A prevalence study of vitamin A deficiency and xerophthalmia in northeastern Thailand

An epidemiologic survey of the prevalence of xerophthalmia and vitamin A deficiency was conducted in May and June 1985 in a multistage random sample of 1,772 children 1-8 years of age from 16 rural villages and the capital city of the Sakon Nakhon province in northeastern Thailand. Data of clinical eye examinations were available for 92% (n = 903) of the eligible children aged 1-5 years (n = 982); history of night blindness was obtained from a reliable source from 93% (n = 1,644) of the whole sample; and biochemical data were available for 60% (1,060) of the children examined. The distribution of clinical signs of xerophthalmia and serum retinol levels differed between the rural and urban areas. In the urban area, no signs of xerophthalmia or deficient serum retinol levels were found in the preschool children examined. The prevalence of night blindness in the rural area was 1.3% in children aged 1-5 years (95% confidence interval (Cl) 0.7-1.9); Bitot's spots were seen in 0.4% (95% Cl 0.1-1.0); 12.7% (95% Cl 9.9-15.5) showed deficient serum retinol levels (less than 0.35 mumol/liter). Of the children aged 1-8 years, 9.6% (95% Cl 7.8-11.4) showed deficient serum retinol levels. In the rural area, the prevalence of night blindness, Bitot's spots, and deficient serum retinol levels indicates a problem of public health importance according to World Health Organization criteria.

Impact of massive doses of vitamin A on nutritional blindness in Bangladesh

Impact of 6-monthly massive dosings of preschool-age children with oral vitamin A (VAC: 200,000 IU of oil soluble retinyl palmitate with 40 IU vitamin E) was evaluated in Bangladesh. In 100 sites, 11,889 households were visited and eyes of 22,335 children aged 3-71 mo were examined. About half the rural target population and less than 20% urban slum population were being reached. Risk of night blindness was halved for children reportedly given VAC, although 2.5% of the reportedly protected population were still night blind. There was no significant reduction in prevalence of Bitot's spot. Risk of corneal ulcers or keratomalacia (X3A/B) was 2.7 times higher in children not given VAC. Based on reported coverage, efficacy of protection against potentially blinding corneal lesions was 63%. For maximum impact on eye lesions, massive dosing with vitamin A at ideally less than 6-monthly intervals needs to be combined with other nutrition and health interventions.

Congenital stationary night blindness

Congenital stationary night blindness (CSNB) seems to be a very rare condition in Scandinavia. From Denmark a 7-generation family with the dominant form was published in 1909, and one family with the X-linked recessive form was reported from Norway. On going through the files of the National Eye Clinic for Visually Impaired, 7 patients were found (1 dominant, 4 X-linked recessive, 1 simplex case and 1 autosomal recessive). Including anamnestic information on relatives, 17 patients had a diagnosis of CSNB. The clinical findings in these cases are reported with stress on alteration in ERG, dark adaptation and the optic discs. The loss of oscillatory potentials in a carrier of CSNB is described. The provisional findings seem to indicate that 3 genetic variants are present in the Danish population. The real prevalence is estimated considerably higher than 17 out of 5 million.

Comparison of riboflavin, vitamin A, and zinc status of Chinese populations at high and low risk for esophageal cancer

In two surveys in The Peoples Republic of China, blood samples were collected for nutritional studies in two counties where the risks of esophageal cancer are very different. The first survey was done in May 1980 in Linxian County (Henan Province) where the risk of esophageal cancer is very high. Blood samples were obtained from 111 persons (58 men, 53 women) who were selected randomly from 528 subjects that underwent endoscopical examination. The second survey was done in May 1981 in Jiaoxian County (Shandong Province) where the risk of esophageal cancer is reported to be relatively low. Blood samples were obtained from 120 persons (66 men, 54 women) who were selected randomly from 252 subjects that had also had undergone endoscopy. The blood samples were used to measure the nutritional status of riboflavin (erythrocyte glutathione reductase activation coefficient), vitamin A (retinol and carotene concentrations), and zinc (plasma and hair zinc concentrations). Only riboflavin status was significantly different in the two communities. The distribution of erythrocyte glutathione reductase activation coefficient values suggested that riboflavin status was much better in the low-risk community. Also in May 1981, a few more blood samples were obtained from some of the participants of the previous year's study in Linxian. A slight improvement in riboflavin and zinc status was detected. We considered the possibility that these changes may have been linked to the socioeconomic changes currently taking place in rural areas. Data were also collected from food allocation records in 15 production brigades in Linxian and 13 production brigades in Jiaoxian in the same years. The records used represented the food consumption of 3,491 and 2,552 persons, respectively, and were used to calculate daily food and nutrient intakes in the two communities. Dietary analyses highlighted the vegetarian nature of the diet, the low consumption of riboflavin, and the virtual dependence on carotene for vitamin A. Both communities consumed very little in the way of animal products or fruit, but intake of these items was higher in Jiaoxian.

Xerophthalmia among Nepalese children

A nationwide sample survey was conducted between July 1980 and June 1981 to determine the prevalence of xerophthalmia among Nepalese children. Population proportionate random samples were drawn from the 12 geopolitical subdivisions of the country by employing multistage sampling technique. The survey population was defined as the child population of rural Nepal between the ages of 0 and 14 years. The per cent prevalence of xerophthalmia in Nepal was 1.65 for Bitot's spots, 0.02 for corneal ulcer, and 0.03 for corneal scar. While cases of Bitot's spots were more prevalent in the plains of Nepal, followed by the mountains and the hills, the reverse was true for corneal lesions. Vitamin A deficiency was found to be responsible for one-third of acquired bilateral blindness in preschool children. All corneal cases in the study were accompanied by diarrhea and malnutrition, indicating xerophthalmia to be symptomatic of the whole spectrum of malnutrition.

Nutritional ocular diseases and their association with diarrhoea in Matlab, Bangladesh

The prevalence of visual defects, especially from causes associated with nutritional deficiencies, and their relation to diarrhoea in rural Bangladesh have been studied. A trained physician and a team of health workers examined visual defects in 149 villages, with a total population of 182 976. According to WHO classification, night blindness (XN) was found in only 0.03 persons/1000 population and 0.04 were found to have conjunctival xerosis (XIA) and Bitot's spot (XIB). Corneal xerosis (X2, X3A, X3B) also was found in 0.04 persons/1000. Night blindness combined with conjunctival xerosis and Bitot's spot (XN + XIA + XIB) was present in 1.69 persons/1000 and all combined stages of active xerophthalmia were seen in 0.06 persons/1000. Xerophthalmia prevailed up to age 19 years. Males had a significantly higher (2.9) incidence/1000 than did females (1.2). The total rate of keratomalacial scar for all ages was 0.31 persons/1000, while corneal opacity from other causes was seen in 2.25 persons/1000 population. More than 2.06 persons/1000 had ocular manifestations of one or more vitamin A deficiencies, while 4.47 persons/1000 had other ocular diseases, except for cataracts. Only 12.0% of all the corneal scars (XS) were due to keratomalacia. History of night blindness is a good indicator of vitamin A deficiency. In 96% of cases, night blindness was associated with conjunctival xerosis and Bitot's spot (XN + XIA + XIB). The onset of approximately 86% of cases of corneal xerosis (X2, X3A, X3B) and night blindness associated with conjunctival xerosis and Bitot's spot (XN + XIA + XIB) was related to diarrhoea.

Interactions of community nutritional status and xerophthalmia in Indonesia

In order to determine which community level factors best explain the variation in the prevalence of xerophthalmia, an analysis was done on risk factors of xerophthalmia from the Indonesian Nutritional Blindness Study (1976 to 1979). Because of the common belief that xerophthalmia is closely linked to malnutrition, and the fact that within the study itself, it was demonstrated that children with xerophthalmia had a much higher prevalence of malnutrition than normal children, the relationship between the prevalence of malnutrition and the prevalence of xerophthalmia was explored. Using two different statistical approaches the prevalence of malnutrition within a community could not be demonstrated to be a good predictor of the prevalence of xerophthalmia within that community.

Mortality associated with mild, untreated xerophthalmia

The high mortality rate among children with severe corneal xerophthalmia is well recognized. The present study investigates, for the first time, mortality among the very much larger number of otherwise healthy free-living children with mild xerophthalmia (night blindness and Bitot's spots). An average of 3481 children (under 6 years of age) living in six Indonesian villages were reexamined by an ophthalmologist, pediatrician, and nutritionist every 3 months for 18 months. The overall prevalence of mild xerophthalmia was 4.9%. During the 18 months of observation, 132 children died. Of these, 24 had mild xerophthalmia and 108 had normal eyes at the 3-monthly examination preceding their death. Mortality rates were calculated for each 3-month interval by classifying all children by their ocular status at the start of the interval, and then dividing the number of deaths within the interval by the number of children of the same ocular status followed up for that interval. Mortality rates for the six 3-month intervals were then added together, and the results expressed as deaths per 1000 "child-intervals" of follow-up. Overall mortality rates for children with mild xerophthalmia and for children with normal eyes were 23.3 and 5.3, respectively, a ratio of 4 to 1. Excess mortality among the mildly xerophthalmic children increased with the severity of their xerophthalmia. Mortality rates for children with night blindness, with Bitot's spots, and with the two conditions concurrently were 2.7, 6.6, and 8.6 times the mortality rate of non-xerophthalmic children. This direct, almost linear relation between mortality and the severity of mild xerophthalmia was still present after standardizing for age and for the presence or absence of respiratory infection and protein-energy malnutrition. In the population studied, 16% of all deaths in children 1 to 6 years of age were directly related to vitamin A deficiency identified by the presence of mild xerophthalmia. These results suggest: that the existence of mild vitamin A deficiency in a community justifies initiation of vigorous intervention measures to reduce mortality, as much as to prevent the rarer cases of blindness; that night blindness and Bitot's spots should be accorded the same respect as is low "weight for height" in identifying those children in urgent need of medical attention; that ocular criteria used for determining the existence and severity of a vitamin A problem be reevaluated; and that the ophthalmic community, which has long been responsible for managing xerophthalmia, must now re-alert nutritionists, pediatricians, and public health workers to the serious systemic consequences accompanying even mild

History of nightblindness: a simple tool for xerophthalmia screening

Among 5925 preschool-age children examined in a house to house rural field study, X1B (Bitot's spot with xerosis) and/or an history of nightblindness (XN) was presented in 325. Mean serum vitamin A levels among those with isolated XN (13.9 microgram/dl), isolated X1B (13.4 micrograms/dl), and coexistent XN/X1B (12.1 microgram/dl) were similar, and significantly below that of normal age/sex/neighborhood matched controls (17.6, 17.1, and 18.3 microgram/dl, respectively). The mean serum vitamin A level of the matched controls was significantly below that of normal, randomly sampled children from the study population as a whole (20.6 microgarm/dl). As independent screening criteria, disregarding the presence of absence of other signs, twice as many children had a history of XN as had X1B (84 and 41% of all clinically abnormal children, respectively). Of randomly sampled children 55% but only 15% of cases of XN had serum vitamin A levels above 20 microgram/dl. Of children with a history of nightblindness 97% had impaired scotopic vision on objective testing, but the mean serum vitamin A levels among test positives and negatives were identical. These results suggest a properly eleicited history of nightblindness can be almost as specific and far more sensitive an index of vitamin A deficiency and early xerophthalmia than the prescence of Bitot's spots (X1B), and that vitamin A deficiency is a clustered, neighborhood phenomenon rather than an isolated, sporadic occurrence.

Vitamin A status of children in Sri Lanka

A representative country-wide rural nutrition status survey determined the extent and distribution of vitamin A deficiency in Sri Lanka in children 6 through 71 months of age. Trained paramedical personnel recorded the presence or absence of selected ophthalmological signs and symptoms associated with vitamin A deficiency in 13,450 children. The results of the country-wide clinical survey indicate that a vitamin A deficiency problem of public health importance may exist in two of 15 health areas. Serum vitamin A levels were determined on 346 survey children from two of 15 health areas and compared with clinical findings for these areas. The lowest mean serum vitamin A, 26.3 microgram/100 ml, occurred in children with clinical eye findings. A high prevalence of clinical eye findings, 34%, and the low mean serum vitamin A value, 28.2 microgram/100 ml, were found in the group of chronically undernourished children--children who are less than 90% of their expected height for age. The survey results enabled planned redirection of the distribution of vitamin A capsules to preschool children in Sri Lanka to areas shown to have the highest prevalences of ophthalmological signs and symptoms and/or the highest prevalence of chronic undernutrition.

The effect of massive doses of vitamin A on the signs of vitamin A deficiency in preschool children

Marked seasonal variation in the prevalence of signs of vitamin A deficiency was found in the 2nd year of a continuing study of children age 0 to 4-1/2 years in a village in West Bengal, confirming results of a previous 18-month study. Administration of 200,000 IU of vitamin A every 4 months completely eliminated night blindness and prevented the development of new cases of Bitot's spot in a statistically significant number of children. The effectiveness of massive doses of vitamin A, administered at intervals of 4 months, as a short-term measure to fight the problem, was confirmed in this village. The study yielded additional evidence of the complex etiology of Bitot's spot, since alternate day dose of vitamin A in addition to massive therapy failed to eliminate these spots.

Xerophthalmia and blindness in Northeast Brazil

Dietary and biochemical data have indicated that hypovitaminosis A is a public health problem in Northeast Brazil. However, there are few reports regarding clinical signs of hypovitaminosis A. Therefore, an epidemiological study was designed to study this problem. The study as done was primarily a review of hospital records of xerophthalmia in each state with attention paid to other nutrition factors. It was found that xerophthalmia is a problem in Northeast Brazil and a cause of blindness in certain areas. However, the number varied greatly from some states to others. Around 1,000 preschool-age children were recorded as blind from vitamin A deficiency in a 1-year period. It was also noted that the peak incidence of xerophthalmia and blindness was around 1 year of age. The government of Brazil is taking urgent measures to combat this deficiency with such measures as the supplementation of sugar with vitamin A and the distribution of massive doses of vitamin A.

A simple method to evaluate the massive dose vitamin A prophylaxis program in preschool children

A massive dose vitamin A prophylaxis program is currently in operation in several States of India. Evaluation of this program on a large scale has so far been difficult due to lack of baseline data on the prevalence of vitamin A deficiency in children. In this study, a simple evaluation method which makes use of the linear relationship that exists between age on one hand and prevalence of ocular signs of vitamin A deficiency (Bitot's spots) on the other is described. Regression coefficients between age and prevalence of vitamin A deficiency of areas not covered by the program (control areas) were found to be significantly different both from zero and from regression coefficients of regularly covered areas (experimental areas). Also, all regression lines of control areas were found to be above the regression zone of experimental areas. These differences between the experimental and control areas which were significant, indicate the impact of the program in areas where the program is in operation. The regression coefficient calculated for one area where the program was discontinued after some time was found to be significantly different from zero, also it was different from the regression zone of the experimental areas. However, the regression coefficient of the discontinued area was found to be significantly different from the experimental areas only at 10% level, indicating a lesser degree of efficiency of the program in this area as compared to regularly fed areas. It is, therefore, suggested that evaluation of the massive dose prophylaxis program be done against the null hypothesis beta = 0.0065--the regression coefficient achievable under field conditions.