Current status of vitamin A deficiency and the National Vitamin A Control Program in Nepal: results of the 1998 National Micronutrient Status Survey.

The overall objective of the Nepal Micronutrient Status Survey (NMSS) was to assess the distribution and severity of micronutrient malnutrition, and to measure the progress achieved by different interventions. Data presented in this paper concern the prevalence of vitamin A deficiency (VAD) and the outreach and coverage of the National Vitamin A Supplementation activity. A multi-stage cluster sample design was employed that provided statistically representative data for each of thirteen eco-development strata (because of low population density, the West Mountains, Mid-west Mountains and Far-west Mountains were combined into a single stratum). The design allowed for aggregate estimates to be made at the national and ecological zone level. The survey showed a significant improvement in the status of clinical vitamin A deficiency in Nepal. The prevalence of both Bitot's spots and night-blindness among preschool children decreased from levels observed in surveys conducted in the previous twenty years. However, the prevalence of night-blindness was found to be 5% among women, and over 1% among school-aged children, which indicates that the entire population is vulnerable to VAD. These observations support findings from other surveys that have noted a high prevalence of maternal night-blindness in Nepal. Biochemical data collected as part of the survey indicated a high prevalence of low serum retinol (< 0.70 mumol/l), particularly among preschool children. Almost one of every three children (32.3%) and one of every six women (16.6%) had low serum retinol values. Low serum retinol among preschool children was associated with young age (6-11 months), rural location, wasting, presence of night-blindness and Bitot's spots, and residence in the Terai or Mountains. Similarly, sub-clinical VAD in women was associated with age (less than 20 years), pregnancy, the presence of night-blindness and residence in the Terai or Mountains. In the 42 districts covered by the National Vitamin A Programme (NVAP), more than 87% of preschool children were reached with vitamin A capsules. In addition to this, the National Immunisation Day (NID) provided oral polio vaccine drops to an estimated 95.7% of children 12-59 months. Awareness of the importance of vitamin A was, however, much higher in the NVAP districts than in non-programme districts. As would be expected, clinical VAD was most prevalent among children who had not received vitamin A during the most recent vitamin A capsule distribution. Indeed, the data show that vitamin A capsule receipt among children conferred a 59% protective effect for night-blindness and a 51% effect for Bitot's spots. These results point to significant progress having been achieved by the NVAP and NID capsule distribution activities.