Impaired bioavailability of vitamin A in adults and children with persistent diarrhoea in Zambia.

BACKGROUND: We have previously demonstrated a strong relationship between low serum retinol concentration and mortality in Zambian AIDS patients with diarrhoea, but were unable to detect any benefit from oral micronutrient supplementation. AIM: To test the hypothesis that this is related to impaired availability of vitamin A, we analysed serum retinol concentration changes over 6 h following oral mega-dose therapy (60, 120 or 180 mg retinol). METHODS: Twenty-four men without diarrhoea, 15 adults with persistent diarrhoea and 11 children (six girls, five boys) with persistent diarrhoea were studied. RESULTS: Men with persistent diarrhoea had lower baseline serum retinol concentrations (median 0.39 micromol/L, interquartile range 0.21-0.56) than controls (median 1.16 micromol/L, interquartile range 0.84-1.47; P=0.0003). After 60 mg retinol, the rise in serum retinol in HIV seropositive controls (median 0.63 micromol/L, interquartile range 0.35-0.77) did not differ significantly from that observed in HIV seronegative controls (median 0.35 micromol/L, interquartile range - 0.04-0.56; P=0.20). Increasing the dose to 120 mg or 180 mg retinol did not enhance the increase in serum retinol concentration. The increase in serum retinol was less in adults with persistent diarrhoea (median 0.25 micromol/L, interquartile range 0.04-0.35) and in children (median 0.11 micromol/L, interquartile range 0.04-0.46) than in men without diarrhoea (median 0.44 micromol/L, interquartile range 0.26-0.74; P=0.03). Adults and children with diarrhoea had greater losses of retinol in urine over a 24-h period than controls, but less than 1% of the ingested dose was excreted. CONCLUSIONS: These results suggest that persistent diarrhoea in this population is associated with reduced bioavailability of retinol. Further work is required to determine the metabolic fate of therapeutic doses of retinol and to determine appropriate replacement strategies for HIV infected individuals.

Vitamin A levels in HIV/AIDS.

OBJECTIVE: To study the correlation of vitamin A concentrations in patients with AIDS, HIV positive symptom free and HIV negative symptom free men and women. DESIGN: A cross-sectional study. SUBJECTS: Male and female volunteers aged between 15 and 60 years willing to undergo an HIV-test. SETTING: Participants came from different backgrounds within the city of Ndola. Some were urban while others were peri-urban dwellers. They were included in the study only if they were willing to undergo the HIV test regardless of their place of residence. MAIN OUTCOME MEASURES: After obtaining consent blood samples were taken from the participants using needle and syringe. Whole blood was used to measure haematological indices while serum was used to measure vitamin A concentrations and HIV status. RESULTS: One hundred and thirty five participants were recruited for the study. Vitamin A was analysed in eighty seven HIV negative symptom free, forty one HIV-positive symptom free and seven AIDS cases. There was a significant difference (p < 0.05) in the variance of vitamin A levels in the three groups. Vitamin A deficiency is defined as blood concentrations below 30 micrograms/dl. Using this cut-off point, the Odds Ratio for deficiency if HIV-positive was found to be 6.3 (2.5, 16.7 p < 0.0001). The Odds Ratio for HIV and serum vitamin A deficiency was approximately the same for males and females. There was a modest correlation between vitamin A concentrations and haemoglobin (r = 0.34, 95% CI 0.18, 0.48, p < 0.0001). CONCLUSION: Vitamin A concentration is lowered in HIV infection. The depletion of vitamin A seems to increase with progression of the infection leading to AIDS disease. Whether regular supplementation of vitamin A to the HIV infected individual can lead to a delayed progression to AIDS needs to be explored.

Iron and vitamin A status of breastfeeding mothers in Zambia.

OBJECTIVE: To determine the prevalence of vitamin A deficiency and iron deficiency anaemia in breastfeeding mothers. DESIGN: Cross sectional descriptive survey. SUBJECTS: Breastfeeding mothers bringing their children to under five clinic. SETTING: A shanty compound in the outskirts of Ndola city, Zambia, Central Africa. MAIN OUTCOME MEASURES: Concentrations of vitamin A, iron, haemoglobin and correlation between vitamin A and iron. RESULTS: Anaemia was found in 29% while iron deficiency was present in 41% of the women studied. Iron deficiency anaemia was responsible for 22% of the anaemia cases. A positive correlation was found between serum vitamin A and haemoglobin concentrations (r = 0.184) and a significant statistical relationship existed (p < 0.05). This statistical significance was even greater when a correlation was made between haemoglobin concentrations and vitamin A concentrations below or equal to 30 micrograms/dl (1.05 mumol/1) (r = +0.351, p < 0.01). CONCLUSION: Vitamin A deficiency and iron deficiency anaemia need to be urgently addressed in this shanty compound and others like it surrounding Ndola city. Supplementing breastfeeding women with vitamin A will not only reduce vitamin A deficiency, but could also help to reduce anaemia.

Severe linear growth retardation in rural Zambian children: the influence of biological variables.

BACKGROUND: The prevalence of stunting in preschool children in Zambia is high; stunting has detrimental effects on concurrent psychomotor development and later working capacity. OBJECTIVE: Our objective was to investigate biological variables that may contribute to linear growth retardation in preschool children in Samfya District, Zambia. DESIGN: Children aged 6-9 mo (n = 108) and 14-20 mo (n = 102) attending mother-and-child health clinics were included. With a mixed-longitudinal design, they were followed up 9 and 21 mo later. Height and weight of children and their mothers were measured. Biochemical measures (eg, serum zinc, retinol, thyrotropin, iron, and acute phase protein concentrations), malaria parasitemia, and intestinal parasitosis were assessed. RESULTS: Height-for-age z scores (HAZ) were low, indicating a high prevalence of stunting (36-79%). Ninety percent of the children were anemic, 53-71% had elevated acute phase proteins, and 80% had malaria parasitemia. Regression analyses showed that maternal height predicted the children's height at 6-9 mo (regression coefficient = 0.05; 95% CI: 0.02, 0.08). The children's height at an early age (6-9 and 14-20 mo) showed a strong relation with their height at later ages (22-30 and 34-41 mo). Serum micronutrient status did not show a significant relation with later HAZ. CONCLUSION: Unlike other studies, we did not identify specific biological factors, such as health and micronutrient status, which contribute to the retardation of linear growth. The normal zinc and iodine statuses of the children suggest that at least these factors are not causal.

Micronutrient supplementation in the AIDS diarrhoea-wasting syndrome in Zambia: a randomized controlled trial.

OBJECTIVE: As HIV has spread through sub-Saharan Africa, persistent diarrhoea has emerged as a major problem in hospitals and in the community in severely affected areas. We have previously demonstrated that antiprotozoal therapy with albendazole reduces diarrhoea in AIDS patients in urban Zambia. This trial was designed to test the hypothesis that the clinical response to albendazole might be improved by oral micronutrient supplementation. DESIGN: Randomized, placebo-controlled trial. SETTING: Home care service of Ndola Central Hospital, Zambia. PATIENTS: HIV-seropositive patients with persistent diarrhoea. INTERVENTION: Patients were randomized to albendazole plus vitamins A, C and E, selenium and zinc orally or albendazole plus placebo, for 2 weeks. MAIN OUTCOME MEASURES: Time with diarrhoea following completion of treatment; mortality; adverse events. RESULTS: Serum vitamin A and E concentrations before treatment were powerful predictors of early mortality, but supplementation did not reduce time with diarrhoea or mortality during the first month, even after taking into account initial vitamin A or E concentrations, CD4 cell count or clinical markers of illness severity. Serum concentrations of vitamins A and E did not increase significantly in supplemented patients compared with those given placebo, and there were no changes in CD4 cell count or haematological parameters. No adverse events were detected except those attributable to underlying disease. CONCLUSIONS: Although micronutrient deficiency is predictive of early death in Zambian patients with the diarrhoea-wasting syndrome, short-term oral supplementation does not overcome it nor influence morbidity or mortality.

Malaria is associated with reduced serum retinol levels in rural Zambian children.

Vitamin A deficiency increases the risk of illness, while infections impair vitamin A status. Malaria is highly prevalent in rural Zambia. We describe the relationship between malaria and vitamin A status. We examined dietary vitamin A intake, malaria parasitaemia and serum concentrations of retinol, C-reactive protein (CRP) and alpha 1-acid glycoprotein (AGP) in 210 children under the age of 2. Vitamin A intake was low. Serum retinol was negatively correlated with malaria parasite count and to serum levels of CRP and AGP. Increased malaria parasite density resulted in raised CRP and AGP levels, which were negatively associated with serum retinol. We conclude that improvement of dietary vitamin A intake and prevention of infectious diseases, especially malaria, could alleviate vitamin A deficiency in this population.

Socio-economic status and serum vitamin A levels in Zambian children.

A vitamin A survey was conducted among school children attending primary schools located in urban residential compounds categorised according to their socio-economic status based on average income, as well as in pre-school children from one compound. The study was done in order to find out the effect of socio-economic status on the distribution of vitamin A levels and to ascertain whether vitamin A deficiency is a public health problem in Zambian children. A total of 814 school going and 381 pre-school children were studied. The serum samples were analysed by High Pressure Liquid Chromatography (HPLC). Using a Chi square analysis there was a significant difference in the results between the more affluent areas with higher monthly average income and the less affluent ones (p < 0.05) showing that the socio-economic status of communities is an important factor in interpreting the distribution of vitamin A levels in children. Vitamin A deficiency was found to be a public health problem only in the pre-school age group. Intervention efforts to reduce vitamin A deficiency should mainly target this group.

PIP: Vitamin A status was assessed among 433 children aged 7-15 years and 381 preschoolers in the following urban residential areas of Ndola district: Kansenshi, Masala, Chifubu, Chibolele, Kabwata, Lumano, and Nkwazi. Serum samples were analyzed by High Pressure Liquid Chromatography. The study was conducted to determine the effect of socioeconomic status upon the distribution of vitamin A levels and whether vitamin A deficiency is a public health problem in Zambian children. Vitamin A levels were significantly higher among children from affluent areas compared to children from less affluent ones. However, vitamin A deficiency was found to be a public health problem only among preschool children. The socioeconomic status of communities is therefore clearly an important factor in interpreting the distribution of vitamin A levels among children.

The vitamin A status of Zambian children attending an under five clinic as evaluated by the modified relative dose response (MRDR) test.

The vitamin A status of 87 children, 7-29 months of age, who were randomly selected from attendees at a pediatric clinic in Ndola, Zambia, were evaluated by the modified relative dose response (MRDR) test. By using a MRDR ratio cut-off point of 0.06, 78% of the children had inadequate vitamin A status. Both male and female children were equally affected. Of those with inadequate vitamin A status, 82% were between 7-19 months of age. A significant inverse relationship (p < 0.005) existed between vitamin A inadequacy and Z scores for height for age, weight for age and weight for height. Children with lower Z scores showed a better vitamin A status in comparison to those with a higher Z score. This unexpected relationship is probably due to an increased demand for vitamin A in children with a higher weight and rapid growth rate. Serum vitamin A values correlated poorly with MRDR values except at extreme ends of the distribution. Although clinical vitamin A deficiency is relatively infrequent in Zambia, we conclude that the vitamin A status of our children nonetheless needs to be improved.

A new spectrophotometric assay for the determination of vitamin A and related compounds in serum.

A new, direct multicomponent spectrophotometric assay for determining the vitamin A, lycopene, the total beta-carotene+beta-cryptoxanthin, the total lutein+alpha-carotene content of human serum is reported. The new method has been validated by performing parallel HPLC assays and is likely to be especially useful for use in population screening programmes. It is also suitable for screening paediatric samples.