Name: Geissler, P. Wenzel Home Country: Kenya Research Country: Kenya Project period: 1995-1998 Type: Ph.D. thesis Title Geophagy among primary school children in Western Kenya. Parasitological, nutritional and anthropological aspects of soil-eating Abstract Geophagy or soil-eating is common among people on all continents and well documented in Africa. It appears to be widespread among children, and has been suggested as a cause of helminth infection and to be related to anaemia and iron deficiency. Geophagy has not received much scientific attention, which astounds as it may be relevant to two major health problems of school age children, namely infection and malnutrition. Especially during the past decade, schoolchildren have been in the focus of international health programmes. In order to understand health problems and contribute to sustainable health interventions, perspectives from natural and social sciences should be combined, and researchers should engage in a dialogue with the studied people. The research presented below has tried to bring together the viewpoints of different human sciences on one topic, and to represent both the scientist's and the concerned children's views. We hope that the multidisciplinary combination of research findings will provide useful information for future improvements of schoolchildren's health. In the related sub-studies presented in this thesis, we investigated geophagy among primary schoolchildren from the Luo community in western Kenya from the viewpoints of parasitology, nutrition and ethnography. We aimed: (1) to describe the prevalence of geophagy among the study population and the types of soil ingested; (2) to assess the potential of the geophageous behaviour of schoolchildren as a source of geohelminth infection; (3) to contribute to the assessment of the nutritional potential of geophagy with special emphasis on iron; and (4) to contribute to the understanding of the cultural context I;"; of geophagy and worms among children in the study community. Chapters 1 to 3 introduce the reader to the topic, provide some background information on design and method, and familiarise the reader with the study area and population. Chapter 4 presents the findings of the first part of the study, which was a cross-sectional survey among 285 primary schoolchildren aged 5-18 years. Prevalence of geophagy among these children and the types and amounts of soil eaten were determined by interviews. Stool samples were taken from a slip-sample of 53 children (19%) and their silica content determined to compare the results with those of the interviews. Geophagy was practised by 73% of the 285 children. The prevalence decreased with age for both sex es, remaining stable for girls between 15 and 18 years, while continuously decreasing for boys in that age range. This suggests that geophagy continues from early childhood to adulthood among the females while it recedes with adolescence among the males. Most of the children ate soil from the surface of termite mounds. All but four of the children practising geophagy reported eating soil at least once daily. The median amount of soil that the children reported eating was 28 g daily, ranging from 8 to 1 08 g. The reported amount of soil eaten daily correlated to the results of the stool silica determinations from the 53 children. Using the median of 1% silica of faecal wet weight as a cut-off point to distinguish geophageous children from non-geophageous, the examination of a single stool sample had a sensitivity of 76% and a specificity of 80% in detecting a geophageous child when compared to the interview method. Chapter 5 presents results from the second part of the study, which addressed the relationship between geophagy and geohelminth infection in a different study population the same study area. In a cross-sectional survey, 204 children aged 10-18 years were interviewed about geophagy and their faeces examined for helminth infections (Ascaris mbricoides, Trichuris trichiura, Schistosoma mansoni, hookworm). Children found infected were treated with albendazole (600 mg in a single doge) and/or Praziquantel (40 19/kg in a single dose). The children were re-examined after 4, 8, and Il months for re- infections. Among the 175 chi1dren, who were followed for the entire study period, reinfection rates and intensity were compared between geophageous and non-geophageous children. Soil samples were collected with the geophageous children and examined for helminth eggs. In the initial cross-sectional survey, 77% of the 204 children reported eating soil daily. Forty-eight percent of all soil samples were contaminated with eggs of A. lumbricoides. The median egg count in contaminated samples was 3 A. lumbricoides eggs per 2 g soil (range 1-15). Twenty-nine (14.2%) of the children were infected with A. lumbricoides and 87 (42.6%) with T. trichiura. Significant associations between geophagy and intensity of infection with A. lumbricoides and T trichiura, but not S. mansoni and hookworm, were found in the cross-sectional survey. Re-infection with A. lumbricoides was twice as high among geophageous children as compared to non-geophageous (27.4% vs. 12.0%; p=0.030). Intensity of re-infection was higher among geophageous children (median 773 epg vs. 95 epg; p=O.027). The relative risk of A. lumbricoides re-infection was 2.28 for geophageous children (95% CI 1.02-5.11), and the attributable fraction in the study population was 56.0% (95% CI 1.7%-80.4%). Significant differences in T. trichiura re-infection intensity were found between geophageous and non-geophageous children (median 68 vs. 20; p=0.049), but not in re-infection rates. No difference was seen in S. mansoni or hookworm re-infection rates or intensities and in the families' socio-economic or educational status between the two groups. Geophagy was associated with an increased fisk of re-infection with A. lumbricoides and higher intensities of T. trichiura infection. Neither family background, nor infection with non-orally transmitted helminth infections were associated with geophagy, suggesting that this association between geophagy and certain geo-helminths was not due to confounding. Geophagy is thus likely to be a source of infection with ascariasis and possibly trichuriasis among primary schoolchildren. Chapter 6 presents the findings of the third part of the study, which assessed the possible relationship between geophagy and iron status and anaemia. A cross-sectional study was conducted among 156 primary schoolchildren (median age 13 years, range 10-18). Geophagy was assessed through interviews, and 114 (73.1%) of the children reported eating soil daily. Haemoglobin (Hh) levels were determined in all 156 children, and serum ferritin concentration in 135. The mean haemoglobin concentration was 12.7 g/dl, and the median ferritin, concentration was 27.2 µg/L. Both the proportion of anaemic (Hb<11.0 g/dl) and of iron depleted (ferritin <12 µg/L) children was higher among the geophageous children than among the non-geophageous (9.6% vs. 0% anaemia; p=O.037; 18.4% vs. 5.4% iron depletion; p=0.046). Serum ferritin and haemoglobin concentrations were not correlated (rs=O.135; p=0.100). Multiple regression analysis showed that geophagy, hookworm eggs per gram faeces and malaria parasite counts per J.1L blood were independent predictors of serum ferritin, when controlling for other helminth infections, age and sex, socio-economic and educational background of the children' s families, and family size (Y = 36.038 - 11.247 (geophagy) - 0.010 (hookworm epg) + 0.001 (malaria parasite counts); R2=0.17). Multiple regression analysis with haemoglobin as the dependent variable and the same independent variables did not reveal any significant predictors. Analysis of the soil eaten by the children revealed a mean HC1-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 Fe to a geophageous child (interquartile range 2.1-7.1 mg). This is equivalent to 32% (interquartile range 14-48%) of the Reference Nutrient Intake (RNI) for girls aged 11-14 years or 42% (interquartile range 19- 63%) of the RNI for boys of that age range. 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 these cross-sectional data no inference about causality can be made. Chapter 7 to 9 present findings of the fourth part of the study, the ethnographic investigations around soil-eating. Chapter 7 describes the social significance and meanings attributed to soil-eating by schoolchildren and their families. Soil-eating is practised among children before puberty, irrespective of their sex, and among women of reproductive age, but not among adult men and old women. To eat soil signifies belonging to the "female", reproductive sphere within the household, which includes children up to adolescence. Through eating soil or abandoning it, the children express their emerging gender identities. Discourses about soil-eating, which describe the practice as unhealthy and bad, draw on "modem" notions of hygiene, which are conveyed, for example, in school. They form part of the discoursive strategies with which men in particular maintain a dominant position in the community. Beyond the significance of soil-eating in relation to age, gender and power, it relates to several larger cultural themes, namely fertility, belonging to a place, and continuity of the lineage. Soil symbolises life-bringing forces and soil-eating is a form of communion with these forces, and with the people with whom one shares land and origin. Soil-eating is a social practice produced in interactions of body, mind and other people, through which children incorporate social and cultural values. Chapter 8 describes people's perceptions of worms and their role in the body. Worms are prominent in people's body-image and ideas about illness. Two models applied to worms can be analytically distinguished as "traditional" and "biomedical", referring to their sources, modes of transmission and relation to wider understandings of lire. The first acknowledges worms as positive agents of both digestion and illness, and aims at maintaining a balanced relationship with them. The latter sees worms as dangerous intruders into bodily order, and demands their expulsion. Both models are used side by side or alternatingly by most people in the village, according to their individual preferences or to the specific context. The different attitudes to worms - one inclusive, the other exclusive - are related to wider concepts of dirt, pollution, affliction and evil and shed light on people's understandings of the body and lire. Chapter 9 takes a closer look at Luo schoolchildren's ideas about worms and their role in the body. To give meaning to their bodily experiences, children make use of the two models described in chapter 8, each of them providing different views on the relationship of worms and the body. The children leam about the traditional model from older caretakers and about the biomedical model in school. They make use of both models in their talk, in drawings of the body and in written compositions. They maintain the basic idea that worms are an unavoidable part of the body, but try to integrate biomedical and traditional notions. The findings show that children, moving at the interface of "traditional" knowledge conveyed informally in the family and "modem" ideas, mainly conveyed in formal institutions, are creatively contributing to the integration of old and new, and actively shaping the ideas about health and the body of a future generation. Chapter 10 summarises the findings of the study, relates them briefly to recent research on the topic, which could not be included in the publications, and identifies open questions for further research. Involved research institutions Institute for Health Research and Development Institute of Anthropology, University of Copenhagen Supervisor(s) J. Ouma, Divsion of Vector Borne Diseases, Nairobi Kenya Susan Whyte, Institute of Anthropology, University of Copenhagen Jens Aagaard Hansen, Institute for Health Research and Development Pascal Magnussen, Institute for Health Research and Development Correspondence