European Journal of Clinical Nutrition (2002) 56, 666–673 ß 2002 Nature Publishing Group All rights reserved 0954–3007/02 $25.00 www.nature.com/ejcn ORIGINAL COMMUNICATION Effects on serum retinol of multi-micronutrient supplementation and multi-helminth chemotherapy: a randomised, controlled trial in Kenyan school children D Mwaniki1, B Omondi1, E Muniu1, F Thiong’o2, J Ouma2, P Magnussen3, PW Geissler3, K Fleischer Michaelsen4 and H Friis3,4* 1Centre for Public Health Research, Kenya Medical Research Institute, Nairobi, Kenya; 2Division of Vector Borne Diseases, Ministry of Health, Nairobi, Kenya; 3Danish Bilharziasis Laboratory, Charlottenlund, Denmark; and 4Research Department of Human Nutrition, The Royal Veterinary and Agricultural University, Frederiksberg, Denmark Objective: To assess the effects of multi-micronutrient supplementation and multi-helminth chemotherapy on serum retinol concentration, using schools as a health delivery system. Study area and population: From 19 primary schools in Bondo District, western Kenya, 977 children between 9 and 18 y were included in the trial. The 644 (65.9%) children on whom baseline serum retinol was available were included in this study. Design: A randomised, placebo-controlled, double-blind, two-by-two factorial trial on the effects of multi-micronutrient supplementation and multi-helminth chemotherapy on serum retinol after 8 months. Intervention: Single treatment with albendazole (600 mg) and praziquantel (40 mg=kg of body weight) and daily multi- micronutrient supplementation with tablet containing 1000 mg vitamin A. Results: Micronutrient supplementation (0.08 mmol=l, 95% CI 0.01, 0.14; P ¼ 0.025), but not treatment (0.03 mmol=l, 95% CI 7 0.04, 0.10; P ¼ 0.38), increased serum retinol. However, treatment did increase serum retinol in S. mansoni-infected (0.09, 95% CI 0.02, 0.16; P ¼ 0.009), but not in uninfected children ( 7 0.07, 95% CI 7 0.18, 0.03; P ¼ 0.18; interaction, P ¼ 0.01). Similarly, reduction in egg output of S. mansoni, but none of the geohelminth, was a predictor, corresponding to a 0.008 mmol=l (95% CI 0.00002, 0.02; P ¼ 0.049) increase in serum retinol per 100 epg reduction. Interestingly, interactions were found between age and sex (P ¼ 0.046), and malaria parasitaemia and sickle cell phenotype (P ¼ 0.04). Conclusion: Multi-micronutrient supplementation and reduction in S. mansoni egg output increased serum retinol, irrespective of initial serum retinol. Sponsorship: The Danish International Development Assistance. European Journal of Clinical Nutrition (2002) 56, 666 – 673. doi:10.1038=sj.ejcn.1601376 Keywords: micronutrients; anthelminthic treatment; malaria; S. mansoni; hookworm; T. trichiura; A. lumbricoides; vitamin A; school children; Kenya Introduction Vitamin A deficiency is widespread in developing countries, *Correspondence: H Friis, Research Department of Human Nutrition, The particularly in young children and women where it is an Royal Veterinary and Agricultural University, Rolighedsvej 30, DK-1958 important cause of immune function impairment (Semba, Frederiksberg C, Denmark. 1994) and increased risk of morbidity and mortality from E-mail: [email protected] infectious and other diseases (Fawzi et al, 1993; Sommer et al, Guarantor: H Friis. Contributors: DM, EM, FT, JO, PM, PWG, KFM and HF were responsible 1984; West et al, 1999). The main causes of vitamin A for concept and planning. DM, BO, JO, FT and PWG were responsible deficiency are inadequate intake of vitamin A-rich foods for laboratory and field work. DM, EM and HF were responsible for such as liver, full milk, butter, eggs, whole fish, green leafy data processing. DM, PM, KFM and HF were responsible for writing vegetables and yellow-orange fruits, as well as increased the manuscript. Received 8 June 2001; revised 24 October 2001; requirements due to a high burden of infectious diseases. accepted 29 October 2001 Accordingly, rational long-term measures to increase vitamin Micronutrients, anthelminthics and serum retinol D Mwaniki et al 667 A status of these populations should comprise promotion of dently randomised to multi-helminth chemotherapy or food diversification and prevention of infectious diseases. identical-looking placebo. Micronutrient supplementation Nevertheless, in the meantime, short-term measures such as comprised a tablet with 13 vitamins and minerals (vitamin vitamin A supplementation and treatment of prevalent A 1000 mg, C 50 mg, B1 1.4 mg, B2 1.6 mg, B6 1.7 mg, B12 2 mg, chronic infections could target high-risk groups where fea- folate 150 mg, niacin 16 mg, iron 18 mg, zinc 20 mg, copper sible and cost-effective. For example, vitamin A deficiency is 2.0 mg, iodine 150 mg, selenium 40 mg; Almega, Ringsted, also frequent in school-age children (Friis et al, 1997), and Denmark) on all schooldays for a full school year. Multi- schools offer a useful entry point for programmes that could helminth chemotherapy was given to children found comprise micronutrient supplementation, treatment of para- infected with any of the geohelminths or S. mansoni with sitic infections, school gardens and health education. albendazole and praziquantel, respectively. Albendazole was In western Kenya, malaria is holoendemic, Schistosoma (S.) given as a single dose of 600 mg, and praziquantel as a single mansoni, hookworm (Necator americanus), Trichuris (T.) tri- dose of 40 mg=kg of body weight. The examinations chiura and Ascaris (A.) lumbricoides infections are prevalent, described below were done at baseline and repeated after 8 and vitamin A status generally poor. We conducted a study months. on the effects of multi-micronutrient supplementation and multi-helminth chemotherapy on serum retinol concentra- tion (serum retinol) among 9 – 18-y-old school children in 19 Serum retinol and haematology primary schools in western Kenya, with the aim to assess the Blood samples were taken from the antecubital veins role of these interventions in future school-based health between 9 am and 1 pm. Serum was prepared and kept programmes. An inverse association between S. mansoni frozen at 7 20C for less than 3 months, and serum retinol egg output, but neither geohelminth egg output nor malaria was measured by high performance liquid chromatography parasitaemia, and low serum retinol, from baseline data has (Hitachi Ltd, Japan) as previously described (Friis et al, 1997). previously been reported (Friis et al, 1997). In this paper we To 100 ml serum were added 5 ml retinyl acetate (100 mg=ml) as report the effect of the interventions on serum retinol. internal standard. The proteins were precipitated using 100 ml of methanol, and retinol was extracted using 200 ml of diethyl ether : dichlormethane : isopropanol mixture Subjects and methods (80 : 19 : 1). The extract was reconstituted with 100 ml The study was conducted on the shores of Lake Victoria in mobile phase (methanol : water, 95 : 5, v=v) and 20 ml injected Bondo District, Nyanza Province in western Kenya. The into a guard-fitted normal-phase stainless steel column residents of the study area were members of the Luo com- (microbondapak C , 3.9Â300 mm, particle size 10 mm, munity and their principal occupations were subsistence 18 Waters Assoc, Milford, MA, USA). Inter-batch coefficient of crop farming, raising Zebu cattle, commercial fishing and variation was 6.2%. A serum retinol value of 0.70 mmol=l petty trade. Malaria was known to be holoendemic in the defined low and 1.05 mmol=ldefined marginal levels. Hemo- study area, and intestinal helminths and S. mansoni were globin concentration (Hb) and total white blood cell (WBC) prevalent, whereas S. haematobium was not endemic. counts were determined using an electronic counter (M530, The study was a randomised, placebo-controlled, double- Coulter Electronics Ltd, England), and differential WBC blind trial on the effects of daily multi-micronutrient sup- counts were determined using conventional manual plementation and multi-helminth chemotherapy, using a methods. two-by-two factorial design. From grades 5 and 6 in 19 primary schools in the study area, 1096 children were iden- tified who had their parents consent to participate. Of these, 38 were ill and therefore received initial treatment and were Clinical examination and anthropometry referred for more definitive management and follow-up. The children were examined clinically, blood samples were These and 81 children that were unavailable for baseline collected, and a thin and a thick blood slide were prepared. examinations were excluded. The remaining 977 children Additionally, questionnaire data and anthropometric mea- were included in the study. Despite initial consent, some surements were obtained on the day of blood sampling. parents or children did not accept blood sampling. Baseline Finally, stool samples were collected on different days. data on serum retinol was therefore only available on 644 Height and weight were measured with the children bare- (65.9%) of the 977 children, and the results of the 8 months footed and wearing light standard clothing. Heights were follow-up of these children are reported here. measured to the nearest 0.5 cm and weights to the nearest 0.1 kg, using a scale-stadiometer (Seca, Germany). Height and weight were related to references as standard deviation Study interventions scores (Z-scores). Height-for-age (HAZ) and weight-for-age After completion of the baseline examinations described (WAZ) Z-scores were computed based on the NCHS-WHO below, the children were randomised to micronutrient sup- growth reference curves. HAZ and WAZ below 7 2 were plementation or identical-looking placebo and indepen- considered to reflect stunting and underweight, respectively. European Journal of Clinical Nutrition Micronutrients, anthelminthics and serum retinol D Mwaniki et al 668 Infections Review Committee, and the Ministry of Health, Kenya. The A single stool sample was collected on each of two or three children and their parents were given information about the consecutive days around the time of blood sampling, and study, and the parents gave their written consent.