Writing in the British Medical Journal, researchers from the University of Oxford in England and Aga Khan University Hospital in Pakistan report that vital supplements of vitamin A could also reduce the risk of mortality associated with diarrhea by 28%.
“Based on these results, we strongly recommend vitamin A supplementation for children aged under 5 in areas at risk of vitamin A deficiency. Despite widespread efforts, vitamin A programmes do not reach all children who could benefit,” wrote the authors, led by Oxford’s Evan Mayo-Wilson.
“Universal distribution could be achieved in several ways. Vitamin A supplementation can be provided when children receive other services like vaccinations, and it can be provided on a large scale,” they noted.
The meta-analysis echoes a review published in the prestigious Cochrane Database of Systematic Reviews, which concluded that vitamin A supplements may save one million lives per year.
The size of the issue
Vitamin A deficiency (VAD) is a public health problem in more than 50 per cent of all countries, especially in Africa and South-East Asia, according to the World Health Organisation, and causes blindness in up to 500,000 children each year. The World Bank has declared vitamin A supplementation as one of the most cost-effective interventions of all time.
The study was welcomed by Howard Schiffer, president of Vitamin Angels as confirming what the charity already knew: “The evidence for the past forty years is unequivocal; vitamin A saves lives!
“Recently, World Health Organization gave a strong recommendation (their strongest) to support vitamin A interventions. It makes sense - in at-risk populations just two doses of vitamin A can reduce child mortality from all causes by 24%. The only amazing thing is that everyone does not know about vitamin A.”
Important and helpful
The meta-analysis was also welcomed by the Micronutrient Initiative, an international organization working to eliminate vitamin and mineral deficiencies, based in Canada. Mark Fryars, VP of program and technical services and Dr Lynnette Neufeld, chief technical adviser, told NutraIngredients-USA that the new meta-analysis was an “important and a helpful addition to the literature”.
In addition to the literature archived at the WHO e-Library of Evidence for Nutrition Actions (eLENA), Fryars and Neufeld said that the recent analysis “uniquely considers interventions in addition to twice yearly mega-doses of vitamin A, and in particular one trial using weekly low dose supplements”.
Study details
The researchers analyzed 43 trials with 215,633 children, and found that 17 trials involving 194,483 children revealed that vitamin A supplementation was associated with a 24% reduction in all cause mortality.
Data also showed a 28% reduction in mortality associated with diarrhea, and reductions in the incidence of measles, diarrhea and vision problems, including night blindness.
“Vitamin A supplementation is associated with large reductions in mortality, morbidity, and vision problems in a range of settings, and these results cannot be explained by bias,” wrote the researchers.
“Until other sources are available, vitamin A supplements should be given to all children at risk of deficiency, particularly in low and middle income countries,” they concluded.
Importance
In an accompanying editorial, Andrew Thorne-Lyman and Wafaie Fawzi from Harvard School of Public Health said the meta-analysis is “unprecedented in its depth and methodological rigour, incorporating a wider number of morbidity and mortality outcomes than previous reviews of preschool vitamin A supplementation.
“This is important because some previous reviews have examined either morbidity or mortality, but not both, leaving questions as to whether inconsistent findings may have resulted from differences in approaches to inclusion and exclusion criteria versus other sources of heterogeneity.”
Thorne-Lyman and Fawzi add that, although the majority of national vitamin A programs supplement children twice a year, the evidence indicates that mortality rates could be reduced even further with more frequent supplementation.
“Lastly, as previous meta-analyses have stated, no more placebo controlled trials of preschool vitamin A supplementation are needed. Instead, effort should focus on finding ways to sustain this important child survival initiative and fine tune it to maximise the number of lives saved.”
Celebration of success
Commenting on the point about frequency of supplementation, the Micronutrient Initiative’s Fryars and Neufeld said it was important to “celebrate the fact that vitamin A supplementation programs for children aged six months to five years with two annual high doses already achieved and managed to maintain very high coverage rates”.
According to UNICEF’s State of the World’s Children report of 2011, coverage by 2009 was estimated to have reached 71% in developing countries overall and 85% in the least developed countries.
“We want to recognize and congratulate the dozens of countries that have been able to achieve these rates, in some cases achieving and maintaining almost universal coverage,” they said.
“This has also been made possible by the collective commitment of the leaders and staff of essential child health programs to integrate the delivery of interventions that target the same age group. This has delivered economies of scale and reduced the burden on the health system that can occur if programs are run separately.
“These integrated packages typically include immunizations, deworming and/or anti-malarial measures, as well as vitamin A supplementation, nutrition and breastfeeding counseling, and screening for acute malnutrition,” added Fryars and Neufeld.
Study: BMJ
2011, 343:d5094, doi: 10.1136/bmj.d5094
“Vitamin A supplements for preventing mortality, illness, and blindness in children aged under 5: systematic review and meta-analysis”
Authors: E. Mayo-Wilson, A. Imdad, K. Herzer, M. Yawar Yakoob, Z.A. Bhutta
Editorial: BMJ
2011, 343, doi:10.1136/bmj.d5294
“Improving child survival through vitamin A supplementation”
Authors: A. Thorne-Lyman, W.W. Fawzi