Obesity status of middle school students in Xiangtan and its relationship with Internet addiction
Funding agencies: The authors acknowledge A Project Supported by Hunan Provincial Sports Bureau [Kt12-016] and A Teaching Research and Reform Project Supported by Hunan University of Science and Technology [G31056] provided by Menglong Li.
Disclosure: The authors report no conflicts of interest. The authors are responsible for the content and writing of the article.
Author contributions: Menglong Li conceived and carried out experiments, analyzed data, and wrote the article. All authors were involved in checking and revising the paper and had final approval of the submitted and published versions.
Abstract
Objective
To investigate the state of middle school students' obesity in Xiangtan, China and to study the influence of Internet addiction on obesity. Subjects: 1,150 junior and senior middle school students in Xiangtan, China.
Design and Methods
The research subjects were select randomly for the study. The height and body weight of human body were measured and the obesity state was judged according to BMI value and the Working Group on Obesity in China (WGOC) standard. The questionnaire for the survey of middle school students' basic situation was designed and a survey of the respondents' personal information and the contributory factors to obesity was conducted. The Middle School Students' Internet Addiction Diagnosis Scale was adopted for measuring and judging the Internet addiction of the research subjects.
Results
(1) The total detection rate of obesity was 23.57%. (2) The overall detection rate of Internet addiction was 21.23%. (3) The detection rate of obesity in middle school students with Internet addiction (32.92%) was significantly higher than that without Internet addiction (21.06%). Logistic regression showed that Internet addiction was an independent risk factor of obesity.
Conclusion
Internet addiction is related to obesity of middle school students.
Introduction
The progress of globalization and the development of social economy have witnessed a continuous upward trend of obesity throughout the world. There are over 1 billion overweight adults in the world, among which at least 300 million are diagnosed as clinically obese (1). Moreover, “obesity plague” has rapidly spread from developed industrial societies to under-developed developing countries such as China, Argentina, Mexico, and Jamaica, in which the growth rate of obesity patients far exceeds that of the developed countries with a remarkably rapid increase of teenage and even preschool obesity patients (2). For instance, one study shows that 23% of Chinese people are overweight and 7% are obese. It has estimated that between 2000 and 2030, 22% of cardiovascular deaths in China will happen in people aged 35-64, compared to just 12% in the United States, over the same period. Diabetes prevalence in China is projected to double by 2030 to more than 42 million cases (3, 4). Jeopardizing personal health and causing great economic loss, the occurrence of most of such diseases is related to obesity. Their existence not only jeopardizes personal health, but also causes great economic loss. Experts anticipate that obesity will become the biggest public health problem in the world in the 21st century (5).
There are two types of obesity: simple obesity and secondary obesity. The former is caused by excessive amount of adipose tissue in the body as the human intake of calories exceeds the consumption while the latter by neurologic-endocrine dysfunction or metabolic diseases (4). The majority of obese patients are patients with simple obesity, most of who are attacked in their youth, or even in their childhood (6). Many investigations show that patients with simple obesity in their youth will remain obese throughout the whole adulthood. Therefore, a research on etiology and pathology of adolescents with simple obesity is of great significance for the prevention and cure of simple obesity (7). Results of Chinese students' constitution and health survey in 2010 reveal that detection rates of obesity in urban males, urban females, rural males and rural females between 7- and 22-years old were 13.33, 5.64, 7.83, and 3.78%, respectively, increasing respectively by 1.94, 0.63, 2.76, and 1.15% compared to 2005; detection rates of overweight were respectively 14.81, 9.92, 10.79, and 8.03%, increasing respectively by 1.56, 1.20, 2.59, and 3.47% compared to 2005 (8).
The occurrence of simple obesity of adolescents is the result of the interaction of multiple factors such as inheritance, excessive eating, a lack of physical activities and social factors, among which a lack of physical activities is the important factor commonly recognized by researchers currently. For example, Hardy et al. found that sedentary behavior on weekdays and serious sedentary behavior at weekends were on a continuous rise with the increase of age of females and that simple obesity could be mitigated by intervening sedentary behavior (9). Lioret et al. considered that overweight and obesity of French adolescents were related to sedentary behavior, physical activities and socioeconomic situation (10). Simon et al. found that adolescents' level of psychological understanding of physical activities changed after 6 months' interference with physical activities and sedentary behavior (11). Researches of Feldman et al. on different levels of physical activities and sedentary behavior found that sedentary behavior was in connection with low-level physical activities (12). In Canada, 15% of adolescents between 11- and 16-years old are overweight and 4.6% are obese. The relation between inadequate physical activity level and long TV watching time of overweight and obese adolescents is higher than that of adolescents with a normal weight (13). The aforementioned researches concern the influence of reduced physical activities on obesity. With the coming of information age and popularization of computer, computer and network are available to more adolescents. Internet addiction thus becomes an issue winning public attention (4). Adolescents with Internet addiction have such behaviors as irregular eating, sedentary behavior, a lack of physical activities and disorder of self-assessment and interpersonal communication. All these might result in the occurrence of obesity (14). Most current researches concern the influence of a lack of physical activities on obesity, but few directly study the relationship between adolescents' Internet addiction and their simple obesity. Against this background, this article, the first of its kind in China, attempts to investigate the state of obesity and Internet addiction of middle school students and the influence of Internet addiction on obesity.
Methods
Research subjects
Research objects were junior and senior middle school students from urban and rural areas in Xiangtan, Hunan, China (Xiangtan is located in central Hunan downstream of Xiangjiang River, about 1,683 km away from Beijing, the capital of China). The research, conducted in 2012, covered 218 middle schools in 2 urban regions and 3 rural regions.
The adopted method of probability sampling in proportion to population size could ensure the samples selected in the city to be representative. Nearly 1,201 middle school students of 8 schools (1 junior middle school and 1 senior middle school for each region) in 4 administrative regions (2 urban and 2 rural ones) from 5 administrative regions were selected randomly and 1,201 questionnaires were circulated. There were 1,150 valid questionnaires returned and the valid questionnaire rate was 95.75%. Of the 1,150 interviewees, there were 601 boys (accounting for 52.2% of the total) and 549 girls (accounting for 47.8% of the total), with 189 students from junior one, 192 from junior 2, 190 from junior three, 187 from senior one, 194 from senior two and 198 from senior three, and an average age of 15.5 ± 2.4. The exclusion criteria for research objects were that all subjects had no secondary obesity through clinical diagnosis, abnormal glucose metabolism through 75 g glucose tolerance test, and serious hepatorenal dysfunction or obvious stress state.
Research tools
Human body measurement and evaluation of simple obesity
Overweight and obesity of research objects were judged according to the “body mass index reference norm for screening overweight and obesity in Chinese children and adolescents” (15) established by the Working Group on Obesity in China (WGOC) in 2003. Taking children and adolescents aged between 7- and 18-years old in 2000 Chinese National Survey on Student Constitution and Health as objects, WGOC of the International Life Science Institute, in 2003, first calculated the percentage distribution of the body mass index (BMI) with age and developed three provisional standards by using the 85th, 90th, and 95th percentiles. WGOC then conducted cross checks and back substitution tests using physical, blood fat biochemical and body composition indicators and determined the 85th and 95th percentiles as cutoff points of overweight and obesity of children and adolescents between 7- and 18-years old. They lastly adjusted, based on the related specific circumstances in China, the cutoff points of 7- and 18-years old by using smoothening, fitting and graduating of the B-spline curve and finally established the “body mass index reference norm for screening overweight and obesity in Chinese children and adolescents” officially.
The height and weight of research objects were measured for three consecutive times before the circulation of the questionnaires and the average value of each was taken. BMI was then calculated according to the average height and weight values.
The specific testing instrument for national physique monitoring (the only testing instrument used by China National Bureau of Sports for national physique monitoring; Brand: Jianming; Model: GMCS-II; Manufacturer: Beijing Everlasting Oriental Technology Development) was used by trained professionals of national physique monitoring to complete the index tests which were conducted in strict accordance with the national physique monitoring test requirements (16).
Design of the questionnaire for the survey of middle school students' basic situation
The questionnaire was designed to include nine questions which cover a survey of the respondents' personal information and the contributory factors to obesity. These questions relate to gender, age, grade, place of residence, owning of family personal computer, family history of obesity, irregular breakfast, average daily exercise time and frequency of snack eating. See Table 1 for more detailed information.
Measurement and judgment of Internet addiction
The middle school students' internet addiction diagnosis scale (IADDS) developed by Zan Lingling et al. was adopted for measuring and judging the Internet addiction of the research objects (17). This scale was developed in strict accordance with psychometrical procedures based on Item Response Theory (IRT) and was composed of 13 items which were distributed in three dimensions: Internet desire and tolerance, negative effects and abstinence reaction. A two-level rating (a positive answer scoring 1 and a negative answer scoring 0) with the optimal value of cut-off being 5 was adopted: a score ≥5 indicated Internet addiction while a score <5 indicated non-Internet addiction. It was of good validity and reliability and could be used to clinical diagnoses for middle school students through experimental tests. Furthermore, upon clinical investigation, items of the scale were concise and precise, in line with middle school students' psychological and linguistic characteristics. In a word, IADDS was convenient to operate and applicable to clinical diagnosis of Internet addiction of Chinese middle school students.
Research process
In March 2012, Xiantan was selected randomly with the method of multistage stratified cluster random sampling; two administrative regions were then selected in urban and rural region respectively. As a result, four regions—Yuhu Region, Yuetang Region, Xiangtan County, and Shaoshan County were selected in total. Then, one junior middle school and one senior middle school were respectively selected in each region with the method of random number table. One class in each grade of each school was respectively selected as sample units for cluster survey.
Field investigation was conducted in an anonymous way. Investigation contents included general demographic characteristics, possible related factors of obesity and middle school students' Internet addiction scale. Before the investigation, all investigators received collective training and the investigation purpose and process were defined. During the investigation, questionnaires were filled in collectively with a class as unit and returned on the spot. The investigation lasted for 20 min. All investigations were permitted by the teaching administrative organization of each school, students, and their parents.
Data processing
Double copies were entered by using the software Epidata 3.2. After the exclusion of invalid questionnaires (e.g., choices with regular pattern and/or answers with logic error) and the deletion of those with missing key index, data were analyzed with the software SPSS 15.0. Measurement data were expressed by the mean ± standard deviation and enumeration data were expressed by case number in percentage. One sample T test was adopted for the comparison of quantitative data among groups and chi-square test was adopted for that of qualitative data among groups. For the analysis on risk factors of obesity, multifactor logistic regression analysis with P < 0.05 being considered statistically significant was applied.
Results
State of internet addiction
The Internet addiction rate of boys was 23.96%, higher than that of girls (18.03%). The difference had statistical significance (χ2 = 6.048, P = 0.014). In terms of different grades, as junior three and senior three students were in the stage of graduation, the Internet addiction detection rate of students in these two grades was relatively lower than that of those students in other grades; the Internet addiction detection rate of students in other grades showed a rising trend with the increase of grade. Chi-square test showed that the difference of Internet addiction detection rate of students in different grades had statistical significance (χ2 = 22.180, P < 0.001). In terms of the place of residence, the Internet addiction detection rate of urban students was 26.85%, higher than that of rural students (15.29%). Its difference had statistical significance (χ2 = 23.052, P < 0.001). In terms of the owning of family personal computer factor, the Internet addiction detection rate of students with family personal computer was 23.23%, higher than that of those without family personal computer (13.90%). The difference had statistical significance (χ2 = 10.488, P = 0.001). Table 2 shows the detail.
| Total number of people | Overweight or obesity | Detection rate | χ2 | P | |
|---|---|---|---|---|---|
| Gender | |||||
| Male | 601 | 176 | 29.28% | 22.863 | 0.000 |
| Female | 549 | 95 | 17.30% | ||
| Grade | |||||
| Junior one | 189 | 49 | 25.93% | 1.880 | 0.865 |
| Junior two | 192 | 43 | 22.40% | ||
| Junior three | 190 | 40 | 21.05% | ||
| Senior one | 187 | 42 | 22.46% | ||
| Senior two | 194 | 49 | 25.26% | ||
| Senior three | 198 | 48 | 24.24% | ||
| Place of residence | |||||
| City | 581 | 159 | 27.37% | 9.421 | 0.002 |
| Countryside | 569 | 112 | 19.68% | ||
| Is there a family computer? | |||||
| Yes | 891 | 218 | 24.47% | 1.786 | 0.181 |
| No | 259 | 53 | 20.46% | ||
| Family history of obesity | |||||
| Yes | 191 | 90 | 47.12% | 70.554 | 0.000 |
| No | 959 | 181 | 18.87% | ||
| Irregular breakfast | |||||
| Yes | 387 | 124 | 32.04% | 23.266 | 0.000 |
| No | 763 | 147 | 19.27% | ||
| Average daily exercise time | |||||
| >1h | 337 | 53 | 15.73% | 31.485 | 0.000 |
| 0.5-1h | 442 | 95 | 21.49% | ||
| 0-0.5h | 371 | 123 | 33.15% | ||
| Frequency of snack eating | |||||
| Often | 530 | 149 | 28.11% | 13.260 | 0.001 |
| Occasionally | 380 | 82 | 21.58% | ||
| Little | 240 | 40 | 16.67% | ||
| Internet addiction | |||||
| Yes | 243 | 80 | 32.92% | 14.975 | 0.000 |
| No | 907 | 191 | 21.06% | ||
| Total | 1150 | 271 | 23.57% |
| Overall number of people | Number of people with internet addiction | Detection rate | χ2 | P | |
|---|---|---|---|---|---|
| Gender | |||||
| Male | 601 | 144 | 23.96% | 6.048 | 0.014 |
| Female | 549 | 99 | 18.03% | ||
| Grade | |||||
| Junior one | 189 | 38 | 20.11% | 22.180 | <0.001 |
| Junior two | 192 | 47 | 24.48% | ||
| Junior three | 190 | 25 | 13.16% | ||
| Senior one | 187 | 46 | 24.60% | ||
| Senior two | 194 | 57 | 29.38% | ||
| Senior three | 198 | 30 | 15.15% | ||
| Place of residence | |||||
| City | 581 | 156 | 26.85% | 23.052 | <0.001 |
| Countryside | 569 | 87 | 15.29% | ||
| Is there a family computer? | |||||
| Yes | 891 | 207 | 23.23% | 10.488 | 0.001 |
| No | 259 | 36 | 13.90% | ||
| Total | 1150 | 243 | 21.13% |
State of obesity
It can be seen from Table 1 that males, students living in the city, students with family history of obesity, irregular breakfast, less exercise and Internet addiction and students often having snacks had a higher detection rate of overweight or obesity (P < 0.05), while grade and owning of family personal computer had no obvious statistical relation with the detection rate of overweight or obesity (P > 0.05).
Logistic regression of influencing factors of obesity
With univariate analysis, the logistic regression result of model 1 showed that the possibility of obesity occurrence of students with Internet addiction is 1.840 times of that of those without Internet addiction. It had statistical significance (P < 0.001). Model two rectified the gender and grade factors. However, Internet addition is still a risk factor of obesity (P = 0.005) as the possibility of obesity occurrence of students with Internet addiction is 1.541 times of that of those without Internet addiction. Model 3 rectified the all the factors except Internet addiction that might influence the occurrence of obesity, showing that Internet addiction is still an independent risk factor of the occurrence of obesity, as the possibility of obesity occurrence of students with Internet addiction is 1.342 times of that of those without Internet addiction, which is of statistical significance (P = 0.011).
Discussion
State of middle school students' internet addiction
This research found that the overall detection rate of Internet addiction in middle school students in Xiangtan was 21.13%. The Internet addiction rate of boys was 23.96% and that of girls was 18.03%. This result was obviously higher than that in many other researches. In other researches concerning middle school students (18-20), the detection rate of Internet addiction was generally between 5 and 10%. The cause of this difference was probably due to the following three reasons. The first reason might be the uses of different Internet addiction diagnosis tools. For example, the application of the diagnosis tool adopted by our research, the IADDS, was obviously to have more detections of Internet addiction than the use of other diagnosis tools (4, 17, 21, 22). Second reason might be the differences of structure and type of investigation samples. Middle school students from different regions and schools with different family backgrounds had different states of Internet addiction. As researches held that the detection rate of adolescents' Internet addiction in economically undeveloped cities was higher than that in economically developed cities (18, 19), it was quite understandable to have a rather high detection rate of Internet addiction for middle school students in Xiangtan as it was economically developed. The third might relate to the rapid growth of adolescents with Internet addiction. In 2005 there were only 11,054 million adolescents with Internet addiction in China while this number increased by approximately twice to 33,299 million in 2009 and continuously went up rapidly in the last few years (1).
This research found that the detection rate of Internet addiction of boys was significantly higher than that of girls, This result was consistent with most other researches (21, 22). Boys are easier to have Internet addiction than girls, which was consistent with many other researches (18, 21). The reason might be that boys are more aggressive, curious and adventurous than girls. Meanwhile, boys' psychological maturity is relatively later than girls' and their self-discipline ability is poorer than that of girls (23). In addition, online game addition occupies a large proportion in Internet addiction and the proportion of boys playing online games is higher than that of girls (21). Some research showed that boys mainly had online game addiction while girls mainly had network communication addiction in Internet addiction (24).
Middle school students' obesity state
This research found that the overall detection rate of obesity for middle school students in Xiangtan City was 23.57%. This result was significantly higher than that of many other researches. For example, an investigation on 15,600 middle school students from 20 middle schools in Hunan found that the detection rate of obesity was 8.1% (23). Similarly, an investigation on middle school students in Changsha found that the obesity rate of middle school students was 14.1% (boys 16.3%, girls 11.7%) and that the rate of overweight and obesity was different in different types of schools (25). The cause of this difference was probably due to the following three reasons. First, there were different rates of obesity in different regions (1, 4). Second, the investigation results might be different due to different investigation time. Furthermore, it was shown by several researches that the rate of obesity in China was on a rapid and continuous rise (1, 21). Third, the effect of dietary habit was also an important reason. Considering the fact that residents in Xiangtan tended to have greasy food and a lot of meat, it was no surprise to get such a high detections of obese middle school students as they assimilated excessive calories (26). Liu Cheng et al. held the same opinion that regional difference might cause huge difference in obesity, an extreme example of which was provided in one of their investigations that the rate of obesity even reached 30% in some regions in China (27).
This research found that the obesity rate of boys was higher than that of girls among middle school students. This result was consistent with researches of Lioret and Simon (10, 11). The reason is that middle school students have developed a mature and sensitive gender role and gender temperament and consciousness. In particular, girls have deeply internalized the expectation and aesthetical standard of the society to the female role. A fine figure has become an important direction of body shape development of females. Therefore, most girls adjust the body consciously from diet, exercise, etc. to avoid obesity and overweight. However, boys feel less social stress in self-awareness of body and therefore pay less attention to the control of weight and body shape. Thus, the obesity rate of boys is higher than that of girls (10, 11). This research also found that middle school students with irregular breakfast and frequent snack eating had a higher detection rate of obesity. This result was consistent with the research of Feldman et al. (12). In addition, this research also found that middle school students with less exercise had a higher detection rate of obesity. The reason might be that obese middle school students had a lower awareness of physical exercise (13).
Influence of middle school students' internet addiction on obesity
This research found that middle school students with Internet addiction had a significantly higher detection rate of obesity than those without Internet addiction and that Internet addiction was a risk factor of middle school students' obesity. The major contributions of Internet addiction to obesity may lie in the following aspects. First, owing to the excessive use of computer, Internet addicts have to sit in front of computer for a long time every day, which causes a lack of physical exercise. This behavior of sedentariness, proven by many researches, could lead to obesity while physical exercise could down-regulate the expression of obese gene (9-12). Second, Internet addicts often have an irregular diet, eat snacks instead of regular meals, and drink nutritional beverage. This may easily cause, to some extent, obesity, which was proven by Lv Ruoran et al. (28). Third, Internet addicts sleep insufficiently. A lack of sleep may have some relationship with obesity, as proven by Angelo Tremblay et al. (29) and Zhu Hanting (30).
Currently, there are few researches on the relationship between Internet addiction and obesity at home and abroad. This research found that Internet addiction contributed to obesity. However, further studies are still needed on the relationship between Internet addiction and obesity. We infer, according to related researches, that Internet addiction and obesity are interactional: obesity produces a mediating effect through cognitive and emotional factors such as self-concept and emotional effect while Internet addiction influences and promotes the occurrence of obesity in return.
Many researches found that the Internet addiction of middle school students and some other people often originated from negative emotions such as negative self-concept, low self-esteem, loneliness and anxiety and bad psychological and behavioral problems such as social anxiety and poor interpersonal relationship. Middle school students lacking self-identification were easy to have Internet addiction (31). The research of Shi Qinxin found that the eagerness for publicity scale of sensation seeking was significantly related to Internet addiction (32). A path analysis on influencing factors of middle school students' Internet addiction found that attention deficit hyperactivity disorder, depression and anxiety had direct and indirect influences on Internet addiction; conduct disorder only had direct influence on Internet addiction; emotional disorder, companion problem and prosocial behavior had indirect influence on Internet addiction through the life quality of youngsters and prosocial behavior had a negative effect on Internet addiction (33).
Most research results held that simple obesity had influences on somatic function and psychological behavior of youngsters to varying degrees and could easily cause mental and behavior problems (34). For example, some researchers found that school-age children with overweight and obesity had different levels of social anxiety (35). Obese middle school students had more serious somatization of mental health, sensitivity of interpersonal relationship, depression, anxiety and terror etc. than students with a normal weight (36). Obese girls had more negative cognition of their own body shape and emotional experience compared to the control group (37).
Obesity leads to negative self-assessment, anxiety, depression and poor interpersonal relationship and finally results in Internet addiction through release seeking or escape via network. This conjecture can be inspired by researches of Sui Mingming and Gao Xiaoyan (38, 39) which found that each dimensionality of body objectification scale (such as the sense of shame and control for body) significantly predicted the tendency of Internet interpersonal relationship addiction. Individuals with a low addiction tendency score often have an objective examination and evaluation for their own body, while those with a high score have a low evaluation of the whole body and even cannot conduct a correct and objective evaluation (38, 39).
Conclusion
Obesity of adolescents has become a major danger threatening the healthy growth of adolescents nationwide. Health problems and psychological development problems of adolescents caused by obesity have become major dangers threatening social development (40). To solve the obesity problem of Chinese adolescents, parents and schools should cooperate and take effective measures to control the Internet addiction of adolescents. Parents should allow children to have more leisure choices rather than net play at weekends. Schools should also have a proper guidance upon adolescents' activities at weekends.
Acknowledgments
The author thanks all the team members for their committed participation in this study. The authors of this manuscript have certified that he complies with the Principles of Ethical Publishing in the International Journal of Obesity.
