GEOPHAGY, IRON STATUS AND ANEMIA AMONG PRIMARY-SCHOOL CHILDREN IN WESTERN KENYA

As part of a cross-sectional study among 156 primary school children ( median age 13 years, range 10-18) in Western Kenya, geophagy was asses sed through interviews. 114 (73.1%) of these children reported eating soil daily Haemoglobin levels were determined in all 156 children and serum ferritin concentrations in 135. The mean haemoglobin (Hb) concen tration was 12.7 g/dl, and median ferritin concentration 27.2 mu g/l. Both the proportion of anaemic (Hb < 11.0 g/dl) and of iron-depleted ( ferritin < 12 mu g/l) children was significantly higher among the geop hageous children than among the nongeophageous (9.6% vs. 0% anaemia; P = 0.037; 18.4% vs. 5.4% iron depletion; P = 0.046). Serum ferritin an d haemoglobin concentrations were not correlated (r = 0.13 5; P = 0.10 0). Multiple regression analysis showed that geophagy, hookworm eggs p er gram faeces and malaria parasite counts per mu l blood were indepen dent predictors of serum ferritin, when controlling for other helminth infections, age and sex, and socio-economic and educational backgroun d of the children's families and family size (y = 36.038-11.247(geopha gy) - 0.010(hookworm epg) + 0.001(malaria parasite counts); R-2 = 0.17 ). Multiple regression analysis with haemoglobin as dependent variable and the same independent variables did not reveal ally significant pr edictors. Analysis of the soil eaten by the children revealed a mean H Cl-extractable iron content of 168.9 mg/kg (SD 44.9). Based on the dat a on the amounts eaten daily and this mean iron content, soil could pr ovide on average 4.7 mg iron to a geophageous child (interquartile ran ge 2.1-7.1 mg), which is equivalent to 32% of the Recommended Nutrient Intake (RNI) for girls (interquartile range 14-48%) or 42% of the RNI for boys (interquartile range 19-63 %). Iron depletion and anaemia ar e associated with geophagy, but only serum ferritin concentrations wer e shown to be dependent upon geophagy in the regression model. From th e cross-sectional data no inference about causality can be made. To cl arify the possible causal relationships involved, longitudinal studies and iron-supplementation intervention studies are needed.