American Journal of Clinical Nutrition, Vol. 70, No. 1, 110,
July 1999
© 1999 American Society for Clinical Nutrition
Improving study design
Harold H Sandstead
University of Texas Medical Branch at Galveston Department of Preventive Medicine and Community Health Ewing Building 700 Harborside Drive Galveston, TX 77555-1109 E-mail: hsandste{at}utmb.edu
Dear Sir:
The recent article by Kikafunda et al (1) prompts me to relate an event that occurred 
30 y ago when Mattie Ray Spivey-Fox, a highly respected basic scientist in nutrition, gently informed a group of clinical investigators that their research design was faulty. Primary human zinc deficiency had been characterized under metabolic ward conditions (2–4). When investigators took the new knowledge to the field, however, they were unable to replicate the observations (5–7). James Halsted organized a meeting to review the problem and Spivey-Fox was one of the attendees. She listened to the presentations and interpretations politely and then proposed a change in research design that provided the subjects with other potentially limiting nutrients. Her proposal was based on the fact that natural conditions seldom result in one deficiency at a time. Implementation of her suggestion resulted in the successful demonstration of improved growth of Iranian schoolboys with zinc repletion (8). The study by Kikafunda et al (1) might have been improved by design changes similar to those suggested by Spivey-Fox.
REFERENCES
-
Kikafunda JK, Walker AF, Allan EF, Tumwine JK. Effect of zinc supplementation on growth and body composition of Ugandan preschool children: a randomized, controlled, intervention trial. Am J Clin Nutr 1998;68:1261–6.[Abstract]
-
Prasad A, Miale A Jr, Farid Z, Sandstead H, Schulert A. Zinc metabolism in patients with syndrome of iron deficiency anemia, hepatosplenomegaly, dwarfism and hypogonadism. J Lab Clin Med 1963;61:537–49.[Medline]
-
Sandstead HH, Prasad AS, Schulert AR, et al. Human zinc deficiency, endocrine manifestations and response to treatment. Am J Clin Nutr 1967;20:422–42.[Abstract]
-
Halsted J, Ronaghy H, Abadi P, et al. Zinc deficiency in man: the Shiraz experiment. Am J Med 1972;53:277–84.[Medline]
-
Ronaghy HA, Caughey JE, Halsted JA. A study of growth in Iranian village children. Am J Clin Nutr 1968;21:488–94.[Abstract]
-
Ronaghy H, Fox MR, Garnsm, et al. Controlled zinc supplementation for malnourished school boys: a pilot experiment. Am J Clin Nutr 1969;22:1279–89.[Abstract]
-
Carter JP, Grivetti LE, Davis JT, et al. Growth and sexual development of adolescent Egyptian village boys. Effects of zinc, iron, and placebo supplements. Am J Clin Nutr 1969;22:59–78.[Abstract]
-
Ronaghy HA, Reinhold JG, Mahloudji M, Ghavami P, Fox MR, Halsted JA. Zinc supplementation of malnourished schoolboys in Iran: increased growth and other effects. Am J Clin Nutr 1974;27: 112–21.[Abstract]
