How to calculate incidence rates from proportionate data
, 4, 1, 1, 2
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: epidemiologyinjuryoccupationalproportionatemaritime
References
- Incidence (epidemiology). In: Wikipedia [Internet]. 2019 [cited 2019 Aug 2]. Available from: https://en.wikipedia.org/w/index.php?title=Incidence_(epidemiology)&oldid=886878644.
- Dean AG, Sullivan KM, Soe MM et al. OpenEpi: Open Source Epidemiologic Statistics for Public Health [Internet]. Open-Epi. 2013 [cited 2019 Mar 16]. Available from: https://www.openepi.com/Menu/OE_Menu.htm.
- Jensen OC. Non-fatal occupational fall and slip injuries among commercial fishermen analyzed by use of the NOMESCO injury registration system. Am J Ind Med. 2000; 37(6): 637–644.
- Abaya A, Rivera J, Roldan S, et al. Does long-term length of stay on board affect the repatriation rates of seafarers? International Maritime Health. 2018; 69(3): 157–162.
- Population Pyramids of the World from 1950 to 2100 [Internet]. PopulationPyramid.net. [cited 2019 Mar 10]. Available from: https://www.populationpyramid. net/ philippines. ; 2017.
- Brandt LP, Kirk NU, Jensen OC, et al. Mortality among Danish merchant seamen from 1970 to 1985. Am J Ind Med. 1994; 25(6): 867–876.
- Jensen OC. Mortality in Danish fishermen. Bull Inst Marit Trop Med Gdynia. 1996; 47(1-4): 5–10.
- Jensen OC. Work related injuries in Danish fishermen. Occup Med (Lond). 1996; 46(6): 414–420.
- Fullerton L, Olson L, Crandall C, et al. Occupational injury mortality in New Mexico. Ann Emerg Med. 1995; 26(4): 447–454.
- Lefkowitz RY, Slade MD, Redlich CA. Risk factors for merchant seafarer repatriation due to injury or illness at sea. Int Marit Health. 2015; 66(2): 61–66.
- Pecchio M, Suárez JA, Hesse S, et al. Descriptive epidemiology of snakebites in the Veraguas province of Panama, 2007-2008. Trans R Soc Trop Med Hyg. 2018; 112(10): 463–466.
- Kaustell KO, Mattila TE, Ahvonen A, et al. Occupational injuries and diseases in fish farming in Finland 1996-2015. Int Marit Health. 2019; 70(1): 47–54.
- Jensen O, Flores A, Bygvraa DA, et al. A Review of Epidemiological Studies in Latin American Fishing. J Agromedicine. 2019 [Epub ahead of print]: 1–10.
- Barreto SM, Miranda JJ, Figueroa JP, et al. Epidemiology in Latin America and the Caribbean: current situation and challenges. Int J Epidemiol. 2012; 41(2): 557–571.
