Anthropometrically determined nutritional status of urban primary schoolchildren in Makurdi, Nigeria

Anthropometry has become a practical tool for evaluating the nutritional status of populations, particularly of children in developing countries [1] and nutritional status is the best indicator of the global well-being of children [2]. One of the major global health problem faced by the developing countries, today is malnutrition [3, 4]. Of course, Nigeria too, is not an exception to this problem of malnutrition [5, 6]. The primary cause of ill-health and premature mortality among children, in developing countries is attributed to undernutrition [7]. In developing countries, it is postulated that poverty and ignorance are primary casual factors of malnutrition [6].

There are several studies [5, 6, 8–10], investigating the problem of undernutrition among children in different parts of Nigeria. However, scanty information exists regarding undernutrition among urban children in Makurdi, Nigeria. Furthermore, most previous studies are focused on children under five years, in neglect of pre-adolescent group. Also, while information on body fat [11], physical fitness [12, 13], anthropometric profiles [14], body weight disorders [15], and centripetal fat patterning [16] exist on children in Makurdi, reliable data on their nutritional status are hardly available. Understanding the nutritional status of children has far-reaching implications for promoting the health of future generations [17]. Therefore, using anthropometric index, the present study evaluates the prevalence of undernutrition among pre-adolescent urban school children aged 9-12 years living in Makurdi, Nigeria. We thought that such data are essentially important from public health standpoint as they would provide reliable bases for instituting appropriate strategies to identify and combat factors associated with nutritional abnormalities in children.

There was no significant sex difference in BMI at ages 9 and 10 years (p > 0.05). However, the mean difference was significant at ages 11 and 12 years, where girls exhibited significantly (p ≤ 0.0001) higher mean BMI values compared to the boys. In this study, BMI increased linearly in girls, while in boys a contrasting downward trend in BMI was observed at ages 10 to 11, which again increased at 12 years of age (Table 1).

Shown in Figure 1 is the nutritional status of pre-adolescent school children stratified by gender. The prevalence of underweight status was higher in boys than the girls, and the difference was statistically significant (p = 0.004; p < 0.05). Conversely, girls tended to be more stunted compared to boys and the difference was statistically significant (p = 0.004; p < 0.05). Based on the WHO classification of severity of malnutrition, the prevalence of underweight and stunting was 31.3% among the children.

Stunting and underweight are comparatively higher among the Indian samples [24–26] than the children in our present study. Of course, India has been reported to have had the highest prevalence of childhood malnutrition in the world [36]. Apart from studies involving Indian children, our sample had far higher percentage of undernutrition compared to other children in other countries.

Consistent with other previous studies in sub-Saharan Africa [27, 37–44], and elsewhere [26, 45], our study showed stunting to be higher in male than in female children. Contrastingly, in Chowdburg et al. [46] study, the prevalence of stunting (21.7%) and wasting (35.8%) was higher in girls compared to boys (13.8% stunting and 22.7% wasting). However, no sex difference was reported in any of the three states (Bihar, West Bengal, Kerala) among Indian [24] children. Collectively, stunting occurred in the 52.7% of the children, a figure which is higher compared to studies conducted on Nigerian children in other regions of the country. For example, Abidoye et al. [5] study reported 34.5% stunted children among 1-4 year old children in urban ghetto in Lagos. With an estimated population of more than 140 million [47], the prevalence of stunting in children under 5 years of age is 38.3% [48].

Underweight is used as a composite indicator to reflect both acute and chronic undernutrition, although it cannot distinguish between them [22]. The results of the present study indicated that 52.7% of the children are underweight, and boys are more underweight (48.8%) compared to girls (38.5%). The prevalence of underweight found in this study is high compared to [5, 9, 41] studies among Nigerian children. These studies reported the prevalence of underweight occurring more in boys than girls similar to our findings in this study. Also, similar results were reported from studies in other countries [49]. It is difficult to explain the variation in the level of underweight between boys and girls seen in this study. Whether both sexes are subjected to different conditions of nutrition and dietary intake is only speculative, as these were not assessed in the present study.

Using WHO 2007 BMI thinness classification, age variations exist in the different BMI thinness classifications (Table 4). While majority of the children exhibited Grade 1 thinness (77.3%), which was predominant at all ages (9-12 years) in both boys and girls, overweight and obesity was absent in boys at ages 9, 10 and 11 and in girls at ages 9 and 10 years. Generally, there is low prevalence of overweight and obesity in our sample when compared with children in developed countries. A possible explanation of the very low prevalence of overweight and obesity and high prevalence of stunted, underweight and thinned children in Makurdi, Nigeria, could be that unlike in most Western countries, the children have limited access to high-calorie snacks and fast food which are hardly affordable. Another plausible explanation is that the Nigerian children may have been engaged in more physically demanding activities compared to their contemporaries in other countries. Majority of the children walk to school daily regardless of the distance and this may have enhanced their physical activity levels [15]. Recent studies have reported higher levels of physical activity in children associated with active travel to school [50, 51].

The high prevalence of both chronic and acute malnutrition observed in the present study is unexpected from an urban region. However, the fact is that most of the children attending primary school in this region are from relatively low socio-economic backgrounds. Therefore the low socio-economic background of these children suggests that factors such as education, occupation and economic status of parents may also account for the high prevalence of undernutrition among our cohort. Could the appalling nutritional situation among our sample be linked to poverty, then the efficacy of the Nigerian government's nutritional intervention programme becomes questionable. Programmes such as the School Meal Programme (SMP), targeted towards heads of households; the Family Support Programme (FSP); and Women Empowerment Programmes (WEP) are not sustainable over time, and some have limited effects [52]. Therefore, making these programmes viable and result-oriented would positively improve the children's nutritional status.

Poor water and sanitation is associated with increased frequency of water and sanitation related morbidity [53]. It is observed that in Makurdi town, the rate of water supply and other sanitary and hygienic facilities are poor. Access to safe water and sanitation is limited to majority of the population, especially those from poor socio-economic backgrounds. Only few people have residential pipe borne water. The majority of the people are served by irregular supply of water by public taps or street vendors. It is possible that most children in this study lived in houses with irregular supply of water. This has implications for the health of these children as the WHO recommended daily water requirements of 200-300 liters per person may be elusive. With poor access to safe water and sanitation, diarrhoeal diseases are more likely to be rampant and could lead to poor nutritional status.

The major staple foods of the people in this region are yam (dioscorea), rice and cassava (manihot esculenta). These food items are mainly carbohydrates. It is possible that in view of the low socio-economic status of the children's parents, many cannot afford to buy meat or fast foods. Such scenario could impact on the children's nutritional status.

Several limitations should also be considered when interpreting the results of the present study. It should be noted that data was not collected on birth weight of the children that might be helpful in further understanding the genesis of the deviation of weight/height scores from the "standard population" observed in this present study, which might likely reflect previous states of malnutrition. Also, data on dietary intake was not available. Again, body mass index-for-age might not necessarily be appropriate in suggesting that so many of the children in this study are severely wasted, stunted and thinned. BMI is only a proxy measure of nutritional status, with an inability to differentiate between fat-free mass and the adipose tissue. Perhaps another pertinent issue concerns the definition of appropriate cut-off points for evaluating nutritional status. The cut-off points used to screen nutritional status in this study was derived based on arbitrarily set BMI values, which reflect changes in BMI that occur with age in the boys and girls [15]. It could be observed that different methodologies were utilized for assessing the nutritional status, which seems justified on the basis that there is need to use international reference data to obtain information about population of developing countries and adequately insert the information into a pattern of general global changes and trends [27]. Besides, only schoolchildren in public schools were studied, so that the results of the present study do not necessarily apply to all Nigerian children living in Makurdi.

Despite these limitations, the study has provided important new information on nutritional status of Nigerian children in Makurdi region, which scanty information exist. Thus, from a public health standpoint, such data could be of paramount importance in formulating urgent intervention strategies in order to stem the health hazards of malnutrition among the Nigerian children in this region.

There is severe malnutrition among the school children living in Makurdi, Nigeria, as most of the children are underweight, stunted and thinned. As the quality of future human resources depends on the present day children, improvement of the nutritional level of today's children should be given top priority [24]. Perhaps, education concerning environmental sanitation and personal hygienic practices, proper child rearing, breast-feeding and weaning practices tailored to the community in this region would possibly reverse the trends.