Development of screening indicators for ranking areas at risk of vitamin A deficiency in Thailand.

The objective of this study was to develop community based screening indicators for identifying areas at risk of vitamin A deficiency. Three hundred children aged 24-71 months in 12 villages of 3 provinces who were previously identified to have various degrees of vitamin A deficiency were randomly selected to participate in the study. These villages were located in Songkhla, Yala and Narathiwat provinces. Data collection included anthropometric measurements, serum retinol analysis, data on dietary intake, illness, and socioeconomic status. Subsamples of 120 children were taken for Modified Relative Dose Response. Statistics used for data analysis were factor analysis, discriminant analysis and Receiver Operating Characteristic curves. Sensitivity and specificity of the screening indicators were calculated and compared with the rate of vitamin A deficiency at > or = 15 per cent of children with serum retinol < 0.70 micromol/l. Findings revealed that the screening indicators could identify areas at risk of vitamin A deficiency with 83.3 per cent efficiency. Data to be used for identifying areas at risk of vitamin A deficiency included home and land ownership for agriculture, dietary intake of vitamin A, access to social services (maternal education and antenatal care), vaccination, infectious diseases (diarrhoea and upper respiratory tract infection with fever) and nutritional status.