Validity of Raunkiaer’s Rule in Epidemiology
János Izsák1, Csaba Siffel2, and Aldo Rosano3
1 Department of Zoology, Berzsenyi College, Szombathely, Hungary
2 Department of Human Genetics and Teratology, WHO Collaborating Centre for the Community Control of Hereditary Diseases, National Center for Epidemiology, Budapest, Hungary
3 Italian Institute of Social Medicine, Rome, Italy
Corresponding author: Prof. János Izsák
Berzsenyi College
Károlyi G. tér 4
H-9701 Szombathely, Hungary
Telephone: +36-94-504 302
Fax number: +36-94-504 404
E-mail: ijanos@bdtf.hu
CEJOEM 2004, Vol.10. No.2.: 170–183
Key words:
Epidemiological rules, Raunkiaer’s rule, infectious diseases, congenital anomalies, lognormal distribution, logseries distribution
Abstract:
Numerous laws and rules of ecological statistics have their equivalents in epidemiology. Such a rule is that of Raunkiaer being a specific
spatial occurrence rule of species. To test the validity of this rule in epidemiology, data on infectious diseases and congenital anomalies recorded
in Hungary were analysed. Applying the ecological scenario to epidemiology, the measure of occurrence of a disease was defined by the number of
sample areas or time periods where the disease was recorded. The number of diseases or diagnosis categories in the occurrence classes was plotted
against the serial numbers of the occurrence classes. The numerical results, characteristic minimum graphs, and statistical analysis of significance
verified the applicability of Raunkiaer’s rule to epidemiology. Accordingly, the majority of diseases are either very common or rather rare. The
number of diseases with moderate occurrence is strikingly low. That is, the rule applied to public health data reveals a notable epidemiological
phenomenon, a possible explanation of which is the demonstrated lognormal distribution of the disease frequencies. In public health, Raunkiaer’s
rule might be useful to analyse statistical phenomena.
Received: 30 January 2004
Accepted: 17 September 2004
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