In addition to having an aging population, Turkey has a younger population compared to European countries. As of the end of 2020, the young population in the 15-24 age group constitutes 15.4% of the total population. Compared to the European Union member countries, Turkey has the highest young population; Latvia has the least percentage of young population with 9.1% as found in 2020 . Improving the quality of young people’s life is very important because of being in the process of completing their emotional, mental, sociocultural, physical and moral development.
World Health Organization (WHO) defines quality of life (QoL) as an individual’s perception of their position in life in the context of the culture and value systems in which they live, and in relation to their goals, expectations, standards and concerns . WHO also defines health as a state of complete physical, mental and social well-being, and not merely the absence of disease or infirmity. As it means, individuals must reach the life quality standards that means to have a healthy life. WHO also defines quality of life as a comprehensive concept that is affected by one’s physical health, beliefs, psychological state, social relationships and environment. There are 6 topics under the WHO definition of quality of life as physical health, psychological state, level of independence, social relations, environmental characteristics, spirituality .
Quality of life can affect unhealthy eating behaviors and even lead to eating disorders . Also as an unhealthy habit, night time snacking can be a risk for sleep and eating disorders [4, 5]. Eating disorders; self-respect and self-control struggles are characterized by a series of unhealthy attitudes and behaviors related to nutrition, body weight, and body shape. Many factors such as genetic, psychological and sociocultural factors contribute to the development of eating disorders . The period of adolescence and transition to early adulthood is a very important period in terms of the highest risk of eating disorders and their emergence, diagnosis and prevention . Night eating syndrome (NES) as one of the causes of obesity associated with excessive weight gain, is a syndrome with symptoms of not eating much during the day, hyperphagia and insomnia in the evening . Diagnostic criteria of NES were determined as follows; more than 25% of the food intake is after the evening meal and/or upon waking up and eating at night for 2 days or more a week, reluctance to eat in the morning and reduced food consumption, cravings after dinner or at night, having difficulty falling asleep for 4 days or more a week . Currently, it is not defined as “Night Eating Disorder” in the ICD-10 Classification, but it can be categorized as “F50.9: Eating disorder, unspecified” .
Apart from being a state of inactivity that allows the organism to rest, sleep is a regeneration phase that prepares the whole body for life again, and is one of the basic daily life activities that affects the quality of life and health of individuals. Lack of sleep affects the functions of the central nervous system, and severe insomnia can cause progressive dysfunction. For this reason, it is accepted that sleep plays a role in the balance and restoration of normal brain functions . Sleep disturbance can lead to eating disorders and NES by reducing sleep efficiency . Eating disorders and NES also affect quality of life. In this study, it was aimed to examine the effects of night eating status, eating and sleep disorders on the quality of life of university students.
Material and methods
The population of the cross-sectional, descriptive study was 5064 students studying at Uskudar University in the 2020/2021 academic year; the sample consists of 846 students who accepted to participate in the study and provided complete information. Data was collected with a diagnostic form, a SCOFF Eating Disorders Scale form, a Night Eating Questionnaire (NEQ) form, a Pittsburgh Sleep Quality Index (PSQI) form, and a World Health Organization Quality of Life Short Form (WHOQOL-BREF-TR) together; all were created in Google Forms and applied online between February and April 2021. Research data was evaluated with IBM SPSS v26® software. Ethics Committee Approval, numbered 61351342/2021-19 and dated 29.01.2021, was obtained from Uskudar University Non-Interventional Research Ethics Committee.
In our study, total number of university students was 5064, and estimated minimum sample size of 384 was calculated using the formula for descriptive studies:
n = [DEFF × Np(1 - p)] / [(d2/Z21 - α / 2 × (N - 1) + p × (1 - p)] .
Our sample consisted of 846 students, as doubled estimated minimum size of sample. In the present study, socio- demographic and health information form with 14 questions and study related 4 scales were used. These scales were adapted to Turkish as explained in the scale’s details.
SCOFF Eating Disorders Scale
SCOFF is a scale used to screen for eating disorders developed by J.F. Morgan et al. in 2000. SCOFF is a screening test suitable for both genders in adolescence and young adulthood. 0 to 5 points can be obtained from the scale. Each item with a ‘yes’ answer is given 1 point and 2 or more points are associated with the risk of eating disorder. The validity and reliability study of the scale for the Turkish population was conducted by O. Aydemir et al. (2015) and found suitable for Turkish society (Cronbach’s Alpha value: 0.74) . In this study, the Cronbach’s Alpha value of the scale was 0.683.
Night Eating Questionnaire (NEQ)
K.C. Allison et al. (2008) is a self-report questionnaire consisting of 14 questions that measures the frequency and presence of NES. The questionnaire includes questions about morning appetite and first food intake of the day, evening and night eating, food intake rate after dinner, cravings, control over night eating behavior, difficulty falling asleep, frequency of waking up at night, awareness and mood during night eating. The total score can be between 0 and 52. The cut-off score of 25 is recommended for screening research in the original study. In Turkish validity and reliability study  Cronbach’s Alpha value was 0.69, while in this study, the Cronbach’s Alpha value was 0.65.
Pittsburgh Sleep Quality Index (PSQI)
Pittsburgh Sleep Quality Index was developed by D.J. Buysse et al. in 1989. Its Turkish validity and reliability study was performed by M. Agargun et al. in 1996. PSQI is a 19-item self-report scale that evaluates sleep quality and disturbance in the past month. Each item of the test is scored equally between 0 and 3. By summing up the subscales, a total PSQI score ranging from 0 to 21 is obtained. While the sleep quality of those with a PSQI total score below 5 were evaluated as “good”, the sleep quality of those with a score of 5 and above were evaluated as “poor”; the higher the score, the worse the quality (Cronbach’s Alpha value: 0.80) . In this study, the Cronbach’s Alpha value was 0.747.
World Health Organization Quality of Life Scale - Short Form Turkish Version (WHOQOL-BREF-TR)
The scale consists of 26 questions characterizing the general perceived quality of life, developed by WHO. E. Eser et al. conducted the Turkish validity and reliability study of the scale in 1999 . The WHOQOL-BREF-TR version of the scale consists of 27 questions, with a national question added during the Turkish validity studies. It consists of 4 sub-dimensions including questions. Scale; “Physical health domain”: questions about ability to carry out daily activities, dependence on drugs and treatment, vitality and exhaustion, mobility, pain and discomfort, sleep and rest, ability to work; “Spiritual health domain”: questions about positive and negative emotions, self-esteem, body image and appearance, personal beliefs and attention; “Social domain”: questions about relationships with other people, social support and sexual life, and “Environment and national environment domain”: home environment, physical safety and security, financial resources, access to health care, leisure time, physical environment and transportation. The scale is applicable to non-elderly adults. WHOQOL-BREF-TR is calculated in the range of 0 to 20 points. Total score can be found from 0 to 100, and also more than 50% means higher quality of life . In this study, the Cronbach’s Alpha value of the scale was 0.843.
Descriptive statistics for categorical variables were presented as frequency and percentage. The conformity of the numerical variables to the normal distribution was checked with the “Shapiro-Wilk Test”. The mean and standard deviation (M±δ) results were given for those whose descriptive statistics of numerical variables show normal distribution. In the comparison of two independent groups, since the data confirmed the assumptions of the parametric tests, the “Independent Sample T-Test” was used. Examination of the relationships between the scales was determined with the “Pearson Product-Moment Correlation Coefficient”. In the interpretation of the correlation coefficient, “very weak correlation if <0.2”, “weak correlation if between 0.2-0.4”, “moderate correlation if between 0.4-0.6” and "high correlation if between 0.6-0.8”, “very high correlation if >0.8” criteria were used. In addition, statistical significance level was taken into account as “α<0.001” in all calculations and interpretations, and hypotheses were established as bidirectional. Statistical analysis of the data was performed with SPSS version 26 statistical analysis software.
In the present study, mean age of participants was 21.4±3.1 years, and mean body mass index was 22.5±8.0 kg/m2, as 84.2% female and 15.8% male as sown in Table 1. Most of the participants (56.1%) think that they have generally good health, and 55.7% of the participants do not find their physical activity level insufficient.
Table 1. Characteristics of participants (n=846)
In Table 2, descriptive statistics of scales were shown. The NES risk was found as 67.7% and SCOFF eating disorders in 38.4% of participants. According to the total mean PSQI score, the sleep quality of all participants was found as “poor”. All our participants had more than 50 in WHOQOL-BREF-TR.
Table 2. NEQ, SCOFF, PSQI and WHOQOL-BREF-TR scores of the participants (n=846)
NEQ - Night Eating Questionnaire; SCOFF - Eating Disorders Scale; PSQ - Pittsburgh Sleep Quality Index; WHOQOL-BREF-TR - World Health Organization Quality of Life Turkish Short Form; M±δ - Mean ± Standard Deviation.
The comparison of the sub-dimension and total scores of the scales are shown on Table 3. A statistically significant difference was found in the total and all sub-dimension scores of the WHOQOL-BREF-TR according to NEQ scores of the participants (p<0.001). The WHOQOL-BREF-TR scale’s physical health, psychological, social relationships, environment domains, and total scores of the participants who had a high risk of NES were statistically lower than those of the participants without risk of NES.
Table 3. Comparison of the sub-dimension and total score of the WHOQOL-BREF-TR according to the NEQ night eating syndrome
NEQ - Night Eating Questionnaire; WHOQOL-BREF-TR - World Health Organization Quality of Life Turkish Short Form; t - Independent Sample T-Test.
In Table 4, WHOQOL-BREF-TR and sub-dimensions according to the SCOFF of the participants are shown. Statistically significant differences were found in the total and all sub-dimension scores of the WHOQOL-BREF-TR according to the SCOFF scores (p<0.001). WHOQOL-BREF-TR sub-dimension (physical health, psychological, social relationships, and environment domains) and mean total scores of the participants with eating disorders were statistically lower than of the students without eating disorders.
Table 4. Sub-dimension and total scores of the WHOQOL-BREF-TR according to SCOFF Eating Disorder Status
SCOFF - Eating Disorder Scale; WHOQOL-BREF-TR - World Health Organization Quality of Life Turkish Short Form; t - Independent Sample T-Test.
Correlations between WHOQOL-BREF-TR and PSQI are given in Table 5. A statistically significant negative correlation was found between the PSQI total score of the participants, the total and all sub-dimension scores of the WHOQOL-BREF-TR. A negative weak correlation was found between the total PSQI score and the physical health domain (r=-0.295, p<0.001). Also, as the total score of PSQI increased, there was a decrease of 24.9% in the psychological domain score (r=-0.249, p<0.001). A statistically significant negative very weak correlation was found between the total score of PSQI and the social relationships domain and the environment domain (Table 5). In addition, as the total score of PSQI increased, there was a 26.9% decrease in the total score of WHOQOL-BREF-TR (r=-0.269, p<0.001).
Table 5. Correlation coefficients between WHOQOL-BREF-TR total and sub-dimension scores and PSQI
PSQI - Pittsburgh Sleep Quality Index; WHOQOL-BREF-TR - World Health Organization Quality of Life Turkish Short Form; r - Pearson Product-Moment Correlation Coefficient.
In this study, we tried to find relations between NES, sleep quality, eating disorders with the quality of life in an early adulthood sample. Many new studies stated about eating disorders prevalence in university students with SCOFF eating disorders assessment method, critical results were found as one in four university students , as well as half of medical faculty students . Studies conducted in the general population and special groups report the prevalence of eating behavior disorders can go up to the range of 58% . In this study, the predisposition to eating disorders was found to be quite high in university students, although it was within the limits of the current literature. As beeing in early adulthood period, university students are spending time at home with social media. General promotion of thinness in social media, broadcasting the body image of popular individuals as role models may be thought to be reason why they put restrictions on their nutrition.
Studies about the NES prevalence in early adulthood differs [19-21]. In a review, it was found that 0.3 to 9.4% of samples found to be at NES risk . In an interventional study the risk was also estimated as 3.3% . In 2022, a big meta-analyses showed that early adulthood can be a risk factor for NES . Similar to the literature, in the present study the prevalence of night eating in university students was found 67.7%. It was correlated with the response to the question “What do you prefer when you want to consume something at night?” (and the statement “I don’t consume anything at night”). NES is one of the most frequently observed eating behavior disorders in recent years . It can be thought the fact that university students continuing their education online from home due to pandemic affects their health behaviors such as day/night confusion, sleep, physical activity and nutrition, and can be a reason behind the prevalence of NES being high in our study.
In this study, WHOQOL-BREF-TR and sub-dimension scores were high, as total score was more than 50 points. Compared to a study conducted on university students, although the WHOQOL total and sub-dimension mean scores were lower in this study, but results were found in parallel with the current literature [22-24]. In a systematic review published in 2016, it was found that eating disorders reduce the quality of life and there is a significant relationship between severity of symptoms of eating disorders and quality of life . In this study, the WHOQOL-BREF and all sub-dimensions’ mean scores of the participants with the high risk in eating disorders were statistically lower than in healthy ones. Individuals with eating disorder risk (binge eating, vomiting, laxative use, compulsive exercise, intense dietary restrictions, and excessive preoccupation with body shape and weight) may have more impairment in functionality and mental health problems . Impairments in functionality cause physical and mental problems, as well as social ones in professional life and interpersonal relationships. Therefore, we think that impaired eating behavior can have a strong effect with lower quality of life. In this study, the total and all sub-dimension mean scores of the WHOQOL-BREF-TR scale were found lower in participants with NES risk. One of the most important indicators in determining the quality of life is the health status.
In literature, the amount of university students having a “poor” sleep quality according to the PSQI assessment was found 64.2%  and 73% . In this study, all of the participants were found to have ‘poor’ sleep quality according to the PSQI assessment. Although this result was quite high compared to the data of the pre-COVID-19 pandemic, it was shown that sleep disorders could be increased by the COVID-19 pandemic. The literature indicates that the quality of life of individuals with low sleep quality will also decrease [21-23]. Similarly, in this study, it was determined that sleep disorder risk as an increase in sleep disturbance was related to quality of life. Increasing scores of PSQI, which measures an individual’s sleep quality over a one-month period, indicate that sleep quality decreases. In some studies that examined the relationship between quality of life and sleep quality with such tools as PSQI and WHOQOL-BREF together, it was stated that the quality of life has a positive relation with the sleep quality [28-30]. Supporting the literature, in this study a statistically significant negative correlation was found between the total score of PSQI and the total, all sub-dimension scores of the WHOQOL-BREF-TR scale in university students. Based on the results obtained from the studies in the literature, it can be deduced that quality of life of individuals may decrease due to sleep quality deterioration. In literature, poor sleep quality was thought to be associated with worse life quality as it can cause serious physiological and psychological problems, and poor academic performance in the context of educational success [5, 10, 21].
Decreased sleep quality is a vicious cycle that poses a risk to eating disorders and quality of life deterioration. Consciousness and awareness about eating can be increased by providing trainings on healthy nutrition to individuals. This study is actual because of the inadequacy of studies on young adults in the literature on quality of life and in terms of guiding future studies on sleep, night eating and life quality.
1. Youth with Statistics. Turkish Statistical Institute (TUIK). URL: https://data.tuik.gov.tr/Bulten/Index?p=Istatistiklerle-Genclik-2020-37242
2. WHOQOL: Measuring Quality of Life. URL: https://www.who.int/tools/whoqol
3. Ágh T., Kovács G., Supina D., Pawaskar M., Herman B.K., Vokó Z., et al. A systematic review of the health-related quality of life and economic burdens of anorexia nervosa, bulimia nervosa, and binge eating disorder. Eat Weight Disord. 2016; 21 (3): 353-64. DOI: https://doi.org/10.1007/s40519-016-0264-x
4. Levine M.P., Piran N., Jasper K. Eating disorders. In: T.P. Gul- lotta, R.W. Plant, M.A. Evans (eds). Handbook of Adolescent Behavioral Problems: Evidence-Based Approaches to Prevention and Treatment. Boston, MA: Springer Science + Business Media, 2015: 305-28. DOI: https://doi.org/10.1007/978-1-4899-7497-6_16
5. Budkevich R.O., Bakumenko O.E., Evdokimov I.A., Budkevich E.V. Effects of nighttime snacking in students on their physiological parameters. Voprosy pitaniia. 2014; 83 (3): 17-24. DOI: https://doi.org/10.24411/0042-8833-2014-00025 (in Russian) [Будкевич Р.О., Бакуменко О.Е., Евдокимов И.А., Будкевич Е.В. Влияние ночного употребления пищи у студентов на некоторые их физиологические показатели // Вопросы питания. 2014. Т. 83, № 3. С. 17-24. DOI: https://doi.org/10.24411/0042-8833-2014-00025]
6. Stunkard A.J., Grace W.J., Wolff H.G. The night-eating syndrome: a pattern of food intake among certain obese patients. Am J Med. 1955; 19 (1): 78-86. DOI: https://doi.org/10.1016/0002-9343(55)90276-x
7. Allison K., Lundgren J., O’Reardon J., Geliebter A., Gluck M., et al. Proposed diagnostic criteria for night eating syndrome. Int J Eat Disord. 2010; 43 (3): 241-7. DOI: https://doi.org/10.1002/eat.20693
8. World Health Organization (WHO). ICD-10 Version: 2019. URL: https://icd.who.int/browse10/2019/en#/F50.2
9. Guyton A.C., Hall J.E. States of brain activity - sleep, brain waves, epilepsy, psychoses. In: Textbook of Medical Physiology. Elsevier; Saunders, 2006: 739-47.
10. Allison K.C., Spaeth A., Hopkins C.M. Sleep and eating disorders. Curr Psychiatry Rep. 2016; 18 (10): 1-8. DOI: https://doi.org/10.1007/s11920-016-0728-8
11. Sullivan K.M., Dean M., Soe M.M. OpenEpi: a web-based epidemiologic and statistical calculator for public health. Public Health Rep. 2009; 124 (3): 471-4. DOI: https://doi.org/10.1177/003335490912400320
12. Aydemir O., Koksal B., Sapmaz S.Y., Yuceyar H. Reliability and validity of Turkish form of SCOFF Eating Disorders Scale. Anatol J Psychiatry (Anadolu Psikiyatri Dergisi). 2015; 16 (S1): 31-6. DOI: https://doi.org/10.5455/APD.174219
13. Atasoy N., Saraçlı Ö., Konuk N., Ankarali H., Guriz S.O., Akdemir A., et al. Validity and reliability study of the Night Eating Questionnaire - Turkish form in the psychiatric outpatient population. Anatol J Psychiatry (Anadolu Psikiyatri Dergisi). 2014; 15 (3): 238-47. DOI: https://doi.org/10.5455/apd.39829
14. Agargun M.Y., Kara H, Anlar O. The validity and reliability of the Pittsburgh sleep quality index. Turk J Psychiatry [Turk Psikiyatri Derg]. 1996; 7 (2): 107-15.
15. Eser E., Fidaner H., Fidaner C., Eser S.Y., Elbi H., Göker E. Psychometric properties of WHOQOL-100 and WHOQOL-BREF. J Psychiatry Psychol Psychopharmacol. 1999; 7 (2): 23-40.
16. Kochan N.Z., Arslan M. Examining the relationship of seasonal change with emotional appetite and eating attitudes: a study on university students. Batı Karadeniz Tıp Dergisi. 2021; 5 (2): 210-7. DOI: https://doi.org/10.29058/mjwbs.859888
17. Telatar T.G. Evaluating the frequency of nutrition and eating disorders and related factors among university students of a medical faculty. Fırat J Med. 2021; 26 (2): 68-73.
18. Uzdil Z., Kayacan A.G., Ozyildirim C., Kaya S., Kılınç G.E., Asal C., Kaya P.S. Investigation of orthorexia nervosa presence and eating attitude in adolescents. Samsun J Health Sci. 2019; 4 (1): 8-13.
19. Bruzas M.B., Allison K.C. A review of the relationship between night eating syndrome and body mass index. Curr Obes Rep. 2019; 8 (2): 145-55. DOI: https://doi.org/10.1007/s13679-019-00331-7
20. Hymowitz G., Salwen J., Salis K.L. A mediational model of obesity related disordered eating: the roles of childhood emotional abuse and self-perception. Eat Behav. 2017; 26: 27-32. DOI: https://doi.org/10.1016/j.eatbeh.2016.12.010
21. Lepley T., Schwager Z., Khalid Z. Identification and management of night eating syndrome in the adolescent and young adult population. Prim Care Companion CNS Disord. 2022; 24 (1): 21r03062. DOI: https://doi.org/10.4088/PCC.21r03062
22. Burdurlu M.C., Cabbar F., Dagasan V., Kulle C., Ozenen D.O., Tomruk C.O. Assessing the quality of life of dental students by using the WHOQOL-BREF scale. Balkan J Dent Med. 2020; 24 (2): 91-5. DOI: https://doi.org/10.2478/bjdm-2020-0015
23. Toker B., Kalipci M.B. Evaluation of the quality of life of university students: Akdeniz University Case. OPUS Int J Soc Res. 2021; 18 (39): 405-30. DOI: https://doi.org/10.26466/opus.843021
24. Arslanoglu C., Acar K., Mor A., Baynaz K., Karakas F., Ipekoglu G., et al. Investigating the quality of life of university students in terms of exercise status. Erzincan University J Educ Faculty. 2021; 23 (1): 187-98. DOI: https://doi.org/10.17556/erziefd.745549
25. Jenkins P.E., Hoste R.R., Doyle A.C., Eddy K., Crosby R.D., Hill L., et al. Health-related quality of life among adolescents with eating disorders. J Psychosom Res. 2014; 76 (1): 1-5. DOI: https://doi.org/10.1016/j.jpsychores.2013.11.006
26. Erdogan N., Karabe, M.P., Tok S., Guzel D., Ekerbicer H.Ç. Determination of sleep quality and affecting factors in students of Sakarya Universıty Medical Faculty. Sakarya Med J. 2018; 8 (2): 395-403. DOI: https://doi.org/10.31832/smj.413752
27. Salva T., Gulluogl M.A., Kay M., Ozdemir K.U. The sleep quality and affecting factors Maltepe University Medical Faculty 1st and 6th Grade Students. Maltepe Med J. 2020; 12 (2): 27-33. DOI: https://doi.org/10.35514/mtd.2020.26
28. Shamsaei F., Yadollahifar S., Sadeghi A. Relationship between sleep quality and quality of life in patients with bipolar disorder. Sleep Sci. 2020; 13 (1): 65-9. DOI: https://doi.org/10.5935/1984-0063.20190135
29. Zarch M.K., Sorbi M.H. Structural relationships between depression, perceived stress, sleep quality, and quality of life: evidence from Iranian elderly. Thrita. 2019; 8 (2): e101115. DOI: https://doi.org/10.5812/thrita.101115
30. De Carvalho J.S.V., Oliveira I., Rosa R., Barata C., Fradinho M., Oliveira L., et al. Sleep quality and quality of life in physicians and nurses working at a Central Hospital. Eur Respir J. 2018; 52: 4372. DOI: https://doi.org/10.1111/jsr.13096