|Year : 2012 | Volume
| Issue : 2 | Page : 92-97
Body weight/image perceptions and prevalence of obesity among adolescents-Kerala, India
Vijayanagara Institute of Medical Sciences (VIMS), Community Medicine, VIMS, Bellary, Karnataka, India
|Date of Web Publication||27-Sep-2012|
Department of Community Medicine, Vijayanagara Institute of Medical Sciences (VIMS), Bellary -583104, Karnataka
Source of Support: None, Conflict of Interest: None
Introduction: Obesity can be seen as the first wave of a defined cluster of non communicable diseases called "New World Syndrome" creating an enormous socioeconomic and public health burden in poorer countries. The rising prevalence of childhood/adolescent obesity cannot be addressed by a single etiology. Multiple factors plays role and among them perception on body weight and image plays vital role in adolescents. So the objective of this study was to know the perceptions of adolescents on their body weight and body image. Materials and Methods: A cross-sectional study was conducted among students of high schools of Thiruvananthapuram city corporation, Kerala, India. The sample size of this study was 1718 and the technique adopted is multistage and stratified random sampling. Data was collected using pre designed and pretested semi-structured questionnaire which is self-administered. Body mass index was calculated based on physical measurements such as height and weight using standard methods. Results: This study revealed that 67.3% of study subjects underestimated their body weight and 15.5% over estimated their body weight. The prevalence of overweight/obesity is high among those who underestimated their body weight (18.7%) compared to subjects who overestimated (6.7%) but the prevalence of underweight is high among the subjects who overestimated their body weight (60.8%) compared to subjects who underestimated (22%). Conclusion: Schools are probably the ideal medium of intervention as they are central to children's lives and information can be relatively quickly dissipated through this channel and Helping adolescents to attain a realistic, positive perception of their body weight and image through health education.
Keywords: Body image, body weight, obesity, overweight
|How to cite this article:|
Ramesh K. Body weight/image perceptions and prevalence of obesity among adolescents-Kerala, India. Int J Health Allied Sci 2012;1:92-7
|How to cite this URL:|
Ramesh K. Body weight/image perceptions and prevalence of obesity among adolescents-Kerala, India. Int J Health Allied Sci [serial online] 2012 [cited 2020 Apr 10];1:92-7. Available from: http://www.ijhas.in/text.asp?2012/1/2/92/101698
| Introduction|| |
Globally, non-communicable diseases are increasingly recognized as a major cause of morbidity and mortality. The countries of the South-East Asia region are facing a double burden, with a heavy load of infectious diseases and an increasing burden due to non-communicable diseases.  The increasing burden of non-communicable diseases, particularly in developing countries including India, threatens to overwhelm already stretched health services. Several diseases come under the umbrella of non-communicable diseases and more common cause is obesity. The problem of obesity is confined not only to adults but also to children and adolescents. Various studies also indicate that the prevalence of overweight and obesity among children of all ages is increasing in developing countries in the past few decades. ,
Parallel to the rise in obesity, there is an increase in body dissatisfaction among adolescents. , Adolescents becoming over conscious of their body image and exhibiting strange eating behaviors is no longer a myth but a harsh reality. False preoccupation about the body has become a major concern since it has led to several unhealthy dietary practices. It has been reported that adolescent girls feeling overweight were more likely to engage in unhealthy weight control practices than those who reported feeling that they were of normal weight or underweight. Longitudinal studies have indicated that dieting also predicts weight gain and obesity. , Weight perception is one of the motivating factors for weight control behaviors  and is a better predictor than actual weight for adolescents to diet or exercise.  Weight behaviors are multifaceted and complex, and their etiology is multi-factorial. Some behaviors are causative for overweight or obesity, some develop as a response, and some are associations. Thus, it is important to understand what mediates weight control behaviors in adolescents.
In this context, this study aims to describe the current perceptions of adolescents on their body weight and body image.
| Materials and Methods|| |
This was a cross-sectional study conducted among High schools of Thiruvananthapuram city Corporation, Capital city of Kerala state, India, during December 2008 to February 2009. This corporation area has high enrolment ratio and literacy rate. Besides, it has a large number of schools with a good mix of students from all levels in the society.
Totally, there are 64 High schools in this area. The present study was undertaken among randomly selected High schools in Thiruvananthapuram city corporation area. The study population consisted of 8 th standard, 9 th standard, and 10 th standard students of High schools. Those not willing to participate in the study and absentees at the time of data collection were excluded from the study.
Sample size is based on level of precision; precision consists of significance level and allowable error. In this study, 5% significance and 20% allowable error are considered. According to a study on "Prevalence of Obesity among school going adolescents, Thiruvananthapuram (2006)" conducted by students of Thiruvananthapuram medical college, the prevalence of overweight and obesity was 10.42%. So the prevalence of 10.42% was taken and the sample size was estimated using statistical formula:
n = 4 pq/d 2
Where, n is the required sample size
P is the prevalence = 10.42 in this study.
q is equal to 100-p
= 89.58 in this case.
"d" is the allowable error, which is equal to 20% of p.
Using the above formula, the sample size estimated was 859.
Since the sampling technique adopted in this study was Multistage and stratified sampling, the sample size estimated using above formula i.e. 859 is doubled to make the sample more representative and compensate for the design effect. So the sample size required for the study was found to be 1718.
Method of Sampling: Multistage and Stratified Random Sampling
Details are as follows
The total strength of High schools was enumerated
Total number of schools - 64
Total strength was - 30,932
Schools were divided into three strata and their respective strength was enumerated.
Government schools - 11,183
Private aided schools - 13,582
Private unaided schools - 6167
Out of total strength, proportion of students from three strata was calculated in percentage.
i.e., Government schools = 11,183 × 100 / 30,932 = 36.15 %
Private aided schools = 13,582 × 100 / 30,932 = 43.90 %
Private unaided schools = 6167 × 100 / 30,932 = 19.95 %
So the strength of Government, Private-aided, and Private-unaided schools were 36.15%, 43.90%, and 19.95%, respectively of the total strength.
Based on above, the number of students to be selected from each stratum was found.
i.e., The sample size required is - 1718
So the numbers of students to be selected from three strata were as follows
Government schools: 36.15% of the sample size
Hence, 1718 × 36.15/100 = 622
Private aided schools: 43.90% of the sample size
Hence, 1718 × 43.90/100 = 754
Private unaided schools: 19.95% of the sample size
Hence, 1718 × 19.95/100 = 342
So the number of students selected from Government, Private-aided, and Private-unaided schools was 622, 784, and 342, respectively.
In each stratum, proportion of students from 8 th , 9 th , and 10 th standard was calculated in percentage.
Based on above, the number of students to be selected from 8 th , 9 th , and 10 th standard in each stratum was found.
i.e. Government schools - sample size required is 622
Hence, students required from 8 th std (Govt.) - 32% of 622 = 200
Similarly, calculation was done to find the number of students to be selected from 8 th , 9 th , and 10 th standard in each stratum. So,
In each standard among all the three strata, sex proportion was found in percentage and similar calculation (as described above) was done to find the number of boys and girls to be selected.
So the students selected for the study were as follows
Selection of students
Stage - 1: one school each was selected randomly from each stratum (government/private aided/private unaided)
Stage - 2: once the schools were selected, the required numbers of boys/girls were selected randomly from each standard (8 th , 9 th , and 10 th).
If the required number of boys/girls of 8 th, 9 th, and 10 th standard was not enough in a selected school, next school was selected randomly and similar procedure was followed. Data was collected using pre-tested semi structured questionnaire which was self-administered. The study subjects were informed about the study and each question was explained while the students fill them up with clarification of doubts. Students were asked whether they knew their body weight, how they perceive themselves (normal/underweight/overweight), and their desired weight. Weight was measured using a bath room weighing scale, every time before measurement it was ensured that it was calibrated to zero, this scale was checked frequently using known weights. This scale was kept on a horizontal surface a subject was made to stand in the centre of the scale in erect position; foot wear was removed before weighing. Height was measured with a measuring tape, using a measuring tape; markings were done on a wall. A subject was made to stand erect, without foot wear with feet together, and head touching the wall. The head was positioned so that the top of the external auditory meatus was in level with the inferior margin of the bony orbit and sufficient pressure was given to compress the hair with a help of a very thin, stiff plastic sheet, and reading was taken.
A measurement called percentile of body mass index (BMI) is used to identify overweight and obesity in study subjects. NCHS/CDC -2000 growth charts for children and adolescents aged 2-20 years i.e. BMI for age and sex percentile growth curves are used to classify the subjects as overweight and obesity. Ethical clearance certificate was issued by the Medical college institution.
| Results|| |
The prevalence of overweight and obesity was high among students of private unaided schools (22.22%). There was no much difference in the prevalence of overweight and obesity among the students of Government and Private-aided schools (17.0% and 17.50%, respectively). Statistical significant difference was found between government and private schools (P=0.03).
The age of the study subjects ranged from 12 to 16 years, maximum numbers of students are in the age group of 14 years (32.3%) and as well as in the age group 13 years (30.6%) which together constituted about 63% of study subjects. It was observed that 3.6% of study subjects belongs to age 16 and 4.7% belong to the age 12 years. Study subjects included were both boys and girls, boys constituted 49.2% (845) and girls 50.8% (873) [Table 1].
The above table depicts that 54.8% of study subjects did not know their body weight and 45.2% knew their body weight. Among the subjects who did not know their body weight, 20.9% are overweight/obese and 22% are underweight. Among those who knew their body weight, 15.1% are overweight/obese and 29.9% are underweight. The prevalence of overweight/obese is high among those who did not know their body weight compared to those who knew their body weight but whereas in the case of underweight it is found reverse i.e. prevalence of underweight is high among those who knew their body weight and this relation was found to be statistically significant [Table 2].
|Table 2: Distribution of study subjects based on – whether they know their body weight|
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Out of 1718 study subjects, 777 (45.2%) subjects knew their body weight and among those who knew their body weight, 67.3% of study subjects underestimated their body weight and 15.5% over estimated their body weight. The prevalence of overweight/obesity is high among those who underestimated their body weight (18.7%) compared to subjects who overestimated (6.7%) but the prevalence of underweight is high among the subjects who overestimated their body weight (60.8%) compared to subjects who underestimated (22%). This is found to be statistically significant (Chi square = 78.100; df = 4; P value = 0.00) [Table 3].
|Table 3: Distribution of study subjects based on – their body weight perception|
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This table shows that 72.7% of study subjects perceived themselves as of normal weight for their age and height, 16.8% perceived as of underweight and 10.5% perceived as of overweight/obese. Among the subjects who perceived themselves as of normal weight, 14.1% are overweight/obese, and 24.3% are underweight. Among the subjects who perceived themselves as of underweight, 7.0% are overweight/obese, and 47.8% are of normal weight. Among the subjects who perceived themselves as of overweight/ obese, 2.8% are underweight and 31.7% are of normal weight and are statistically significant (chi-square = 363.65; df = 4; P value = 0.00) [Table 4].
|Table 4: Distribution of study subjects based on – their body image perception|
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24.6% of study subjects have desire to add some more weight but among them, 9.2% are overweight/obese and 47.6% are of normal weight.31.4% of study subjects have desire to lose weight but among them, 11.7% are underweight and 51.4% are of normal weight.44.0% of study subjects have no desire to add or lose weight but among them, 10.0% are overweight/obese and 25.65 are underweight. This association was found to be statistically significant (Chi square = 257.66; df = 4; P value = 0.00) [Table 5].
|Table 5: Distribution of study subjects based on – their desired body weight|
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| Discussion|| |
The present study throws light upon adolescents' perception on their body weight and image. This study revealed that 13.4% subjects are overweight/obese, 25.5% are underweight, and remaining 56.2% are of normal weight. Knowing one's body weight is an important factor which has an influence on their body weight. Here more than 50% of study subjects did not know their body weight which means they are not at all concerned about their body weight and prevalence of overweight/obesity and underweight among them are 20.9% and 22% respectively, whereas the prevalence of overweight/obesity is found to be low (15.1%) among the subjects who knew their body weight compared to those who did not know but interestingly prevalence of underweight is more among those who knew their body weight (29.9%) compared to those who did not know their body weight (22%). Not knowing one's body weight may act like a double-edged sword because if an individual does not know his/her body weight, it may lead to either of the two extremes of malnutrition.
In the present study, the subjects who knew their body weight were asked to write their body weight and then their written body weight was compared with their actual body weight which was measured at the time of data collection. 82.8% subjects have false perception of their body weight i.e., 67.3% of subjects underestimated their body weight and 15.5% overestimated their body weight. The prevalence of overweight/obesity is high among those who underestimated their body weight (18.7%) compared to subjects who overestimated (6.7%), but the prevalence of underweight is high among the subjects who overestimated their body weight (60.8%) compared to subjects who underestimated (22%).
The prevalence of faulty body images was observed among the respondents. Around 72% of the study subjects perceived themselves as of having normal weight while only 60% of them are actually of normal weight. Among the subjects who perceived themselves as of underweight, 7.0% are overweight/obese and 47.8% are of normal weight. Earlier studies by Levy and Heaton  and Story et al. have also reported the prevalence of faulty body images among college girls.
24.6% of the study subjects desired to be heavier even 47.6% and 9.2% of them are actually of normal weight and overweight/obese and 31.4% of the study subjects desired to lose weight even though 11.7% of them are underweight. Studies conducted by Ash and McClelland  have reported that a vast majority of subjects under their study listed a desirable weight loss. Lindberg and O'Neil  have also reported that majority of the respondents in his study were bothered about being overweight. Sztainer and Hannan  have also reported that half of the girls under their study were trying to lose weight.
| Conclusion|| |
This study found considerable differences in body weight/image perception and prevalence of overweight/obesity. A large proportion of these adolescents could not appropriately classify their weight status; and nearly 70% of them underestimated their own body weight. Body weight perception and dissatisfaction are correlates for weight control practices. Overweight adolescents should be better informed and empowered to follow recommended weight loss strategies.
| Acknowledgment|| |
I am thankful to Dr. Leela Itty Amma, Prof. & HOD of Community Medicine Department, Medical College, Thiruvananthapuram for guiding me and I am grateful to all the students for participating in my study and principles of respective schools for giving permission.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]