[The practical application on the numbers of control in 1:R matched case-control study].
We applied the data base of a screening program for colorectal cancer in the general population of Jiashan county, Zhejiang province to verify the theory of Pitman Efficiency in 1:R matched case-control study. Forty one detected cases of colorectal cancer were matched with normal controls as 1:R (R from 1 to 50) who were randomly selected from the screened population including 62,667 subjects. Results showed that the number of risk factors with statistical significance and its coincidence rate with results of 1:50 match were increased along with the increasing of R value; meanwhile the trends of standard deviation with 1:R over 1:50 weakened and the stability of results increased accordingly. The change of these values, however, reached their plateau when R > 4. The authors suggest that when taking consideration of sensitivity and stability of matched study, 1:4 of 1:5 ratio might be the most suitable case-control match, particularly when the resources are limited or the study has a exploratory nature.
Zhou
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Cancer Institute Zhejiang Medical University, Hangzhou.
Liu
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Yu
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D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D011897:Random Allocation; D012307:Risk Factors