TRENDS AND MORTALITY EFFECTS OF VITAMIN A DEFICIENCY IN CHILDREN IN 138 LOW-INCOME AND MIDDLE-INCOME COUNTRIES BETWEEN 1991 AND 2013: A POOLED ANALYSIS OF POPULATION-BASED SURVEYS.

Wednesday, 9th of September 2015

TRENDS AND MORTALITY EFFECTS OF VITAMIN A DEFICIENCY IN CHILDREN IN 138 LOW-INCOME AND MIDDLE-INCOME COUNTRIES BETWEEN 1991 AND 2013: A POOLED ANALYSIS OF POPULATION-BASED SURVEYS.

Full article Website; http://www.ncbi.nlm.nih.gov/pubmed/26275329

 

Stevens GA1, Bennett JE2, Hennocq Q2, Lu Y3, De-Regil LM4, Rogers L5, Danaei G6, Li G2, White RA7, Flaxman SR8, Oehrle SP9, Finucane MM10, Guerrero R11, Bhutta ZA12, Then-Paulino A13, Fawzi W14, Black RE15, Ezzati M16.

Author information

1Department of Health Statistics and Information Systems, World Health Organization, Geneva, Switzerland.

2MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK.

3Department of Global Health and Population, Harvard T H Chan School of Public Health, Boston, MA, USA.

4Micronutrient Initiative, Ottawa, Ontario, Canada.

5Department of Nutrition for Health and Development, World Health Organization, Geneva, Switzerland.

6Department of Global Health and Population, Harvard T H Chan School of Public Health, Boston, MA, USA; Department of Epidemiology, Harvard T H Chan School of Public Health, Boston, MA, USA.

7Department of Infectious Disease Epidemiology, Division of Infectious Disease Control and Department of Health Statistics, Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway.

8School of Computer Science & Heinz College, Carnegie Mellon University, Pittsburgh, PA, USA.

9Independent Consultant, Geneva, Switzerland.

10Mathematica Policy Research, Cambridge, MA, USA.

11PROESA-Research Center for Social Protection and Health Economics, Universidad Icesi, Cali, Colombia.

12Center of Excellence in Women and Child Health, Aga Khan University, Karachi, Pakistan; Centre for Global Child Health, Hospital for Sick Children, Toronto, Ontario, Canada.

13Universidad Autónoma de Santo Domingo, Santo Domingo, Dominican Republic.

14Department of Global Health and Population, Harvard T H Chan School of Public Health, Boston, MA, USA; Department of Epidemiology, Harvard T H Chan School of Public Health, Boston, MA, USA; Department of Nutrition, Harvard School of Public Health, Boston, MA, USA.

15Johns Hopkins University, Bloomberg School of Public Health, Baltimore, MD, USA.

16MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK. Electronic address: majid.ezzati@imperial.ac.uk.

Abstract

BACKGROUND:

Vitamin A deficiency is a risk factor for blindness and for mortality from measles and diarrhoea in children aged 6-59 months. We aimed to estimate trends in the prevalence of vitamin A deficiency between 1991 and 2013 and its mortality burden in low-income and middle-income countries.

METHODS:

We collated 134 population-representative data sources from 83 countries with measured serum retinol concentration data. We used a Bayesian hierarchical model to estimate the prevalence of vitamin A deficiency, defined as a serum retinol concentration lower than 0·70 μmol/L. We estimated the relative risks (RRs) for the effects of vitamin A deficiency on mortality from measles and diarrhoea by pooling effect sizes from randomised trials of vitamin A supplementation. We used information about prevalences of deficiency, RRs, and number of cause-specific child deaths to estimate deaths attributable to vitamin A deficiency. All analyses included a systematic quantification of uncertainty.

FINDINGS:

In 1991, 39% (95% credible interval 27-52) of children aged 6-59 months in low-income and middle-income countries were vitamin A deficient. In 2013, the prevalence of deficiency was 29% (17-42; posterior probability [PP] of being a true decline=0·81). Vitamin A deficiency significantly declined in east and southeast Asia and Oceania from 42% (19-70) to 6% (1-16; PP>0·99); a decline in Latin America and the Caribbean from 21% (11-33) to 11% (4-23; PP=0·89) also occurred. In 2013, the prevalence of deficiency was highest in sub-Saharan Africa (48%; 25-75) and south Asia (44%; 13-79). 94 500 (54 200-146 800) deaths from diarrhoea and 11 200 (4300-20 500) deaths from measles were attributable to vitamin A deficiency in 2013, which accounted for 1·7% (1·0-2·6) of all deaths in children younger than 5 years in low-income and middle-income countries. More than 95% of these deaths occurred in sub-Saharan Africa and south Asia.

INTERPRETATION:

Vitamin A deficiency remains prevalent in south Asia and sub-Saharan Africa. Deaths attributable to this deficiency have decreased over time worldwide, and have been almost eliminated in regions other than south Asia and sub-Saharan Africa. This new evidence for both prevalence and absolute burden of vitamin A deficiency should be used to reconsider, and possibly revise, the list of priority countries for high-dose vitamin A supplementation such that a countrys priority status takes into account both the prevalence of deficiency and the expected mortality benefits of supplementation.