title: Calculating measures of biological interaction.
abstract: An editorial in this issue explains that the degree of biological interaction between risk factors is measured as the deviation from additivity by the corresponding disease rates and not for example as deviation from multiplicativity. It is the purpose of this article to describe how a logistic regression model, or a Cox regression model, can be defined in order to produce the output that is needed for assessment of biological interaction. We will also demonstrate how common software can be programmed to deliver this output. Finally, we show how this output can be used as input in an Excel sheet that is set up to calculate the measures of biological interaction to be used for the assessment.
authors.affiliation: Stockholm Centre for Public Health, Sweden. tomas.andersson@imm.ki.se
authors.forename: Tomas
authors.initials: T
authors.lastname: Andersson
authors.forename: Lars
authors.initials: L
authors.lastname: Alfredsson
authors.forename: Henrik
authors.initials: H
authors.lastname: Källberg
authors.forename: Slobodan
authors.initials: S
authors.lastname: Zdravkovic
authors.forename: Anders
authors.initials: A
authors.lastname: Ahlbom
mesh_terms: D001699:Biometry; D003627:Data Interpretation, Statistical; D015340:Epidemiologic Research Design; D006801:Humans; D016015:Logistic Models; D017720:Molecular Epidemiology / Q000379:methods* / Q000706:statistics & numerical data; D016016:Proportional Hazards Models; D012307:Risk Factors; D012984:Software