Failure of twice-weekly iron supplementation to increase blood haemoglobin and serum ferritin concentrations: results of a randomized controlled trial.

In order to increase the intestinal absorption of iron whilst simultaneously minimising the side-effects and thus increasing compliance, once- or twice-weekly, instead of daily, iron supplementation has been widely recommended. In a randomized, placebo-controlled, double-blind study in western Kenya, a tablet of ferrous dextran (containing 60 mg elemental iron) or an identical-looking placebo tablet was provided twice-weekly for 12 months to each child or adult investigated. At baseline each subject had a moderately low blood concentration of haemoglobin (Hb). Initial Hb and serum ferritin (SF) concentrations were determined and each subject was tested for malarial and helminth infection and treated, if necessary, with the appropriate anthelminthic drug(s). Overall, 200 children (aged 4-15 years) and 129 adults (aged 16-63 years) completed the 12-month study. At baseline, 47.5% of the children and 58.1% of the adults were anaemic, hookworm (detected in 60.0% of the children and 69.9% of the adults) was the most common helminth infection, and malaria was endemic. The results of bivariate analyses indicated that twice-weekly iron supplementation had no significant effect on blood Hb or SF concentrations, either in the children or the adults investigated. The results were confirmed in multiple linear-regression analyses, which revealed that the predictors of the final Hb concentration in the children investigated were age and infection, after enrollment, with Ascaris lumbricoides. Gender and the serum concentration of alpha-1-antichymotrypsin (ACT) at final follow-up were predictors of the final SF concentration in the children. In adults, the predictors of the final Hb concentration were gender and HIV infection, and the predictors of the final SF concentration were age and the serum concentration of ACT at the final follow-up. Twice-weekly iron supplementation did not increase Hb or iron stores in children or adults. Since compliance appeared to be high, this lack of effect may be the result of an inadequate dose of iron or of subjects who have deficiencies in micronutrients other than iron.

The impact of iron supplementation on reinfection with intestinal helminths and Schistosoma mansoni in western Kenya.

A randomized, placebo-controlled, double-blind trial was carried out in 1994-96 among 231 children and 181 adults in order to determine the effects of iron on reinfection rates and intensities of hookworm, Ascaris lumbricoides, Trichuris trichiura and Schistosoma mansoni. Adults given 60 mg elemental iron twice-weekly for 12 months had significantly lower reinfection rates of A. lumbricoides (16.7% vs 31.9%, P = 0.046), T. trichiura (6.9% vs 20.6%, P = 0.03) and S. mansoni (38.3% vs 61.8%, P = 0.008) compared to adults given placebo. In contrast, adults allocated to iron had a significantly higher reinfection rate of hookworm at the 4-month examination (11.1% vs 0%, P = 0.009), but the difference was not significant at 8- and 12-month follow-up examinations. Iron supplementation had no effect on reinfection intensities in adults. Surprisingly, iron supplementation had no effect on either reinfection rates or intensities in children. Multiple logistic regression analyses controlling for baseline infection status confirmed the effect in adults of iron on A. lumbricoides, T. trichiura and S. mansoni reinfection rates. The effect is suggested to be due to reduced risk behaviour, to improved immune function or to unfavourable host gut conditions caused by an increased oxidative stress. In each case, the lack of effect in children remains to be explained. In contrast, iron supplementation apparently was short-lived in favour of hookworm infection, an effect that needs further clarification. The findings suggest that iron supplementation has a role to play in helminth control programmes and that intraluminal factors may contribute to the regulation of some helminth infections.

Diagnosis of Rhodesian sleeping sickness in the Lambwe Valley (1980-1984).

In primary Rhodesian sleeping sickness patients, parasitological diagnosis was best performed by rodent inoculation of blood (98.5%+) followed by Giemsa-stained thick blood smears (93.3%+). Parasitological diagnosis in relapse patients was sometimes impossible and clinical diagnosis based on CSF examination was necessary. Early during a disease outbreak in 1980, 89% of the infections were detected by mobile field teams, but once established in the endemic area a stationary diagnostic facility detected most of the cases. A total number of 23,751 examinations for Rhodesian sleeping sickness and malaria were made by mobile field teams during 1980-1984; 102 primary cases (0.43%) and 25 (0.10%) relapse cases were diagnosed. A total of 9339 individuals (39%) had patent malaria infections. The IFAT was positive in 89% of the primary sleeping sickness patients and 77% of the relapse patients. Seventy-nine per cent of the primary patients were positive in a CFT test, and 77% of the relapse patients were considered positive.