Saudi Journal of Kidney Diseases and Transplantation

: 2020  |  Volume : 31  |  Issue : 3  |  Page : 697--698

Author's reply

Ehsan Valavi1, Majid Aminzadeh2,  
1 Department of Pediatric Nephrology, Chronic Renal Failure Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
2 Division of Pediatric Endocrinology and Metabolism, Hyperlipidemia Research Center, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran

Correspondence Address:
Ehsan Valavi
Department of Pediatric Nephrology, Chronic Renal Failure Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz

How to cite this article:
Valavi E, Aminzadeh M. Author's reply.Saudi J Kidney Dis Transpl 2020;31:697-698

How to cite this URL:
Valavi E, Aminzadeh M. Author's reply. Saudi J Kidney Dis Transpl [serial online] 2020 [cited 2022 May 23 ];31:697-698
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Full Text

To the Editor,

In response to the letter of Professor Al- Mendalawi regarding our research article entitled “Changes in Body Mass Index after Pediatric Renal Transplantation,” it is a challenging issue concerning about necessity of individual growth chart for each population.

First, we thank Tanner and colleagues for their idea and preparing such a great tool for the control and follow-up of children and adolescents during the most dynamic changes in anthropometric indices.

As we know (except in congenital or severe chronic disorders), one single visit and one point on the curve could not be indicative of child health. Instead, having at least two-time examination with a minimum 6-month interval is preferred to 1) calculate growth velocity; and 2) evaluate changes in weight to height proportion (BMI change) and is more informative. In other words, change in Z-score over time is more valuable than a single time Z-score calculation.

In our study, we used some definitions like thin or obese to explain the much simpler change in patient’s condition over the course of treatment. Using a local curve however may change the number of each group but if we change the way of result analysis as change in the median or mean of all Z- scores or making graph lines for each case Z-score from before to after treatment, in this case type of curve has no intervention.

However having a local curve may be useful in screening (aim of Kelishadi’s study[1]) and an Iranian child may have different height percentiles on local curve compare to WHO curve; but in longitudinal follow ups that we need in health assessment having a growth line quite parallel to the WHO curve (whatever in north Europe or Far East) is the most powerful indicator of normal growth.

Based on the above facts:

  1. Kelishadi has not compared their percen-tile with the WHO one if they were significantly different
  2. Important point is that Kelishadi’s study has provided only one series of percentiles for each year (because of small case number- near only 20 child per year in each province for each sex) while we could find a detailed data for each year and month (12 data series for each year) in WHO site that made us able to precisely evaluate changes of BMI Zs (for example from 7 years 4 months old pretreatment to 10 years, 3 months posttreatment).

An interesting longitudinal study that we think is more reliable performed by Amirhakimi[2] found no significant difference between the Iranian and WHO curve. This was a valuable result because the author has followed a group of completely healthy small children among a normally distributed population up to late adolescence that makes that more reliable.

Finally, to the best of our knowledge, neither health ministry nor researchers (even Kelishadi’s et al) do not use these local findings as to the reference for screening in health centers or national standards for cohorts or other researches like what we did. The software used by ministry health centers all over the country still using WHO data.


1Kelishadi R, Qorbani M, Hosseini M, Bahreynian M, Djalalinia S, Motlagh ME, et al. Percentiles for anthropometric measures in Iranian children and adolescents: The CASPIAN-IV study. J Pediatr Endocrinol Metab 2016;29:1069-76.
2Amirhakimi GH. A longitudinal growth study from birth to maturity for weight, height and head circumference of normal Iranian children compared with Western norms: A standard for growth of Iranian children. IJMS 2003;28:9-16.