open access
How to calculate incidence rates from proportionate data
, 4, 1, 1, 2
Affiliations- Centre of Maritime Health and Society, Institute of Public Health, University of Southern Denmark, Esbjerg, Denmark
- Graduate School, Frederick University, Nicosia, Cyprus
- University of Panamá, Faculty of Health, Panama
- Caja Seguro Social, Rep. of Panamá, Vacamonte, Panama
open access
Abstract
This paper describes the methodological aspects of calculation of incidence rates from incomplete data in occupational epidemiology. Proportionate measures in epidemiological studies are useful e.g. to describe the proportion of slips, trips and falls compared to other types of injury mechanisms within single age-strata. However, a comparison of proportions of slips, trips and falls among the different age-strata gives no meaning and can hamper the conclusions. Examples of a constructed example and some selected studies show how estimates of incidence rates can be calculated from the proportionate data by applying estimates of denominators available from other information. The calculated examples show how the risks based on the incidence rates in some cases differ from the risks based on the proportionate rates with the consequence of hampering the conclusions and the recommendations for prevention. In some cases the proportionate rates give good estimates of the incidence rates, but in other studies this might cause errors. It is recommended that estimates of the incidence rates should be used, where this is possible, by estimation of the size of the population. The paper is intended to be useful for students and teachers in epidemiology by using the attached Excel training file.
Abstract
This paper describes the methodological aspects of calculation of incidence rates from incomplete data in occupational epidemiology. Proportionate measures in epidemiological studies are useful e.g. to describe the proportion of slips, trips and falls compared to other types of injury mechanisms within single age-strata. However, a comparison of proportions of slips, trips and falls among the different age-strata gives no meaning and can hamper the conclusions. Examples of a constructed example and some selected studies show how estimates of incidence rates can be calculated from the proportionate data by applying estimates of denominators available from other information. The calculated examples show how the risks based on the incidence rates in some cases differ from the risks based on the proportionate rates with the consequence of hampering the conclusions and the recommendations for prevention. In some cases the proportionate rates give good estimates of the incidence rates, but in other studies this might cause errors. It is recommended that estimates of the incidence rates should be used, where this is possible, by estimation of the size of the population. The paper is intended to be useful for students and teachers in epidemiology by using the attached Excel training file.
Keywords
epidemiology; injury; occupational; proportionate; maritime
About this articleTitle
How to calculate incidence rates from proportionate data
Journal
Issue
Article type
Review article
Pages
187-192
Published online
2019-10-03
Page views
1520
Article views/downloads
1106
DOI
Pubmed
Bibliographic record
IMH 2019;70(3):187-192.
Keywords
epidemiology
injury
occupational
proportionate
maritime
Authors
Olaf Chresten Jensen
Agnes Flores
Despena Andrioti Bygvraa
Fereshteh Baygi
George Charalambous
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