Background: Pediatric obesity is becoming a public health challenge in both developed and developing countries. While poverty is a known risk factor for pediatric obesity in developed countries, the role of socioeconomic class in developing countries remains unclear. This study aims to determine the prevalence of adolescent obesity in Enugu, south-east Nigeria, and relate same to socioeconomic class. Materials and Methods: A cross-sectional study of adolescents aged 10-19 years in Enugu metropolis. The participants were enrolled by multistage sampling method. Their weights and heights were measured and body mass index (BMI) was calculated. The participants were classified as obese, overweight, and normal using age- and sex-specific BMI percentiles. Socioeconomic class was determined using parental income and educational level. Data were analyzed with the Statistical Package for Social Sciences (SPSS) version 20.0. Results: A total of 2,419 participants were included in the study (1,242 males and 1,177 females). Their mean age was 14.80 ± 2.07 years. The prevalence rates of obesity and overweight were 5.7% and 7.2%, respectively. Females were more likely to be overweight and obese [odds ratio (OR) = 2.55, P < 0.001, OR = 2.66, P < 0.001, respectively]. Adolescents from the upper socioeconomic class were more likely to be obese [OR = 2.57, P < 0.001, 95% confidence interval (CI): 1.80–3.67]. Conclusion: Adolescent obesity in Enugu, south-east Nigeria, is more common among children from the upper socioeconomic class.
Keywords: Adolescents, Enugu, obesity, prevalence
|How to cite this article:
Ubesie AC, Okoli CV, Uwaezuoke SN, Ikefuna AN. Affluence and adolescent obesity in a city in south-east Nigerian: A cross-sectional survey. Ann Trop Med Public Health 2016;9:251-4
|How to cite this URL:
Ubesie AC, Okoli CV, Uwaezuoke SN, Ikefuna AN. Affluence and adolescent obesity in a city in south-east Nigerian: A cross-sectional survey. Ann Trop Med Public Health [serial online] 2016 [cited 2020 Nov 26];9:251-4. Available from: https://www.atmph.org/text.asp?2016/9/4/251/184791
Developing countries are faced with the double burden of malnutrition. On one extreme, undernutrition continues to contribute directly and indirectly to more than 50% of under-five mortality. This has been attributed to high rate of poverty and its determinants in these regions. On the other extreme, there is also a rising incidence of epidemic obesity. Several factors, such as availability of more Western diets and sedentary lifestyles, have been linked to the rising rates of overweight and obesity among the children in developing countries.
Globally, an estimated 170 million children under the age of 18 years are overweight and the incidence is still rising. There are myriads of medical problems associated with pediatric obesity, and these include cardiovascular complications, impaired glucose tolerance and diabetes, orthopedic disease, and malignancies. Adolescent obesity is also a known risk factor for obesity in later life and consequent metabolic syndrome. Overweight or obese children who become obese in adulthood have increased risk for type 2 diabetes, hypertension, dyslipidemia, and carotid-artery atherosclerosis. Reducing the rising incidence of obesity in developing countries, such as Nigeria, requires an understanding of the associated risk factors. Expectedly, there has been much emphasis on undernutrition in Nigeria and other developing countries. Nigeria, a country in sub-Saharan Africa, is an economy in transition and home to both the very rich and the very poor. While undernutrition is linked to poverty, children from affluent families may be at risk of overnutrition due to the indulgence in Western diets. However, there are limited data regarding the role of poverty and affluence on the prevalence of adolescent obesity in this clime. This study aims to determine the prevalence of adolescent obesity in Enugu, south-east Nigeria, and relate the same to socioeconomic class.
|Materials and Methods|
Study design and population
An observational cross-sectional study was conducted in nine secondary schools in Enugu metropolis from September 2012 to April 2013. Enugu is a cosmopolitan city that serves as the capital of Enugu State, south-east Nigeria, and is made up of three local government areas (LGAs). During the period of the study, the city had 89 registered secondary schools that consisted of 35 public and 54 private secondary schools. The study population was selected from the nine secondary schools: Three from each LGA that make up Enugu metropolis.
The three LGAs that make up Enugu metropolis were sampled using a multistage random sampling method. Secondary schools in each LGA were stratified into three groups: Boys, girls, and coeducational schools. One school was selected from each group by the simple random sampling. A total of nine schools were selected from the three LGAs. The study participants were selected by the simple random sampling using a statistical table of random numbers until the allotted number for the specific school was obtained.
Apparently, healthy adolescents from secondary school aged 10-19 years who assented to the study and whose caregivers gave informed consent were included in the study.
The adolescents whose ages could not be ascertained were excluded from the study.
Data were collected from the participants using a pretested, structured, interviewer-administered questionnaire. Their socioeconomic class was determined based on the method proposed by Oyedeji, which used parental educational and occupational attainment. In this classification, social classes 1 and 2 represent the upper, class 3 the middle class, while classes 4 and 5 constitute the lower socioeconomic class. The weight of each study participant was measured using a calibrated standardized digital weighing scale (OMRONBF400) to the nearest 0.5 kg and each person was standing without the shoe but was wearing only the school uniform. The zero mark was corrected before each measurement. The scale was recalibrated daily using 1 kg and 5 kg known weights to ensure accuracy. Height was measured using a stadiometer; each participant was barefooted with heels placed together, back placed against the wall, and chin raised. Height was measured to the nearest 0.1 cm. The height and weight of the study participants were used to calculate their body mass index (BMI). Obesity was defined as BMI ≥95th percentile for age and sex, and overweight as BMI >85th percentile but <95th percentile for age and sex.
Ethical clearance was obtained from the Health Research and Ethics Committee of the University of Nigeria Teaching Hospital, Enugu. Approval to conduct the study was also obtained from the State Post-Primary School Management Board while permission for the students to participate in the study was obtained from the principals of the selected schools.
Data were analyzed on Statistical Package for Social Sciences (SPSS) version 20.0 (SPSS-Inc., Chicago, IL). The Chi-square test was used to test for significant association of categorical variables while Student’s t-test and analysis of variance (ANOVA) were used to compare means of continuous outcome variables. Pearson correlation analysis was also done to determine the strength of relationship between anthropometric indices and blood pressure. Logistic regression model was used to test for association of significant risk factors and the outcome variables after univariate analysis. The odds ratio (OR) of risk factors used in the logistic regression model were calculated. P-value <0.05 was taken as statistically significant and all reported P-values were two-sided.
We were unable to explore and exclude genetic causes of overweight and obesity.
Characteristics of the study population
A total of 2,419 participants were included in the study. There were 1,242 males and 1,177 females. Their ages ranged from 10 years to 19 years with a mean age of 14.80 ± 2.07 years.
Prevalence of obesity
Of the 2,419 study participants, 137 were obese giving a prevalence of 5.7%. Obesity was observed in 96 of 1,177 females (8.2%) and 41 of 1,242 males (3.3%). One hundred and seventy three study participants (7.2%) were observed to be overweight. The prevalence rates of overweight in males and females were 4.3% and 10.2%, respectively. The female gender was significantly associated with overweight [OR = 2.55, P< 0.001, confidence interval (CI) = 1.82-3.56] and obesity (OR = 2.60, P< 0.001, CI = 1.79-3.78). The prevalence rate of obesity and the relationship between gender and BMI are shown in [Table 1].
|Table 1: Gender comparison of the BMI grouping of the study participants
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Obesity and socioeconomic class
Fifty-five of the 527 study participants (10.4%) who were from the upper socioeconomic class and 46 out of 1,114 (4.1%) study participants from lower socioeconomic class were obese as shown in [Table 2]. The prevalence rates of overweight in the upper, middle, and lower socioeconomic classes were 6.8%, 6.9%, and 7.5%, respectively [Table 2]. Adolescents in the upper socioeconomic class were three times more likely to be obese. Among the males, the prevalence rates of obesity within the upper and lower socioeconomic classes were 9.0% and 1.6%, respectively, while overweight was 5.4% in the upper class and 4.2% in the lower class. Males in the upper socioeconomic class were six times more likely to be obese (P< 0.001, OR = 5.83, C.I = 3.06–11.08). The prevalence rate of obesity was 12.1% in the upper class and 6.8% in the lower class among the females. Overweight was observed in 21 (8.5%), 40 (10.4%), and 59 (10.8%) female study participants within the upper, middle, and lower socioeconomic classes, respectively. Females in the upper socioeconomic class were two times more likely to be obese (P = 0.012, OR = 1.79, C.I = 1.14-2.84).
|Table 2: Comparison of BMI and socioeconomic class categories
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The overall prevalence of obesity in this study was 5.7%. The male and female prevalence rates were 3.3% and 8.2%, respectively (P< 0.001). An earlier study in the same city among adolescents aged 10–18 years reported 1.9% prevalence rate of obesity. This finding therefore suggests a rising prevalence of adolescent obesity in this urban setting. It has been documented that overweight and obesity are now commonly seen in low- and middle-income countries, particularly in urban settings. On the other hand, a previous study conducted in the south-west region of Nigeria reported an adolescent obesity rate of 9.4%. The study however was conducted in only one school that may have resulted in selection bias. A cross-sectional study conducted in seven African countries (Benin, Djibouti, Egypt, Ghana, Mauritania, Malawi, and Morocco) as part of the Global School-based Student Health Survey showed wide variation of adolescent obesity rates. In that study, obesity was defined using the World Health Organization (WHO) standards. Obesity rates were highest in Egypt (8.1%) and Djibouti (7.4%) and lowest in Malawi (1.4%) and Ghana (1.2%).
Females were significantly more obese than males in the present study. This observation has previously been reported by other authors., The reason for higher rates of obesity among females may be due to increased fat mass among females in contrast to males who enlarge their fat free mass.,
Obesity was significantly higher among adolescents from the upper socioeconomic class in our survey. A previous Nigerian study reported similar relationship between obesity and socioeconomic status. Nigeria like most developing countries is in “nutrition transition” that is characterized by increased consumption of Western diets as opposed to traditional foods. Individuals from the upper socioeconomic class are more likely to indulge in high-energy junk food that is seen as a symbol of affluence. This is in contrast to developed countries where obesity is more common among lower socioeconomic class and rural dwellers. Obesogenic factors, such as addiction to television, computer games, and internet, that contribute to sedentary lifestyle are now common among affluent Nigerian families. Thus, childhood and adolescent obesity may become a potential public health epidemic in Nigeria and other developing countries. Interestingly, our study observed overweight among the adolescents in the various socioeconomic classes although there was no statistically significant difference among the groups. Therefore, it is possible that affluence may be a tipping point for obesity in this environment.
There is rising prevalence of adolescent obesity in the south-eastern part of Nigeria, especially among the female population and affluent families. A comprehensive health-promotion approach is required to reverse this potential epidemic.
OCV conceived the study and collected the data. UAC performed the statistical analysis and drafted the manuscript. USN and IAN did the literature review. All the authors participated in the study design, revision of the draft manuscripts, and agreed on the final version of the manuscript.
We are grateful to the children and their families that participated in this study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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Source of Support: None, Conflict of Interest: None
[Table 1], [Table 2]