[Prevalence of vitamin A deficiency in children under six years of age in Tibet, China].

OBJECTIVE: To understand the prevalence of vitamin A deficiency (VAD) among children under six years of age in Tibet, China. METHODS: Totally, 1 257 children under six years of age were selected from two cities, two farming counties, two semi-farming counties and two livestock farming counties with stratified cluster sampling to asses VAD status in Tibet. Family information, children's feeding and disease history in the previous two weeks were collected by questionnaire. Blood specimen was collected from each child and serum was separated for detection of vitamin A concentration with microfluorescent spectrophotometry. RESULTS: Totally, 1 257 children under six years of age were surveyed, with 635 boys, 622 girls, 862 aged over two years, and 98.5% of Tibet nationality. Six cases of night blindness and two cases of xerophthalmia were detected from them, with prevalence of clinical VAD of 0.96%. Eighteen of 1071 mothers with children under six years of age were found suffering from night blindness, accounting for 1.7%. Clinical cases of VAD both in children and mothers came from all four sampling strata. Average serum concentration of vitamin A and prevalence of subclinical VAD (serum vitamin A lower than or equal to 0.70 micromol/L) was 1.15 micromol/L and 5.4% and 1.12 micromol/L and 4.7% in cities and livestock farming counties, respectively, significantly higher than those in farming (1.04 micromol/L and 11.0%) and semi-farming counties (1.05 micromol/L and 12.3%), respectively, as compared to average levels of 1.09 micromol/L and 8.4% in the autonomous region as a whole. Prevalence of subclinical VAD in children under six months and those aged six to eleven months were 22.2% and 13.3%, respectively, significantly higher than those in children aged one year (8.5%), two to three years (5.4%) and four to five years (7.9%), respectively. There was also significant difference in serum level of vitamin A between children at varied ages, but no significant difference both in serum level of vitamin A and prevalence of subclinical VAD between gender was found. CONCLUSIONS: In general, status of VAD in children of Tibet was milder than that at national level. But, moderate subclinical VAD in some areas, such as farming and semi-farming counties, did exist, so vitamin A supplementation aiming to children, especially those under one year of age, in those areas should be urged.

[Survey on vitamin A deficiency in children under-6-years in China].

OBJECTIVE: To understand the prevalence and spatial distribution of vitamin A deficiency (VAD) in China among children at ages under six years. METHODS: About 8,600 children under 6 years of age in 14 cities and 28 counties of 14 provinces were selected with stratified cluster sampling for survey, including interview with questionnaire for their family information and nutritional status. Blood specimens were collected for measuring serum level of VA with fluorescent spectrophotometry in laboratory. RESULTS: Totally, 8,669 children under 6 (2,877 in urban area and 5,792 in rural area) were surveyed in 14 provinces, with 4,629 males and 4,040 females. Eight cases of night blindness and seven cases of xerophthalmia were found among the children at ages of two to five years. Sixty-one mothers of the children in this group were also found suffering from night blindness. All the cases of night blindness and xerophthalmia both in children and mothers were living in rural areas. Based on their serum levels of VA, 11.7% of the all 1 018 children were diagnosed as VAD, with serum VA concentrations below or equal to 0.70 micro mol/L. Prevalence of VAD was 15.0% and 5.8% in rural (23.3% in the poverty-stricken counties) and urban areas, respectively, and 5.8%, 11.5% and 16.8% in the coastal, inland and remote areas, respectively. The average serum level of VA was 1.20 micro mol/L and 0.99 micro mol/L for urban and rural areas, respectively, with a national average of 1.06 micro mol/L. And, babies under six months of age with an average serum levels of VA < or = 0.70 micro mol/L accounted for 33.4%, and those at ages of four to five years with the same level of VA accounted for 8%. There was significant difference in serum levels of VA between ages, but no significant difference between genders. CONCLUSION: VAD did exist in children of China, especially in the remote and poverty-stricken rural areas and VA supplementation is urgently needed for the children in these regions.

Prevalence of subclinical vitamin A deficiency and its affecting factors in 8 669 children of China.

OBJECTIVE: The survey will reveal current status of subclinical vitamin A deficiency (SVAD) and explore its affecting factors in children of China. METHODS: Totally 8 669 children aged under 6 years were randomly selected from 14 provinces for clinical examination, health and dietary questionnaire and serum level of vitamin A measurement with fluorescence method. The cut-off value for SVAD was defined as