The Story of Vitamin A
The landmark work on vitamin A by Alfred Sommer, MD, MHS, dean emeritus of the School of Public Health, has been credited with saving the lives of millions of children around the world.
In 1976, Dr. Sommer, who had just finished his residency in ophthalmology at Johns Hopkins' Wilmer Institute, began a series of complex intervention trials in Indonesia that revealed that even mild vitamin A deficiency (VAD) dramatically increases childhood mortality rates, primarily because VAD reduces resistance to infectious diseases such as measles and diarrhea.
Too Good to Be True?
In fact, the survival of children randomized to vitamin A was so much greater than that of children not receiving vitamin A, that many scientists considered the study flawed, and the results too good to be true.
Before Sommer undertook these studies, scientists knew that VAD could lead to blindness; they were unaware, however, that a vitamin A-deficient child faces a 25 percent greater risk of dying from a range of childhood ailments such as measles, malaria, or diarrhea. As a result of his research, night blindness is today viewed not as a mild, early sign of VAD, but as evidence of late, severe deficiency.
Proving The Link
To definitively prove the link between even mild VAD and pediatric mortality, Sommer and his colleagues ran a number of large-scale, community-based, randomized trials from 1983 through 1992. Keith West, PhD, professor, International Health and Ophthalmology, Joanne Katz, ScD, professor, International Health, and James Tielch, PhD, professor, International Health, among others still at the School, all played major roles.
Their work showed that ensuring adequate vitamin A intake can mitigate the effects of common diseases such as measles and diarrhea; reduce child mortality in at-risk populations by 23 to 34 percent to avert up to one million deaths a year; and prevent as many as 400,000 cases of childhood blindness each year.
By 1992 the World Health Organization (WHO), UNICEF, the Food and Agriculture Organization of the United Nations, and the Convention on the Rights of Children had all declared the control of VAD a global goal.
Finding The Best Treatment
Sommer and his team then set themselves the task of demonstrating that oral, high-dose, vitamin A supplementation—a treatment tailor-made for developing countries since it does not require a sterile injectable preparation—could effectively, quickly, and cheaply treat the debilitating consequences of VAD. As a result, the World Development Report (World Bank) declared vitamin A supplementation one of the most cost-effective of all health interventions.
Three Cents = Big Returns
With vitamin A capsules costing only 2 to 3 cents each, increasing vitamin A intake is now recognized as one of the most cost-effective public health interventions for child survival. The full cost of delivering the capsules to children ages six months to five years at six-month intervals is about 50 cents per child per year.
Moreover, a World Bank study estimates that for every dollar invested in supplementation, more than $100 would be returned in increased productivity associated with reduced childhood mortality, lower health care costs, and improved worker performance.
Delivering the Goods
In 1995, out of 72 countries where VAD was prevalent, only six had adequate vitamin A supplementation rates. In 1998, the year WHO and its major partners launched the Vitamin A Global Initiative, vitamin A supplements were delivered through national immunization days to more than 12 million vitamin A-deficient children in 40 countries.
Today, thanks in large part to Dr. Sommer's work, more than 40 countries are reaching the large majority of their children with at least one high-dose vitamin A supplement a year. UNICEF estimates that between 1998 and 2000 as many as 1 million child deaths may have been prevented because of this global vitamin A supplementation program.
The Job is Not Done
Much work, however, remains to be done. Worldwide, more than 100 million young children and many of their mothers are vitamin A-deficient. Within these groups, approximately 14 million suffer from clinical eye problems (night blindness and xerophthalmia) and as many as 3 million children die annually as a result of VAD.
An estimated 250,000 to 500,000 vitamin A-deficient children become blind every year, half of them dying within 12 months of losing their sight. And nearly 600,000 women die from childbirth-related causes each year, the vast majority of them from complications that could be reduced through better nutrition, including provision of vitamin A.
The Latest Research: Good News for Mothers
The most recent studies by Dr. Sommer and his colleagues have shown that supplementing women of childbearing age with vitamin A or beta-carotene reduces maternal mortality by an average of 45 percent, by improving their resistance to infection and reducing anemia.