- Email: [email protected]
Transcultural adaptation of the Night Eating Questionnaire (NEQ) for its use in the Spanish population
Eating Behaviors 13 (2012) 260–263
Contents lists available at SciVerse ScienceDirect
Eating Behaviors
Transcultural adaptation of the Night Eating Questionnaire (NEQ) for its use in the Spanish population☆ Violeta Moizé a,⁎, Marci E. Gluck b, Ferran Torres c, Alba Andreu a, Josep Vidal a, d, Kelly Allison e a
Obesity Unit, Department of Endocrinology and Nutrition, Hospital Clinic Universitari, Barcelona, Spain Obesity and Diabetes Clinical Research Section, Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases National Institutes of Health, Phoenix, AZ, United States c Biostatistics and Data Management Platform, IDIBAPS, Hospital Clinic, Biostatistics Unit, School of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain d Centro de Investigación Biomédica en Red en Diabetes y Enfermedades Metabólicas (CIBER-DEM), Instituto de Salud Carlos III, Barcelona, Spain e University of Pennsylvania School of Medicine, Department of Psychiatry, Center for Weight and Eating Disorders, United States b
a r t i c l e
i n f o
Article history: Received 15 December 2011 Received in revised form 28 January 2012 Accepted 21 February 2012 Available online 7 March 2012 Keywords: Night eating syndrome Nocturnal ingestion Eating behavior Assessment Transcultural adaptation
a b s t r a c t Background: Establishing valid and reliable methods of assessing night eating symptoms is an important goal to maximize identification and treatment of the night eating syndrome (NES). The 14-item Night Eating Questionnaire (NEQ) is the only published and validated assessment instrument but is not yet adapted to Spanish. Methods: We examined the factor structure, internal consistency and validity of the NEQ in Spanish. The study had 4 phases: a) translation from English to Spanish; b) back-translation from Spanish to English, c) administration of translated version to a Spanish sample, and d) a re-test in 36 participants two weeks later. Reliability, stability, and scale structure were evaluated by Cronbach's α, test–re-test, and factor analysis, respectively. Divergent validity was assessed by correlation with the Spanish versions of the State-Trait Anxiety Inventory (STAI) and the Beck Depression Inventory (BDI-II). Results: Two-hundred forty-four individuals (181 f; BMI 34.3 ± 10 kg/m2; age 40.5 ± 15 y) completed the questionnaire. The mean NEQ score was 12.5 ± 7. The Cronbach's α coefficient for the total score was 0.79, the intraclass correlation was 0.85, and the factor analysis yielded a similar four factor solution as the original scale. Correlation for the test–re-test total score was 0.86. Total NEQ score was significantly correlated with the BDI-II (r = 0.48 p b 0.001), but this correlation was not significant during the test–re-test (r = 0.28, p = 0.10) or with STAI at either time point (0.05, p = 0.40; r = 0.07, p = 0.69, respectively). Conclusions: The Spanish version of the NEQ demonstrated adequate internal consistency for the majority of domains and excellent reproducibility. There was divergent validity with anxiety and a relationship between night eating and depression. These results suggest that the Spanish-version of the NEQ is an instrument that is valid for use in clinical research. © 2012 Elsevier Ltd. All rights reserved.
1. Introduction Night eating syndrome (NES) is characterized by a delayed circadian pattern of eating (Allison et al., 2010), including two core features: evening hyperphagia and/or nocturnal ingestions. The prevalence is 1.5% in the general population (Rand, Macgregor, & Stunkard, 1997; StriegelMoore, Franko, Thompson, Affenito, & Kraemer, 2006), 4%–43% of persons seeking obesity treatment (Ceru-Björk, Andersson, & Rössner, 2001; Colles, Dixon, & O'Brien, 2007; Napolitano, Head, Babyak, & Blumenthal, 2001; Stunkard et al., 1996), and 9%–42% of persons
☆ Supported in part by the Intramural Research Program of the NIH, NIDDK. ⁎ Corresponding author at: UnidadFuncional de Obesidad, Hospital Clinic, Villarroel Street 170. 08036, Barcelona, Spain. Tel.: + 34 93 227 54 00x9846; fax: + 34 93 451 66 38. E-mail address: [email protected] (V. Moizé). 1471-0153/$ – see front matter © 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.eatbeh.2012.02.005
seeking bariatric surgery (Adami, Meneghelli, Bressani, & Scopinaro, 1999; Allison et al., 2006; Hsu, Betancourt, & Sullivan, 1996). Establishing valid and reliable methods of assessing NES remains an important goal to maximize identification and treatment of the disorder. The Night Eating Questionnaire (NEQ) is the only published and validated survey that screens for severity of night eating symptoms (Allison, Lundgren, et al., 2008). It contains 14 items that assess the two core features, as well as additional symptoms, such as morning anorexia, desire to eat at night, sleep difficulties, and depressed mood. One item assesses degree of awareness during nocturnal ingestions and is used only to differentiate possible cases of sleep-related eating disorder, a parasomnia, from those with NES (Howell & Schenck, 2009). Cronbach's alpha for the original NEQ total score was .70, and principal components analysis yielded a four factor solution: (1) Nocturnal Ingestions, (2) Evening Hyperphagia, (3) Morning Anorexia, and (4) Mood/Sleep (Allison, Lundgren, et al., 2008).
V. Moizé et al. / Eating Behaviors 13 (2012) 260–263
The English version of the NEQ was published in 2008 and has been successfully translated into Portuguese and validated by a Brazilian group (Cronbach's alpha of .78; Harb, Caumo, & Hidalgo, 2008). Although other translations of the NEQ have been published (Italian — Cardetti, Carpegna, Ferrato, Paola, & Vinai, 2008) or used in studies (German — Olbrich et al., 2009), no others have included a validation study. Because the Spanish speaking population in the United States and world-wide is increasing rapidly, the translation of this scale seems paramount. Assessment tools in Spanish for disordered eating behaviors that influence obesity seem limited. While NES affects persons across the weight spectrum, there is also an increased risk of NES with increasing BMI (Andersen, Stunkard, Sorensen, Pedersen, & Heitman, 2004; Gluck, Venti, Salbe, & Krakoff, 2008; Lundgren et al., 2006; Tholin et al., 2009). Expanding our toolbox of screening measures in the Spanish language would be helpful to identify potential targets for improving mental health and the manifestations of obesity. Therefore, in the present study we performed a translation and validation study of the NEQ. We translated the measure into Spanish, and then we examined the factor structure, internal consistency and validity of the translated measure. We also evaluated depression and anxiety to analyze the scale's concurrent and divergent validity. Finally, we assessed the test–re-test reliability of the translation.
2. Methods 2.1. Procedures The questionnaire validation included four phases. First, the English version of the NEQ was translated into Spanish by a bilingual, native Spanish speaker (from Spain). It was then translated back into English and compared with the original version. Next, the Spanish version was administered to 244 participants and again to a subgroup (n= 36) 2 weeks later to assess test–re-test reliability.
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All volunteers participated in the informed consent process, and the study was approved by the ethical committee of the Hospital Clinic. 2.4. Analysis Scale structure and stability were evaluated using principal components analysis to yield the factor structure and Cronbach's alpha. Correlations were used to evaluate scale reliability within the test–re-test sample. Concurrent/divergent validity was evaluated by examining correlations between the Spanish NEQ and the STAI and BDI-II. The factor structure was examined using principal components analysis with varimax rotation; eigenvalues greater than one were extracted. Item loadings of ≥0.40 were considered to load on a factor. 3. Results 3.1. Factor structure The NEQ score total score ranged from 1 to 41 (M = 12.5 ± 7). Our overall analysis revealed that the factor structure is similar to that yielded by the English version. The four-factor structure explained 66.2% of the variance. Factor structure, item loadings, and item-total correlations for items 1–12 and 14 of the total sample of completed NEQ's (general population and test–re-test) using principal components analysis are presented in Table 1. (Item 13 was not included as discussed in the introduction.) The eigenvalues for factors one through four were 4.5, 1.6, 1.4 and 1.1, respectively. The percent of variability that each factor accounts for in the overall model is also shown in Table 1. As in the original, the Nocturnal Ingestions factor explained the most variance. Items 7 and 9 did not behave as in the original work. Item 7 loaded on the Mood/Sleep dimension at only 0.1 in the Spanish version compared to 0.73 in the English version (Allison, Lundgren, et al., 2008). Item 9 loaded at 0.31 as compared to 0.87 (Allison, Lundgren, et al., 2008) on the Nocturnal Ingestions factor, but loaded on the Mood/ Sleep factor at 0.72 as compared to 0 in the English version.
2.2. Participants
3.2. Test–re-test and reliability analysis
We recruited a convenience sample of 244 participants (181 f; age = 40.5 ± 15.7 years) from Barcelona city. Participants originated from a bariatric surgery clinic, including bariatric patients, their friends, and family members attending clinic appointments. Additionally, we recruited university students, hospital personnel, and family members of the hospital personnel. Participants' heights and weights were obtained by self-report, and BMI was calculated (M = 34.3 ± 10 kg/m 2). Of these, 36 participants (28 f; age 39.6 ± 14 years; BMI 31.8 ± 12 kg/m 2) who had completed the first questionnaire completed the questionnaires a second time within a two week period.
Participant characteristics of those in the re-test sample did not differ from the remaining sample. Cronbach's alpha was 0.79 when
2.3. Measures 1. Night Eating Questionnaire (NEQ; Allison, Lundgren, et al., 2008): a 14-item validated, self-report measure that assesses the behavioral and psychological symptoms of NES. 2. Beck Depression Inventory — Spanish Version (BDI-II): a widely used 21-item self-report measure to assess symptoms of depression. It has high internal consistency (alpha .89; Bernal, Bonilla, & y Santiago, 1995), and good construct validity (Bonilla, Bernal, Santos, & Santos, 2004). 3. State Trait and Anxiety Inventory — Spanish Version (STAI; Spielberger, Gorsuch, Lushene, Vagg, & Jacobs, 1983): a wellknown, 40-item instrument, measuring levels of anxiety.
Table 1 Factor structure, item loadings, and item-total correlations for items 1–12 and 14 of the NEQ using principal components analysis (n = 244). Item
Nocturnal ingestions
Evening hyperphagia
Mood/ sleep
Morning anorexia
Correlation (r) with total score*
1 2 3 4 5 6 7$ 8 9$ 10 11 12 14 Total variance explained (%)
0.02 0.06 0.23 0.14 0.26 0.09 − 0.03 0.11 0.31$ 0.90 0.89 0.89 0.77 34.9
− 0.11 0.25 0.79 0.83 0.74 0.19 − 0.34 0.04 0.00 0.13 0.16 0.20 0.20 12.2
0.06 0.15 0.19 0.10 0.09 0.65 0.10$ 0.80 0.72$ 0.21 0.13 0.17 0.12 10.5
0.81 0.73 − 0.08 − 0.01 0.21 0.12 − 0.29 0.06 − 0.02 − 0.01 0.05 0.06 0.05 8.7
0.26 0.38 0.63 0.54 0.59 0.50 0.11 0.55 0.58 0.70 0.68 0.69 0.61
Notes: *p b 0.001 for all items except for # 7, where p = 0.092. Items highlighted in bold load on each original factor. $ : Loading of items 7 and 9 did not behave as in the original work (Allison, Engel, et al., 2008; Allison, Lundgren, et al., 2008).
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V. Moizé et al. / Eating Behaviors 13 (2012) 260–263
including all items and 0.82 when excluding those inconsistent items with the original work. Test–re-test correlations were greater than 0.8 with statistically significant p-values for all items except for 8 and 9 (r = 0.25 and 0.23, respectively). Test–re-test correlations for items 1–12 and 14 of the NEQ and the NEQ global score (n = 36) are presented in Table 2. The total NEQ score was not significantly different at the two time points (9.2 ± 4.4 and 8.5 ± 4.0, p = 0.10). 3.3. Convergent validity Total NEQ score was correlated with the BDI-II (r = 0.48, p b 0.001), but not during the test–re-test (r = 0.28, p = 0.10), or with the STAI at either time point (r = 0.05, p = 0.40; r = 0.07, p = 0.69, respectively). When excluding items 7 and 9, the correlations of the total NEQ score were 0.47 (p b 0.001) with the BDI-II and − 0.02 (p = 0.78) with the STAI. When excluding both mood items (items 6 and 7), the correlations of the total NEQ score were 0.41 (p b 0.001) with the BDI-II and 0.00 (p = 0.97) with the STAI. BMI correlations with the total NEQ score, STAI, and BDI-II were r = 0.22 (p b 0.001), r = −0.02 (p = 0.79), and r = 0.33 (p b 0.001), respectively. When excluding items 7 and 9, the correlation remained similar (r = 0.20, p = 0.001). 4. Discussion The Spanish version of the NEQ showed adequate internal consistency and excellent reproducibility from the English version. Item 7, which assesses the circadian pattern of mood, did not seem informative in this version because it did not load on any of the four factors. Further, item 9, which assesses frequency of awakenings, loaded more strongly on the Mood/Sleep factor than the Nocturnal Ingestions factor as it had in the English version, but this loading was strong and seemed informative. This finding may be explained by differences in the samples, as the English version was initially validated using participants who were seeking information to help with their night eating as compared to a community sample, used in the current study. In the validation study of the Portuguese version the instrument showed satisfactory internal consistency (Harb et al., 2008). Similar to our analysis, it showed marginally better psychometric adequacy when item 7 was removed. However, in contrast to our analysis, item 9 of the Portuguese version behaved similarly to that of the English version. As item 7 has performed poorly now on two translations of the NEQ, future validation studies should continue to examine the adequacy of its inclusion on the NEQ, and, in consideration of the larger nosological picture, the clinical utility of the circadian pattern of mood to the diagnosis of NES should also be examined. Table 2 Test–re-test correlations for items 1–12 and 14 of the NEQ and the NEQ global score (n = 36). Item
Correlation (r) with total score
p-value
1 2 3 4 5 6 7 8 9 10 11 12 14 NEQ global score
0.83 0.96 0.84 0.72 0.89 0.90 0.89 0.25 0.23 1.00 NE 1.00 1.00 0.86
b.001 b.001 b.001 b.001 b.001 b.001 b.001 0.156 0.184 b.001 NE b.001 b.001 b.001
Notes: NE: not estimable; all subjects had the 0 value for both measurements.
Interestingly, the Morning Anorexia items showed the second weakest correlation with the NEQ total score. A previous study using item response theory analysis (Allison, Engel, et al., 2008) found that the morning anorexia items were not significant contributors of an overarching night eating construct (Allison, Engel, et al., 2008). Based on that study, morning anorexia was moved from a core feature of NES to a possible modifier in the proposed diagnostic criteria (Allison et al., 2010). In this current analysis, the Morning Anorexia factor contributed to the internal consistency of the questionnaire, but not nearly as significantly as did the Nocturnal Ingestions factor. The positive relationship observed between the total NEQ score with the BDI-II is consistent with previous studies (Allison, Stunkard, & Their, 2004; Gluck, Geliebter, & Satov, 2001; Lundgren, Allison, O'Reardon, & Stunkard, 2008). That the relationship remained even after excluding the mood related items suggests that night eating and depressed mood are distinct symptoms that are likely to co-exist. However, it is unclear why the relationship diminished among the re-test sample. In practice, clinicians should assess depression in individuals presenting for treatment for their night eating. While anxiety disorders are common among night eaters (Lundgren et al., 2008), anxiety per se, is not a symptom of NES, confirmed by the lack of relationship observed between the STAI and NEQ. It is possible that some individuals eat in the evening or during the night in response to anxiety, but this is not a core feature of the disorder and thus is not assessed in the questionnaire. Finally, as the severity of night eating symptoms increased, so did BMI and depressed mood. Although previous studies have shown a higher risk of obesity (e.g., Colles et al., 2007; Lamerz et al., 2005; Lundgren et al., 2006; Tholin et al., 2009) and weight gain (Gluck et al., 2008), among those reporting night eating behaviors, NEQ scores in normal weight treatment seekers tend to be higher (Lundgren et al., 2008; Marshall, Allison, O'Reardon, Birketvedt, & Stunkard, 2004). NES may be more common among those of increasing weight, but persons of normal weight may have more severe symptoms, including more daytime food restriction and overexercise, pushing a higher percentage of their food consumption to the nighttime hours (Lundgren et al., 2008). This study had both strengths and limitations. We adopted an opportunistic recruitment method and therefore, the results might not be generalizable to a wider population. While the current sample included patients seeking surgical treatment for obesity, it also included clinic staff and family members who might have answered differently than persons seeking treatment for weight loss or disordered eating, which likely improved the range and variability of scores and serves to strengthen the outcomes. 5. Conclusions In conclusion, the Spanish version of the NEQ demonstrated adequate internal consistency and appears to be largely equivalent to the original English version with excellent reproducibility. These results suggest that the Spanish-version of the NEQ is a valid instrument that is suitable for use in clinical research. Future research should establish the sensitivity and specificity of cut-off scores for diagnosis of NES using the Spanish translation of the NEQ. Role of Funding Sources Hospital Clinic provided financial support for the conduct of the research and/or preparation of the manuscript. This study has been supported, in part, by the Intramural Research Program of the NIH, NIDDK. Contributors Authors Allison, Moize and Torres, designed the study and wrote the protocol. Authors Moizé and Andreu collected data. Authors Gluck, Vidal, Andreu, conducted literature searches and provided summaries of previous research studies. Author Torres conducted the statistical analysis. Author Allison, Moizé, Gluck and Torres
V. Moizé et al. / Eating Behaviors 13 (2012) 260–263 wrote the first draft of the manuscript and all authors contributed to and have approved the final manuscript.
Conflict of Interest All authors declare that they have no conflicts of interest.
References Adami, G. F., Meneghelli, A., Bressani, A., & Scopinaro, N. (1999). Body image in obese patients before and after stable weight reduction following bariatric surgery. Journal of Psychosomatic Research, 46(3), 275–281. Allison, K. C., Engel, S. G., Crosby, R. D., de Zwaan, M., O'Reardon, J. P., Wonderlich, S. A., et al. (2008). Evaluation of diagnostic criteria for night eating syndrome using item response theory analysis. Eating Behaviors, 9, 398–407. Allison, K. C., Lundgren, J. D., O'Reardon, J. P., Geliebter, A., Gluck, M. E., Vinai, P., et al. (2010). Proposed diagnostic criteria for night eating syndrome. International Journal of Eating Disorders, 43(3), 241–247. Allison, K. C., Lundgren, J. D., O'Reardon, J. P., Martino, N. S., Sarwer, D. B., Wadden, T. A., et al. (2008). The Night Eating Questionnaire (NEQ): Psychometric properties of a measure of severity of the Night Eating Syndrome. Eating Behaviors, 9(1), 62–72. Allison, K. C., Stunkard, A. J., & Their, S. L. (2004). Overcoming night eating syndrome: A step-by-step guide to breaking the cycle. Oakland, CA: New Harbinger. Allison, K. C., Wadden, T. A., Sarwer, D. B., Fabricatore, A. N., Crerand, C. E., Gibbons, L. M., et al. (2006). Night eating syndrome and binge eating disorder among persons seeking bariatric surgery: Prevalence and related features. Surgery for Obesity and Related Diseases, 2(2), 153–158. Andersen, G. S., Stunkard, A. J., Sorensen, T. I. A., Pedersen, L., & Heitman, B. L. (2004). Night eating and weight change in middle-aged men and women. International Journal of Obesity, 28, 1138–1143. Bernal, G., Bonilla, J., & y Santiago, J. (1995). Confiabilidad interna y validez de construcción lógica de dos instrumentos para medir sintomatología psicológica en una muestra clínica: El Inventario de Depresión de Beck y la Lista de Cotejo de Síntomas-36. Revista Latinoamericana de Psicología, 27, 207–229. Bonilla, J., Bernal, G., Santos, A., & Santos, D. (2004). A revised Spanish version of the Beck Depression Inventory: Psychometric properties with a Puerto Rican sample of college students. Journal of Clinical Psychology, 60(1), 119–130. Cardetti, S., Carpegna, G., Ferrato, N., Paola, V., & Vinai, P. (2008). Night eating syndrome. In P. Todisco, & P. Vinai (Eds.), La fame infinita: Mauale di diagnosi e terapia del disturbda alimentazione incontrollata (pp. 157–169). Torino, Italy: Centro Scientifico Editore. Ceru-Björk, C., Andersson, I., & Rössner, S. (2001). Night eating and nocturnal eating — Two different or similar syndromes among obese patients? International Journal of Obesity, 25, 365–372. Colles, S. L., Dixon, J. B., & O'Brien, P. E. (2007). Night eating syndrome and nocturnal snacking: Association with obesity, binge eating and psychological distress. International Journal of Obesity, 31, 1722–1730.
263
Gluck, M. E., Geliebter, A., & Satov, T. (2001). Night eating syndrome is associated with depression, low self-esteem, reduced daytime hunger and less weight loss in obese outpatients. Obesity Research, 9(4), 264–267. Gluck, M. E., Venti, C. A., Salbe, A. D., & Krakoff, J. (2008). Nighttime eating: commonly observed and related to weight gain in an inpatient food intake study. American Journal of Clinical Nutrition, 88, 900–905. Harb, A. B., Caumo, W., & Hidalgo, M. P. (2008). Translation and adaptation of the Brazilian version of the Night Eating Questionnaire. Cadernos de Saúde Pública, 24(6), 1368–1376. Howell, M. J., & Schenck, C. H. (2009). Treatment of nocturnal eating disorders. Current Treatment Options in Neurology, 11(5), 333–339. Hsu, L. K., Betancourt, S., & Sullivan, S. P. (1996). Eating disturbances before and after vertical banded gastroplasty: A pilot study. International Journal of Eating Disorder, 19(1), 23–34. Lamerz, A., Kuepper-Nybelen, J., Bruning, N., Wehle, C., Trost-Brinkhues, G., Brenner, H., et al. (2005). Prevalence of obesity, binge eating and night eating in a cross sectional field survey of 6-year-old children and their parents in a German urban population. Journal of Child Psychology and Psychiatry, 46, 385–393. Lundgren, J. D., Allison, K. C., Crow, S., O'Reardon, J. P., Berg, K. C., Galbraith, J., et al. (2006). Prevalence of the night eating syndrome in a psychiatric population. The American Journal of Psychiatry, 163, 156–158. Lundgren, J. L., Allison, K. C., O'Reardon, J. P., & Stunkard, A. J. (2008). A descriptive study of non-obese persons with night eating syndrome and a weight-matched comparison group. Eating Behaviors, 9, 352–359. Marshall, H. M., Allison, K. C., O'Reardon, J. P., Birketvedt, G., & Stunkard, A. J. (2004). The night eating syndrome among nonobese persons. International Journal of Eating Disorders, 35, 217–222. Napolitano, M. A., Head, S., Babyak, M. A., & Blumenthal, J. A. (2001). Binge eating disorder and night eating syndrome: Psychological and behavioural characteristics. International Journal of Eating Disorders, 30, 193–203. Olbrich, K., Mühlhans, B., Allison, K. C., Hahn, E. G., Schahin, S. P., & de Zwaan, M. (2009). Night eating, binge eating, and related features in patients with obstructive sleep apnea syndrome. European Eating Disorders Review, 17, 120–127. Rand, C. S., Macgregor, A. M., & Stunkard, A. J. (1997). The night eating syndrome in the general population and among postoperative obesity surgery patients. International Journal of Eating Disorder, 22(1), 65–69. Spielberger, C. D., Gorsuch, R. L., Lushene, P. R., Vagg, P. R., & Jacobs, A. G. (1983). Manual for the State-Trait Anxiety Inventory (Form Y). Palo Alto: Consulting Psychologists Press, Inc. Striegel-Moore, R. H., Franko, D. L., Thompson, D., Affenito, S., & Kraemer, H. C. (2006). Night eating: Prevalence and demographic correlates. Obesity, 14(1), 139–147. Stunkard, A. J., Berkowitz, R., Wadden, T., Tanrikut, C., Reiss, E., & Young, L. (1996). Binge eating disorder and the night eating syndrome. International Journal of Obesity, 20, 1–6. Tholin, S., Lindroos, A., Tynelius, P., Akerstedt, T., Stunkard, A. J., Bulik, C. M., et al. (2009). Prevalence of night eating in obese and nonobese twins. Obesity, 17(5), 1050–1055.
Contents lists available at SciVerse ScienceDirect
Eating Behaviors
Transcultural adaptation of the Night Eating Questionnaire (NEQ) for its use in the Spanish population☆ Violeta Moizé a,⁎, Marci E. Gluck b, Ferran Torres c, Alba Andreu a, Josep Vidal a, d, Kelly Allison e a
Obesity Unit, Department of Endocrinology and Nutrition, Hospital Clinic Universitari, Barcelona, Spain Obesity and Diabetes Clinical Research Section, Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases National Institutes of Health, Phoenix, AZ, United States c Biostatistics and Data Management Platform, IDIBAPS, Hospital Clinic, Biostatistics Unit, School of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain d Centro de Investigación Biomédica en Red en Diabetes y Enfermedades Metabólicas (CIBER-DEM), Instituto de Salud Carlos III, Barcelona, Spain e University of Pennsylvania School of Medicine, Department of Psychiatry, Center for Weight and Eating Disorders, United States b
a r t i c l e
i n f o
Article history: Received 15 December 2011 Received in revised form 28 January 2012 Accepted 21 February 2012 Available online 7 March 2012 Keywords: Night eating syndrome Nocturnal ingestion Eating behavior Assessment Transcultural adaptation
a b s t r a c t Background: Establishing valid and reliable methods of assessing night eating symptoms is an important goal to maximize identification and treatment of the night eating syndrome (NES). The 14-item Night Eating Questionnaire (NEQ) is the only published and validated assessment instrument but is not yet adapted to Spanish. Methods: We examined the factor structure, internal consistency and validity of the NEQ in Spanish. The study had 4 phases: a) translation from English to Spanish; b) back-translation from Spanish to English, c) administration of translated version to a Spanish sample, and d) a re-test in 36 participants two weeks later. Reliability, stability, and scale structure were evaluated by Cronbach's α, test–re-test, and factor analysis, respectively. Divergent validity was assessed by correlation with the Spanish versions of the State-Trait Anxiety Inventory (STAI) and the Beck Depression Inventory (BDI-II). Results: Two-hundred forty-four individuals (181 f; BMI 34.3 ± 10 kg/m2; age 40.5 ± 15 y) completed the questionnaire. The mean NEQ score was 12.5 ± 7. The Cronbach's α coefficient for the total score was 0.79, the intraclass correlation was 0.85, and the factor analysis yielded a similar four factor solution as the original scale. Correlation for the test–re-test total score was 0.86. Total NEQ score was significantly correlated with the BDI-II (r = 0.48 p b 0.001), but this correlation was not significant during the test–re-test (r = 0.28, p = 0.10) or with STAI at either time point (0.05, p = 0.40; r = 0.07, p = 0.69, respectively). Conclusions: The Spanish version of the NEQ demonstrated adequate internal consistency for the majority of domains and excellent reproducibility. There was divergent validity with anxiety and a relationship between night eating and depression. These results suggest that the Spanish-version of the NEQ is an instrument that is valid for use in clinical research. © 2012 Elsevier Ltd. All rights reserved.
1. Introduction Night eating syndrome (NES) is characterized by a delayed circadian pattern of eating (Allison et al., 2010), including two core features: evening hyperphagia and/or nocturnal ingestions. The prevalence is 1.5% in the general population (Rand, Macgregor, & Stunkard, 1997; StriegelMoore, Franko, Thompson, Affenito, & Kraemer, 2006), 4%–43% of persons seeking obesity treatment (Ceru-Björk, Andersson, & Rössner, 2001; Colles, Dixon, & O'Brien, 2007; Napolitano, Head, Babyak, & Blumenthal, 2001; Stunkard et al., 1996), and 9%–42% of persons
☆ Supported in part by the Intramural Research Program of the NIH, NIDDK. ⁎ Corresponding author at: UnidadFuncional de Obesidad, Hospital Clinic, Villarroel Street 170. 08036, Barcelona, Spain. Tel.: + 34 93 227 54 00x9846; fax: + 34 93 451 66 38. E-mail address: [email protected] (V. Moizé). 1471-0153/$ – see front matter © 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.eatbeh.2012.02.005
seeking bariatric surgery (Adami, Meneghelli, Bressani, & Scopinaro, 1999; Allison et al., 2006; Hsu, Betancourt, & Sullivan, 1996). Establishing valid and reliable methods of assessing NES remains an important goal to maximize identification and treatment of the disorder. The Night Eating Questionnaire (NEQ) is the only published and validated survey that screens for severity of night eating symptoms (Allison, Lundgren, et al., 2008). It contains 14 items that assess the two core features, as well as additional symptoms, such as morning anorexia, desire to eat at night, sleep difficulties, and depressed mood. One item assesses degree of awareness during nocturnal ingestions and is used only to differentiate possible cases of sleep-related eating disorder, a parasomnia, from those with NES (Howell & Schenck, 2009). Cronbach's alpha for the original NEQ total score was .70, and principal components analysis yielded a four factor solution: (1) Nocturnal Ingestions, (2) Evening Hyperphagia, (3) Morning Anorexia, and (4) Mood/Sleep (Allison, Lundgren, et al., 2008).
V. Moizé et al. / Eating Behaviors 13 (2012) 260–263
The English version of the NEQ was published in 2008 and has been successfully translated into Portuguese and validated by a Brazilian group (Cronbach's alpha of .78; Harb, Caumo, & Hidalgo, 2008). Although other translations of the NEQ have been published (Italian — Cardetti, Carpegna, Ferrato, Paola, & Vinai, 2008) or used in studies (German — Olbrich et al., 2009), no others have included a validation study. Because the Spanish speaking population in the United States and world-wide is increasing rapidly, the translation of this scale seems paramount. Assessment tools in Spanish for disordered eating behaviors that influence obesity seem limited. While NES affects persons across the weight spectrum, there is also an increased risk of NES with increasing BMI (Andersen, Stunkard, Sorensen, Pedersen, & Heitman, 2004; Gluck, Venti, Salbe, & Krakoff, 2008; Lundgren et al., 2006; Tholin et al., 2009). Expanding our toolbox of screening measures in the Spanish language would be helpful to identify potential targets for improving mental health and the manifestations of obesity. Therefore, in the present study we performed a translation and validation study of the NEQ. We translated the measure into Spanish, and then we examined the factor structure, internal consistency and validity of the translated measure. We also evaluated depression and anxiety to analyze the scale's concurrent and divergent validity. Finally, we assessed the test–re-test reliability of the translation.
2. Methods 2.1. Procedures The questionnaire validation included four phases. First, the English version of the NEQ was translated into Spanish by a bilingual, native Spanish speaker (from Spain). It was then translated back into English and compared with the original version. Next, the Spanish version was administered to 244 participants and again to a subgroup (n= 36) 2 weeks later to assess test–re-test reliability.
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All volunteers participated in the informed consent process, and the study was approved by the ethical committee of the Hospital Clinic. 2.4. Analysis Scale structure and stability were evaluated using principal components analysis to yield the factor structure and Cronbach's alpha. Correlations were used to evaluate scale reliability within the test–re-test sample. Concurrent/divergent validity was evaluated by examining correlations between the Spanish NEQ and the STAI and BDI-II. The factor structure was examined using principal components analysis with varimax rotation; eigenvalues greater than one were extracted. Item loadings of ≥0.40 were considered to load on a factor. 3. Results 3.1. Factor structure The NEQ score total score ranged from 1 to 41 (M = 12.5 ± 7). Our overall analysis revealed that the factor structure is similar to that yielded by the English version. The four-factor structure explained 66.2% of the variance. Factor structure, item loadings, and item-total correlations for items 1–12 and 14 of the total sample of completed NEQ's (general population and test–re-test) using principal components analysis are presented in Table 1. (Item 13 was not included as discussed in the introduction.) The eigenvalues for factors one through four were 4.5, 1.6, 1.4 and 1.1, respectively. The percent of variability that each factor accounts for in the overall model is also shown in Table 1. As in the original, the Nocturnal Ingestions factor explained the most variance. Items 7 and 9 did not behave as in the original work. Item 7 loaded on the Mood/Sleep dimension at only 0.1 in the Spanish version compared to 0.73 in the English version (Allison, Lundgren, et al., 2008). Item 9 loaded at 0.31 as compared to 0.87 (Allison, Lundgren, et al., 2008) on the Nocturnal Ingestions factor, but loaded on the Mood/ Sleep factor at 0.72 as compared to 0 in the English version.
2.2. Participants
3.2. Test–re-test and reliability analysis
We recruited a convenience sample of 244 participants (181 f; age = 40.5 ± 15.7 years) from Barcelona city. Participants originated from a bariatric surgery clinic, including bariatric patients, their friends, and family members attending clinic appointments. Additionally, we recruited university students, hospital personnel, and family members of the hospital personnel. Participants' heights and weights were obtained by self-report, and BMI was calculated (M = 34.3 ± 10 kg/m 2). Of these, 36 participants (28 f; age 39.6 ± 14 years; BMI 31.8 ± 12 kg/m 2) who had completed the first questionnaire completed the questionnaires a second time within a two week period.
Participant characteristics of those in the re-test sample did not differ from the remaining sample. Cronbach's alpha was 0.79 when
2.3. Measures 1. Night Eating Questionnaire (NEQ; Allison, Lundgren, et al., 2008): a 14-item validated, self-report measure that assesses the behavioral and psychological symptoms of NES. 2. Beck Depression Inventory — Spanish Version (BDI-II): a widely used 21-item self-report measure to assess symptoms of depression. It has high internal consistency (alpha .89; Bernal, Bonilla, & y Santiago, 1995), and good construct validity (Bonilla, Bernal, Santos, & Santos, 2004). 3. State Trait and Anxiety Inventory — Spanish Version (STAI; Spielberger, Gorsuch, Lushene, Vagg, & Jacobs, 1983): a wellknown, 40-item instrument, measuring levels of anxiety.
Table 1 Factor structure, item loadings, and item-total correlations for items 1–12 and 14 of the NEQ using principal components analysis (n = 244). Item
Nocturnal ingestions
Evening hyperphagia
Mood/ sleep
Morning anorexia
Correlation (r) with total score*
1 2 3 4 5 6 7$ 8 9$ 10 11 12 14 Total variance explained (%)
0.02 0.06 0.23 0.14 0.26 0.09 − 0.03 0.11 0.31$ 0.90 0.89 0.89 0.77 34.9
− 0.11 0.25 0.79 0.83 0.74 0.19 − 0.34 0.04 0.00 0.13 0.16 0.20 0.20 12.2
0.06 0.15 0.19 0.10 0.09 0.65 0.10$ 0.80 0.72$ 0.21 0.13 0.17 0.12 10.5
0.81 0.73 − 0.08 − 0.01 0.21 0.12 − 0.29 0.06 − 0.02 − 0.01 0.05 0.06 0.05 8.7
0.26 0.38 0.63 0.54 0.59 0.50 0.11 0.55 0.58 0.70 0.68 0.69 0.61
Notes: *p b 0.001 for all items except for # 7, where p = 0.092. Items highlighted in bold load on each original factor. $ : Loading of items 7 and 9 did not behave as in the original work (Allison, Engel, et al., 2008; Allison, Lundgren, et al., 2008).
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including all items and 0.82 when excluding those inconsistent items with the original work. Test–re-test correlations were greater than 0.8 with statistically significant p-values for all items except for 8 and 9 (r = 0.25 and 0.23, respectively). Test–re-test correlations for items 1–12 and 14 of the NEQ and the NEQ global score (n = 36) are presented in Table 2. The total NEQ score was not significantly different at the two time points (9.2 ± 4.4 and 8.5 ± 4.0, p = 0.10). 3.3. Convergent validity Total NEQ score was correlated with the BDI-II (r = 0.48, p b 0.001), but not during the test–re-test (r = 0.28, p = 0.10), or with the STAI at either time point (r = 0.05, p = 0.40; r = 0.07, p = 0.69, respectively). When excluding items 7 and 9, the correlations of the total NEQ score were 0.47 (p b 0.001) with the BDI-II and − 0.02 (p = 0.78) with the STAI. When excluding both mood items (items 6 and 7), the correlations of the total NEQ score were 0.41 (p b 0.001) with the BDI-II and 0.00 (p = 0.97) with the STAI. BMI correlations with the total NEQ score, STAI, and BDI-II were r = 0.22 (p b 0.001), r = −0.02 (p = 0.79), and r = 0.33 (p b 0.001), respectively. When excluding items 7 and 9, the correlation remained similar (r = 0.20, p = 0.001). 4. Discussion The Spanish version of the NEQ showed adequate internal consistency and excellent reproducibility from the English version. Item 7, which assesses the circadian pattern of mood, did not seem informative in this version because it did not load on any of the four factors. Further, item 9, which assesses frequency of awakenings, loaded more strongly on the Mood/Sleep factor than the Nocturnal Ingestions factor as it had in the English version, but this loading was strong and seemed informative. This finding may be explained by differences in the samples, as the English version was initially validated using participants who were seeking information to help with their night eating as compared to a community sample, used in the current study. In the validation study of the Portuguese version the instrument showed satisfactory internal consistency (Harb et al., 2008). Similar to our analysis, it showed marginally better psychometric adequacy when item 7 was removed. However, in contrast to our analysis, item 9 of the Portuguese version behaved similarly to that of the English version. As item 7 has performed poorly now on two translations of the NEQ, future validation studies should continue to examine the adequacy of its inclusion on the NEQ, and, in consideration of the larger nosological picture, the clinical utility of the circadian pattern of mood to the diagnosis of NES should also be examined. Table 2 Test–re-test correlations for items 1–12 and 14 of the NEQ and the NEQ global score (n = 36). Item
Correlation (r) with total score
p-value
1 2 3 4 5 6 7 8 9 10 11 12 14 NEQ global score
0.83 0.96 0.84 0.72 0.89 0.90 0.89 0.25 0.23 1.00 NE 1.00 1.00 0.86
b.001 b.001 b.001 b.001 b.001 b.001 b.001 0.156 0.184 b.001 NE b.001 b.001 b.001
Notes: NE: not estimable; all subjects had the 0 value for both measurements.
Interestingly, the Morning Anorexia items showed the second weakest correlation with the NEQ total score. A previous study using item response theory analysis (Allison, Engel, et al., 2008) found that the morning anorexia items were not significant contributors of an overarching night eating construct (Allison, Engel, et al., 2008). Based on that study, morning anorexia was moved from a core feature of NES to a possible modifier in the proposed diagnostic criteria (Allison et al., 2010). In this current analysis, the Morning Anorexia factor contributed to the internal consistency of the questionnaire, but not nearly as significantly as did the Nocturnal Ingestions factor. The positive relationship observed between the total NEQ score with the BDI-II is consistent with previous studies (Allison, Stunkard, & Their, 2004; Gluck, Geliebter, & Satov, 2001; Lundgren, Allison, O'Reardon, & Stunkard, 2008). That the relationship remained even after excluding the mood related items suggests that night eating and depressed mood are distinct symptoms that are likely to co-exist. However, it is unclear why the relationship diminished among the re-test sample. In practice, clinicians should assess depression in individuals presenting for treatment for their night eating. While anxiety disorders are common among night eaters (Lundgren et al., 2008), anxiety per se, is not a symptom of NES, confirmed by the lack of relationship observed between the STAI and NEQ. It is possible that some individuals eat in the evening or during the night in response to anxiety, but this is not a core feature of the disorder and thus is not assessed in the questionnaire. Finally, as the severity of night eating symptoms increased, so did BMI and depressed mood. Although previous studies have shown a higher risk of obesity (e.g., Colles et al., 2007; Lamerz et al., 2005; Lundgren et al., 2006; Tholin et al., 2009) and weight gain (Gluck et al., 2008), among those reporting night eating behaviors, NEQ scores in normal weight treatment seekers tend to be higher (Lundgren et al., 2008; Marshall, Allison, O'Reardon, Birketvedt, & Stunkard, 2004). NES may be more common among those of increasing weight, but persons of normal weight may have more severe symptoms, including more daytime food restriction and overexercise, pushing a higher percentage of their food consumption to the nighttime hours (Lundgren et al., 2008). This study had both strengths and limitations. We adopted an opportunistic recruitment method and therefore, the results might not be generalizable to a wider population. While the current sample included patients seeking surgical treatment for obesity, it also included clinic staff and family members who might have answered differently than persons seeking treatment for weight loss or disordered eating, which likely improved the range and variability of scores and serves to strengthen the outcomes. 5. Conclusions In conclusion, the Spanish version of the NEQ demonstrated adequate internal consistency and appears to be largely equivalent to the original English version with excellent reproducibility. These results suggest that the Spanish-version of the NEQ is a valid instrument that is suitable for use in clinical research. Future research should establish the sensitivity and specificity of cut-off scores for diagnosis of NES using the Spanish translation of the NEQ. Role of Funding Sources Hospital Clinic provided financial support for the conduct of the research and/or preparation of the manuscript. This study has been supported, in part, by the Intramural Research Program of the NIH, NIDDK. Contributors Authors Allison, Moize and Torres, designed the study and wrote the protocol. Authors Moizé and Andreu collected data. Authors Gluck, Vidal, Andreu, conducted literature searches and provided summaries of previous research studies. Author Torres conducted the statistical analysis. Author Allison, Moizé, Gluck and Torres
V. Moizé et al. / Eating Behaviors 13 (2012) 260–263 wrote the first draft of the manuscript and all authors contributed to and have approved the final manuscript.
Conflict of Interest All authors declare that they have no conflicts of interest.
References Adami, G. F., Meneghelli, A., Bressani, A., & Scopinaro, N. (1999). Body image in obese patients before and after stable weight reduction following bariatric surgery. Journal of Psychosomatic Research, 46(3), 275–281. Allison, K. C., Engel, S. G., Crosby, R. D., de Zwaan, M., O'Reardon, J. P., Wonderlich, S. A., et al. (2008). Evaluation of diagnostic criteria for night eating syndrome using item response theory analysis. Eating Behaviors, 9, 398–407. Allison, K. C., Lundgren, J. D., O'Reardon, J. P., Geliebter, A., Gluck, M. E., Vinai, P., et al. (2010). Proposed diagnostic criteria for night eating syndrome. International Journal of Eating Disorders, 43(3), 241–247. Allison, K. C., Lundgren, J. D., O'Reardon, J. P., Martino, N. S., Sarwer, D. B., Wadden, T. A., et al. (2008). The Night Eating Questionnaire (NEQ): Psychometric properties of a measure of severity of the Night Eating Syndrome. Eating Behaviors, 9(1), 62–72. Allison, K. C., Stunkard, A. J., & Their, S. L. (2004). Overcoming night eating syndrome: A step-by-step guide to breaking the cycle. Oakland, CA: New Harbinger. Allison, K. C., Wadden, T. A., Sarwer, D. B., Fabricatore, A. N., Crerand, C. E., Gibbons, L. M., et al. (2006). Night eating syndrome and binge eating disorder among persons seeking bariatric surgery: Prevalence and related features. Surgery for Obesity and Related Diseases, 2(2), 153–158. Andersen, G. S., Stunkard, A. J., Sorensen, T. I. A., Pedersen, L., & Heitman, B. L. (2004). Night eating and weight change in middle-aged men and women. International Journal of Obesity, 28, 1138–1143. Bernal, G., Bonilla, J., & y Santiago, J. (1995). Confiabilidad interna y validez de construcción lógica de dos instrumentos para medir sintomatología psicológica en una muestra clínica: El Inventario de Depresión de Beck y la Lista de Cotejo de Síntomas-36. Revista Latinoamericana de Psicología, 27, 207–229. Bonilla, J., Bernal, G., Santos, A., & Santos, D. (2004). A revised Spanish version of the Beck Depression Inventory: Psychometric properties with a Puerto Rican sample of college students. Journal of Clinical Psychology, 60(1), 119–130. Cardetti, S., Carpegna, G., Ferrato, N., Paola, V., & Vinai, P. (2008). Night eating syndrome. In P. Todisco, & P. Vinai (Eds.), La fame infinita: Mauale di diagnosi e terapia del disturbda alimentazione incontrollata (pp. 157–169). Torino, Italy: Centro Scientifico Editore. Ceru-Björk, C., Andersson, I., & Rössner, S. (2001). Night eating and nocturnal eating — Two different or similar syndromes among obese patients? International Journal of Obesity, 25, 365–372. Colles, S. L., Dixon, J. B., & O'Brien, P. E. (2007). Night eating syndrome and nocturnal snacking: Association with obesity, binge eating and psychological distress. International Journal of Obesity, 31, 1722–1730.
263
Gluck, M. E., Geliebter, A., & Satov, T. (2001). Night eating syndrome is associated with depression, low self-esteem, reduced daytime hunger and less weight loss in obese outpatients. Obesity Research, 9(4), 264–267. Gluck, M. E., Venti, C. A., Salbe, A. D., & Krakoff, J. (2008). Nighttime eating: commonly observed and related to weight gain in an inpatient food intake study. American Journal of Clinical Nutrition, 88, 900–905. Harb, A. B., Caumo, W., & Hidalgo, M. P. (2008). Translation and adaptation of the Brazilian version of the Night Eating Questionnaire. Cadernos de Saúde Pública, 24(6), 1368–1376. Howell, M. J., & Schenck, C. H. (2009). Treatment of nocturnal eating disorders. Current Treatment Options in Neurology, 11(5), 333–339. Hsu, L. K., Betancourt, S., & Sullivan, S. P. (1996). Eating disturbances before and after vertical banded gastroplasty: A pilot study. International Journal of Eating Disorder, 19(1), 23–34. Lamerz, A., Kuepper-Nybelen, J., Bruning, N., Wehle, C., Trost-Brinkhues, G., Brenner, H., et al. (2005). Prevalence of obesity, binge eating and night eating in a cross sectional field survey of 6-year-old children and their parents in a German urban population. Journal of Child Psychology and Psychiatry, 46, 385–393. Lundgren, J. D., Allison, K. C., Crow, S., O'Reardon, J. P., Berg, K. C., Galbraith, J., et al. (2006). Prevalence of the night eating syndrome in a psychiatric population. The American Journal of Psychiatry, 163, 156–158. Lundgren, J. L., Allison, K. C., O'Reardon, J. P., & Stunkard, A. J. (2008). A descriptive study of non-obese persons with night eating syndrome and a weight-matched comparison group. Eating Behaviors, 9, 352–359. Marshall, H. M., Allison, K. C., O'Reardon, J. P., Birketvedt, G., & Stunkard, A. J. (2004). The night eating syndrome among nonobese persons. International Journal of Eating Disorders, 35, 217–222. Napolitano, M. A., Head, S., Babyak, M. A., & Blumenthal, J. A. (2001). Binge eating disorder and night eating syndrome: Psychological and behavioural characteristics. International Journal of Eating Disorders, 30, 193–203. Olbrich, K., Mühlhans, B., Allison, K. C., Hahn, E. G., Schahin, S. P., & de Zwaan, M. (2009). Night eating, binge eating, and related features in patients with obstructive sleep apnea syndrome. European Eating Disorders Review, 17, 120–127. Rand, C. S., Macgregor, A. M., & Stunkard, A. J. (1997). The night eating syndrome in the general population and among postoperative obesity surgery patients. International Journal of Eating Disorder, 22(1), 65–69. Spielberger, C. D., Gorsuch, R. L., Lushene, P. R., Vagg, P. R., & Jacobs, A. G. (1983). Manual for the State-Trait Anxiety Inventory (Form Y). Palo Alto: Consulting Psychologists Press, Inc. Striegel-Moore, R. H., Franko, D. L., Thompson, D., Affenito, S., & Kraemer, H. C. (2006). Night eating: Prevalence and demographic correlates. Obesity, 14(1), 139–147. Stunkard, A. J., Berkowitz, R., Wadden, T., Tanrikut, C., Reiss, E., & Young, L. (1996). Binge eating disorder and the night eating syndrome. International Journal of Obesity, 20, 1–6. Tholin, S., Lindroos, A., Tynelius, P., Akerstedt, T., Stunkard, A. J., Bulik, C. M., et al. (2009). Prevalence of night eating in obese and nonobese twins. Obesity, 17(5), 1050–1055.