Prevalence of and factors associated with underestimation of body weight among secondary school childern in Karachi, Pakistan

Date of Award


Document Type


Degree Name

Master of Science in Epidemiology & Biostatistics (MSc Epidemiology & Biostats)


Community Health Sciences


Objective: To determine the prevalence and factors associated with underestimation of body weight among secondary school children, in Karachi, Pakistan. Methodology: It was a school based, cross sectional analytical study conducted in Karachi. Study population was school children of grade 9-10 (boys and girls). Sample size was 902, and we carried out multistage stratified, cluster sampling technique. Ethical approval was taken from Ethical Review Committee (ERC) of Aga Khan University. Data was collected through self administered questionnaire, followed by anthropometric measurements of students. Our outcome variable was "underestimation of body weight" assessed by verbal response and body images. The statistical analysis was carried out by using software SAS, and SPSS. Multivariable logistic regression technique was applied to determine the factors independently associated with the underestimation of body weight among secondary school children, in Karachi. Results: A total of 917 students participated from seventeen different schools. Approximately 81% of the students were from private schools. About 52% of the students were boys. The mean (±SD) age of the students was 15 (±1.3) years. Majority of the students (45.8%) were Urdu speaking. Prevalence of overweight and obesity was found to be 8.6%, 3.6% respectively. The overall prevalence (95% C.I) of underestimation was 14.7% (12.4 - 17.0). Among boys it was 20% (95% C.I: 16.4 - 23.6), whereas among girls it was 9.1% (95% C.I: 6.4 - 11.8). The prevalence of underestimation was associated with male gender [adjusted OR=3.36 (95% C.I: 1.41 - 8.00)], students from high socioeconomic status [adjusted OR=5.58 (95% C.I: 2.25 - 13.79)], students having number of sibling greater than three [adjusted OR=0.59 (95% C.I: 0.40 - 0.89)], and overweight/obese students [adjusted OR=11.54 (95% C.I: 4.03 - 33.06)]. Conclusion: Prevalence of underestimation of body weight among secondary school children was high in our population. Looking at increasing trend of overweight/obesity among children, underestimation of body weight seems to be raised in near future. Its potential health consequences which included; (i) rise in childhood obesity, responsible for early progression of arthrosclerosis, CVD and premature death (ii) rise in adolescent obesity, responsible for insulin resistance, hypercholesterolemia, CVD, DM, osteoarthritis and many types of cancers in adulthood, point to an urgent efforts which need multifaceted cooperation at several levels with engagement of parents, schools and society at large. This will not only help in prevention of childhood morbidity and mortality but will also prevent adulthood obesity, chronic diseases and ultimate overall mortality. Key words: school children, underestimation of body weight, Pakistan.

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