Background
In developing countries, including those in sub-Saharan Africa, malnutrition represents an additional burden and often co-exists with malaria [
1]. While under nutrition increases the general susceptibility of an individual to viral, bacterial and parasitic infections [
2,
3], infections negatively impact on the nutritional status, resulting in a vicious cycle of under nutrition and infection [
4,
5]. Synergism between malnutrition and infection is responsible for much of the excess mortality among individuals in less developed regions.
Nutritional status may be assessed by subjective clinical evaluation, or by the use of anthropometric indicators and reference standards to determine poor nutritional status based on low weight-for-age (underweight), low height-for-age (stunting), or low weight-for-height (wasting). Wasting is considered a manifestation of acute malnutrition, whereas stunting represents long-term malnutrition [
6]. Undernutrition among children is a critical problem because its effects are long lasting and go beyond childhood. There is growing evidence that the health and nutrition of young children has a long-term effect on their cognitive development [
7]. Stunting, which is the main type of malnutrition in young children, has been associated with impaired cognitive development, reduced academic achievement, and decreased physical work capacity in adulthood, with negative consequences on economic development of societies [
8]. Stunting and wasting have also been strongly associated with the risk of death in children [
9].
The influence of nutrition on the disease burden of malaria is unclear. The contradictory results on the interaction between nutritional status and malaria [
10,
11], warrants further investigation in various epidemiological settings, to assert the antagonistic or synergistic relationship. Knowledge on the burden of stunting and other nutritional indices are lacking in children in the Mount Cameroon area where malaria is a major public health problem. This study examines the prevalence, severity and predictors of malnutrition and its influence on malaria parasitaemia and anaemia severity in children in the Mount Cameroon area.
Discussion
The nutritional status of a person is the most important determinant factor in the health status of that individual, especially children and adolescents for a period of growth. The fundamental relationship between undernutrition and malaria is multifaceted. While some findings show that undernutrition increases susceptibility to malaria [
6], others indicate that malaria increases the likelihood of a child having poor nutritional outcomes [
22]. This study investigated the prevalence, intensity and predictors of malnutrition in children living in an area
meso endemic for malaria as well as its influence on the prevalence of asymptomatic and clinical malaria parasitaemia and anaemia severity.
Malnutrition was common (22.8 %) in the community with an overall prevalence of 17.1 % for stunting, the most common form of malnutrition. This is lower than the 58.1 % observed in children of the same community in 2006 by Nkuo-Akenji et al. [
23] as well as 30.2 % in Dibanda in the same Mount Cameroon area by Mbuh and Nembo [
24] and 38.64 % for stunting by Tine et al. [
25] in Senegal. The decline in the prevalence of malnutrition in the community may be linked to the recorded decline in malaria parasite prevalence observed in the population over the years and the regular de-worming campaign carried out in school children by the Ministry of Public Health in Cameroon. Infectious diseases have been reported to have a negative impact on nutritional status, resulting in a vicious cycle of under nutrition and infection [
4,
5]. Furthermore, the acquisition of knowledge by caregivers/parents on the health and nutritional status of their children following the education on the outcome of the previous study and knowledge on proper feeding habits may have played a significant role in improving the nutritional status of the children. Although an improvement in the nutritional status was observed analyses of the mean HAZ, WAZ and WHZ scores revealed that majority of the children did not attain their maximum growth potential as all three mean scores were less than 1 each. Children whose weight-for-age is less than −1 SD are at increased risk of death [
26].
Malnutrition was significantly higher in males (29.3 %) than females (17.3 %) and the binomial logistic regression analysis revealed male children were significantly at odds of being malnourished than females. More specifically, stunting was significantly higher in males while the prevalence of wasting although not significant was common in females than males. The observation is in line with Kamugisha et al. [
27] who reported that stunting and underweight were common among males than females in all age groups. In addition, in a meta-analysis of 16 demographic and health surveys in Sub-Saharan Africa, boys were reported to be more stunted than girls [
28]. The authors attributed it to the biological vulnerability of male children than the female children. This vulnerability may be a contributing factor to the higher malaria morbidity reported in male children in the Mount Cameroon area [
29,
30] hence increasing the likelihood of male children having poor nutritional outcome.
Severe nutritional conditions (z score less than −3) such as underweight and wasting were uncommon in the study population, while the presence of severe stunting (4.9 %) was comparable to that reported by Ehrhardt et al. [
31] in African children (5.8 %). The presence of severe stunting in the community which probably reflects long standing processes affecting growth of the children adversely is a cause for concern as stunting has been associated with impaired cognitive development [
8]. While Pongou et al. [
32] has reported a positive effect of maternal education and health seeking behaviour on child nutritional status in Cameroon, there is therefore the need for immediate interventions on factors directly linked to growth such as; feeding habits, nutritional intake, education of caregiver/family head and proper health seeking behaviours which may go to reverse the effects of malnutrition.
The observation of age as a significant predictor of malnutrition is not unusual. In line with Ehrhardt et al. [
31], the prevalence of malnutrition was significantly highest in children ≤ 5 years than their counterparts. The prevalence of chronic malnutrition in the under five (19.7 %) is similar to those obtained by Maketa et al. [
33] in the Democratic Republic of Congo. However, the prevalence values for stunting, underweight and wasting were lower when compared with children of the same age group in Ethiopia [
34]. All three forms of malnutrition had similarities in the age pattern of distribution nevertheless, only the difference in prevalence of underweight was statistically significant. Amongst children under five years of age, those between 1.1 to 3 years of age had a 2 fold risk of being malnourished than the others as revealed in the binomial regression analysis. This is critical as a child’s optimal growth occurs during the first 2 years of life. Some of the children in this age group include those on transition from breast milk to complementary foods which when given may not be adequate both in nutrient content and amount of intake to meet the requirements for growth. In as much as children in this age group are at high risk of malaria, the increased risk of gastrointestinal infection associated with the introduction of complementary foods may also contribute to malnutrition.
Although the relationship between the presence of malaria parasite and nutritional status was not significant, malnourished children were 1.35 times at odds of being malaria parasite positive and had higher GMPD than normal children. The manifestation of chronic and acute nutritional deficits which results in stunting and wasting respectively influenced the prevalence of malaria parasite in the population. Overall, while children who were stunted and underweight had a higher prevalence of malaria parasite, those wasted had a lower prevalence. On closer examination, in line with Crookston et al. [
35], no significant relationship was observed between the presence of asymptomatic malaria parasitaemia and stunting as well as the other forms of malnutrition. On the other hand, children who were stunted and underweight had significantly higher prevalence of clinical malaria parasitaemia. In the same light Friedman et al. [
11] in Kenya reported stunting to be associated with clinical malaria. The nutritional inadequacies of these children may have influenced their vulnerability to the expression of clinical infection as Caulfield et al. [
6] suggested malnutrition influences the susceptibility to and manifestation of malaria.
Wasting which is a form of acute malnutrition has been reported as a risk factor for malaria following the low humoral responses to malarial antigens in wasted children [
36]. Interestingly, findings from the study revealed the prevalence of malaria parasitaemia was lower in those wasted than in the well nourished. In addition to the lower clinical and asymptomatic malaria parasitaemia observed (Table
3), children who were wasted also had a higher parasitaemia when compared with their counterparts (Fig.
2). This probably suggests that children with acute malnutrition in this
meso endemic area were able to regulate or were protected to some extent against infection per se, its clinical presentation but not the parasite densities. However these findings need further investigation in a
holo endemic area to assert the role of acute malnutrition in malaria endemic areas.
Malnutrition is known to be a leading factor to anaemia and findings from the study revealed mild, moderate and severe anaemia to be significantly higher in malnourished children. The multivariate analysis revealed anaemic children were 1.4 times at odds of being malnourished than their well nourished counterparts but it was not a statistically significant risk factor when compared with being male and of the 1.1 – 3 years age group. However, the significant influence of malnutrition on the prevalence and severity of anaemia was only discernible in children who were malaria parasite negative while its additive influence was insignificant in those positive (Table
5). While these findings demonstrate the significant contribution of malnutrition to the presence and severity of anaemia in the population, it also highlights anaemia due to
P. falciparum infection as a significant public health problem. Hence in malaria endemic areas there is a need for integrated interventions targeting both malnutrition and malaria so as to improve upon the health and growth potential of the children.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
IUNS was involved in all phases of the study, including study design, data collection, data analysis, interpretation, and write-up of the manuscript; OSMB participated in data collection, supervision and revision of the manuscript; HKK participated in supervision and revision of the manuscript; TRN participated in data collection and laboratory analysis; TN-A participated in supervision and revision of the manuscript. All authors read and approved the final manuscript.
IUNS: PhD and Lecturer of Parasitology. OSMB: PhD and Lecturer in Physiology. HKK: PhD and Associate Professor of Medical Parasitology. TRN: MSc in Parasitology. TN-A PhD and Professor of Parasitology.