Risk factors for anaemia in schoolchildren in Tanga Region, Tanzania

Anaemia is one of the major public health problems affecting more than half of school children along the coast in Tanzania. Due to the multiplicity of its causes it sometimes becomes difficult to find appropriate intervention measures. In order to assist schools in implementing appropriate public health measures for anaemia in Tanga Region of Tanzania risk factors were investigated in school children. A total of 845 schoolchildren age 7-14 years were randomly selected in a cross-sectional survey conducted in 20 randomly selected schools for inclusion in the investigations. Socio-economic, environmental and biological data were collected, as well as academic information, health care and feeding practices. Diagnosis of anaemia was based on haemoglobin concentration below 115 g/L determined by HemoCue meter. Serum Retinol was determined by High performance liquid chromatography and serum ferritin by an Enzyme linked immunosorbent assay. Urine from each child was tested for blood using a haematest reagent strip and those testing positive were examined microscopically by filtration method for Schistosoma haematobium ova. A faecal sample collected from them was also examined microscopically for ova and larvae of intestinal worms. To analyse variables associated with anaemia a stepwise multiple regression model was used. The prevalence of anaemia was 79.6%. Micronutrient deficiencies were highly prevalent. Iron deficiency (SF <20 microg/dl) was affecting 33%, vitamin A deficiency (SR < 20 microg/dL) 31.9% and 25% of the children had mild iodine deficiency (UIE < 20 microg/L). Intestinal helminths were also highly prevalent; 68% of children had hookworm and 54% had urinary schistosomiasis. Inadequate diet was a feature in >50% of children. About 10% of households had no latrines and multiple infection rank score was high especially in older age children. The risk of having anaemia was two times higher in children with iron deficiency (RR=2.1) and 49% higher in those with vitamin A deficiency. These deficiencies correlated significantly with the anaemia (P<0.05). Vitamin A deficiency and infections with hookworm and schistosomiasis were the most significant factors predicting for anaemia (r=0.318 and r2=0.101). We therefore conclude that high prevalence of infections and nutritional deficiencies are important risk factors for anaemia in this community. The high attributable fractions for hookworm, schistosomiasis, iron deficiency and vitamin A confirms that these are significant risk factors to be considered when designing public health measures for anaemia prevention in this community.