Sustainability of a nutrition education programme to prevent night-blindness in Bangladesh

Five-year follow-up of a food-based vitamin A intervention in Tanzania

OBJECTIVE

: To evaluate the long-term effects of a horticultural and nutrition education intervention in rural Tanzania.

DESIGN

: A quasi-experimental post-test design was used.

SETTING

: The research was carried out in 10 villages in Singida region, Tanzania.

SUBJECTS

: Mothers and their children aged 6-71 months (n = 236) from an experimental (Ilongero) and control (Ihanja) area were interviewed regarding knowledge and practices related to vitamin A nutrition. Intake of vitamin A-rich foods by the children during the 7 days prior to the interview was recorded. Stools were examined for helminths and serum samples were analysed for retinol and C-reactive protein (CRP) (n = 146) for the children aged 12-71 months.

RESULTS

: Knowledge and practices were more favourable to vitamin A intake in the experimental area than in the control area, and an increased frequency of intake of green leaves was associated with higher serum retinol values. The experimental area had lower mean serum retinol levels (13.7 microg dl(-1), n = 75) than the control area (19.3 microg dl(-1), n = 71). One likely confounder was the higher helminth infestation in the experimental area (n = 75, 79%) than in the control area (n = 71, 49%) (P < 0.001). Children with helminths (n = 94) had a lower mean serum retinol level than those without (n = 52) (12.3 +/- 5 vs. 24 +/- 10 microg dl(-1); P = 0.001).

CONCLUSIONS

: Food-based vitamin A programmes can make sustainable improvements in knowledge and dietary practices but these may not necessarily be reflected in increases in serum retinol. Programme implementation and evaluation should take confounders into consideration as, in this case, helminth infestation.

Relationships between vitamin A, iron status and helminthiasis in Bangladeshi school children

OBJECTIVE

To explore the relationships between biochemical indicators of vitamin A and iron status and the intestinal helminths Ascaris lumbricoides and hookworm in primary school children.

SETTING

Two rural governmental schools in northwestern Bangladesh.

DESIGN

Cross-sectional study.

SUBJECTS

The sample consisted of 164 children in grades 3-5.

METHODS

Serum retinol and beta-carotene (by high-performance liquid chromatography, HPLC), haemoglobin (HemoCue), ferritin (enzyme-linked immunoadsorbent assay, ELIZA) and height and weight were measured. Dietary intake of vitamin A was assessed using a food frequency questionnaire and faecal analyses were done using Stoll's egg-count technique.

RESULTS

The mean serum retinol was 26.8 microg dl(-1) and 20% had a level of < 20 microg dl(-1), the cut-off value for low vitamin A status. There was a strong positive association between serum beta-carotene and serum retinol (r = 0.44, P < 0.001), suggesting those with higher retinol levels had a higher carotene intake. Thirty-one per cent were anaemic (Hb < 11.5 g dl(-1)), 30% had iron deficiency (serum ferritin < 12.0 microg l(-1)) and 14% were suffering from iron deficiency anaemia. Children with a serum retinol level of 20 microg dl(-1) had significantly lower ferritin (14.0 compared to 26.0 microg l(-1), P = 0.005) and Hb levels (11.7 compared to 12.4 g dl(-1), P = 0.005) than those with higher levels. The proportion of iron deficiency anaemia was significantly greater among children with hookworm. Our data suggest that hookworm exerts its impact on iron status independently of the vitamin A status of the host.

CONCLUSIONS

Programmes to improve iron status should consider including both vitamin A prevention programmes and deworming.

Protein energy malnutrition, vitamin A deficiency and night blindness in Bangladeshi children

The occurrence of night blindness and serum vitamin A concentrations among children in rural Bangladesh were studied in relation to protein energy malnutrition, dietary habits and intake of vitamin A capsules. In 1992, 124 night-blind children were registered in a cross-sectional survey in the northern part of Bangladesh, and age-, sex- and neighbourhood-matched controls were selected. Of these, the first reported night-blind child from a household (n = 105) and their controls were included in the analyses. Our results showed that night blindness was associated with protein energy malnutrition when using the mid-upper arm circumference (MUAC) as a measure of nutritional status. The odds ratio for a confirmed diagnosis of night blindness among children with a MUAC < 80% of the reference versus normal children was 5.4 (CI 1.9-15.5). Low MUAC was associated with low intake of beta-carotene-rich and vitamin A-containing foods as well as with low serum vitamin A in the total series of cases and controls. This may indicate that night blindness is only one aspect of the general protein energy malnutrition problems in this population. We therefore suggest that measures to prevent vitamin A-related morbidity and mortality should include improvement of the general diet with increased consumption of dietary vitamin A.

Serum vitamin A in relation to socio-economic, demographic and dietary characteristics in Bangladeshi children

The purpose of this study was to examine socio-economic conditions, demographic factors, use of vitamin A capsules and dietary practices in relation to the risk of low serum vitamin A. One hundred and twenty four night blind cases were identified by parents in a cross-sectional survey in Bangladesh in 1992. Age-, sex- and neighbourhood-matched controls were selected. Venous blood was collected from 87 cases and 97 controls for the determination of serum vitamin A. Information about socio-economic conditions, demographic factors, use of vitamin A capsules and dietary practices was obtained by interview. The level of serum vitamin A was strongly related to age and consumption of beta-carotene rich foods. The preschool years (2-6 years) are important risk periods for vitamin A deficiency among children. We conclude that long-term prevention of vitamin A deficiency should rely on efforts to improve local diet.