Mohammad M Rahman, Sten H Vermund, Mohammad A Wahed, George J Fuchs, Abdullah H Baqui, Jose O Alvarez et al
Rahman M M, Vermund S H, Wahed M A, Fuchs G J, Baqui A H, Alvarez J O et al.
Simultaneous zinc and vitamin A supplementation in Bangladeshi children: randomised double blind controlled trial
BMJ 2001; 323 :314
doi:10.1136/bmj.323.7308.314
Vitamin A and Zinc Supplementation
Editor,
The study by Rahman et al addresses a worthwhile aspect of vitamin A
and zinc supplementation.(1) However, they have made certain conclusions
relating to diarrhoea that are not fully supported by the evidence they
present. Although giving zinc and vitamin A may well have a beneficial
effect, in several instances the confidence intervals of the rate ratio
span 1 which implies the results are not significant. We would like to
suggest that only cautious inferences should be drawn from this data.
Presenting figures for individual study groups would make
interpreting the results easier. Including the combined supplement groups
in the data for zinc and vitamin A obscures the independent effects of
these interventions. This may have increased the power of the study but a
comparison of zinc or vitamin A alone with the combination would have been
valuable.
We are confused with the values obtained for “person year risk” in
tables 2 and 3; is this a typographical error? “Person day risk” would be
more consistent with the number of subjects and length of follow up.
We agree with Rahman et al about the public health potential of
simultaneous zinc and vitamin A supplementation. However, further
research, possibly with a larger sample population, is required to
establish a working protocol.
Dominic Lea, Emma Fletcher, Caroline Angit, Noor Abdullah, Neil
Greening
(Stage 3 Medical Students)
Department of Epidemiology and Public Health,
The Medical School,
University of Newcastle upon Tyne,
Newcastle NE2 4HH
1 Rahman MM, Vermund SH, Wahed MA, Fuchs GJ, Baqui AH, Alvarez JO.
Simultaneous zinc and vitamin A supplementation in Bangladeshi children:
randomised double blind controlled trial. BMJ 2001; 323: 314-318
Competing interests: No competing interests