Epidemiology of leprosy
To the Editor:
I read with great interest the article titled "Epidemiological Characteristics of Leprosy Reactions: 15 years experience from North India," Int. J. Lepr. Other Mycobact. Dis. 72 (2004) 125-;133. Prof. Bhushan Kumar and his co-authors have to be complimented on a painstaking analysis of 2600 patients with leprosy reactions attending their reputed "tertiary care institute in Northern India, which is a low endemic area for leprosy." This is indeed a very useful clinical contribution.
However, I wonder whether it is an "epidemiological study" (as the title implies) based on a specific population from which the sample of patients is derived. As far as I know "Epidemiology" is defined as the study of the distribution and determinants of disease in human population. Whereas the basis of clinical research is the observation on individual patients, epidemiology requires observation of communities of people among whom disease occurs. The word epidemiology means something about people (EPI = upon; DEMOS = people).
While factors like onset, risk factors like age, sex etc. which also form important parameters of epidemiology are well described in the article, the occurrence of reactions and incidence over a period of time in specific communities or population groups is not available. This information will be necessary for planning management of reactions under field conditions. The title of the paper may be a misnomer.
I would invite comments from the authors or any epidemiologist on these points.
-Dr. R. Ganapati
Director,
Bombay Leprosy Project,
11 VN Purav Marg, Sion-Chunabhatti,
Mumbai -; 400 022, India
The Author's Reply:
We thank Dr. Ganapati for his interest, appreciation, and comments regarding our article "Epidemiological Characteristics of Leprosy Reactions: 15 years experience from North India," which appeared in Vol. 72 (2004) of THE INTERNATIONAL JOURNAL OF LEPROSY AND OTHER MYCOBACTERIAL DISEASES, pp. 125-;133.
The definition of "epidemiology" in its true sense as mentioned by Dr. Ganapati is well known and accepted by all the health care professionals. However, we used the word "epidemiological characteristics" to describe various parameters/variables of reactions in relation to our large group of leprosy patients.
The risk factors and incidence over a period of time is discussed in relation to pauci- and multibacillary disease. It was beyond the scope of this hospital-based analysis to interpret results with respect to "communities" and "population groups." Our results do provide important inputs for planning management of reactions both under institutional and field conditions, however being a hospital based study, both the incidence and severity of leprosy reactions may not be totally comparable to the situation in field. We have also given the data from the field studies vis-à-vis the hospital based figures for purposes of completeness and to help the readers/epidemiologists to draw their own conclusions.
We are thankful to Dr. Ganapati and your journal for giving us the opportunity to put across our point of view about the basic and the practical usage of a term.
- Bhushan Kumar M.D., MNAMS,
Sunil Dogra M.D., DNB MNAMS,
Inderjeet Kaur M.D., MNAMS,
Department of Dermatology, Venereology & Leprology
Postgraduate Institute of Medical Education and Research,
Chandigarh, India.