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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
1989-9-11
pubmed:abstractText
Methods of determining the required number of disease cases for estimation of relative odds in prospective studies are evaluated, with examples from coronary heart disease. Data from a British prospective study of coronary heart disease are used in simulation exercises to assess the reliability of estimation formulae for both continuous and categorical risk factors. For continuous risk factors, a univariate formula based on estimation of the standardized relative odds (Whittemore A. S. JAMA 1981; 76: 27-32 [1]), gives reliable estimation of the required number of disease cases, provided the risk factor has a near normal distribution. An extension of the formula to adjustment for other risk factors, was less satisfactory, perhaps because of departures from multivariate normality. For categorical risk factors, an adaption of a univariate method for case control studies (Smith PG, Day NE. Int J Epidemiol 1984; 13: 356-365 [2]), gives reliable estimates of the number of cases required. However, this depends on approximate prior knowledge of the relative odds. In general, prospective studies of coronary heart disease risk factors should aim for at least 400 cases to enable sufficient accuracy of estimation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0895-4356
pubmed:author
pubmed:issnType
Print
pubmed:volume
42
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
639-48
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Sample size requirements for prospective studies, with examples for coronary heart disease.
pubmed:affiliation
Department of Clinical Epidemiology & General Practice, Royal Free Hospital Medical School, London, England.
pubmed:publicationType
Journal Article