The prevalence of anaemia and iron and vitamin A deficiency were assessed in adolescent school girls of low socio-economic status in an urban (n=576) and a rural area (n=339). Their general nutritional status (anthropometry), haemoglobin concentration, iron status, (erythrocyte protoporphyrin, serum iron and total iron binding capacity and serum ferritin concentration) and vitamin A status (serum vitamin A concentration and conjunctival impression cytology) were assessed.
Twenty percent of the subjects studied had low body mass index values (<fifth percentile) for each age group. The prevalence of anaemia was 18.0%. There was no significant difference in prevalence between girls in the urban area and those in the rural area. Depleted iron stores (serum ferritin<12ug/L) were noted in 22.5% of subjects, while a further 28.7% had marginal iron stores. The urban group had a significantly lower mean percentage transferrin saturation (p<0.05) and mean serum ferritin concentration (p<0.001) than the rural group, indicating that iron deficiency was a greater problem in the urban area than in the rural area. The prevalence of vitamin A deficiency as indicated by low serum vitamin A concentration (<20ug/dL) and abormal or borderline conjunctival impression cytology (CIC) was 21.1% and 16.0% respectively. There was no significant difference in vitamin A status between urban and rural subjects, but, 12 subjects (2.5%) in the urban area and one subject (0.35%) in the rural area had very low serum vitamin A concentrations.
It is noteworthy that subjects with abnormal or borderline conjunctival impressions in the urban area had significantly lower serum vitamin A levels than those with normal impressions. Although CIC is a less sensitive indicator of vitamin A status than serum vitamin A concentration there was an association between serum vitamin A concentration and occurrence of borderline or abnormal conjunctival impressions. CIC is a useful field test to assess vitamin A status of a population, specially when HPLC facilities are not available.
Our results suggest that although the prevalence of anaemia was low in both areas, the prevalence of iron deficiency was higher in the urban area. This difference could be due to reduced access to home grown foods and unsatisfactory living conditions in the urban area. Serum ferritin levels should be estimated in population surveys, as measurement of haemoglobin alone underestimates the problem of iron deficiency.