Overweight and Obesity: The emerging Trend of Childhood Malnutrition in Urban Centre in Nigeria
Background: Overweight and obesity initially thought to be the problem of the developed countries is rapidly rising in the developing countries constituting a high proportion of nutritional problem in these countries. Several factors, including changing life style and improved economic power are believed to contribute to this trend. This pattern if unchecked is known to lead to several medical complications and hence the need to assess the burden of this condition, factors contributing to the rise and possible ways of reversing the trend.
Method: Four hundred and twenty primary school children from public and private schools were selected using multistage stratified random sampling. Relevant information were obtained using a questionnaire, and anthropometric indices were recorded. Data obtained were analysed using SPSS version 16, and frequencies were compared using Chi square.
Result: Seventy three (17.4%) of the pupils were found to be overweight/obese. Pupils from private school accounted for majority of these cases with 28 (13.3%) and 29 (13.8%) of them being overweight and obese respectively. High socioeconomic class and consumption of energy dense diet were significantly associated with high prevalence of overweight/obesity (P<0.001). In contrast regular physical activity was significant associated with low prevalence (p <0.001).
Conclusion and Recommendation: Prevalence of overweight/obesity among primary school pupils is quite high in Lagos, Nigeria. High socioeconomic class, consumption of energy dense food and lack of adequate physical activities appear to be major factors contributing to this high prevalence. Introduction of daily school meal and mandatory physical activity in all the schools would go a long way in imbibing healthy eating and life style pattern into these children. Public enlightenment and campaign on the importance of healthy life style and complications associated with overweight and obesity would probably reverse the trend.
Key Words: Overweight, Obesity, Primary School Pupils
Malnutrition is a serious public health problem that is caused by either deficient or excess intake of nutrients in relation to requirements. Under nutrition (Nutrient deficiency) has been the prevalent type of malnutrition in developing countries like Nigeria.1-3 This has been attributed to the synergistic interaction between several factors, most importantly, inadequate nutrient intake and infection.4-6 This is not the case with developed countries like the United States of America (USA), where over-nutrition is a major challenge amongst the school aged children. Studies done in the USA on the overweight status and eating patterns among adolescents showed that the prevalence of over-nutrition was higher amongst those from a low socio-economic class.7-9
Recently, overweight thought to be the problem of the developed world is spreading to the developing world.10 Several studies in Africa and other developing countries have documented an emerging trend of malnutrition with overweight and obesity increasing at an alarming rate in comparison to under nutrition.10-12 However, in these developing countries, contrary to the finding in USA, overweight and obesity appear to be commoner among the high socioeconomic class.13-15 The effect of urbanization and the associated change in life style have been shown to contribute immensely to the current trend of malnutrition in the developing countries.16,17 However, children of low socioeconomic status from such urban centres remain significantly associated with under nutrition rather than over nutrition.18 This further underscores the central role of socioeconomic status in malnutrition.
The increasing rate of overweight/obesity means that obesity-related chronic diseases are likely to become common among the children. Being overweight is known to significantly increase the risk of asthma, Type 2 diabetes, gallstone, heart disease, high blood pressure and several other diseases.19 This will further impose a great challenge to the already over stretched health care system in the developing countries.
We thus aim to assess and compare the prevalence of overweight/obesity among primary school pupils attending public and private schools, in Ikeja Local Government area of Lagos and to identify common factors associated with overweight. The information generated would be useful in guiding the concerned authorities in designing appropriate interventions in the various schools.
Materials and Methods
Study area: The study was carried out in public and private primary schools in Ikeja Local Government Area (LGA) of Lagos State Nigeria. Ikeja is the capital city of Lagos state, the most populated and urbanized state in Nigeria with over 10million residents.20There are 114 registered private primary schools and 32 public primary schools in Ikeja Local Government Area.
Study design: It is a field-based cross-sectional descriptive study
Study Population: This consists of pupils in public and private primary schools in Ikeja LGA.
Sample Size determination: Calculated minimum sample size for each group of school is 200 pupils.
Sampling method: Multistage stratified random sampling was used. Based on the numbers of schools, three Private and two public primary schools were selected. Participants were selected randomly using the class register as a template in each of the classes of the schools selected.
Exclusion criteria: children whose parents denied consent, children with obvious skeletal deformity and those with known chronic medical conditions like Chronic renal failure, heart disease etc.
Ethical consideration: Ethical clearance was sought and obtained from the Ikeja LGA Education Authority. The head teachers of the selected schools also gave well informed expressive approval after receiving appropriate information. All the selected pupils were given consent form and introductory note to the study to their parents for their signature or thumb print. There was no consequence for the pupil if he or she refused to participate or parents denied assess. Data obtained were treated with confidentiality and only for the purpose of this research.
Study procedure: A structured questionnaire was used in collection of relevant information required to meet the objective of the study. All the participating pupils were interviewed at school, while the section to be completed by the parents were sent through their wards and were returned the following day. Information obtained included socio-demographic data like: age, gender, parents’ occupation, average monthly income and educational attainment. Information on dietary intake include type of diet, frequency and 24 hours dietary recall. Involvement in exercise and physical activity were also sought. Socioeconomic status was assessed using the model by Ogunlesi et al 21, while the dietary pattern of the child was assessed using food frequency questionnaire (FFQ). Weight was measure using a bathroom weighing scale with sensitivity of 0.5KG while height was measure using a stadiometer. Nutritional status was determined using the Z- score system in accordance with National Centre for Health Statistics/ World Health Organization (WHO) reference value.22
Data analysis: The data obtained were entered into and analysed using EPI INFO version 3.5.1. Tables were used in data presentation. Chi square and Fisher’s Exact test were used in comparing frequencies.
A total of 420 children were studied, 210 pupils from each group. The children from the private schools were younger with a mean age of 7.7±1.9 years as against 10.3±2.6 years for those in public school (t=11.58, p=<0.001). The female pupils were slightly more than the male with M:F ratio ≈ 1:1.1 in both groups. Majority 176 (83.3) of the pupils from the private schools were of high socio-economic class, while those from public schools were predominantly of the middle socio-economic class (X2=305.34, p=<0.001). Table 1 depicts the socio-demographic features of the study population.
The dietary pattern among the two study groups were significantly different; 90 (42.9%) pupils from the private school consumed beef daily as against 49(23.3) from the public schools. Similarly, approximately half 103(49.1) of the pupils from the private school eat white bread daily as against 45 (21.4%) from the public schools. Seventy five (35.7%) and 29 (13.8%) eats eggs while 44(21.0) and 11(5.2%) eat fried plantain and yam for public and private schools respectively. Again 25 (11.9%) and 13(6.2%) from private and public schools consume at least a can of coke/Fanta daily. These differences were all statistically significant P= <0.001 in all except for consumption of Coke/Fanta where P= 0.412.
Regarding extracurricular activity, the pupils in public schools engaged more in physical activity compared to those in private schools. One hundred and thirteen (53.9%) pupils from the public schools trek daily for a distance of at least one kilometre as against 8 (3.8%) pupils from the private schools. Similarly, 77(36.7%) pupils from the public schools engage in competitive sports daily as against 33(15.7%) from the private. The difference between the two groups regarding physical activity was statistically significant P= <0.001. In contrary, Pupils from private schools engaged significantly more in non-physical activity, 150(71.4%) and 34(16.2%) of them watch television and play computer game daily as against 122(58.1) and 20(9.5%) from the public schools respectively for television and computer games. Again the difference regarding non-physical activity was significant P= <0.001.
Table II shows the distribution of the study population by BMI percentile. The nutritional status varied significantly between the pupils from the public and private school. While under-nutrition was the predominant form of malnutrition in the public schools 33(15.7%), overweight and obesity predominated in the private schools 57(27.1%).
Table III below show the effect of various studied variable on BMI percentile. The highest frequency of overweight was observed among those aged 5-6years while the least frequency was among those aged 11 and above. This pattern was statistically significant (X2=21.90, p= 0.01). Although more female pupils when compared to male pupils, were found to be overweight, but this was not statistically significant. More than half (50.9%) of the pupils of low socioeconomic class were undernourished while majority of overweight children (76.7%) were of high socioeconomic class. This pattern was statistically significant (X2=150.0, p=<0.001). Daily consumption of selected high calorie food items were associated with significantly higher frequencies of overweight when compared to other pupils who do not consume such food items regularly. In contrast, physical activity was associated with significantly low frequency of overweight.
The overall prevalence of 17.4% for overweight and obesity in this study is quite alarming though similar to the findings from previous studies.6, 12, 23 Owa et al12 reporting from Nigeria in 1997 found a prevalence of 18% for obesity among children aged 5-15 years using fat mass percentage and body mass index based on the US standard. Similarly, Mogre et al23 reported a prevalence of 17.4% for overweight and obesity from Ghana in 2013 among school aged children (5-14 years). This finding from this study and the others above further support the rising trend of overweight and obesity among children in developing countries and that the burden of the problem might not be different from that in the developed countries.24 However, other studies have found much lower prevalence for overweight/obesity. Adegoke et al 14 in 2009 reported a prevalence of 3.1% for overweight/obesity from Ile-Ife South West Nigeria using anthropometry, while Alkali et al 15 in 2015 reported a prevalence of 6.5% from Gombe in North East Nigeria. These lower prevalence reported by Adegoke et al(14) and Alkali et al15 may be due to the difference in socioeconomic status between the study-populations, while greater than 86% of our study population were either of middle or upper socioeconomic class, 48.2% of those studied by Adegoke et al14 were of low socioeconomic class with only 19.6% belonging to the upper class. Although Alkali et al15 didn’t give socioeconomic distribution of their study population but Gombe located in the North East of Nigeria is a small town with small scale businesses and subsistence farming as major occupation compared to Lagos which is the most industrialized City in Nigeria. Furthermore, we studied children in primary schools alone but Adegoke et al14 as well as Alkali et al15 studied both primary and secondary school children. It has been severally documented that prevalence of overweight/obesity decreases in children with advancing age.25,26
In contrast to the developed countries where overweight/obesity is commoner among the low socioeconomic class7-9, majority 56 (76.7%) of these overweight children in this study were of high socioeconomic class. This pattern is similar to findings from other studies from other developing countries13-15,27. This fact was further confirmed by the significantly higher incidence of overweight/obesity among pupils from Private schools compared to those from public schools. In Nigeria, Privates schools particularly in the urban centres charge exorbitant fees affordable only to the rich while public schools are usually free and attended by the low socioeconomic class. In this study, 83.8% of the pupil in public schools were of high socioeconomic class as against 1.9% of those in public schools.
Several factors could be responsible for this increasing pattern of overweight/obesity among the affluent class in the developing countries. In the first place, the parents of these children are likely of the working class with little or no time to plan and prepare healthy food for them.28 It is also known that such parents in an effort to compensate for the deficient care constantly provide junk food and snacks for these children.29 Nutritional habit and pattern have been shown to influence the nutritional status of the society.30 These are further driven by aggressive advertising practises, relatively low cost of energy dense food and improved purchasing power which are now most prevalent in developing countries and conducive for the development of overweight and obesity and subsequently the associated morbidities.31 This is in agreement with the finding in this study from Lagos, the most urbanized State in Nigeria, in which Children from the private schools and of high socioeconomic status significantly consumed food of high energy density such as soft drink, egg, white bread, etc when compared to those from the public and low socioeconomic status.
Sedentary life style has been well documented as a cause of overweight and obesity29,32,33 in children. Pupils from the private schools were significantly less involved in physical activities when compared to those from the public schools but engaged more in indoor activities like television viewing and computer games. Similar to previous studies, this practise was significantly associated with overweight and obesity. The low level of physical activity among those in private schools could be due to several reasons. Most of these children are usually driven in car to school by their parents or use the school bus. This is in contrast to the public school which lack school bus and majority, 53.9%, of the pupils trek to school daily. Secondly, while most public schools are usually sited in a planned location with enough space for sporting activity the same cannot be said of the private schools which do not have enough space for outdoor activities with only 15.7% of the pupils engaged in competitive sports. Pressure on the pupils from affluent society for good academic performance including regular extra lessons at home after school hours could also contribute to lack of outdoor activities at home.
In this study, overweight and obesity were higher among the younger age groups compared to the older pupils with the highest frequency of 18.2% among those aged 5-6years. Similar pattern of decreasing incidence with advancing age among children less than 13 years was also observed in a study from India25 and Saudi Arabia26. However, other studies have found a contrary pattern: increasing incidence with advancing age34. The reason for this variability in finding is not clear.
Females had slightly higher prevalence of overweight and obesity when compared to the male, though this difference was not significant. This is similar to the finding of Mohana et al 35 from India. The effect of gender on overweight and obesity in children remains inconclusive, while several studies have found significantly higher prevalence among the female gender 34,36-38 others have reported significantly higher prevalence among the males.39-41 The reason for this variability is not clear but studies with higher female prevalence have suggested cultural factors as a possible explanation as female children in certain society mostly engage in indoor activities.
Conclusion and Recommendations
The prevalence of overweight and obesity among children living in urban centres in developing countries like Nigeria is quite high and is comparable to that in the developed country. This problem is mainly a problem of children from high socioeconomic status. Dietary pattern and sedentary life style are important factors contributing to the high prevalence among these group of children. In contrast, under-nutrition has remain a major problem among the low socioeconomic status. We recommend introduction of school meal program in both the public and private school to augment calorie intake among the public school children and modulate same for those in private schools. Provision of sporting facilities must be made mandatory requirement for registering of private school and if already a requirement must be enforced on new and existing private schools. Finally, public enlightenment on the medical implications of overweight/obesity in children should be aggressively pursued by the relevant agencies before the complications begin to set in.
Conflict of Interest
The authors had no conflict of interest whatsoever to declare
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