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Impact of the coronavirus disease 2019 pandemic on obesity, internet addiction, and sleep quality in adolescents

      Highlights

      • Covid-19 has caused an increase in children's obesity levels.
      • Covid-19 has caused an increase in children's internet addiction levels.
      • Covid-19 has caused a decrease in the sleep quality of children.

      Abstract

      Purpose

      This descriptive cross-sectional study aimed to examine the effects of the coronavirus disease-19 (COVID-19) pandemic on obesity, Internet addiction, and sleep quality in adolescents.

      Methods

      In this study, data were collected from 395 healthy adolescents using a sociodemographic form, an Internet addiction scale, and a sleep quality scale. Descriptive statistics were analyzed as numbers, percentages, and mean values. The Wilcoxon test was performed to compare the mean body mass index (BMI), Internet addiction, and sleep quality scores of the participants before and after the COVID-19 pandemic. The differences were significant at a p value of <0.05.

      Results

      The mean age of the participants was 15.04 ± 1.81 years, and 53% of them were female. The difference between the mean BMI scores of adolescents before and after the COVID-19 pandemic was significant (p < 0.01). The difference between the mean Internet addiction scale scores of the participants before and after the COVID-19 pandemic was significant (p < 0.01). The difference between the mean sleep quality scale scores before and after the COVID-19 pandemic was also significant (p < 0.01). Approximately 27.1% and 34.9% of the participants were obese before and after COVID-19, respectively.

      Conclusion

      The obesity rate, BMI, and Internet addiction levels of children increased, whereas their sleep quality decreased after the COVID-19 pandemic.

      Practical implications

      During the pandemic period, online trainings for parents should be organized on planning physical activities during closure periods, regulating the adolescents' sleep and eating habits.

      Keywords

      Introduction

      Coronavirus disease (COVID-19), which emerged in December 2019 in the Wuhan Province of China, was declared a pandemic by the World Health Organization in March 2020. This epidemic caused mental stress among individuals of all age groups (
      • Tamiolaki A.
      • Kalaitzaki A.E.
      That which does not kill us makes us stronger: COVİD 19 and postraumatic growth.
      ; ). To prevent the spread of the disease, workplaces and schools were closed, and home quarantine policies were implemented for children and adults. This caused a substantial loss of employment or income in various families, and children were unable to perform developmental tasks freely (). The children were provided with distance education without any orientation and were unable to adapt to this process without support (
      • Balhara Y.S.
      • Kattula D.
      • Singh S.
      • Chukkali S.
      • Bhargava R.
      Impact of lockdown following COVID-19 on the gaming behavior of college students.
      ;
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      Ways to strengthen the psychological resilience of children in the pandemic process: Recommendations to families, teachers and mental health specialists.
      ).
      The COVID-19 pandemic adversely affected the health, healthcare systems, and the economy, causing significant morbidity and mortality. It is an urgent public health problem, causing global mental, social, and economic difficulties. During the COVID-19 pandemic, 860 million children and young people were quarantined worldwide (
      • Munro A.P.
      • Faust S.N.
      Children are not COVID-19 super spreaders: Time to go back to school.
      ). Several researchers have stated that children whose lives have been profoundly affected by the COVID-19 pandemic have the greatest risk of deterioration of their health (
      • Golberstein E.
      • Wen H.
      • Miller B.F.
      Coronavirus disease 2019 (COVID-19) and mental health for children and adolescents.
      ;
      • Munro A.P.
      • Faust S.N.
      Children are not COVID-19 super spreaders: Time to go back to school.
      ). The COVID-19 pandemic has caused and continues to cause increased stress and health problems among adolescents for a variety of reasons, including getting sick, fear of death, losing loved ones, home quarantine, and economic problems (
      • Golberstein E.
      • Wen H.
      • Miller B.F.
      Coronavirus disease 2019 (COVID-19) and mental health for children and adolescents.
      ;
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      Covid-19 report, UNESCO. (2021). Covid-19 education response. How many students are at risk of not returning to school?.
      ).
      The implementation of social distancing and home quarantine policies significantly reduced the physical activity of the adolescents. Isolation promoted a sedentary lifestyle and increased the food consumption in children; increased food consumption, in turn, reportedly caused weight gain and obesity (
      • Golberstein E.
      • Wen H.
      • Miller B.F.
      Coronavirus disease 2019 (COVID-19) and mental health for children and adolescents.
      ;
      • Rundle A.G.
      • Park Y.
      • Herbstman J.B.
      • Kinsey E.W.
      • Wang Y.C.
      COVID-19 related school closings and risk of weight gain among children.
      ). The prevalence of a sedentary lifestyle and physical inactivity led to a significant increase in the body mass index (BMI; 21–70%) of children after the pandemic compared with that in the pre-pandemic period (
      • Dutta M.
      COVID-19 and Impact of School Closures on the Children of the United States; a Point of View with an Empirical Analysis.
      ;
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      Impact of obesity on influenza A virus pathogenesis, immune response, and evolution.
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      The effects of COVID-19 on the eating habits of children and adolescents in Italy: A pilot survey study.
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      • Xie X.
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      • Liu Q.
      • Zhang J.
      • Song R.
      Mental health status among children in home confinement during the coronavirus disease 2019 outbreak in Hubei Province, China.
      ;
      • Workman J.
      How much may COVID-19 school closures increase childhood obesity?.
      ). The adolescents had a difficult time coping with the sudden changes that occurred during the pandemic, with some of them experiencing social isolation, anxiety, and sleep and nutrition problems (
      • Çaykuş E.
      • Çaykuş T.
      Ways to strengthen the psychological resilience of children in the pandemic process: Recommendations to families, teachers and mental health specialists.
      ;
      • Ünver H.
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      COVID-19 pandemic-onset anorexia nervosa: Three adolescent cases.
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      • Xiang Y.T.
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      • Zhang Q.
      • Cheung T.
      • Ng C.H.
      Timely mental health care for the 2019 novel coronavirus outbreak is urgently needed.
      ).
      Hence, the adolescents had the tendency to engage in unhealthy behaviors such as the excessive use of the Internet to cope with these problems (
      • Király O.
      • Potenza M.N.
      • Stein D.J.
      • King D.L.
      • Hodgins D.C.
      • Saunders J.B.
      • Demetrovics Z.
      Preventing problematic internet use during the COVID-19 pandemic: Consensus guidance.
      ). The
      • Turkish Statistical Institute
      Household informatics technologies usage research.
      found that the Internet usage rate of individuals aged between 16 and 24 years relatively increased (84.3%) in Türkiye. When the literature was analyzed, the time spent using the Internet and watching television increased during the period of the pandemic, and the prevalence of Internet addiction increased by 24.4% (
      • Király O.
      • Potenza M.N.
      • Stein D.J.
      • King D.L.
      • Hodgins D.C.
      • Saunders J.B.
      • Demetrovics Z.
      Preventing problematic internet use during the COVID-19 pandemic: Consensus guidance.
      ;
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      • Xiang J.
      • Yan M.
      • Li H.
      • Huang S.
      • Shen C.
      Comparison of throat swabs and sputum specimens for viral nucleic acid detection in 52 cases of novel coronavirus (SARS-Cov-2)-infected pneumonia (COVID-19).
      ;
      • Medrano M.
      • Cadenas-Sanchez C.
      • Oses M.
      • Arenaza L.
      • Amasene M.
      • Labayen I.
      Changes in lifestyle behaviours during the COVID-19 confinement in Spanish children: A longitudinal analysis from the MUGI project.
      ;
      • Oflu A.
      • Bükülmez A.
      • Elmas E.
      • Tahta E.G.
      • Çeleğen M.
      Comparison of screen time and digital gaming habits of Turkish children before and during the coronavirus disease 2019 pandemic.
      ). Similarly, during the quarantine period, the adolescents tended to spend more time using the Internet and watching television (
      • Nagata J.M.
      • Magid H.S.A.
      • Gabriel K.P.
      Screen time for children and adolescents during the coronavirus disease 2019 pandemic.
      ). The adolescents often ate their meals in front of the screen during the pandemic. This practice can delay satiety and cause excessive consumption of food. Excessive consumption of food has led to an increased risk of obesity (
      • Chang T.H.
      • Chen Y.C.
      • Chen W.Y.
      • Chen C.Y.
      • Hsu W.Y.
      • Chou Y.
      • Chang Y.H.
      Weight gain associated with COVID-19 lockdown in children and adolescents: A systematic review and meta-analysis.
      ;
      • Khan M.A.
      • Shah S.M.
      • Shehab A.
      • Ghosal S.
      • Muhairi S.J.
      • Al-Rifai R.H.
      • Nauman J.
      Screen time and metabolic syndrome among expatriate adolescents in the United Arab Emirates.
      ;
      • Mulugeta W.
      • Hoque L.
      Impact of the COVID-19 lockdown on weight status and associated factors for obesity among children in Massachusetts.
      ;
      • Ten Velde G.
      • Lubrecht J.
      • Arayess L.
      • van Loo C.
      • Hesselink M.
      • Reijnders D.
      • Vreugdenhil A.
      Physical activity behaviour and screen time in Dutch children during the COVID-19 pandemic: Pre-, during-and post-school closures.
      ).
      Besides obesity and Internet addiction, the pandemic adversely affected the sleep habits and quality in children (
      • Burkart S.
      • Parker H.
      • Weaver R.G.
      • Beets M.W.
      • Jones A.
      • Adams E.L.
      • Armstrong B.
      Impact of the COVID-19 pandemic on elementary schoolers’ physical activity, sleep, screen time and diet: A quasi-experimental interrupted time series study.
      ;
      • Çaykuş E.
      • Çaykuş T.
      Ways to strengthen the psychological resilience of children in the pandemic process: Recommendations to families, teachers and mental health specialists.
      ;
      • Fidancı İ.
      • Aksoy H.
      • Taci D.Y.
      • Fidancı İ.
      • Başer D.A.
      • Cankurtaran M.
      Evaluation of the effect of the Covid-19 pandemic on sleep disorders and nutrition in children.
      ;
      • Ünver H.
      • Rodopman A.A.
      • Erdoğdu A.B.
      • İlbasmış Ç.
      COVID-19 pandemic-onset anorexia nervosa: Three adolescent cases.
      ;
      • Yurteri N.
      • Sarigedik E.
      Evaluation of the effects of COVID-19 pandemic on sleep habits and quality of life in children.
      ). The results of the study revealed that during the pandemic, children delayed their sleeping and waking up times, their sleep habits changed, and their sleep quality decreased by 20%–28% (
      • Bruni O.
      • Malorgio E.
      • Doria M.
      • Finotti E.
      • Spruyt K.
      • Melegari M.G.
      • Ferri R.
      Changes in sleep patterns and disturbances in children and adolescents in Italy during the Covid-19 outbreak.
      ;
      • Burkart S.
      • Parker H.
      • Weaver R.G.
      • Beets M.W.
      • Jones A.
      • Adams E.L.
      • Armstrong B.
      Impact of the COVID-19 pandemic on elementary schoolers’ physical activity, sleep, screen time and diet: A quasi-experimental interrupted time series study.
      ;
      • Yurteri N.
      • Sarigedik E.
      Evaluation of the effects of COVID-19 pandemic on sleep habits and quality of life in children.
      ). Since the schools were closed during the pandemic, the children tended to spend more time in front of the screen, eat more, sleep less, and perform less physical activity. These factors may have led to an increase in the risk of obesity during the pandemic (
      • Burkart S.
      • Parker H.
      • Weaver R.G.
      • Beets M.W.
      • Jones A.
      • Adams E.L.
      • Armstrong B.
      Impact of the COVID-19 pandemic on elementary schoolers’ physical activity, sleep, screen time and diet: A quasi-experimental interrupted time series study.
      ;
      • Bruni O.
      • Malorgio E.
      • Doria M.
      • Finotti E.
      • Spruyt K.
      • Melegari M.G.
      • Ferri R.
      Changes in sleep patterns and disturbances in children and adolescents in Italy during the Covid-19 outbreak.
      ; Çakır et al., 2019;
      • Király O.
      • Potenza M.N.
      • Stein D.J.
      • King D.L.
      • Hodgins D.C.
      • Saunders J.B.
      • Demetrovics Z.
      Preventing problematic internet use during the COVID-19 pandemic: Consensus guidance.
      ;
      • Lin Y.
      • Tremblay M.S.
      • Katzmarzyk P.T.
      • Fogelholm M.
      • Hu G.
      • Lambert E.V.
      • ISCOLE Research Group
      Temporal and bi-directional associations between sleep duration and physical activity/sedentary time in children: An international comparison.
      ;
      • Wang X.
      • Lei S.M.
      • Le S.
      • Yang Y.
      • Zhang B.
      • Yao W.
      • Cheng S.
      Bidirectional influence of the COVID-19 pandemic lockdowns on health behaviors and quality of life among Chinese adults.
      ).
      Previous studies examined the effect of obesity, Internet addiction, or sleep problems, either as a single variable or a combination of any two variables. However, studies examining the effects of these three variables on each other could not be found (
      • Bruni O.
      • Malorgio E.
      • Doria M.
      • Finotti E.
      • Spruyt K.
      • Melegari M.G.
      • Ferri R.
      Changes in sleep patterns and disturbances in children and adolescents in Italy during the Covid-19 outbreak.
      ;
      • Burkart S.
      • Parker H.
      • Weaver R.G.
      • Beets M.W.
      • Jones A.
      • Adams E.L.
      • Armstrong B.
      Impact of the COVID-19 pandemic on elementary schoolers’ physical activity, sleep, screen time and diet: A quasi-experimental interrupted time series study.
      ;
      • Çakır E.
      Examination of the relationship between high school students' motivation to participate in physical activity and body mass index.
      ;
      • Király O.
      • Potenza M.N.
      • Stein D.J.
      • King D.L.
      • Hodgins D.C.
      • Saunders J.B.
      • Demetrovics Z.
      Preventing problematic internet use during the COVID-19 pandemic: Consensus guidance.
      ;
      • Lin Y.
      • Tremblay M.S.
      • Katzmarzyk P.T.
      • Fogelholm M.
      • Hu G.
      • Lambert E.V.
      • ISCOLE Research Group
      Temporal and bi-directional associations between sleep duration and physical activity/sedentary time in children: An international comparison.
      ;
      • Medrano M.
      • Cadenas-Sanchez C.
      • Oses M.
      • Arenaza L.
      • Amasene M.
      • Labayen I.
      Changes in lifestyle behaviours during the COVID-19 confinement in Spanish children: A longitudinal analysis from the MUGI project.
      ;
      • Nagata J.M.
      • Magid H.S.A.
      • Gabriel K.P.
      Screen time for children and adolescents during the coronavirus disease 2019 pandemic.
      ;
      • Oflu A.
      • Bükülmez A.
      • Elmas E.
      • Tahta E.G.
      • Çeleğen M.
      Comparison of screen time and digital gaming habits of Turkish children before and during the coronavirus disease 2019 pandemic.
      ;
      • Ünver H.
      • Rodopman A.A.
      • Erdoğdu A.B.
      • İlbasmış Ç.
      COVID-19 pandemic-onset anorexia nervosa: Three adolescent cases.
      ;
      • Workman J.
      How much may COVID-19 school closures increase childhood obesity?.
      ;
      • Xie X.
      • Xue Q.
      • Zhou Y.
      • Zhu K.
      • Liu Q.
      • Zhang J.
      • Song R.
      Mental health status among children in home confinement during the coronavirus disease 2019 outbreak in Hubei Province, China.
      ;
      • Yurteri N.
      • Sarigedik E.
      Evaluation of the effects of COVID-19 pandemic on sleep habits and quality of life in children.
      ). Therefore, this study aimed to examine the impact of the COVID-19 pandemic on obesity, Internet addiction, and sleep quality in adolescents.

      Methods

      Aim and design

      This descriptive, comparative, correlational, and cross-sectional study was conducted to examine the impact of the COVID-19 pandemic on obesity, Internet addiction, and sleep quality in adolescents.

      Participants

      The participants included healthy adolescents who were brought to the general pediatric outpatient clinics of the Pediatrics and Surgery Training and Research Hospital in the western region of Turkiye, which has a bed capacity of 320, an average of 800 outpatient visits per day, and an average of 450 emergency service applications.
      The number of participants required for the study was determined to be 395 adolescents who were admitted in the hospital based on a significance level of 0.05, a statistical power of 80%, and a low effect size, which were evaluated using the GPOWER statistical analysis program. The study was conducted between May and September 2021. A total of 401 parents were interviewed at the outpatient clinic, and the parents of 395 adolescents agreed to include their children in the study. The study was conducted after receiving consent from their parents, and the response rate was 98.7%.

      Data collection tools

      Data were collected using the Informed Voluntary Consent Forms, Sociodemographic Data Collection Form, Internet Addiction Scale for Adolescents, and Sleep Quality Scale and Sleep Variables Questionnaire.
      Data were collected in the outpatient clinic or electronically, depending on the participants' preference. The data collection forms were filled within 15–20 min. The information was gathered in an outpatient setting following the COVID-19 prevention protocols. The questions included in all questionnaires were related to the information on the pre-COVID and post-COVID periods.

      Sociodemographic data collection form

      This form consists of questions related to the parents' age, job, and education status; parents' economic status; number of children, age, and sex; the type of house they lived in; and the height and weight of the children before and after the pandemic. The following formula was used to calculate the BMI: weight (kilograms)/height (meters2). BMI classification was determined according to the World Health Organization's BMI Z value for male and female adolescents (). These data were compared with the hospital data.

      Sleep quality scale and sleep variables questionnaire

      The Sleep Quality Scale and Sleep Variables Questionnaire (SQS-SVQ) were developed by
      • Meijer A.M.
      • Van den Wittenboer G.L.H.
      The joint contribution of sleep, intelligence and motivation to school performance.
      . The SQS-SVQ measures sleep quality, parental control, total sleep time, sleep efficiency, and the corrected mid-point of sleep on free days (MSFsc). The Cronbach's alpha internal consistency coefficient of the scale was 0.67 for the parameters measuring sleep quality.
      • Önder İ.
      • Masal E.
      • Demirhan E.
      • Horzum M.B.
      • Beşoluk Ş.
      Psychometric properties of sleep quality scale and sleep variables questionnaire in Turkish student sample.
      conducted a validity and reliability study in Türkiye. As in the original scale, the SQS-SVQ consists of seven scale items and eight questionnaire items for measuring sleep quality in the Turkish sample. The internal consistency coefficient of the SQS was 0.72, whereas the test-retest correlations of the SQS-SVQ ranged from 0.67 to 0.88. The minimum and maximum obtainable scores on the scale were 7 and 21 points, respectively. The higher the score obtained from the scale, the lower the quality of sleep.

      Internet addiction scale for adolescents

      • Taş İ.
      Internet addiction scale for adolescents: Validity and reliability study.
      developed an Internet addiction scale for adolescents based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, for online gaming addiction. The questions were answered using the following response opinions: “Never,” “Rarely,” “Sometimes,” “Often,” and “Always.” The single-factor structure explains approximately 40% of the variance of the scale. The factor loads ranged between 0.548 and 0.707. Results of the confirmatory factor analysis showed that the fit indices were sufficient, and the scale could be used to determine the presence and severity of Internet addiction. The item-total score correlation was 0.427–0.587. The test-retest correlation coefficient calculated was r = 0.72, whereas the Cronbach's alpha internal consistency coefficient was 0.81. Higher scale scores indicated a higher level of Internet addiction. The total score ranged from 5 to 45 points. Participants who obtained a score of 30 points or more were considered to have Internet addiction.

      Statistical analysis

      The SPSS 25.0 statistical package program was used to analyze the data. Descriptive statistical methods (percentage, mean, and standard deviation) were used for evaluating the data. The normality of continuous data was evaluated based on the Gaussian curve, mean score, minimum and maximum ranges of the scores, and results of the Kolmogorov-Smirnov test. As the mean BMI, the mean Internet addiction scale score, and the mean sleep scale score in this study were not normally distributed, non-parametric tests were used for evaluation. The Wilcoxon test was conducted to compare the pre-COVID-19 and post-COVID-19 BMI averages, the mean Internet addiction score, and the mean sleep quality score of the participants. The McNemar's test was performed to compare the pre-COVID-19 and post-COVID-19 pandemic obesity status. The relationship among COVID-19, sleep, Internet addiction, and BMI was examined using the structural equation model (SEM), which was used to determine the mean BMI attributable to the COVID-19 pandemic. The differences between the study groups were significant at p < 0.05.

      Ethical considerations

      This study was approved by the ethics committee and the relevant institution. The information was gathered in the outpatient clinic or, if the participants preferred, via the Internet by e-mailing them a Google Form. The permission to use the measurement tools for the study was obtained from the scale owners via e-mails. The researchers obtained permission from the Ministry of Health before the study was conducted during the COVID-19 pandemic.

      Results

      The mean age of the participants was 15.04 ± 1.81 years, and 53% of them were female. The participants' mothers were mostly primary school graduates (28.9%), whereas their fathers were mainly high school graduates (31.1%). Half of the participants (51.1%) had sufficient income to sustain their needs. (See Table 1)
      Table 1Distribution of the descriptive characteristics of all participants.
      VariablesCategoriesn% / Mean ± SD
      Age39515.04 ± 1.81
      GenderFemale21053
      Male18547
      Mother's educationIlliterate123
      Literate276.8
      Primary school11428.9
      Middle school8220.8
      High school8421.3
      University and higher education7619.2
      Father's educationIlliterate30.8
      Literate20.5
      Primary school6817.2
      Middle school9022.8
      High school12331.1
      University and higher education10827.6
      Income statusIncome is less than expenditures8722
      Income is equal to expenditures20251.1
      Income is greater than expenditures10626.8
      SD = Standard Deviation.
      The mean body mass index (BMI) values of the children before and after the pandemic were 22.82 ± 3.87 kg/m2 and 24.38 ± 4.24 kg/m2, respectively, and the BMI increased significantly after the pandemic (p < 0.01). (See Table 2)
      Table 2Pre-COVID-19 and post-COVID-19 body mass index values.
      BMI values (kg/m2)zp
      MSD
      Pre-COVID-1922.823.8713.539< 0.01
      Post-COVID-1924.384.24
      BMI = Bady Mass Index, M = Mean, SD = Standard Deviation.
      Approximately 27.1% of the participants (n = 107) were obese before the pandemic, whereas 34.9% of them (n = 120) were obese after the pandemic. The percentage of obese participants was significantly higher after the pandemic (p < 0.01). (See Table 3)
      Table 3Obesity status of the participants before and after the COVID-19 pandemic.
      Pre-COVİD-19Post-COVİD-19Total
      Non-obeseObese
      n%
      n%n%
      Non-obese25488.23411.828872.9
      Obese32.810497.210727.1
      Total25765.113834.9395100.0
      Mc NeamerX2

      p
      24.324

      <0.001
      The mean Internet addiction scale scores of the participants before and after the COVID-19 pandemic were 18.68 ± 6.19 and 24.71 ± 7.42, respectively. The Internet addiction levels of children increased significantly after the COVID-19 pandemic (p < 0.01). (See Table 4)
      Table 4Pre-COVID-19 and post-COVID-19 Internet addiction scale scores.
      Internet Addiction Scale Scoreszp
      MSD
      Pre-COVID-1918.686.1915.032< 0.01
      Post-COVID-1924.717.42
      M = Mean, SD = Standard Deviation.
      The mean sleep quality scale scores before and after the pandemic were 16.09 ± 1.84 and 13.74 ± 2.49, respectively. The sleep quality of the children decreased significantly after the COVID-19 pandemic (p < 0.01). (See Table 5)
      Table 5Sleep quality scale scores before and after the COVID-19 pandemic.
      Sleep Quality Scale Scoreszp
      MSD
      Pre-COVID-1916.091.8413.490< 0.01
      Post-COVID-1913.742.49
      M = Mean, SD = Standard Deviation.
      A moderate negative relationship was found between COVID-19 and sleep quality (r = −0.40), whereas a moderate positive relationship was found between Internet addiction (r = 0.42) and BMI (r = 0.30). A low level of significant relationship was observed between sleep quality and BMI (r = 0.04) and between Internet addiction and BMI (r = 0.07). The COVID-19 pandemic, changes in sleep quality, and Internet addiction contributed to 10% of the changes in the BMI (r2 = 0.10). In addition, the change created by the COVID-19 pandemic contributed to 25% of the change in sleep quality (r2 = 0.25) and 16% of the change in Internet addiction rate (r2 = 0.16). All fit indices were above 0.90. (See Fig. 1)

      Discussion

      In this study, the effects of the COVID-19 pandemic on obesity levels, Internet addiction, and sleep quality in adolescents were investigated.
      Results showed that the post-COVID-19 BMI of adolescents was significantly higher than the pre-COVID-19 BMI. The obesity status of the adolescent in this study increased by approximately 7% after the COVID-19 pandemic. Similar studies found that unhealthy weight gain associated with pediatric BMI changes occurred in children who were already vulnerable during the pandemic (
      • Chang T.H.
      • Chen Y.C.
      • Chen W.Y.
      • Chen C.Y.
      • Hsu W.Y.
      • Chou Y.
      • Chang Y.H.
      Weight gain associated with COVID-19 lockdown in children and adolescents: A systematic review and meta-analysis.
      ;
      • Dutta M.
      COVID-19 and Impact of School Closures on the Children of the United States; a Point of View with an Empirical Analysis.
      ;
      • Eskici G.
      Covid-19 pandemic: Nutritional recommendations for quarantine.
      ;
      • Mulugeta W.
      • Hoque L.
      Impact of the COVID-19 lockdown on weight status and associated factors for obesity among children in Massachusetts.
      ;
      • Naja F.
      • Hamadeh R.
      Nutrition amid the COVID-19 pandemic: A multi-level framework for action.
      ;
      • Storz M.A.
      The COVID-19 pandemic: An unprecedented tragedy in the battle against childhood obesity.
      ;
      • Ten Velde G.
      • Lubrecht J.
      • Arayess L.
      • van Loo C.
      • Hesselink M.
      • Reijnders D.
      • Vreugdenhil A.
      Physical activity behaviour and screen time in Dutch children during the COVID-19 pandemic: Pre-, during-and post-school closures.
      ;
      • Workman J.
      How much may COVID-19 school closures increase childhood obesity?.
      ). During the pandemic, schools were closed, and social restrictions were imposed to stop the spread of COVID-19. Social restrictions led to a decrease in physical activity, decrease in sleep quality, increase in the consumption of snacks and emotional eating to cope with stress, and increase in screen time in adolescents. These increasing unhealthy behaviors have led to an increase in the incidence of obesity (
      • Di Pietro G.
      • Biagi F.
      • Costa P.
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      • Mazza J.
      The likely impact of COVID-19 on education: Reflections based on the existing literature and recent international datasets.
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      Early effects of the COVID-19 pandemic on physical activity and sedentary behavior in children living in the US.
      ;
      • Dutta M.
      COVID-19 and Impact of School Closures on the Children of the United States; a Point of View with an Empirical Analysis.
      ;
      • Eskici G.
      Covid-19 pandemic: Nutritional recommendations for quarantine.
      ;
      • Naja F.
      • Hamadeh R.
      Nutrition amid the COVID-19 pandemic: A multi-level framework for action.
      ;
      • Rundle A.G.
      • Park Y.
      • Herbstman J.B.
      • Kinsey E.W.
      • Wang Y.C.
      COVID-19 related school closings and risk of weight gain among children.
      ;
      • Storz M.A.
      The COVID-19 pandemic: An unprecedented tragedy in the battle against childhood obesity.
      ;
      • Workman J.
      How much may COVID-19 school closures increase childhood obesity?.
      ). In the literature, it is emphasized that providing adequate opportunities for adolescents to do physical activity during the period of social restrictions, increasing their social interactions, and providing healthy nutrition reduces the risk of obesity during the pandemic (
      • Chang T.H.
      • Chen Y.C.
      • Chen W.Y.
      • Chen C.Y.
      • Hsu W.Y.
      • Chou Y.
      • Chang Y.H.
      Weight gain associated with COVID-19 lockdown in children and adolescents: A systematic review and meta-analysis.
      ;
      • Dutta M.
      COVID-19 and Impact of School Closures on the Children of the United States; a Point of View with an Empirical Analysis.
      ;
      • Eskici G.
      Covid-19 pandemic: Nutritional recommendations for quarantine.
      ;
      • Mulugeta W.
      • Hoque L.
      Impact of the COVID-19 lockdown on weight status and associated factors for obesity among children in Massachusetts.
      ;
      • Naja F.
      • Hamadeh R.
      Nutrition amid the COVID-19 pandemic: A multi-level framework for action.
      ;
      • Storz M.A.
      The COVID-19 pandemic: An unprecedented tragedy in the battle against childhood obesity.
      ;
      • Ten Velde G.
      • Lubrecht J.
      • Arayess L.
      • van Loo C.
      • Hesselink M.
      • Reijnders D.
      • Vreugdenhil A.
      Physical activity behaviour and screen time in Dutch children during the COVID-19 pandemic: Pre-, during-and post-school closures.
      ;
      • Workman J.
      How much may COVID-19 school closures increase childhood obesity?.
      ).
      Our results showed that the Internet addiction levels of adolescents increased during the pandemic period. Moreover, 50.8% of adolescents spent >10 h a day playing digital games online and using the social media. The literature shows that during the pandemic period, social isolation limited the adolescents' time with their friends, reduced their recreational activities, and they experienced higher levels of boredom owing to the limited activities that they could perform at home (
      • Chang T.H.
      • Chen Y.C.
      • Chen W.Y.
      • Chen C.Y.
      • Hsu W.Y.
      • Chou Y.
      • Chang Y.H.
      Weight gain associated with COVID-19 lockdown in children and adolescents: A systematic review and meta-analysis.
      ;
      • Dunton G.F.
      • Do B.
      • Wang S.D.
      Early effects of the COVID-19 pandemic on physical activity and sedentary behavior in children living in the US.
      ;
      • Király O.
      • Potenza M.N.
      • Stein D.J.
      • King D.L.
      • Hodgins D.C.
      • Saunders J.B.
      • Demetrovics Z.
      Preventing problematic internet use during the COVID-19 pandemic: Consensus guidance.
      ;
      • Mulugeta W.
      • Hoque L.
      Impact of the COVID-19 lockdown on weight status and associated factors for obesity among children in Massachusetts.
      ;
      • Xiang Y.T.
      • Yang Y.
      • Li W.
      • Zhang L.
      • Zhang Q.
      • Cheung T.
      • Ng C.H.
      Timely mental health care for the 2019 novel coronavirus outbreak is urgently needed.
      ). Adolescents showed higher Internet usage rate during the pandemic to reduce their boredom and increase their sociability (
      • Balhara Y.S.
      • Kattula D.
      • Singh S.
      • Chukkali S.
      • Bhargava R.
      Impact of lockdown following COVID-19 on the gaming behavior of college students.
      ;
      • Tsenoli M.
      • Smith J.E.M.
      • Khan M.
      A community perspective of COVID-19 and obesity in children: Causes and consequences.
      ;
      • Zhang L.
      • Liu Y.
      Potential interventions for novel coronavirus in China: A systematic review.
      ). In this study, we attributed the increase in Internet addiction levels to the fact that children use the Internet more often to socialize, reduce their boredom, enjoy, and cope with their emotional problems.
      Our findings showed a significant decrease in the sleep quality of adolescents. The literature shows that especially during the pandemic period, longer screen time, staying up late at night, and getting up late in the morning disrupted the sleep patterns and decreased the sleep quality in children (
      • Bruni O.
      • Malorgio E.
      • Doria M.
      • Finotti E.
      • Spruyt K.
      • Melegari M.G.
      • Ferri R.
      Changes in sleep patterns and disturbances in children and adolescents in Italy during the Covid-19 outbreak.
      ;
      • Cellini N.
      • Di Giorgio E.
      • Mioni G.
      • Di Riso D.
      Sleep and psychological difficulties in Italian school-age children during COVID-19 lockdown.
      ;
      • Tetik N.G.
      • Şen G.K.
      Impact of adolescents’ sleeping problems and habits on the quality of their sleep.
      ;
      • Ünver H.
      • Rodopman A.A.
      • Erdoğdu A.B.
      • İlbasmış Ç.
      COVID-19 pandemic-onset anorexia nervosa: Three adolescent cases.
      ;
      • Xie X.
      • Xue Q.
      • Zhou Y.
      • Zhu K.
      • Liu Q.
      • Zhang J.
      • Song R.
      Mental health status among children in home confinement during the coronavirus disease 2019 outbreak in Hubei Province, China.
      ;
      • Yurteri N.
      • Sarigedik E.
      Evaluation of the effects of COVID-19 pandemic on sleep habits and quality of life in children.
      ). The severity of daytime sleepiness of children increased during the pandemic period, and adolescents slept more during the day in order to overcome both daytime sleepiness and boredom (
      • Bruni O.
      • Malorgio E.
      • Doria M.
      • Finotti E.
      • Spruyt K.
      • Melegari M.G.
      • Ferri R.
      Changes in sleep patterns and disturbances in children and adolescents in Italy during the Covid-19 outbreak.
      ;
      • Cellini N.
      • Di Giorgio E.
      • Mioni G.
      • Di Riso D.
      Sleep and psychological difficulties in Italian school-age children during COVID-19 lockdown.
      ;
      • Tetik N.G.
      • Şen G.K.
      Impact of adolescents’ sleeping problems and habits on the quality of their sleep.
      ;
      • Ünver H.
      • Rodopman A.A.
      • Erdoğdu A.B.
      • İlbasmış Ç.
      COVID-19 pandemic-onset anorexia nervosa: Three adolescent cases.
      ;
      • Xie X.
      • Xue Q.
      • Zhou Y.
      • Zhu K.
      • Liu Q.
      • Zhang J.
      • Song R.
      Mental health status among children in home confinement during the coronavirus disease 2019 outbreak in Hubei Province, China.
      ;
      • Yurteri N.
      • Sarigedik E.
      Evaluation of the effects of COVID-19 pandemic on sleep habits and quality of life in children.
      ). This disruption in the adolescents' sleep habits led to the decrease in their physical activity levels, increase in screen time, and excessive intake of energy, thus increasing the risk of obesity. For this reason, it is important to re-establish the sleep routines of adolescents to the pre-pandemic time, reduce their screen time by providing appropriate activities, and design a suitable nutrition program to maintain their health during the pandemic period.
      We found a significant relationship among Internet addiction, BMI, and sleep quality. Internet addiction and sleep quality were responsible for 10% of the change in BMI during the pandemic period. In particular, longer screen time resulted in the reduction of physical activity levels, changes in sleep hours, and an increase in the consumption of junk food. Both decreased activity and increased energy intake increase the risk of obesity (
      • Bruni O.
      • Malorgio E.
      • Doria M.
      • Finotti E.
      • Spruyt K.
      • Melegari M.G.
      • Ferri R.
      Changes in sleep patterns and disturbances in children and adolescents in Italy during the Covid-19 outbreak.
      ;
      • Cellini N.
      • Di Giorgio E.
      • Mioni G.
      • Di Riso D.
      Sleep and psychological difficulties in Italian school-age children during COVID-19 lockdown.
      ;
      • Chang T.H.
      • Chen Y.C.
      • Chen W.Y.
      • Chen C.Y.
      • Hsu W.Y.
      • Chou Y.
      • Chang Y.H.
      Weight gain associated with COVID-19 lockdown in children and adolescents: A systematic review and meta-analysis.
      ;
      • Dunton G.F.
      • Do B.
      • Wang S.D.
      Early effects of the COVID-19 pandemic on physical activity and sedentary behavior in children living in the US.
      ;
      • Király O.
      • Potenza M.N.
      • Stein D.J.
      • King D.L.
      • Hodgins D.C.
      • Saunders J.B.
      • Demetrovics Z.
      Preventing problematic internet use during the COVID-19 pandemic: Consensus guidance.
      ;
      • Mulugeta W.
      • Hoque L.
      Impact of the COVID-19 lockdown on weight status and associated factors for obesity among children in Massachusetts.
      ;
      • Ten Velde G.
      • Lubrecht J.
      • Arayess L.
      • van Loo C.
      • Hesselink M.
      • Reijnders D.
      • Vreugdenhil A.
      Physical activity behaviour and screen time in Dutch children during the COVID-19 pandemic: Pre-, during-and post-school closures.
      ;
      • Xiang Y.T.
      • Yang Y.
      • Li W.
      • Zhang L.
      • Zhang Q.
      • Cheung T.
      • Ng C.H.
      Timely mental health care for the 2019 novel coronavirus outbreak is urgently needed.
      ;
      • Yurteri N.
      • Sarigedik E.
      Evaluation of the effects of COVID-19 pandemic on sleep habits and quality of life in children.
      ). In this study, increased Internet addiction and decreased sleep quality were associated with an increase in BMI. The results of this study are consistent with previous findings (
      • Bruni O.
      • Malorgio E.
      • Doria M.
      • Finotti E.
      • Spruyt K.
      • Melegari M.G.
      • Ferri R.
      Changes in sleep patterns and disturbances in children and adolescents in Italy during the Covid-19 outbreak.
      ;
      • Cellini N.
      • Di Giorgio E.
      • Mioni G.
      • Di Riso D.
      Sleep and psychological difficulties in Italian school-age children during COVID-19 lockdown.
      ;
      • Dunton G.F.
      • Do B.
      • Wang S.D.
      Early effects of the COVID-19 pandemic on physical activity and sedentary behavior in children living in the US.
      ;
      • Király O.
      • Potenza M.N.
      • Stein D.J.
      • King D.L.
      • Hodgins D.C.
      • Saunders J.B.
      • Demetrovics Z.
      Preventing problematic internet use during the COVID-19 pandemic: Consensus guidance.
      ;
      • Xiang Y.T.
      • Yang Y.
      • Li W.
      • Zhang L.
      • Zhang Q.
      • Cheung T.
      • Ng C.H.
      Timely mental health care for the 2019 novel coronavirus outbreak is urgently needed.
      ;
      • Yurteri N.
      • Sarigedik E.
      Evaluation of the effects of COVID-19 pandemic on sleep habits and quality of life in children.
      ).

      Practice implications

      During the pandemic period, online trainings for parents should be organized on planning physical activities during closure periods, regulating the adolescents' sleep habits, and managing negative habits of children to managing problematic behaviors such as consuming junk food and emotional eating.
      Adolescents should be taught to cope with the stress that results in emotional eating, urged to be physically active after appropriate physical activity programs are implemented when the restrictions are finally removed, and encouraged to foster and maintain relations with friends following the pandemic prevention protocols. It is necessary to create online physical activity groups for adolescents during the closure periods, to increase their physical activity levels and cope with stress.
      Sleep patterns should be enforced by the parents, with bedtimes and wake-up times planned in consultation with the adolescents, and the screen time should be determined according to the periods recommended in the literature.

      Limitations

      This study has several limitations. First, a convenience sampling was performed. The convenience sampling may affect the generalizability of the study results. However, it is thought that the large sample size and the inclusion of children from various provinces in the study may reduce the limitations.
      However, the fewer follow-ups of healthy children during the pandemic and the fact that the children were only referred to the hospital during emergency situations and during follow-up might have affected the study results.

      Conclusion

      This study determined that the BMI and Internet addiction levels of adolescents increased, whereas their sleep quality decreased during the pandemic period. Moreover, increased Internet addiction decreased the sleep quality, and increased Internet usage time and decreased sleep quality were associated with the changes in BMI. Internet addiction and sleep quality were determined to be important factors underlying the changes in BMI.

      Funding

      The authors received no financial support for the research, authorship, and/or publication of this article.

      Ethical statement

      Non-Interventional Clinical Research Ethics Committee (IRB no:2021/15–05).

      Authors' contributions

      FD, DO, MB and BÖ conceptualized and designed the study, acquired, analyzed and interpreted the data, and drafted the manuscript. All authors designed the study, search literature and revised the manuscript. All authors read and approved the final manuscript.

      Declaration of Competing Interest

      The authors declare that they have no conflicts of interest.

      Acknowledgment

      We thank all the participants of this study.

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