Between perception and reality: BMI in adolescence

Introduction

The body image is “the picture we have in our minds of the size, shape and form of our bodies; and to our feelings concerning these characteristics and our constituent body parts” (Peter Slade, 1988).

The body image is composed of the characteristics of the person as a whole. Therefore, it consists of a perceptual component – which indicates how the size and shape of one’s own body is viewed; an attitudinal component – which defines what one thinks and knows about his/her own body; an affective  component – in which the feelings one has towards his/her own body emerge; and a behavioural component, which includes, for example, nutrition and physical activity.

The perception of their body among infants is linked to proprioception, or rather related to the information detected by peripheral receptors concerning the control of position, movement and balance of the body. This is where a process begins, which later will lead the child to recognition of his/her own reflected image around the age of three.

Adolescence entails a transformation of the body and it is in this very period that the creation of the body image takes place. This can be influenced by social, psychological and emotional factors, through interaction with peer group, parents and the mass media.

This causes in the adolescent an incessant comparison between his/her own body and the ideal one, thus leading to the creation of an idea of self which in both sexes could result in dissatisfaction with their own physical form. This phenomenon can cause high levels of suffering, resulting in an interference with the individual’s life.

The basis of this study came from the idea of portraying the reality of adolescents about the perception of their own body, by examining a sample made up of male and female students (aged 17-19) attending third, fourth and fifth year of four Italian high schools in Lecce. The first objective of the study will be to observe the perceived BMI by each single student and the actual BMI calculated according to their height and weight.

Subsequently, in order to answer the second objective of the study, we are going to analyse if the perception of BMI is overestimated or underestimated among both sexes. Finally, the distribution of real and perceived BMI in the male and female population taken into consideration is going to be observed based on the age group.

Body Mass Index is a biometric value created in 1832 by Adolphe Quetelet, a Belgian mathematician and statistician. Known at the time as ‘the Quetelet Index’, it was developed through anthropometric studies of human growth.

This index was reviewed in 1972 and renamed as Body Mass Index by physiologist Ancel Keys.

The BMI links one’s body weight to height and it is calculated by dividing body weight (kg) by the square of the body height (m). BMI assesses the following weight categories: Normal weight (18.50 -24.99), Severely underweight (<16.00), Underweight (16.00 -18.49), Overweight (25.00 -29.99), Class I obesity (30.00 -34.99), Class II obesity (35.00 -39.99) and Class III obesity (≥ 40.00).

Methodology and materials

The following clinical study is an observational, descriptive, retrospective and multicenter study.

A paper questionnaire was given to students aged between 17 and 19 years attending the third-, fourth- and fifth-year classes of the following Italian high schools, all located in Lecce: I.I.S.S. “E. Fermi” – which contributed to the study with 205 questionnaires, L.S.S. “G. Banzi Bazoli” (69 questionnaires), L.S. “Pietro Siciliani” (74 questionnaires) and L.S. “Galileo Costa” (74 questionnaires).

A total of 422 students participated anonymously in the study, 156 of whom were female and 266 were male. The consent for the data collection was requested in 2015 through a registered procedure addressed to principals of involved schools. The study was conducted in 2015.

Participation in the study was on voluntary basis and no incentives were offered. The aim of the study was explained to the students by the professors of the participating classes.

The sample was selected through simple randomization. The data were processed by guaranteeing and respecting the principles of the Declaration of Helsinki.

Questions and answers required for this study were taken from a questionnaire on adolescent risk factors.

The test consisted of two sections: the first – called ‘initial data’ – included three multiple choice questions, namely the interviewee’s sex, blood type and age.

The second section consisted of questions on risk factors such as smoking, alcohol, sedentary or active lifestyle, obesity, and drugs. These will be the subject of a further in-depth analysis.

Five questions concerning the ‘obesity’ topic were taken from the questionnaire: gender Q1, age Q2, height Q3, weight Q4 and self-perception of BMI Q5.

The used BMI classification has considered 4 categories: underweight (≤ 18.49), normal weight (18.50 – 24.99), overweight (25.00 – 29.99) and obesity (≥ 30.00), without any variation between classes of obesity.

This choice of classification was due to the fact that the study does not aim to investigate in detail what type of obesity or underweight is present in the analysed population, but it mainly focuses on the perception of one’s own body by the boys and girls sampled, based on the four macro-ranges taken into consideration.

The assessed statistical data were processed using Microsoft Excel spreadsheets (Microsoft Corporation, Redmond, USA) through multivariate statistics calculations.

In order to meet the study objectives, it was necessary to calculate the BMI based on the height and the weight reported by the interviewee. This data was subsequently compared with the perception declared by the same.

In order to meet further objectives, whereas there was a discrepancy between the actual BMI data and the perceived one, the over- or underestimation by the interviewee was then calculated. Finally, the latter two phenomena were statistically analysed to observe their distribution in the two sexes.

All answers collected in the questionnaire were processed and the results for each question were summarized in numbers (n) and percentages (%). The statistical significance of the observed data was evaluated by the Pearson’s chi-square test. A p-value <0.05 was considered statistically significant. Analyses were performed using the R software (version 3.5.2). Tables and figures were used to show the results.

Results and discussion

The total population included 422 students, of whom 156 were female (37%) and 266 were male (63%). The students were divided into three categories: 109 pupils aged 17, of whom 63 were male (58%) and the remaining female; 199 aged 18, of whom 124 (62.3%) male and the remaining female; and a third group of 19-year-olds made up of 114 students of whom 79 (69%) male and 35 (18%) female.

For this population the actual BMI was therefore investigated in order to assess the class of obesity between students. The result was that in the general population the 0.37% of males (1 male aged 18) and the 1.28% of females (2 girls, one aged 18 and the other aged 19) were actually obese.

On the contrary, males were more conspicuous regarding the overweight group: in fact, the 17.30% of males (n 46) and the 8.98% of females (n 14) belonged to this subgroup. Concerning males, the highest percentage was found in the age group of 17-year-olds (20.64% vs. 16.93% of 18-year-olds and 15.19% of 19-year-olds). As far as the overweight girls are concerned, the distribution was divided as follows: 13.04% among 17-year-olds, 8% for 18-year-olds and a lower percentage, 5.71%, in the 19-years-olds.

The difference between the two sexes was noticed to be higher especially for the underweight category, which was more significant among girls (13.46% of the total female population) rather than in boys (4.51%).

Based on these data we checked the perceived BMI trying to understand if there was an actual distortion in one’s body perception.

From these results it was found that 22.56% of all male participants (60 boys) had an altered perception of their body, with a predominance of boys who saw themselves thinner (underestimation of their own BMI in 46 males) and a remaining 23.34% (14 boys) who overestimated their own weight. As for females, the absolute percentage of altered perception of their own BMI was higher (28.20%, namely 44 girls); nevertheless only 13.64% (namely 6 girls) of them underestimated their own BMI, whereas the 86.36% (38 girls) overestimated it.

In the context of this altered perception, no boy has ever perceived being obese, while in one case of the girls group the altered perception led to the conception of obesity.

Analysing these data by dividing them in age groups, it was found that as regards the seventeen-year-olds the majority of the boys (84.14%, namely 53 boys) perceived themselves as normal weight (vs. 76.19% normal weight of actual BMI); 7.93% (5 boys) as overweight (vs. 20.64% of actual BMI) and 7.93% (5 boys) as underweight (vs. 3.17% of actual BMI). None of them had the perception of obesity, confirming the actual data that obese people were absent in this group. As far as the seventeen-year-old female subgroup is concerned, 82.61% (38 girls) perceived themselves as normal weight (vs. 73.91% of actual normal weight BMI), 15.22% (7 girls) as overweight (vs. 13.04 % of actual BMI), 2.17% (1 girl) as underweight vs. an underweight BMI reality of 13.05% (6 girls).

As for the 18-year-olds, most of the boys (76.61%, namely 95 boys vs. 75.81% of actual BMI) perceived themselves as normal weight (data overlapping with the actual values), the 13.71% as overweight (17 boys) and the 9.68% (12 boys) as underweight (slightly higher data than the actual one, where the percentage of underweight respondents was 6.45%). No one had the perception of obesity even though there was one such subject in this range. As far as the 18-year-old female subgroup is concerned, 78.67% (59 girls) perceived themselves as normal weight and the data corresponded exactly to reality; 20% (15 girls) perceived themselves as overweight, although only 8% of the interviewees were actually overweight; 1.33% (1 girl) perceived herself as underweight despite being not the only one in reality (12%, namely 9 girls).

Finally, as for the group of nineteen-year-olds, most of the boys (83.54%, namely 66 boys) perceived themselves as normal weight (data almost overlapping with the actual values, 82.28%); 7.60% as overweight (6 boys), namely half of those actually overweight; and 8.86% (7 boys) as underweight (notwithstanding the actual value being 2.53%). None had the perception of obesity and no real obese case was actually included in this subgroup. As far as the 19-year-old female variable is concerned, the 60% (21 girls) perceived themselves as normal weight regardless the percentage of girls with a truly normal BMI weight being higher (74.29%); the 28.57% (10 girls) as overweight, although only 5.71% of the interviewees were actually overweight; and 8.57% (3 girls) as underweight, despite being much more in reality (17.14%, namely 6 girls). Then one girl (2.86%), which was actually obese, had a correct perception.

Analysing these data, it emerged that for girls the perception is more altered in the underweight range – where perception is always lower than reality – and in the overweight group – where on the other hand it is always higher than reality. In fact, in 17-year-old girls with altered BMI, the 25% underestimate themselves, while the remaining 75% overestimate their own BMI. This overestimated alteration in the perception of one’s BMI tends to increase in the 18-year-olds, in which the overestimation is equal to 85.72%, up to 100% as far as concerning the 19-year-olds, although the examined sample is significantly lower.

As for males, however, this data is reversed, so much so that a greater percentage of boys perceive themselves as underweight even when they are not. In 18-year-olds, for instance, with an altered perception of their own BMI, the 66.70% underestimate themselves.

Nonetheless, the total altered perception remains more significant in females.

The data obtained through the observational study, concerning the actual and perceived BMI, was statistically analysed in order to understand its statistical significance.

According to the data concerning the actual BMI distributed within the male and female population and taking into account the four variables relating to weight (underweight, normal weight, overweight, obesity), we obtain the chi-square equal to 16,025, the p-value = 0.001, 3 degrees of freedom, Cramer’s V equal to 19.5% of association. Therefore, we state that the observed results are statistically significant with a p <0.05.

In regards to the collected data of the perceived BMI distributed within the male and female population and taking into account the four variables relating to weight, we obtain a chi-square = 13.734, a p-value = 0.003, 3 degrees of freedom, a Cramer’s V equal to 18.2% of association. We can therefore state that even in the perceived BMI there is a statistical significance of p <0.05.

It shall be taken into account that, with the same BMI, women tend to have more body fat than men, and young people less than the elderly. Moreover, those who have a very developed muscle mass weigh more, not falling within the range of obese or overweight subjects.

Both sexes perceived their own body image in an altered way, albeit with different characteristics for one and for the other. These results are similar to previous studies in the literature.

In literature females seem more inclined to mistakenly consider their body mass index and so does result also in our study, albeit Chung et al. as other previous studies have highlighted exactly the opposite.

The female tends to overestimate the weight in relation to a slimmer body shape taken as a model. Therefore, the students perceive the body weight problem probably because of the role models promoted by mass media and supported by modern society. These statements match our findings exactly.

‘Positive stereotype’ of thinness prevails in Western society, and this leads women to pursue such ideals because by doing so they are considered more competent and, above all, successful. This explains why some women assimilate the idea of thinness and develop a self-evaluation criterion that is excessively dependent on weight and physical fitness. From the 2015 ISTAT data it emerges that in the 18-24 age group 9.5% of the total population is underweight, also including severe thinness. In particular, it’s 3.4% of the total male sample, whereas it’s 15.9% concerning females.

In 2019, the percentage of underweight people in the total population decreased, reaching 8.1%. In particular, in the female sample the percentage was 12.6%, while there was a slight increase in the male sample, reaching 4%. It can be noticed a percentage increase in the male sample equal to +0.6%, while the female sample is positively surprising, registering -3.3%.

Epidemiological data suggest a link between frequent ‘dieting’ and the developing of an eating disorder such as anorexia or bulimia, a real red flag among adolescents. These phenomena are closely related to some socio-cultural factors: in studies conducted before 2002 there was a disparity in the prevalence of eating disorders among the different ethnic groups in the United States. In particular, there was a higher prevalence among white women not from Latin America, whereas recent studies show instead that the prevalence has become similar in different ethnic groups.

Teenagers are more likely to be exposed to subliminal body weight messages, resulting in a worse perception of BMI. It is considered that the increase of socio-cultural factors in eating disorders has started from the ideal of thinness which has been developing over the last fifty years in Western countries.

From a study conducted on two samples of female students from Fiji in 1995 – before the introduction of satellite television – and in 1998 – 3 years after the arrival of satellite television – it emerged an increase in the frequency of self-induced vomiting from 0% to 11% and an increase in the percentage of girls with scores of at least 20 on the Eating Attitudes Test from 12.7% to 29.2%. The Eating Attitude Test (EAT-26) is the widest used test in the world to evaluate the symptoms and peculiar concerns of eating disorders. The test has been used in many studies as a screening tool in order to early identify subjects with this type of disorders.

A Chinese study showed how body weight and the perception of correct weight may be related to a socio-economic level, and similar results also emerged in USA.

Chung also observed that both women and men of all age groups, who perceived themselves as overweight, were more likely to engage in weight loss behaviours rather than healthy children, nor less than those who accurately perceived themselves as overweight.

Several studies found a prevalence of eating disorders and concerns about weight and fitness in subjects engaged in sports such as dancing and swimming. Among pre-adolescent and adolescent girls, pressures to pursue the ideal of thinness from their own family favour body dissatisfaction more than the pressure from mass media or peers. This leads to an altered perception of their bodies among girls, who are constantly confronted with a model of thinness that does not actually exist.

Wang et al. didn’t find differences related to the living place (rural context or city), nonetheless it is intuitive that a sedentary lifestyle or a life without sport is a risk factor for the development of obesity.

The misperception of BMI can potentially influence children and adolescents to adopt unhealthy lifestyle, also using, for example, nicotine or alcohol. School is a crucial place for teaching the culture of health.

Obesity, just like being overweight, is an important risk factor for chronic cardiovascular diseases such as hypertension and heart attack, as well as metabolic diseases such as type 2 diabetes or hypercholesterolemia.

The onset of obesity in children and adolescents prematurely exposes children and young people to breathing difficulties, cardiovascular problems, as well as to disorders of the digestive system and of a psychological nature.

When obesity is not impacted by organic pathology such as adrenal pathology, genetic or drug pathology, weight can be controlled by prevention and therefore by adopting healthy lifestyle, correct diet and undertaking adequate physical activities.

WHO has established the ‘Commission on Ending Childhood Obesity’ for the management of childhood obesity, identifying in 2016 six recommendations in order to approach and intervene more effectively in different world countries.

The most relevant action plan in Europe to prevent childhood obesity is the ‘Action Plan on Childhood Obesity 2014-2020’, published in February 2014. This plan establishes eight priority areas of intervention and identifies the 3 main types of decisive stakeholders to achieve objectives.

In addition, the WHO European Office has encouraged the ‘Childhood Obesity Surveillance Initiative’ (COSI) project, aimed at collecting data on the spread of excess weight and at making a comparison between thirty countries, including Italy, which take part in European surveillance.

In 2015, the ISTAT data show that in the youngest group taken into consideration, i.e. those aged 18 to 24, 2.3% of the total population is obese. In particular, of the entire male sample, 2.6% are obese, in comparison with 2% of the female sample.

In 2019, the percentage of obese people among the total population increased, reaching 3%. Among the male sample is 3.1%, while in the female one is 2.9%. It can be noticed the percentage increase in the female sample equal to +0.9%, compared to the male sample increasing of +0.5%.

Below a BMI of 18.49 there is underweight and severe thinness. It is important to emphasize that the types of thinness are not all the same: it can, in fact, depend on excessive sports activity and/or reduced nutrition, or on the person’s body constitution. On the contrary, pathological thinness is linked to certain diseases such as infections, tumours, mental or digestive disorders and endocrine diseases.

Dissatisfaction with body image and weight seems to be not significantly related to self-esteem for boys, while it is for girls only. Appearance perception has been a significant area of study for psychologists, due to the negative outcomes caused by a dissatisfaction perceived with the results of one’s appearance. Several researches suggested association between dissatisfaction with body image and poor mental adjustment, poor welfare and depression. There is certainly a correlation with distress.

The limit of this study can be maybe found in the homogeneous population of students, all coming from schools in the same city and, consequently, with the same cultural background.

Furthermore, this study does not prospectively evaluate any changes in body perception or in BMI following food and health education. Lifestyle, family situation nor any comorbidities are taken into consideration.

Through this study we solely intended to provide a snapshot of the current situation among adolescents from a specific Italian region, in order to continue with prospective studies aimed at modifying reference models and health goals.

References

1. Androutsos O., Brug J., Chinapaw MJ., De Bourdeaudhuij I., Dössegger A., Kovacs E. et al., (Ottobre 2013). Associations of physical activity and sedentary time with weight and weight status among 10- to 12-year-old boys and girls in Europe: a cluster analysis within the ENERGY project. International Journal of Pediatric Obesity.
2. Appelhans BM., Avery EA., Dugan, SA., Jackson, KL., Janssen, I., KazlauskaiteR. et al. (2014). Body image satisfaction and depression in midlife women: The Study of Women’s Health Across the Nation (SWAN). Archives of Women’s Mental Health,
3. Aristizabal JC., González-Zapata LI., Restrepo-Mesa SL. et al. (Aprile 2019). Reliability and validity of body weight and body image perception in children and adolescents from the South American Youth/Child Cardiovascular and Environmental (SAYCARE) Study. Public Health Nutrition.
4. Aronne LJ., Louise J. (2002). Classification of obesity and assessment of obesity-related health risks. Obesity Research.
5. Arrigo T., D’Angelo G., Di Rosa G., Gitto E., Manti S., Marseglia L. et al., (Dicembre 2014). Stress ossidativo nell’obesità: una componente critica nelle malattie umane. Giornale internazionale di scienze molecolari.
6. Badmin N., Furnham A. & Sneade I. (2002). Body Image Dissatisfaction: Gender Differences in Eating Attitudes, Self-Esteem, and Reasons for Exercise. The Journal of Psychology.
7. Baharudin A., Manickam MA., Zainuddin AA., et al., (Settembre 2014). Self-perception of body weight status and weight control practices among adolescents in Malaysia. Asia-pacific Journal of Public Health.
8. Barba C. et al. (2004). Indice di massa corporea appropriato per le popolazioni asiatiche e sue implicazioni per le strategie politiche e di intervento. Lancet.
9. Bauman A, Baur L., Rutter H, (Marzo 2019). Too little, too slowly: international perspectives on childhood obesity. Public Health Research and Practice.
10. Berenson, GS., Freedman, DS. & Horlick, M., (2013). Un confronto tra le equazioni dello spessore delle pliche cutanee di Slaughter e l’IMC nella previsione del grasso corporeo e dei livelli dei fattori di rischio di malattie cardiovascolari nei bambini. The American Journal of Clinical Nutrition.
11. Bibby H., Cheung PC., Ip PL., Lam ST., (2007). A study on body weight perception and weight control behaviours among adolescents in Hong Kong. Hong Kong medical journal: Xianggang yi xue za zhi / Hong Kong Academy of Medicine.
12. Bohr Y., Garfinkel, PE., Garner, D.M. & Olmsted, M.P., (1982). The eating attitudes test: Psychometric features and clinical correlates. Psychological Medicine.
13. Booy R., Haines MM., Head J., Stansfeld S., Taylor SJ., Viner RM., (2005). Body mass, weight control behaviours,weight perception and emotional well being in a multiethnic sample of early adolescents. International journal of obesity.
14. Bray GA. et al. (2001). Valutazione del grasso corporeo in bambini afroamericani e bianchi di 10 anni più grassi e magri: lo studio dei bambini di Baton Rouge. The American Journal of Clinical Nutrition
15. Brigham EP., Diette GB., Hansel NN., Koehler K., Matsui EC., McCormack MC. Et al. (Novembre- Dicembre 2018). Overweight/obesity enhances associations between secondhand smoke exposure and asthma morbidity in children. The Journal of Allergy and Clinical Immunology.
16. Burgio E., Lopomo A., Migliore L., (2016). Progress in Molecular Biology and Translational Science, Chapter Six – “Epigenetics of Obesity”
17. Cartabellotta A., Montomoli M., (Settembre 2015). Linee guida cliniche per l’identificazione, la valutazione e il trattamento del sovrappeso e dell’obesità negli adulti-Evidence GIMBE Foundation.
18. Chou CP., Clark F., Palmer PH., Reynolds K., Spruijt-Metz D, Xie B et al., (2006). Weight perception and weightrelated sociocultural and behavioral factors in Chinese adolescents. Preventive medicine.
19. Chung AE., Perrin EM., Skinner AC. (Luglio-Agosto 2013). Accuracy of child and adolescent weight perceptions and their relationships to dieting and exercise behaviors: a NHANES study. Academic Pediatrics.
20. Chung AE., Perrin EM., Skinner AC., (2013). Accuracy of child and adolescent weight perceptions and their relationships to dieting and exercise behaviors: a NHANES study. Academic pediatrics.
21. D’Agostino G., De Lorenzo A., Maiolo C. (Dicembre 2002) La terapia dell’obesità: implicazioni cliniche di interesse medico-legale”.
22. De Simone, S., & Di Trapani, G. (2014). The quality assessment in healthcare organizations. International Journal of Trends in Management, Economics & Technology, 3(V), 8–12.
23. Di Trapani, G., & Esposito, A. (2016). Rischio di pandemia: una minaccia per la salute e per la sostenibilità economica internazionale. Rivista Elettronica Di Diritto, Economia, Management, 3–2016, 123–136. https://www.clioedu.it/elenco-completo-no/item/rivista-elettronica-di-diritto-economia-management-n-3-2016
24. Engels RC., Monshouwer K., Ter Bogt TF., Van Dorsselaer SA., Verdurmen JE., Vollebergh WA., (2006). Body mass index and body weight perception as risk factors for internalizing and externalizing problem behavior among adolescents. The Journal of adolescent health: official publication of the Society for Adolescent Medicine.
25. EU. 24 Febbraio 2014. Action Plan on Childhood Obesity 2014-2020.
26. Ferreiro, F., Senra, C. & Seoane, G., (2014). Toward understanding the role of body dissatisfaction in the gender differences in depressive symptoms and disordered eating: A longitudinal study during adolescence. Journal of Adolescence.
27. Ferreiro, F., Senra, C. & Seoane, G., (2014). Toward understanding the role of body dissatisfaction in the gender differences in depressive symptoms and disordered eating: A longitudinal study during adolescence. Journal of Adolescence.
28. Fields JB., Jones MT., Merrigan JJ., White JB. (Novembre 2018). Body Composition Variables by Sport and Sport-Position in Elite Collegiate Athletes. The Journal of Strength & Conditioning Research
29. Flegal, KM & Graubard, BI, (2009). Stime di morti in eccesso associate all’indice di massa corporea e ad altre variabili antropometriche. The American Journal of Clinical Nutrition
30. Flegal, KM et al., (2010). Elevata adiposità e alto indice di massa corporea per età nei bambini e negli adolescenti statunitensi in generale e per gruppo etnico razziale. The American Journal of Clinical Nutrition.
31. Freedman, DS. et al., (2009). Relazione tra indice di massa corporea e spessore delle pliche cutanee con fattori di rischio di malattie cardiovascolari nei bambini: il Bogalusa Heart Study. The American Journal of Clinical Nutrition.
32. Garrow, JS. & Webster, J., (1985). Indice di Quetelet (W / H2) come misura della grassezza. International Journal of Obesity.
33. González-Gross M., Meléndez A. (Settembre 2013). Sedentarism, active lifestyle and sport: Impact on health and obesity prevention. Nutricion Hospitalaria.
34. Han TS. et al., (1998). Qualità della vita in relazione al sovrappeso e alla distribuzione del grasso corporeo. American Journal of Public Health.
35. Heyward VH. & Wagner DR., (2000). Misure della composizione corporea in neri e bianchi: una revisione comparativa. The American Journal of Clinical Nutrition
36. ISTAT, (2019). Aspetti della vita quotidiana-Persone. Disponibile su: http://dati.istat.it/Index.aspx?DataSetCode=DCCV_AVQ_PERSONE1&Lang
37. Istituto superiore di Sanità, (2020). Obesità. Disponibile su: https://www.issalute.it/index.php/la-salute-dalla-a-alla-z-menu/o/obesita
38. Istituto Superiore di Sanità: L’epidemiologia per la sanità pubblica, (18 maggio 2017). Obesità. Disponibile su: https://www.epicentro.iss.it/obesita/
39. Istituto Superiore di Sanità: L’epidemiologia per la sanità pubblica, (03 Aprile 2014). Obesità infantile: l’Action Plan europeo 2014-2020. Disponibile su://www.epicentro.iss.it/obesita/ActionPlan2014-2020
40. Jebb SA. & Prentice AM., (2001). Oltre l’indice di massa corporea. Obesity Reviews.
41. Kasen S. et al., (2008). Obesità e psicopatologia nelle donne: uno studio prospettico di tre decenni. International Journal of Obesity.
42. Kuczmarski RJ. et al., (2002). 2000 CDC Growth Charts per gli Stati Uniti: metodi e sviluppo. Vital and Health Statistics Series.
43. Lawlor DA. et al., (2010). Associazione tra adiposità generale e centrale nell’infanzia, e cambiamento in queste, con fattori di rischio cardiovascolare nell’adolescenza: studio prospettico di coorte. British Medical Journal.
44. Lee AM., Lee S., (Aprile 2000). Disordered eating in three communities of China: a comparative study of female high school students in hong kong, Shenzhen, and rural hunan. International Journal of Eating Disorders.
45. Luppino FS. et al., (2010). Sovrappeso, obesità e depressione: una revisione sistematica e una meta-analisi di studi longitudinali. Archivi di psichiatria generale.
46. NHLBI, (2013). Gestione del sovrappeso e dell’obesità negli adulti: revisione sistematica dell’evidenza dal gruppo di esperti sull’obesità.
47. Petrucci, L., Margarito, A., & Di Trapani, G. (2020). Colon-rectal Cancer and Lars Management. Journal of Advanced Health Care Print, Volume 2,. https://doi.org/10.36017/jahc2009-002
48. Riahi R., Motlagh ME.et al., (Ottobre 2019). Body Weight Misperception and Psychological Distress Among Children and Adolescents: The CASPIAN-V Study Osong Public Health Res Perspect.
49. Sarnacchiaro, P., & Di Trapani, G. (2011). La valutazione della Patient Satisfaction nelle strutture sanitarie con tecniche statistiche di analisi multidimensionale: un caso studio. In L’azienda sanitaria. Innovazione tecnologica, evoluzione organizzativa e governo clinico (pp. 373–385). Franco Angeli – Codice editore 1862.161.
50. Standley R., Sullivan V., Wardle J., (2009). Self-perceived weight in adolescents: over-estimation or under-estimation. Body image.
51. Steinberger J. et al., (2005). Confronto delle misurazioni del grasso corporeo mediante BMI e pliche cutanee rispetto all’assorbimetria a raggi X a doppia energia e la loro relazione con i fattori di rischio cardiovascolare negli adolescenti. International Journal of Obesity.
52. Sun Q. et al., (2010). Confronto tra misure assorbimetriche a raggi X a doppia energia e misure antropometriche dell’adiposità in relazione a fattori biologici correlati all’adiposità. American Journal of Epidemiology.
53. Wang Y. et al. (2018). Children and adolescents in Jilin City, China. Plos one.
54. Wohlfahrt-Veje, C. et al., (2014). Grasso corporeo durante l’infanzia in 2647 bambini danesi sani: concordanza di BMI, circonferenza della vita, pliche cutanee con assorbimetria a raggi X doppia. European Journal of Clinical Nutrition.
55. World Health Organization, (1997). Obesity: Preventing and Managing the Global Epidemic. Report of a WHO Consultation on Obesity. Geneva.
56. World Health Organization, (2002). Diet, physical activity and health, Fifty-fifth world health assembly, Techinical Reports Series. Geneva, Switzerland.
57. World Health Organization, (2017). WHO European Childhood Obesity Surveillance Initiative (COSI). Disponibile su: https://www.euro.who.int/en/health-topics/disease-prevention/nutrition/activities/who-european-childhood-obesity-surveillance-initiative-cosi
58. World Health Organization, (Giugno 1997). Obesity: preventing and managing the global epidemic of obesity. Report of the WHO Consultation of Obesity. Geneva, Switzerland,
59. Yang X., Yue M., Liu H., Pang Y., Wang Y., Wu F. et al., (2018). The association between BMI and body weight perception among children and adolescents in Jilin City, China. Plos one.