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Vitamin A defi ciency: slow progress towards elimination
Gretchen Stevens and colleagues’ study1 in The Lancet
Global Health analyses 134 reports from 83 countries
of population-representative data for serum retinol
concentration and shows several trends in vitamin A
defi ciency. First, prevalence is diminishing in a statistically
signifi cant way in east and southeast Asia and Oceania.
Second, Latin America and Caribbean nations might be
making progress. Third, prevalence remains unchanged
in sub-Saharan Africa and south Asia. Stevens and
colleagues’ most interesting conclusion is that this
“evidence for both prevalence and absolute burden of
vitamin A defi ciency should be used to reconsider, and
possibly revise, the list of priority countries for high-dose
vitamin A supplementation”.
However, several caveats need to be considered,
including the use of cross-sectional data, exclusion of
children younger than 6 months, absence of clinical
vitamin A defi ciency assessments, gaps in serum retinol
data for certain populations and for 55 countries, use
of mortality data from randomised controlled trials of
vitamin A supplementation for diarrhoea and malaria
rather than population-level data, the assumption
that all post-neonatal measles deaths occur in children
aged 6–59 months old, and use of serum retinol as the
biomarker of defi ciency.
Nonetheless, we might need to focus on retinol
concentration not mortality to assess and guide
our eff orts to eliminate vitamin A defi ciency, as
recommended by WHO for population-level surveys,
even though this measure can be problematic in
individuals because of the well known eff ects of acute
infl ammation due to infection or injury on serum retinol
concentrations.2 Controlling for acute infl ammation
by including biomarkers for it3 might not be necessary
at the population level, because adequate vitamin A
status might, by itself, diminish infl ammation through
a reduction in the frequency or severity of infections in
these populations.
Despite these limitations, the authors provide
important estimates, with uncertainty distributions,
for the prevalence of vitamin A defi ciency, and a clear
picture of trends from 1991 to 2013. The association
between vitamin A defi ciency and eye pathology and all-
cause mortality is well known, as is the contribution of
vitamin A defi ciency to reduced resistance to infections,
especially diarrhoea and measles, and increased mortality
in children younger than 5 years.4 These benefi ts have
driven the scale-up of vitamin A supplementation
programmes as preventative public health measures
around the world. However, the coverage of these
programmes has not been effi cient in east or southern
Africa (67%) and south Asia (53%).5 Lagging coverage
and continued evidence of vitamin A defi ciency is the
basis for the suggestion by Stevens and colleagues that
future eff orts refocus on these regions. This suggestion
makes sense if we are confi dent that progress elsewhere
would not be compromised as a result.
During the past two decades, mortality from
diarrhoeal disease has substantially decreased and
measles has been eliminated as a public health issue
wherever eff ective immunisation programmes fl ourish.
Continued eff orts to control diarrhoeal disease and
enhance measles vaccine coverage per se suggest
that vitamin A supplementation programmes should
now focus on the reduction of defi ciency rather than
diarrhoea or measles morbidity or mortality as the
outcome.
What then should be done to accelerate progress
towards elimination of vitamin A defi ciency in children?
Initiation of supplementation programmes where
they do not exist and strengthening of programmes
where coverage is poor is step one. However, high-dose
supplementation only provides protection from hypo-
retinolaemia for 2–3 months in children younger than
5 years and favourably shifts the distribution of serum
retinol for less than 2 months,6 indicating that biannual
supplementation is not suffi cient by itself to prevent
vitamin A defi ciency. Improvement of dietary intake of
foods rich in vitamin A (eg, animal products) or beta-
carotene is a more sustainable solution, but high-cost,
access, and cultural dietary practices have restricted
its potential to alleviate vitamin A defi ciency. Other
options have been tested or are under development,
such as fortifi cation of centrally processed foods
(although these might not reach poor populations in
rural areas); addition of vitamin A sprinkles to food in
the home, day-care centres, and schools;7 promotion of
beta-carotene rich foods such as sweet potatoes;8 and
genetically engineered crops with high concentrations
of beta-carotene such as golden rice.9 By addressing
See Articles page e528
Comment
e503
www.thelancet.com/lancetgh Vol 3 September 2015
gaps in vitamin A suffi ciency around the world,
redirecting attention to areas of the world struggling
to make progress while continuing to monitor other
regions through systematic population-representative
sampling of serum retinol, promotion of research into
sustainable dietary solutions including a campaign to
legitimise genetically modifi ed crops high in vitamin A
or precursors, and alignment of all of these eff orts with
Sustainable Development Goal 2 to “end hunger, achieve
food security and improved nutrition and promote
sustainable agriculture”,10 we can not only sustain the
favourable trends described by Stevens and colleagues
but also hasten progress in other parts of the world.
*Davidson H Hamer, Gerald T Keusch
Center for Global Health and Development, Boston University
School of Public Health (BUSPH), Boston, MA 02118, USA (DHH);
Department of Global Health, BUSPH, Boston, MA, USA (DHH);
Section of Infectious Diseases, Department of Medicine, Boston
Medical Center, Boston, MA, USA (DHH, GTK); Tufts University
Friedman School of Nutrition Science and Policy, Boston, MA, USA
(DHH); and National Emerging Infectious Diseases Laboratories,
Boston University School of Medicine, Boston, MA, USA (GTK)
dhamer@bu.edu
We declare no competing interests.
Copyright © Hamer et al. Open Access article distributed under the terms of
CC BY-NC-ND.
1 Stevens GA, Bennett JE, Hennocq Q, et al. Trends and mortality eff ects of
vitamin A defi ciency in children in 138 low-income and middle-income
countries between 1991 and 2013: pooled analysis of population-based
surveys. Lancet Glob Health 2015; 3: e528–36.
2 Thurnham DI, McCabe GP, Northrop-Clewes CA, Nestel P. Eff ects of
subclinical infection on plasma retinol concentrations and assessment of
prevalence of vitamin A defi ciency: meta-analysis. Lancet 2003;
362: 2052–58.
3 Bresnahan KA, Chileshe J, Arscott S, et al. The acute phase response aff ected
traditional measures of micronutrient status in rural Zambian children
during a randomized, controlled feeding trial. J Nutr 2014; 144: 972–78.
4 Mayo-Wilson E, Imdad A, Herzer K, Yakoob MY, Bhutta ZA. Vitamin A
supplements for preventing mortality, illness and blindness in children
aged under 5: systematic review and meta-analysis. Br Med J 2011;
343: 1–19.
5 UNICEF. UNICEF Global Databases. Nutrition: vitamin A supplementation.
October, 2014. http://data.unicef.org/nutrition/vitamin-a (accessed
June 13, 2015).
6 Palmer AC, West KP, Dalmiya N, Schultink W. The use and interpretation of
serum retinol distributions in evaluating the public health impact of
vitamin A programmes. Public Health Nutr 2012; 15: 1201–15.
7 Varma JL, Das S, Sankar RS, Mannar MGV, Levinson FJ, Hamer DH.
Community-level micronutrient fortifi cation of a food supplement in
India: a controlled trial with pre-school children aged 36-66 months.
Am J Clin Nutr 2007; 85: 1127–33.
8 Hotz C, Loechl C, Lubowa A, et al. Introduction of ß-carotene rich orange
sweet potato in rural Uganda resulted in increased vitamin A intakes
among children and women and improved vitamin A status among
children. J Nutr 2012; 142: 1871–80.
9 Tang G, Qin J, Dolnikowski GG, Russell RM, Grusak MA. Golden Rice is an
eff ective source of vitamin A. Am J Clin Nutr 2009; 89: 1776–83.
10 Dubé L, Pingali P, Webb P. Paths of convergence for agriculture, health,
and wealth. Proc Natl Acad Sci U S A 2012; 109: 12294–301.
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