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Large-dose vitamin A capsules prevent blindness, child mortality in developing world
Vitamin A intervention programs have helped prevent blindness and death in an estimated half million children annually.
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Vitamin A deficiency is a widespread problem in the developing world, resulting in blindness and death in children, according to a physician.
“There are probably 3 million children and pregnant women who develop some form of xerophthalmia every year,” Alfred Sommer, MD, said at the American Ophthalmological Society meeting. “Half a million will go blind, and 1 to 2 million deaths [occur each] year.”
As vitamin A deficiency gets more severe, systemic consequences occur.
“The ocular signs, which we thought were the first signs of mild deficiency such as night blindness, are actually late signs, after there has already been a dramatic increase in mortality,” Sommer said.
Retinol, one form of vitamin A, is an essential element in rhodopsin. Bright light exposure results in immediate photobleaching of the pigment, which takes an estimated 45 minutes to fully regenerate.
“If you’re bleached because of exposure to bright light, then it’s difficult to regenerate rhodopsin if you’re vitamin A deficient,” Sommer said. “Children would sit in their huts at night, unable to find their food, and couldn’t walk around their village.”
Prevalence
Sommer discussed the results of a recent study on blinding malnutrition which showed how ocular manifestations that lead to blindness were preventable by one large dose of vitamin A every 6 months. The study was published in the Lancet.
“We were able to document that there were 63,000 new cases of corneal ulcerations in Indonesia annually,” Sommer said. “We can estimate that there are roughly 500,000 new cases of corneal ulcerations each year in Asia, and that a 2-cent capsule of vitamin A twice a year would prevent all [of] that.”
Unfortunately, this problem was not enough to change global policy, he said.
Mortality and global policy
Sommer said the Ministry of Health would allow $1 to $2 a year to be spent per child for survival, which was to be designated for vaccinations.
“They really didn’t want to take money away from child survival just because some children are going to go blind,” Sommer said. “That’s when the whole issue changed.”
A child with severe vitamin A deficiency, which leads to keratomalacia, has a 95% chance of dying.
“There is no question that a child with severe vitamin A deficiency and keratomalacia is likely to die, and that’s why you don’t see them when you do prevalence surveys of blindness because those who have gone blind have largely died,” Sommer said.
Children with night blindness had three times the rate of mortality, children with Bitot’s spots had six times the rate of mortality, and those with both night blindness and Bitot’s spots had nine times the rate of mortality than children with normal eyes, he said.
To prove that the association between vitamin A deficiency and increased mortality was causal, a large randomized trial was conducted.
The trial included 22,000 children from 450 villages who were randomized to receive a vitamin A capsule at 1 month and again at 7 months compared with those who received the placebo. There was a 35% reduction in mortality in the vitamin A villages compared with those in the non-vitamin A villages. All children received vitamin A after conclusion of the study, which was published in the Lancet.
Signs and symptoms
Parents and guardians of the children who died were interviewed for signs and symptoms, which largely included diarrhea and measles. Children who received the vitamin A were 50% less likely to die from measles or diarrhea.
“I went off to Africa and visited with a bunch of different hospitals where children had measles and where corneal blindness associated with measles was very common,” Sommer said.
Sommer set up a study to determine the cause of blindness in children who contracted measles in Africa. The results showed that classical vitamin A deficiency was responsible for at least 50% of the corneal ulcers and 100% of blindness.
“We asked the obvious question,” he said. “If all these kids are going blind from [a] vitamin A deficiency related to measles, then maybe the very high death rates that are associated with measles in Africa are also due to vitamin A deficiency.”
Another randomized trial was conducted among children who had severe measles; those treated with vitamin A had half the case fatality as those receiving routine treatment.
“This is actually treating kids with severe vitamin A deficiency [who] would otherwise die within a few days,” Sommer said. The study was published in the British Medical Journal.
Policy change
The three published papers rapidly led to a policy change by the World Health Organization and UNICEF that entitled all children inflicted with measles to receive vitamin A.
Sommer said that vitamin A is considered by the World Bank as among the least-expensive health intervention and the most cost-effective means of increasing child survival.
“UNICEF has taken this on as a major issue,” he said. “They have programs in 70 different countries and give away over half a billion large doses of vitamin A capsules. By their estimate, half a million children every year do not die or go blind because of their intervention programs.” – by Christi Fox
References:
Barclay AJ, et al. Br Med J (Clin Res Ed). 1987;294(6,567):294-296.
Sommer A, et al. Lancet. 1986; 1(8491):1169-1173.
Sommer A, et al. Lancet. 1981;doi:10.1016/S0140-6736(81)92581-2.
Stuart JA, Birge RR. Characterization of the primary photochemical events in bacteriorhodopsin and rhodopsin. In: Lee AG, ed. Rhodopsin and G-Protein Linked Receptors, Part A. Vol 2. Greenwich, Conn: JAI Press; 1996:33-140.
For more information:
Alfred Sommer, MD, can be reached at Johns Hopkins University School of Hygiene and Public Health, 615 N. Wolfe Street, Suite E6527, Baltimore, MD 21205, U.S.A.; +1-410-502-4167; email: asommer@jhsph.edu.
Disclosure: Sommer has equity/stock options in Becton Dickinson and T. Rowe Price.