Geophagy among primary schoolchildren and its impact on geohelminth infection were studied in western Kenya. In a cross-sectional survey, 204 children aged 10-18 years were interviewed about geophagy and examined for helminth infections (Ascaris lumbricoides, Trichuris trichiura, Schistosoma mansoni, hookworm). Children found infected were treated with albendazole (600 mg in a single dose) and/or praziquantel (40 mg/kg in a single dose). The children were re-examined after 4, 8 and 11 months. In the initial cross-sectional survey, 77% of the children ate soil daily and 48% of all soil samples were contaminated with eggs of A. lumbricoides (median egg count in contaminated samples was 3/2 g of soil; range 1-15). Twenty-nine children (14.2%) were infected with A. lumbricoides and 87 (42.6%) with T. trichiura. Significant associations between geophagy and infection intensity with A. lumbricoides and T. trichiura, but not S. mansoni or hookworm, were found. Re-infection with A. lumbricoides was twice as common among geophagous children as among non-geophagous children (27.4% vs. 12.0%; P = 0.030). The intensity of reinfections was higher in geophagous children (median 773 eggs/g vs. 95 eggs/g; P = 0.027). The relative risk for A. lumbricoides reinfection was 2.28 for geophagous children (95% confidence interval [95% CI] 1.02-5.11), and the fraction of reinfection attributable to geophagy was 56.0% (95% CI 1.7%-80.4%). There was a significant difference in T. trichiura infection intensity between geophagous and non-geophagous children (median no. of eggs/g 68 vs. 20; P = 0.049), but not in reinfection rates. No difference between the groups was seen in S. mansoni or hookworm reinfection rate or intensity, or in the families' socioeconomic or educational status. Geophagy was associated with an increased risk of reinfection with A. lumbricoides and possibly with T. trichiura. Neither family background nor infection with non-orally transmitted helminths was associated with geophagy, suggesting that this association was not due to confounding, but causal. Geophagy is therefore likely to be a source of ascariasis and possibly trichiuriasis among primary schoolchildren.

SummaryAs part of a cross-sectional study among 156 primary school children (median age 13 years, range 10᎐18) in Western Kenya, geophagy was assessed 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) concentration was 12.7 g/dl, and median ferritin concentration 27.2 g/l. Both the proportion of anaemic (Hb Ͻ 11.0 g/dl) and of iron-depleted (ferritin Ͻ 12 g/l) children was significantly higher among the geophageous children than among the nongeophageous (9.6% vs. 0% anaemia; P ϭ 0.037; 18.4% vs. 5.4% iron depletion; P ϭ 0.046). Serum ferritin and haemoglobin concentrations were not correlated (r ϭ 0. 13 5; P ϭ 0. 100). Multiple regression analysis showed that geophagy, hookworm eggs per gram faeces and malaria parasite counts per l blood were independent predictors of serum ferritin, when controlling for other helminth infections, age and sex, and socio-economic and educational background of the children's families and family size (y ϭ 36.038᎐11.247(geophagy) ᎐ 0.010(hookworm epg) ϩ 0.001(malaria parasite counts); R 2 ϭ 0.17). Multiple regression analysis with haemoglobin as dependent variable and the same independent variables did not reveal any significant predictors. Analysis of the soil eaten by the children revealed a mean HCl-extractable iron content of 168.9 mg/kg (SD 44.9). Based on the data on the amounts eaten daily and this mean iron content, soil could provide on average 4.7 mg iron to a geophageous child (interquartile range 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 are associated with geophagy, but only serum ferritin concentrations were shown to be dependent upon geophagy in the regression model. From the cross-sectional data no inference about causality can be made. To clarify the possible causal relationships involved, longitudinal studies and iron-supplementation intervention studies are needed.

Parasitic determinants of serum retinol concentrations were studied in 159 preschool (0.25-5.1 y) and 695 primary school (9.2-17 y) children in western Kenya. Mean serum retinol was 0.63 micromol/L in preschool and 0.94 micromol/L in primary school children; 62% and 24%, respectively, had serum retinol < 0.70 micromol/L. Serum retinol was lower in boys than in girls among both preschool (P = 0.04) and primary school children (P = 0.0001). Schistosoma mansoni, Ascaris lumbricoides, hookworm, and Trichuris trichiura egg output and malarial parasitemia were determined and their relation with serum retinol assessed. Among preschool children, sex, elevated serum concentrations of C-reactive protein, and malarial parasitemia were significant predictors of serum retinol. Among the 63 children from whom stool samples were available, none of the helminth infections were significant predictors of serum retinol. For primary school children, age, sex, and S. mansoni egg output were predictors of serum retinol. Malarial parasitemia among nonimmune preschool children may contribute to low serum retinol, whereas malarial parasitemia did not have any effects in semiimmune primary school children. In contrast, the inverse relation between S. mansoni and serum retinol found in primary school children could be due to an effect of infection on serum retinol or an increased susceptibility to infection among children with low serum retinol. Although parasitic infections may contribute to poor vitamin A status in children, they do not explain the age and sex differences.

Objective: To assess the effects of multi-micronutrient supplementation and multi-helminth chemotherapy on haemoglobin concentration (Hb), using schools as a health delivery system. Study area and population: Nine hundred seventy-seven children between 9 and 18 y of age from 19 primary schools in Bondo District, western Kenya, were included in the trial. The 746 (76.4%) children on whom baseline Hb was available were included in this study. Design: The study was a randomized, placebo-controlled, double-blind, two-by-two factorial trial of the effects of multimicronutrient supplementation and multi-helminth chemotherapy on Hb after 8 months. Intervention: Single treatment of infected children with albendazole (600 mg) for geohelminths and praziquantel (40 mg=kg) for Schistosoma mansoni and daily supplementation with 13 micronutrients. Results: Multi-micronutrient supplementation (3.5 g=l, 95% CI 1.7, 5.3; P ¼ 0.0002) and anthelminthic treatment (2.0 g=l, 95% CI 0.2, 3.9; P ¼ 0.03) increased Hb independently (interaction, P ¼ 0.33). The effects were also independent of baseline Hb and general nutritional status. The treatment effect was due to reductions in S. mansoni and hookworm intensities of infection, in that Hb increased by 0.4 and 0.2 g=l, respectively, per 100 epg reductions in egg output. Interestingly, among S. mansoniinfected children, the effect of treatment seemed stronger in those with compared to those without co-existing malaria parasitaemia (interaction, P ¼ 0.09). Conclusion: Multi-micronutrient supplementation and multi-helminth chemotherapy increased Hb among school children, irrespective of initial Hb and nutritional status.

A randomized, placebo-controlled, double-blind, two-by-two factorial trial was carried out among 977 schoolchildren from 19 primary schools in Nyanza Province, Kenya from February 1995 to February 1996. The interventions were multimicronutrient supplementation (vitamin A, 1000 micrograms; vitamin B1, 1.4 mg; vitamin B2, 1.6 mg; vitamin B6, 1.7 mg; vitamin B12, 2.0 micrograms; folate, 150 micrograms; niacin, 16 mg; vitamin C, 50 mg; vitamin D, 5 micrograms; vitamin E, 8 mg; iron, 18 mg; zinc, 20 mg; copper, 2.0 mg; iodine, 150 micrograms; selenium, 40 micrograms) and multihelminth chemotherapy (albendazole 600 mg in a single dose and/or praziquantel 40 mg/kg in a single dose). This paper reports the effects of the supplementation given on all school days on reinfection with hookworm, Ascaris lumbricoides, Trichuris trichiura and Schistosoma mansoni after 11 months. Baseline prevalence and geometric mean intensity for hookworm, A. lumbricoides, T. trichiura and S. mansoni in all children investigated were 54.7%, 13.8%, 45.6% and 70.0%, respectively and 8.6, 2.7, 5.9 and 19.4 eggs per gram (epg), respectively. Children received a mean of 2.3 multimicronutrient/placebo tablets per school week, giving a compliance rate of 46%. Children given multimicronutrients had a slightly, but significantly, lower intensity of S. mansoni reinfection compared with children given placebo (5.5 epg vs. 7.7 epg, P = 0.047). Multiple linear regression analyses controlling for baseline infection status confirmed this, as children who received micronutrients were reinfected with S. mansoni at only 69% of the intensity of those who received placebo. Multiple logistic regression analyses revealed that micronutrient supplementation was associated with a lower S. mansoni reinfection rate (odds ratio = 0.7) although this was only of borderline significance (P = 0.090). There were no significant differences in reinfection rates or intensities of hookworm, A. lumbricoides and T. trichiura. The effect on S. mansoni infection intensity is particularly interesting given the low compliance, suggesting that full micronutrient supplementation might have a role to play in S. mansoni control programmes.