The main aim of this cross-sectional study was to analyze the prevalence and determinants of obesity and overweight among school-aged children of Conakry. Data of children from 36 public and private schools were analyzed. The results showed that the prevalence of obesity was 2.5% and overweightness was 9.0%. These frequencies observed in our study show the real presence of these nutritional imbalances in the primary schools of Conakry. This could be explained by changes in children's eating habits through the consumption of fatty and sugary foods, but also the lack of physical activity. Some studies in West Africa [11,16,22] and elsewhere [1,4,5,15,23–25] have reported various frequencies regarding obesity and overweight. In Europe, a study in seven countries among primary school children revealed proportions of 15.6% overweightness and 4.9% obesity . These differences in prevalence could be explained by changes in dietary habits including the consumption of foods rich in fat and carbohydrates, but also the cultural differences between these populations. These figures show the extent and dynamics of obesity and overweight in primary schools around the world in recent years. Otherwise, the difference in prevalence could be explained by the difference in population, sampling, the definition of obesity and the overweightness indicators, the tools, and the techniques used to measure weight and height.
We found statistically significant differences by common school attendance. The commune of Matam recorded the highest frequencies of obesity and overweightness. While the communes of Matoto and Dixinn have recorded common frequencies for obesity and different prevalence of being overweight. This study found that girls were more obese and overweight than boys. These results could be explained by the consumption of sugars, sweets, cakes but also sedentary lifestyle and physical inactivity of young girls. In addition, the fact that girls have a higher prevalence of obesity could be explained by the role of puberty in the development of body fat and its impact on the over estimation of body weight in girls at this time . Studies in Africa [4,5,10,11,15,18,23,27–29] and elsewhere [30–32] have shown similar results. However, other authors have reported that young boys were more obese [1,33–39] and overweight [33,34] than girls.
This current study reveals obesity was more frequently among children who got to school by car or by bus than children who took other means of transportation (i.e., motorcycle, bicycle) or walking. This result could hide the standard of living of some of the pupils' parents. Furthermore, the prevalence of obesity was higher among pupils who needed 45-60 minutes to get to school than among those who needed 30-45 minutes and 15-30 minutes to get to school. This result implies the distance travelled or the traffic difficulties faced by schoolchildren during their journey to school. Nevertheless, the prevalence of overweight was higher among pupils who needed 15-30 minutes to get to school than among those who took 30-45 minutes and 45-60 minutes. In addition, obesity was low among schoolchildren who have environment rich in fruits and fish. The prevalence of overweight was higher among children who did not watch TV on weekends than children who spend 1-4 hours and 5 to 8 hours of their time watching TV on weekends. The frequency of overweight children who didn’t watch TV on weekends may imply that they spend most of the weekend sleeping or doing sedentary activities (video games, social networks, and computers). Authors in Ethiopia revealed that preschool children who watched television more than 2 hours a day had 4 times more likely chance of being overweight/obese . One study showed that children skipping breakfast, eating fast food and snacks more than or equal to once a week, and being involved in sedentary lifestyle more than one hour a day were significantly more likely to be overweight and obese while those participating in physical activity more than twice a week were significantly less likely to be overweight and obese .
In the present study, the results of the multivariate analyses showed that school children who got to school by car or by bus, and female gender were risk factors associated with obesity. Our findings showed that consumption fruits and fish were protective factors of obesity. As for overweightness, children who got to school in others mode of transportation (i.e., motorcycle, bicycle), who study in the primary schools at Matoto commune, and who get to school between 15-30 minutes were independently at risk of being overweight. The study also reveals association between children who spent their time by watching television five to more than eight hours on weekends, and overweightness. This could be explained by the lack of light in the neighbourhoods of Conakry. Previous studies have reported that public school learning, high parental socio-economic class, preference for sugary foods, physical inactivity or not exercising, sedentary lifestyle such as spending free time watching TV and playing computer games, sleeping in the afternoon and not having close friends were significantly associated with overweight and obesity in children .
This study has limitations. The cross-sectional and retrospective nature of our study implies a memory bias that can relate both to information about eating habits and physical activities (i.e., mode of transport to and from school, time to go to school, time spent watching television on weekends or each day) reported by children and their parents. This memory bias, a source of informational bias, can lead to an underestimation or overestimation of the strength of the relationship between obesity/overweightness, and the dietary habits and physical activities of children. Data on the eating habits, physical activities (i.e., transportation of travel for the school, time to go to school, time spent watching television on weekends or each day) of school children would been useful if they were collected prospectively.
However, to our knowledge, this study is one of the few studies to address the problem of obesity and overweight in primary schools in the of Conakry city, or even in Guinea. In addition, our study could be one of the first to include so many school children (i.e., about two thousand four hundred school children). The findings show the need to set up a monitoring and nutritional education program in schools to prevent possible health consequences for these school children as denoted by WHO  in the medium and long term (adulthood). Furthermore, the establishment of regular physical education and sports activities in primary schools could be a solution to these phenomena.