Abstract
Five-year age-specific incidence rates were shown to produce small but systematic errors in the calculation of the expected number of tumours in a hypothetical but realistic study population. Underestimates occurred at younger ages (under 55) and overestimates at older ages, with a small overestimate (0.22%) overall. Larger errors (up to 12%) were obtained when there was a rapid change in the single-year age structure of the study population. Interpolation between five-year rates will normally produce an inaccurate set of one-year rates. It is shown, with the example of a logarithmic interpolation, that these rates tend to produce errors of similar size to the five-year rates but with a small underestimate overall (0.37%). However, the interpolated rates produced the smaller errors (up to 1%) when the study population age structure undergoes rapid change. A method is suggested for partially correcting the error in the interpolated rates.
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- CASE R. A., LEA A. J. Mustard gas poisoning, chronic bronchitis, and lung cancer; an investigation into the possibility that poisoning by mustard gas in the 1914-18 war might be a factor in the production of neoplasia. Br J Prev Soc Med. 1955 Apr;9(2):62–72. doi: 10.1136/jech.9.2.62. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Crombie I. K., Cramer N. Five-year age-specific incidence rates. I. Their nature and limitations. J Epidemiol Community Health. 1980 Sep;34(3):223–228. doi: 10.1136/jech.34.3.223. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gafey W. R. Epidemiological studies in industry. J Occup Med. 1973 Oct;15(10):782–785. [PubMed] [Google Scholar]
- Goodkin G. Mortality factors in diabetes. A 20 year mortality study. J Occup Med. 1975 Nov;17(11):716–721. [PubMed] [Google Scholar]
- McMichael A. J., Spirtas R., Kupper L. L. An epidemiologic study of mortality within a cohort of rubber workers, 1964-72. J Occup Med. 1974 Jul;16(7):458–464. [PubMed] [Google Scholar]
- Pell S. Mortality of workers exposed to chloroprene. J Occup Med. 1978 Jan;20(1):21–29. doi: 10.1097/00043764-197801000-00006. [DOI] [PubMed] [Google Scholar]
- Robinson T. R. 20-year mortality of tetraethyl lead workers. J Occup Med. 1974 Sep;16(9):601–605. doi: 10.1097/00043764-197409000-00005. [DOI] [PubMed] [Google Scholar]