI-total and domain scores with published norms available for women with female sexual arousal disorder and controls [12] were conducted using t-tests. All tests were two-tailed and statistical significance was set at p < 0.05.



Table 1 provides the sociodemographic, weight, and health history profile of the sample. The mean age of participants was 42 years (range = 21 to 62 years). Nearly 80% of participants were Caucasian and 70% were married. Almost half (47.1%) of the participants had at least a college/university degree. Participants were severely obese (BMI = 46.1 ± 7.6 kg/m2; range = 35-71 kg/m2). With respect to reportedly diagnosed health conditions, 42% of participants had hypertension and approximately 20% had diabetes. Forty-five percent of participants reported depression diagnosis, and 32% reported diagnosis of an anxiety disorder. Regarding reported gynecological health conditions/events, approximately 27% of participants had experienced menopause and 31% had gynecological surgery. Thirteen percent of participants reported being on contraceptives and 3% reported being on hormone replacement therapy. Medications most commonly taken were those to treat depression (40%), gastroesophageal reflux disease (28%), hypercholesterolemia (18%), hypertension and other cardiovascular conditions [e.g., diuretics (15%) beta-blockers (13%)], diabetes (13%) and abnormal thyroid (13%)

Table 1
Characteristics of participants

Female sexual dysfunction (FSD)

Figure 1 shows the distribution of total-FSFI scores for the sample. The average total score on the FSFI was 24.6 ± 6.4 out of a maximum total score of 36. Using the established cutoff score of 26.55, 61 of 102 (59.8%) participants were classified as having FSD.

Figure 1
Distribution of Female Sexual Function Index (FSFI) total scores

Analyses examining differences between participants reporting and not reporting FSD revealed that FSD participants were significantly older (43.9 ± 9.5 vs 38.2 ± 10.4 years; p = 0.005) and more likely to have experienced menopause (34.4% vs 14.6%, p = 0.02). The groups did not differ significantly on other variables, including demographics, weight, health conditions and medication usage.

Female Sexual Function Index (FSFI) scores

FSFI-total and domain scores of the bariatric surgery candidates were compared with published norms available for women with female sexual arousal disorder (FSAD) and healthy women controls [13]. FSFI-total scores of bariatric surgery candidates (26.4 ± 6.3) were lower relative to the control group (30.5 ± 5.3) and higher compared to the FSAD group (19.2 ± 6.6) (ps < 0.0001). FSFI domain scores for these three groups are shown in Figure 2. Bariatric surgery candidates scored significantly lower than controls across all of the domains (ps < 0.0001). When compared to the FSAD group, participants scored significantly higher on all domains (ps < 0.0001), except desire where scores were similar (p > 0.30).

Figure 2
Comparison of Female Sexual Function Index (FSFI) domain scores (M ± SD) in bariatric surgery candidate with norms of women with female sexual arousal disorder (FSAD) and controls


This study assessed female sexual dysfunction (FSD) in a sample of severely obese women evaluated for bariatric surgery using a validated measure. Approximately 60% of participants had scores below the cut-off, indicating presence of FSD. These findings support prior research showing marked impairment in sexual function in women who are obese [6, 7], and particularly those seeking bariatric surgery [8-11].

To place these data in context, we compared our findings to other studies which utilized the FSFI cut-off score of ≥ 26.55 to distinguish women with and without FSD. As shown in Figure 3, the percentage (59.8) of participants who reported FSD in the current study is markedly higher than that reported in two large Finnish population samples, one composed of 2,081 participants aged 33-43 years (32.6%) [3] and the other composed of 5,463 participants aged 18-49 years (34%) [5]. The FSD rate shown in bariatric surgery candidates is also somewhat higher than that reported among women attending general outpatient clinics (42%-56%) [4, 14-16]. Relative to various targeted patient and non-patient populations, FSD prevalence among bariatric surgery candidates was higher than that found in female partners of infertile couples (26%) [17] and women with hypertension (42%) [18], similar to that found among female medical residents (60%) [19], and lower than that shown in women with urogynecological problems (64%-68%) [20, 21].

Figure 3
Percentage (%) of bariatric surgery candidates reporting female sexual dysfunction (FSD) compared to percentages reported in previous studies utilizing the Female Sexual Function Index (FSFI).

We also compared participants in the present sample who reported FSD with those who did not report such problems. Findings showed that aging and menopause were associated with FSD, consistent with previous studies [4, 16]. Physiological and psychological changes brought on by aging and menopause may contribute to FSD. Age-related issues including health problems (e.g., hypertension, diabetes, lower urinary tract symptoms, depression, etc.) and medications to treat such problems [22], partner's sexual dysfunction (e.g., erectile dysfunction) [23], and challenges inherent to longer relationships (e.g., compatibility, faithfulness, and changing sexual needs and preferences) [5, 18] can influence the association between age and FSD. In addition, loss of estrogen and concomitant decline in circulating androgens during the menopausal transition can adversely impact the structure and integrity of reproductive structures, thereby elevating risk of FSD [24].

We also evaluated FSFI-total and domain-specific sexual function in the entire sample within the context of published norms available for women with female sexual arousal disorder (FSAD) and healthy controls [12]. Participants reported a level of global sexual function that was lower than healthy controls and higher than women with FSAD. This same pattern of findings was observed across every domain with the exception of desire, where participants and the FSAD group scored similarly. These findings suggest that women seeking bariatric surgery have worse sexual function than healthy control women but better sexual function in most areas compared to women diagnosed with FSAD. Although this is a cross-study comparison, the three groups did not differ in age and were similar on other demographic characteristics (e.g., race, education, and marital status).

Compared to bariatric surgery candidates in the only other study that utilized the FSFI [11], participants in the present study scored higher on total sexual function (24.6 ± 6.3 vs 21.3 ± 11.9) and on every domain [arousal (3.8 ± 1.4 vs 3.2 ± 2.1), lubrication (4.6 ± 1.5 vs 3.7 ± 2.3), orgasm (4.1 ± 1.6 vs 3.6 ± 2.3), satisfaction (4.0 ± 1.5 vs 3.8 ± 2.2), and pain (5.1 ± 1.5 vs 3.8 ± 2.6)], except desire (3.0 ± 1.0 vs 3.3 ± 1.4). The reasons for the higher scores among our sample are not clear. The present sample included only those women who reported being sexually active during the measurement period so as to obtain accurate full scale scores. Whether this was also the case for the prior study is unknown. FSFI domain scores (with the exception of desire) for participants who are sexually inactive during the measurement period will be zero, thereby artificially reducing average scores for a given sample [12].

This study has several limitations. The study sample was comprised of 58% of the total number of patients approached to participate. Thus, participants who felt comfortable in completing the FSFI may have been different from those who were ineligible or declined to participate for various reasons (e.g., feelings of embarrassment). We did not assess level of sexual distress caused by FSD. Sexual distress, characterized by negative feelings and anxiety about one's sexuality or sexual activities, is considered to be an important aspect of sexual disorders [5]. Similarly, our study did not include validated measures of depression or anxiety. While previous research utilizing the FSFI suggests that depression and anxiety contribute to elevated risk of FSD [4, 16], we did not find higher FSD prevalence in participants with prior diagnosis of depression or anxiety or those who used medications to treat these problems. Although, the high rate (40%) of antidepressants use among our sample may have contributed to lower sexual function scores in general. A common side effect of antidepressants is sexual problems related to desire, arousal and orgasmic function [22]. Future research should consider to what extent any changes in sexual function after bariatric surgery are associated with discontinued use of antidepressants. Another limitation is that we did not ask participants to identify their sexual orientation. In a recent study [25], FSFI-measured sexual functioning of lesbian women (FSFI-total score = 29.5) was similar to published norms for healthy controls (FSFI-total score = 30.5) [12]. Consequently, future research should consider sexual orientation when assessing FSD in bariatric surgery patients. Finally, while the FSFI is a widely used measure of sexual function with excellent psychometric properties, suggestions were recently provided to strengthen its utility and validity [26].

The present study focused on sexual dysfunction in women seeking bariatric surgery. However, other aspects of psychosocial functioning are also of concern in these patients. Prior studies have documented high rates of psychopathology, particularly mood and anxiety disorders, in these women as well as reduced health-related quality of life and body image dissatisfaction [8, 11, 27]. Bariatric surgery is associated with improvements in each of these areas, although positive changes are not universal and may be seen primarily in the first postoperative years [27].

It will be important for future studies to assess whether impairment in sexual function among severely obese women resolves after weight loss. Kolotkin et al. [28] found that sexual quality of life improved with weight loss in women undergoing non-surgical treatment. In another study [29], weight losses achieved through an 8-week combination of sibutramine and behavioral intervention yielded improvements in FSFI total score and domain scores relating to arousal and lubrication. More recently, Kolotkin and colleagues [30] found improvements in sexual quality of life in female gastric bypass surgery patients at 2 years postoperatively. Thus, while it appears that weight loss achieved through both non-surgical and surgical means improves sexual function, further research is needed to determine whether weight loss following bariatric surgery contributes to normalization of sexual function in women with preoperative sexual dysfunction.


The present study found that severely obese women seeking bariatric surgery are clearly a population with diminished sexual function, with approximately 60% of participants reporting FSD. This finding supports the use of validated measures to assess sexual function in women evaluated for bariatric surgery and to identify patients with FSD for whom further treatment may be necessary. Additional research is needed to examine whether weight loss following bariatric surgery contributes to resolution of FSD.


This research was funded in part by an American Diabetes Association Mentor-based Postdoctoral Fellowship awarded to Dr. Rena Wing. Dr. Bond is supported by a grant from the National Institutes of Diabetes and Digestive and Kidney Diseases (K01: DK083438-01). Appreciation is expressed to Jennifer Trautvetter, B.A., Tammy Monk, M.S., and Angelica Adams, B.S., for their assistance with data collection.


Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.


1. Salonia A, Munarriz RM, Naspro R, et al. Women's sexual dysfunction: a pathophysiological review. BJU Int. 2004;93:1156–64. [PubMed]
2. Shifren JL, Monz BU, Russo PA, Segreti A, Johannes CB. Sexual problems and distress in United States women: prevalence and correlates. Obstet Gynecol. 2008;112:970–8. [PubMed]
3. Witting K, Santtila P, Jern P, et al. Evaluation of the Female Sexual Function Index in a population based sample from Finland. Arch Sex Behav. 2008;37:912–24. [PubMed]
4. Aslan E, Beji N, Gungor I, Kadioglu A, Dikencik B. Prevalence and risk factors for low sexual function in women: a study of 1,009 women in an outpatient clinic of a university hospital in Istanbul. J Sex Med. 2008;5:2044–52. [PubMed]
5. Witting K, Santtila P, Varjonen M, et al. Female sexual dysfunction, sexual distress and compatability with partner. J Sex Med. 2008;5:2587–99. [PubMed]
6. Esposito K, Ciotola M, Giugliano F, et al. Association of body weight with sexual function in women. Int J Impot Res. 2007;19:353–7. [PubMed]
7. Melin I, Falconer C, Rössner S, Altman D. Sexual dysfunction in obese women: impact of lower urinary tract dysfunction. Int J Obes. 2008;32:1312–18. [PubMed]
8. Kolotkin RL, Binks M, Crosby RD, Østbye T, Gress RE, Adams TD. Obesity and sexual quality of life. Obesity. 2006;14:472–9. [PubMed]
9. Kolotkin RL, Crosby RD, Gress RE, Hunt SC, Engel SG, Adams TD. Health and health-related quality of life: differences between men and women who seek gastric bypass surgery. Surg Obes Relat Dis. 2008;4:651–9. [PMC free article] [PubMed]
10. Kolotkin RL, Crosby RD, Pendelton R, Strong M, Gress R, Adams T. Health-related quality of life in patients seeking gastric bypass surgery vs non-treatment seeking controls. Obes Surg. 2003;13:371–7. [PubMed]
11. Assimakopoulos K, Panayiotopoulos S, Iconomou G, et al. Assessing sexual function in obese women preparing for bariatric surgery. Obes Surg. 2006;16:1087–91. [PubMed]
12. Rosen R, Brown C, Heiman J, et al. The Female Sexual Function Index (FSFI): a multidimensional self-report for the assessment of female sexual function. J Sex Marital Ther. 2000;26:191–208. [PubMed]
13. Wiegel M, Meston C, Rosen R. The Female Sexual Function Index (FSFI): cross-validation and development of clinical cut-off scores. J Sex Marital Ther. 2005;31:1–20. [PubMed]
14. Ferenidou F, Kapoteli V, Moisidis K, Koutsogiannis I, Giakoumelos A, Hatzichristou D. Presence of a sexual problem may not affect women's satisfaction from their sexual function. J Sex Med. 2008;5:631–9. [PubMed]
15. Garcia S, Moreno S, Aponte H. Prevalence of sexual dysfunction in female outpatients and personnel at a Colombian hospital: correlation with hormonal profile. J Sex Med. 2008;5:1208–13. [PubMed]
16. Chedraui P, Pérez-López FR, San Miguel G, Avila C. Assessment of sexuality among middle-aged women using the Female Sexual Function Index. Climacteric. 2009;12:213–221. [PubMed]
17. Nelson CJ, Shindel AW, Naughton CK, Ohebshalom M, Mulhall JP. Prevalence and predictors of sexual problems, relationship stress, and depression female partners of infertile couples. J Sex Med. 2008;5:1907–14. [PubMed]
18. Doumas M, Tsiodras S, Tsakiris A, et al. Female sexual dysfunction in essential hypertension: a common problem being uncovered. J Hypertens. 2006;24:2387–92. [PubMed]
19. Ferguson GG, Nelson CJ, Brandes SB, Shindel AW. The sexual lives of residents and fellows in graduate medical education programs: a single institution survey. J Sex Med. 2008;5:2756–65. [PubMed]
20. Pauls RN, Segal JL, Silva WA, Kleeman SD, Karram MM. Sexual function in patients presenting to a urogynecology practice. Int Urogynecol J Pelvic Floor Dysfunct. 2006;17:576–80. [PubMed]
21. Verit FF, Verit A, Yeni E. The prevalence of sexual dysfunction and associated risk factors in women with chronic pelvic pain: a cross-sectional study. Arch Gynecol Obstet. 2006;274:297–302. [PubMed]
22. Phillips NA. Female sexual dysfunction: evaluation and treatment. Am Fam Physician. 2000;62:127–36. [PubMed]
23. Cayan S, Bozlu M, Canpolat B, Akbay E. The assessment of sexual functions in women with male partners complaining of erectile dysfunction: does treatment of male dysfunction improve female partner's sexual functions? J Sex Marital Ther. 2004;30:333–41. [PubMed]
24. Graziottin A, Leiblum SR. Biological and psychosocial pathophysiology of female sexual dysfunction during the menopausal transition. J Sex Med. 2005;2(suppl 3):133–145. [PubMed]
25. Sarwer DB, Thompson JK, Mitchell JE, Rubin JP. Psychological considerations of the bariatric surgery patient undergoing body contouring surgery. Plast Reconstr Surg. 2008;121:423e–434e. [PubMed]
26. Tracy JK, Junginger J. Correlates of lesbian sexual functioning. J Womens Health. 2007;10:499–509. [PubMed]
27. Meyer-Bahlburg HFL, Dolezai C. The Female Sexual Function Index: a methodological critique and suggestions for improvement. J Sex Marital Ther. 2009;33:217–24. [PubMed]
28. Kolotkin RL, Binks M, Crosby RD, Østbye T, Mitchell JE, Hartley G. Improvements in sexual quality of life following modest weight loss. Int J Impot Res. 2008;20:487–492. [PubMed]
29. Kim KK, Kang HC, Kim SS, Youn BB. Influence of weight reduction by sibutramine on female sexual function. Int J Obes. 2006;30:758–763. [PubMed]
30. Kolotkin RL, Crosby RD, Gress RE, Hunt SC, Adams TD. Two-year changes in health-related quality of life in gastric bypass patients compared with severely obese controls. Surg Obes Relat Dis. 2009;5:250–6. [PubMed]